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Background: Transfusion-transmitted Babesia microti is well recognized in the Northeast and upper Midwestern United States. Blood donation screening in Babesia-endemic states has occurred under investigational protocols prior to US Food and Drug Administration-licensed test availability. Here, we provide a prospective screening summary of nucleic acid testing (NAT) as part of a multicenter Babesia pivotal trial followed by extended investigational use., Methods: From June 2017 to February 2018, 176,928 donation samples were tested with Procleix Babesia Assay (Grifols Diagnostic Solutions), a blood screening NAT for Babesia species ribosomal RNA detection using whole blood samples. During the pivotal trial, donations were collected in 11 endemic states plus Washington, DC, and Florida (nonendemic). Whole blood lysate samples were either tested in pools of 16 or individually. Reactive samples were confirmed by Babesia microti antibody and polymerase chain reaction (PCR) testing. If unconfirmed, further testing used a second PCR assay capable of detecting multiple Babesia species. Follow-up samples were also tested. Extended investigational testing followed pivotal trial completion., Results: The pivotal trial identified 61 confirmed positives (176,608 donations): 35 (57%) PCR positive, 59 (97%) antibody positive, and two (3%) NAT positive/antibody negative, for a total yield of one positive per 2895 donations, including one Florida resident; others were from seven endemic states. During extended investigational testing of 496,270 donations in endemic states through January 2019, 211 (1:2351) repeat reactive donations were identified., Conclusions: Babesia was detected in donors from multiple US states, including one previously not associated with positive blood donors. This study supports the use of the Procleix Babesia Assay using individual testing or pools of up to 16., (© 2019 AABB.)

Background: The erythrocytic protozoan parasite Babesia microti, the cause of human babesiosis, is transmitted not only by tick bites but also via blood transfusion. B. microti is endemic in the northeastern/upper midwestern United States, where partial screening of blood donations has been implemented. In Canada, a 2013 study of approximately 14,000 donors found no B. microti antibody-positive samples, suggesting low risk at that time., Methods: Between June and October 2018, 50,752 Canadian donations collected from sites near the US border were tested for Babesia nucleic acid by transcription-mediated amplification (TMA). Reactive donations were tested for B. microti by IgG immunofluorescence assay and polymerase chain reaction. A subset of 14,758 TMA nonreactive samples was also screened for B. microti antibody. Donors who tested reactive/positive were deferred, asked about risk factors, and were requested to provide a follow-up sample for supplemental testing., Results: One sample from Winnipeg, Manitoba, was TMA and antibody reactive. Of the 14,758 TMA-nonreactive donations tested for antibody, four reactive donations were identified from southwestern Ontario near Lake Erie. None of the interviewed donors remembered any symptoms, likely tick exposure, or relevant travel within Canada or the United States., Conclusions: This is the largest B. microti prevalence study performed in Canada. The results indicate very low prevalence, with only one TMA-confirmed-positive donation of 50,752 tested. This donor was from the only region in Canada where autochthonous infection has been reported. Seropositive donations in southwestern Ontario suggest low prevalence; travel should not be ruled out given the proximity to the US border., (© 2019 AABB.)

Background: Trypanosoma cruzi is endemic to the Americas where it demonstrates multiple lineages over a vast geographic range (i.e., United States to Argentina). These lineages possess divergent geographic and biologic characteristics, including variations in disease manifestations. Herein, we report the frequency of parasitemia among seropositive US blood donors and the potential association between parasite lineage and transfusion transmission., Study Design and Methods: Blood donors identified as T. cruzi seropositive during screening were enrolled in follow-up studies, including hemoculture testing and a risk factor questionnaire. Positive hemocultures were expanded to obtain sufficient parasites for molecular lineage determination and analysis. Country of birth, obtained from the questionnaire, was used to predict parasite lineage in the absence of demonstrable parasitemia for infected donors., Results: Eighteen (6.8%) of 263 seropositive donors were hemoculture positive. Among the 17 hemocultures expanded for lineage determination, TcV was identified more frequently (n = 12), compared to TcI (n = 2), TcII (n = 1), and TcVI (n = 2). When presumptive parasite lineages were compared to hemoculture results, only two of 157 (1.3%) TcI versus 13 of 38 (34.2%) TcII/TcV/TcVI non-US donors were parasitemic; three of 44 (6.8%) US donors were TcV or TcVI., Conclusions: Based on lineage determination for donors with parasitemia; hemoculture positivity associated with presumptive parasite lineage; and implicated donors from US, Canadian, and Spanish transfusion cases, donors from Southern South America are significantly more likely to have parasitemia and transmit infection to blood recipients (TcII, TcV, or TcVI vs. TcI). Thus, parasite lineage may be associated with risk of transfusion-transmitted T. cruzi., (© 2017 AABB.)

Background: Human granulocytic anaplasmosis, caused by Anaplasma phagocytophilum, poses an increasing public health risk in the United States. Since 2000, case reports have increased annually; 2782 cases were reported in 2013. Despite the increasing frequency of clinical cases, only eight cases of transfusion-transmitted anaplasmosis (TTA) have been reported. We investigated if current leukoreduction practices impact transfusion risk., Study Design and Methods: Whole blood units (WBUs) with integral red blood cell (RBC) leukoreduction filters were collected and spiked with A. phagocytophilum-infected HL-60 cells equivalent to 0.01, 1, or 5% of total neutrophils. After 24 hours at 4°C WBUs were processed into plasma and RBCs, the latter subsequently leukoreduced (LR RBCs). To evaluate the removal of A. phagocytophilum by filtration, pre- and postfiltration samples were compared by culture and polymerase chain reaction (PCR)., Results: Compared to Day 0 or Day 1 positive controls, LR RBCs demonstrated reduced levels of A. phagocytophilum by culture and PCR. At 0.01% infection levels LR RBCs yielded no positive cultures and a log reduction of 2.5 by PCR. Similarly, at 1 and 5% infections levels, LR RBCs produced only 44% (4/9) and 56% (5/9) positive cultures, respectively. PCR results were comparable, 3.0 log reduction for 1% and 3.3 log reduction for 5% infection levels., Conclusions: The recent increase in TTA suggests that A. phagocytophilum may represent an emerging blood safety issue. However, the current study indicates that the widespread practice of leukoreduction might passively reduce, but not eliminate, TTA risk. In the absence of viable testing or pathogen inactivation and/or reduction options, leukoreduction may offer some protection from transmission risk., (© 2014 AABB.)

Background and Aims: Hymenophyllaceae (filmy ferns) are typically plants of shady, constantly moist habitats. They attain greatest species diversity and biomass in humid tropical montane forests and temperate hyperoceanic climates. This paper presents ecophysiological data bearing on their worldwide ecological niche space and its limits., Methods: Chlorophyll fluorescence was used to monitor recovery in desiccation experiments, and for measurements of 95 % saturating irradiance [photosynthetic photon flux density (PPFD(95 %))] of photosynthetic electron flow and other parameters, in the New Zealand Hymenophyllum sanguinolentum, and three species each of Hymenophyllum and Trichomanes from forests in Trinidad and Venezuela., Key Results: Hymenophyllum sanguinolentum was comparable in desiccation tolerance and light responses with the European species. The more common species in the two tropical forests showed PPFD(95 %) >100 µmol m(-2) s(-1), and withstood moderate desiccation (-40 MPa) for several days. The four most shade-adapted species had PPFD(95 %) ≤51 µmol m(-2) s(-1), and were sensitive to even mild and brief desiccation (-22 MPa for 3 d)., Conclusions: Light and desiccation responses of filmy ferns can be seen as an integrated package. At low light and windspeed in humid forests, net radiation and saturation deficit are low, and diffusion resistance high. Water loss is slow and can be supported by modest conduction from the sub-stratum. With higher irradiance, selection pressure for desiccation tolerance increases progressively. With low light and high humidity, the filmy fern pattern of adaptation is probably optimal, and the vascular plant leaf with mesophyll and stomata offers no advantage in light capture, water economy or CO(2) uptake. Trade-offs between light adaptation and desiccation tolerance, and between stem conduction and water absorption through the leaf surface, underlie adaptive radiation and niche differentiation of species within the family. Hymenophyllaceae are a rare example of an evolutionary shift of adaptive strategy from typical vascular plant adaptation to the poikilohydry most typical of bryophytes.

CO(2) fixation in mosses saturates at moderate irradiances. Relative electron transport rate (RETR) inferred from chlorophyll fluorescence saturates at similar irradiance in shade species (e.g. Plagiomnium undulatum, Trichocolea tomentella), but many species of unshaded habitats (e.g. Andreaea rothii, Schistidium apocarpum, Sphagnum spp. and Frullania dilatata) show non-saturating RETR at high irradiance, with high non-photochemical quenching (NPQ). In P. undulatum and S. apocarpum, experiments in different gas mixtures showed O(2) and CO(2) as interchangeable electron sinks. Nitrogen + saturating CO(2) gave high RETR and depressed NPQ. In S. apocarpum, glycolaldehyde (inhibiting photosynthesis and photorespiration) depressed RETR in air more at low than at high irradiance; in CO(2) -free air RETR was maintained at all irradiances. Non-saturating electron flow was not suppressed in ambient CO(2) with 1% O(2) . The results indicate high capacity for oxygen photoreduction when CO(2) assimilation is limited. Non-saturating light-dependent H(2) O(2) production, insensitive to glycolaldehyde, suggests that electron transport is supported by oxygen photoreduction, perhaps via the Mehler-peroxidase reaction. Consistent with this, mosses were highly tolerant to paraquat, which generates superoxide at photosystem I (PSI). Protection against excess excitation energy in mosses involves high capacity for photosynthetic electron transport to oxygen and high NPQ, activated at high irradiance, alongside high reactive oxygen species (ROS) tolerance.

Background: Babesia microti is an intraerythrocytic parasite, transmitted naturally to humans by infected ixodid ticks, that causes babesiosis. In recent years, B. microti has been identified as a growing public health concern that has also emerged as a critical blood safety issue in the absence of appropriate interventions to reduce transmission by blood transfusion. Thus, we evaluated the ability of the Mirasol pathogen reduction technology (PRT; CaridianBCT), which uses riboflavin (RB) and ultraviolet (UV) light, to diminish the presence of B. microti in apheresis plasma and platelets (PLTs)., Study Design and Methods: Apheresis plasma and PLT units were spiked with B. microti-infected hamster blood and subsequently treated using the Mirasol PRT system. Control and experimental samples were collected at different stages during the treatment process and injected into hamsters to detect the presence of viable parasites. Four weeks postinoculation, hamster blood was tested for B. microti infection by blood smear and real-time polymerase chain reaction analysis., Results: None of the blood smears from animals injected with samples from PRT-treated plasma or PLT units were positive by microscopy, while all the non-PRT-treated plasma and PLT units were demonstrably parasitemic. Parasite load reduction in hamsters ranged between 4 and 5 log in all PRT-treated units compared to untreated controls., Conclusion: The data indicate that the use of RB and UV light efficiently reduces the presence of viable B. microti in apheresis plasma and PLT products, thereby reducing the risk of transfusion-transmitted Babesia potentially associated with these products. Based on this observed "proof of principle," future studies will determine the efficacy of the Mirasol PRT in whole blood.

The function of vena cava filters, preventing pulmonary embolism while maintaining caval patency, is associated with the design. Several characteristics have been reported. This report evaluates retrievable filter designs in comparison with previously marketed designs with respect to efficacy and safety. Three inferior vena cava (IVC) filters (Gunther Tulip, Bard Recovery, and the Cordis OptEase) were compared on the basis of design characteristics associated with function, shape, number of trapping levels, and fixation. Adverse events reported in the literature and to the US Food and Drug Administration Manufacturers and User Facility Device Experience Database (MAUDE) were summarized. The major differences among device types include the fixation, the volume and number of trapping levels, and the amount of metal in the IVC. The MAUDE registry reported adverse events that had been hypothesized from the analysis of in vitro and in vivo testing. The Recovery and OptEase filters had the highest number of clinically important reports. From 12 to 57% were retrieved between 3 days and 11 months. Adaptations made to facilitate retrieval led to unacceptable sequelae. The small number removed, the length of time they are left in place, and the risks associated with retrieval suggest that optional filters may not be equivalent to approved permanent devices.

Background and Aims: This study explores basic physiological features and time relations of recovery of photosynthetic activity and CO2 uptake following rehydration of a desiccation-tolerant moss in relation to the full temporal sequence of cytological changes associated with recovery to the normal hydrated state. It seeks reconciliation of the apparently conflicting published physiological and cytological evidence on recovery from desiccation in bryophytes., Methods: Observations were made of water-stress responses and recovery using infrared gas analysis and modulated chlorophyll fluorescence, and of structural and ultrastructural changes by light and transmission electron microscopy., Key Results: Net CO2 uptake fell to zero at approx. 40 % RWC, paralleling the fluorescence parameter PhiPSII at 200 micromol m(-2) s(-1) PPFD. On re-wetting the moss after 9-18 d desiccation, the initially negative net CO2 uptake became positive 10-30 min after re-wetting, restoring a net carbon balance after approx. 0.3-1 h. The parameter Fv/Fm reached approx. 80 % of its pre-desiccation value within approx. 10 min of re-wetting. In the presence of the protein-synthesis inhibitors chloramphenicol and cycloheximide, recovery of Fv/Fm (and CO2 exchange) proceeded normally in the dark, but declined rapidly in the light. Though initial recovery was rapid, both net CO2 uptake and Fv/Fm required approx. 24 h to recover completely to pre-desiccation values. The fixation protocols produced neither swelling of tissues nor plasmolysis. Thylakoids, grana and mitochondrial cristae remained intact throughout the drying-re-wetting cycle, but there were striking changes in the form of the organelles, especially the chloroplasts, which had prominent lobes and lamellar extensions in the normally hydrated state, but rounded off when desiccated, returning slowly to their normal state within approx. 24 h of re-wetting. Sub-cellular events during desiccation and re-wetting were generally similar to those seen in published data from the pteridophyte Selaginella lepidophylla., Conclusions: Initial recovery of respiration and photosynthesis (as of protein synthesis) is very rapid, and independent of protein synthesis, suggesting physical reactivation of systems conserved intact through desiccation and rehydration, but full recovery takes approx. 24 h. This is consistent with the cytological evidence, which shows the thylakoids and cristae remaining intact through the whole course of dehydration and rehydration. Substantial and co-ordinated changes in other cell components, which must affect spatial relationships of organelles and metabolic systems, return to normal on a time span similar to full recovery of photosynthesis. Comparison of the present data with recently published results suggests a significant role for the cytoskeleton in desiccation responses.

Background: Endovascular approaches promise to revolutionize therapy for thoracic aortic disease. This study describes a long-term analysis of endovascular thoracic aortic repair., Methods: Seventy-three patients (mean age, 67.4 years) underwent endovascular thoracic aortic repair from 1993 to 2005. Indications for intervention included aneurysm (38%), dissection (23%), or penetrating ulcer or pseudoaneurysm (34%). Rupture was present in 16 patients (22%). Seventy-one percent were considered high risk for open surgery for reasons of age or comorbid conditions. Treated segments included ascending aorta (n = 1), distal arch (n = 24), and proximal (n = 50) or distal (n = 55) descending aorta. The total descending thoracic aorta was covered in 31 patients. Procedural success was achieved in 96%. Devices were delivered by femoral (79%), retroperitoneal iliac (18%), or carotid (2.7%) exposure. Devices used included Excluder (n = 30), Talent (n = 23), Zenith (n = 3), AneuRx (n = 5), and custom-fabricated (n = 14). Follow-up was 100% complete., Results: Thirty-day mortality was 5.5%. Significant morbidity included stroke (8.2%) and need for dialysis (4.1%). Although 3 patients had transient spinal cord ischemia (4.1%), none had permanent sequelae. Intervention for fusiform aneurysm was independently associated with a composite end point of 30-day mortality, need for dialysis, and stroke (p = 0.015). Eight patients (11%) had new or persistent endoleaks, and aortic reintervention was performed in 7 patients (9.6%). Mean survival for the entire cohort was 46.8 +/- 5.1 months. Intervention for penetrating ulcer or pseudoaneurysm (p = 0.045) was independently associated with long-term all-cause mortality., Conclusions: An endovascular approach produces acceptable results for a broad range of thoracic aortic disease. However, the potential for endoleak or need for reintervention mandates continued close follow-up to achieve satisfactory long-term results.

Background: Use of hypothermic circulatory arrest (HCA) for operations on the descending thoracic aorta is controversial. While deep hypothermia may provide better end-organ and spinal cord function, prolonged cardiopulmonary bypass and circulatory arrest may increase morbidity. This study assessed outcomes after use of HCA for descending thoracic aortic resection in a large cohort of consecutive patients., Methods: Hypothermic circulatory arrest was utilized if arch or extensive descending thoracic aortic resection was required, or if aortic pathology precluded cross-clamping. One hundred thirty-two patients (mean age, 61.3 years) were identified. Diagnosis included fusiform (41.2%) or saccular aneurysm (10.7%) and acute (4.6%) or chronic (38.9%) dissection. Twenty-one patients presented with rupture. Arch resection (distal arch 100, total arch 11) was required in 111 patients (84.1%). The extent of descending thoracic aortic resection (required in 94%) included proximal third in 41 patients, proximal two-thirds in 6, and complete thoracic aorta in 77. The proximal anastomosis was performed with total body HCA while the distal anastomosis was constructed with lower body HCA only (duration upper body HCA 33.7 +/- 8.0 minutes; total duration lower body HCA 71.3 +/- 24.2 minutes)., Results: Thirty-day mortality was 6.0%. Neurologic events included stroke (6.8%) and permanent lower extremity paralysis-paresis (4.5%). Temporary dialysis was needed in 7 (5.3%), though only 2 patients required permanent dialysis (1.9%). Independent predictors of a composite endpoint of death, stroke, permanent paralysis, or dialysis included duration of lower body HCA (p = 0.03) and major postoperative infection (p = 0.003)., Conclusions: Adjunctive use of deep hypothermic circulatory arrest for descending thoracic aortic resection affords excellent preservation of end-organ and spinal cord function with acceptable rates of mortality and significant morbidity.

Background: Management of patients with multiple trauma requires prophylaxis for venous thromboembolism (VTE). This involves recognition of the physiologic factors that are associated with VTE risk. Currently, there is no effective strategy for risk assessment. The purpose of this study is to investigate the relationship of serum P-selectin and interleuken-10 (IL-10) with VTE as a possible physiologic marker., Methods: Patients admitted to two trauma centers with an Injury Severity Score >/=9 had blood samples drawn and underwent duplex ultrasound scanning of the lower extremities before initiating prophylaxis at admission, on days 3 and 7, and weekly until discharge. Patients were prophylaxed according to institutional protocols., Results: One hundred eighty-six patients were enrolled with a VTE incidence of 17.8%. The population was predominantly male (60%), with a mean age of 48 years. sP-selectin levels were not statistically different between the groups (64.4 versus 74.8 pg/mL). However, IL-10 was significantly lower in the VTE group at both the initial and subsequent blood draws (21 versus 165 ng/mL, p = 0.012). Further, the ratio of sP-selectin to IL-10 (3.92 versus 0.92, p = 0.014) was statistically higher in the VTE group at admission., Conclusion: An elevated sP-selectin to IL-10 ratio appears to be associated with the development of VTE in patients at high risk and may prove to be a useful clinical marker for this dreaded complication among trauma patients. Early recognition of this high-risk group improves the accuracy of the risk/benefit determination for prophylaxis and identifies a group in whom routine ultrasound screening would be cost-effective.

Objective: This study tested the hypothesis that high-risk patients can undergo carotid endarterectomy without associated increased risk of stroke, transient ischemic attack (TIA), or death., Summary Background Data: Carotid endarterectomy (CEA) has clearly been shown to be effective in reducing the risk of stroke in selected symptomatic and asymptomatic patients with extracranial carotid stenosis. However, recently, carotid angioplasty with stenting (CAS) has been suggested as an alternative treatment in high-risk surgical patients., Methods: Medical records for consecutive patients who underwent CEA from 1996 to 2001 were reviewed for demographics, medical history, and hospital course. High-risk patients were defined as those experiencing a myocardial infarction (MI) or an exacerbation of congestive heart failure (CHF) within 4 weeks before CEA; unstable angina; steroid-dependent chronic obstructive pulmonary disease (COPD); prior ipsilateral CEA, neck dissection or irradiation; high carotid bifurcation; and those with combined cardiac-carotid procedures. Poor postoperative outcome was defined as stroke, TIA, or death within 30 days. Univariate, multivariate, and Kaplan-Meier analysis were used as appropriate., Results: Four hundred twenty-nine patients underwent 499 CEAs, of which 84 (17%) were considered high risk. The overall stroke-death rate among all patients was 2.8%. A total of 11 postoperative strokes (2.2%), 7 TIAs (1.4%), and 3 deaths (0.6%) occurred within 30 days after surgery. There was no difference in 30-day poor outcome between high- and low-risk patients (4.8% vs. 4.1%, P = 0.77). When these risk factors were assessed independently, those with recent MI were at higher risk for poor outcome (odds ratio [OR], 13.3; 95% confidence interval [CI], 2.2-82.0; P = 0.03). Multivariate analysis also revealed that a history of contralateral stroke or TIA conferred an increased risk of poor outcome (OR, 3.0; 95% CI, 1.1-8.4; P = 0.02), whereas use of preoperative angiotensin-converting enzyme inhibitors was associated with reduced risk (OR, 0.36; 95% CI, 0.11-1.0; P = 0.05), as was a history of hyperlipidemia (OR, 0.33; 95% CI, 0.13-0.87; P = 0.03). By log-rank analysis, 12-month survival was significantly worse in the high-risk group as compared with the low-risk (96% vs. 91%, P = 0.03)., Conclusions: Patients considered a surgical high risk can undergo CEA without any worse outcome compared with those patients deemed low risk. The benefit of CAS will likely be marginal, and only controlled clinical trials will be able to determine if certain subgroups demonstrate improved outcome with CAS. Carotid endarterectomy remains the standard of care, even in high-risk surgical patients.

Hypothesis: There is a difference in outcomes when patients have neurogenic thoracic outlet syndrome in addition to subclavian vein thrombosis., Methods: Analysis of a prospectively developed database, medical record review, and a patient questionnaire were used to summarize clinical experience from December 1990 to December 2001 on the basis of the patient's original evaluation. Patients were stratified on the presence (group 1) or absence (group 2) of additional neurogenic pathologic features., Results: Of 928 patients evaluated for thoracic outlet syndrome, 71 underwent 73 operative procedures for subclavian vein obstruction. Men predominated (55%), and the mean age was 32 years. Group 1 (41%) had more preoperative disability, a higher incidence of persistent pain (24%), and less likelihood of returning to full activity compared with group 2 (67% vs 93%; P = .01). Catheter-directed thrombolysis was used in 65% of veins. Preoperative balloon angioplasty was used selectively (34%), and only 4% required stents. Supraclavicular decompression and venolysis were usually delayed 3 weeks to allow for healing of the venous endothelium. Complications included wound infection (3%) and postoperative hematoma (8%)., Conclusions: Patients with isolated subclavian vein obstruction have a more favorable outcome relative to those with combined neurogenic and venous pathologic features. Decompression following thrombolysis should be delayed to reduce the incidence of postoperative complications.

Venous thromboembolism (VTE) is a costly complication of hospitalization. The sequelae make it a concern for public health planners. The Nationwide Inpatient Sample (NIS) contains data for hospital discharges in the United States. These data were reviewed to determine their suitability for health policy planning. International Classification of Diseases, Ninth Revision, Clinical Modification codes for VTE were applied to the NIS data. The sample was queried for demographic information, mortality, length of hospital stay, diagnosis, and treatment. The rates were standardized for geographic region and disease acuity. Statistical analysis included descriptive reporting of means and event rates; analysis of variance and logistic regression were used for regional effects and modeling of mortality. Between 1993 and 2000, 636,814 discharges involved VTE (1.2%). This rate was consistent over time and within regions. Regional differences existed in the acceptance of new technology and hospital charges. Mortality varied from 6.3% (Midwest) to 7.9% (Northeast) and was associated with admission type, comorbidities, pulmonary embolism, and discharge from the Northeast region. White race, chronic venous insufficiency, and female gender were protective variables. The NIS data report a consistent mortality rate despite improved therapy. Regional diagnostic, treatment, and economic differences exist. The data are useful for the purposes of public health care planning and stimulating clinical trial questions.

Background and Aims: Data are presented from 39 species of mosses and 16 liverworts for ratios of chlorophylls and total carotenoids, and light saturation of photosynthetic electron flow or photosynthetic CO2 uptake, in relation to the postulate that bryophyte cells in general show shade-plant characteristics., Methods: Pigment concentrations were measured by spectrophotometer in 80 % acetone extracts. Light-saturation curves were constructed by (modulated) chlorophyll florescence and for some species by infra-red gas analysis., Key Results: The pigment measurements were widely variable but broadly in line with the findings of previous authors. Median values (mosses/liverworts) were: total chlorophyll, 1.64/3.76 mg g(-1); chlorophyll a : b, 2.29/1.99; chlorophylls : carotenoids, 4.74/6.75). The PPFD values at 95 % saturation (estimated from fitted curves) also ranged widely, but were almost all <1000 micromol m(-2) s(-1); the median for mosses was 583 and for liverworts 214 micromol m(-2) s(-1). The two highest PPFD95% values were from Polytrichum species with lamella systems forming a ventilated photosynthetic tissue. Total chlorophyll, chlorophyll a : b and chlorophylls : carotenoids all correlated significantly with PPFD95%., Conclusions: Bryophytes include but are not inherently shade plants. Light-saturation levels for species of open sun-exposed habitats are lower than for vascular sun plants and are probably limited by CO2 diffusion into unistratose leaves; this limit can only be exceeded by bryophytes with ventilated photosynthetic tissues which provide increased area for CO2 uptake.

Introduction: Established American Heart Association guidelines recommend the use of statin drugs, angiotensin converting enzyme (ACE) inhibitors, and antiplatelet agents in patients with systemic atherosclerosis, such as those undergoing operative intervention to treat peripheral atherosclerotic disease. Many of these patients have not received treatment of coronary heart disease and have not been prescribed these medications. Whether statin drugs and ACE inhibitors confer an improvement in graft patency, limb salvage, and operative mortality is unknown., Methods: Consecutive patients who underwent infrainguinal bypass between 1997 and 2002 were evaluated for demographic data, comorbid disease, medication use, as well as cumulative graft patency, limb salvage, and mortality. Univariate, multivariate logistical regression, and Kaplan-Meier analyses were performed. P <.05 was considered significant., Results: Two hundred ninety-three patients (mean age, 64 years; 67% men) underwent 338 infrainguinal bypass procedures with autologous vein (n = 218), prosthetic grafts (n = 88), or composite prosthetic-vein grafts (n = 32). Limb salvage was the operative indication in 75% of procedures. Coexisting diseases included hypertension (70%), diabetes (52%), hyperlipidemia (37%), coronary heart disease (51%), congestive heart failure (14%), and active tobacco use (30%). Statin drugs were taken by 56% of patients, ACE inhibitors by 54% of patients, and antiplatelet agents or warfarin sodium (Coumadin) by 93% of patients. Postoperative graft surveillance was done in 39% of patients. Cumulative graft patency was 73%, limb salvage was 85%, and mortality was 9%, with a mean follow-up of 17 months. Factors independently associated with increased graft patency included statin drug use (odds ratio [OR], 3.7; 95% confidence interval [CI], 2.1-6.4), male sex (OR, 2.8; 95% CI, 1.6-5.0), and graft surveillance (OR, 2.4; 95% CI, 1.3-4.5). Factors associated with decreased amputation rate were statin drug use (OR, 0.34; 95% CI, 6.15-0.77) and graft surveillance (OR, 0.23; 95% CI, 6.1-0.63). Factors associated with decreased mortality included graft surveillance (OR, 0.18; 95% CI, 0.1-0.56), whereas congestive heart failure (OR, 6.5; 95% CI, 2.5-17) and hemodialysis-dependent renal failure (OR, 29; 95% CI, 6.1-140) were associated with increased mortality. Kaplan-Meier analysis showed that only ACE inhibitors were associated with lower mortality (P =.05), Conclusions: Patients undergoing infrainguinal bypass are undertreated with respect to cardioprotective medications. ACE inhibitor use is associated with lower mortality, and statin drug use is associated with improved graft patency and limb salvage. Institution of consensus guidelines concerning these medications should be considered by all vascular specialists, including vascular surgeons.

Background: Septic patients are at risk of thromboembolism. However, the Food and Drug Administration guidance for intravascular filters states that "filters should not be implanted in patients with risk of septic embolism." The purpose of this study is to evaluate this restriction., Hypothesis: There is no difference in outcomes following filter placement in patients with and without septicemia., Data Sources: A registry of vena caval filter experiences containing information regarding filter placement and annual examinations of more than 2600 patients obtained during a 15-year period was reviewed. We conducted a MEDLINE search of publications reporting clinical sequelae of filter placement in septic patients., Data Extraction: The registry was searched for patients with a diagnosis of sepsis at filter placement; survival rates, adverse events, and recurrent sepsis or thromboembolism were noted. The MEDLINE search joined results from 7 MeSH headings (vena cava filter,sepsis, septic thromboembolism, vena caval filter contraindication, and filter adverse events) related to filters and sepsis., Data Synthesis: One-hundred seventy-five patients (6.7%) met the criteria and received Greenfield filters. None of the adverse events were related to sepsis, and no filter was removed. Follow-up data were available for 56 patients, with a combined recurrent pulmonary embolism and caval occlusion rate of 1.7%. The 30-day mortality rate was 33%. We noted a significant difference in survival related to the use of anticoagulation therapy (P =.001) and to age (P =.004). The MEDLINE search did not identify any clinical reports of septic filters or the need to remove a filter because of sepsis., Conclusions: Based on our review, the Greenfield filter is a safe method of prophylaxis for septic patients. Rescinding the restriction for use of vena caval filters in septic patients should be considered by regulatory bodies.

Objective: To determine the contemporary clinical relevance of acute lower extremity ischemia and the factors associated with amputation and in-hospital mortality., Summary Background Data: Acute lower extremity ischemia is considered limb- and life-threatening and usually requires therapy within 24 hours. The equivalency of thrombolytic therapy and surgery for the treatment of subacute limb ischemia up to 14 days duration is accepted fact. However, little information exists with regards to the long-term clinical course and therapeutic outcomes in these patients., Methods: Two databases formed the basis for this study. The first was the National Inpatient Sample (NIS) from 1992 to 2000 of all patients (N = 23,268) with a primary discharge diagnosis of acute embolism and thrombosis of the lower extremities. The second was a retrospective University of Michigan experience from 1995 to 2002 of matched ICD-9-CM coded patients (N = 105). Demographic factors, atherosclerotic risk factors, the need for amputation, and in-hospital mortality were assessed by univariate and multivariate logistic regression analysis., Results: In the NIS, the mean patient age was 71 years, and 54% were female. The average length of stay (LOS) was 9.4 days, and inflation-adjusted cost per admission was $25,916. The amputation rate was 12.7%, and mortality was 9%. Decreased amputation rates accompanied: female sex (0.90, 0.81-0.99), age less than 63 years (0.47, 0.41-0.54), angioplasty (0.46, 0.38-0.55), and embolectomy (0.39, 0.35-0.44). Decreased mortality accompanied: angioplasty (0.79, 0.64-0.96), heparin administration (0.50, 0.29-0.86), and age less than 63 years(0.27, 0.23-0.33). The University of Michigan patients' mean age was 62 years, and 57% were men. The LOS was 11 days, with a 14% amputation rate and a mortality of 12%. Prior vascular bypasses existed in 23% of patients, and heparin use was documented in 16%. Embolectomy was associated with decreased amputation rates (0.054, 0.01-0.27) and mortality (0.07, 0.01-0.57)., Conclusions: In patients with acute limb ischemia, the more widespread use of heparin anticoagulation and, in select patients, performance of embolectomy rather than pursuing thrombolysis may improve patient outcomes.

Introduction: Peripheral vascular occlusive disease (PVOD) and rheumatologic disease (RD) are common in older patients. The effect that coexistence of these diseases may have on patient health has not been rigorously investigated. The present study was undertaken in an attempt to characterize patients with PVOD plus RD in terms of inflammatory serologic disorders, medications, and procedures, and their relation to limb salvage., Methods: Medical records were reviewed retrospectively for all patients with diagnosed coexistent PVOD and non-arteritis RD treated over 15 years at the University of Michigan Hospital. Demographics, operative and medical therapies, and serologic studies were analyzed. Univariate and multivariate analysis and the Kaplan-Meier method were used to assess these variables in relation to limb salvage., Results: Forty-one patients (34 women, 7 men), with mean age of 67 years, were studied. Mean antinuclear antibody titer was 274, C-reactive protein concentration was 3.1 mg/mL, and sedimentation rate was 49. Twenty-nine percent of patients had claudication, 49% had rest pain, and 32% had tissue loss. Mean ankle brachial index was 0.55. Medications included nonsteroidal anti-inflammatory drugs (67% of patients), corticosteroids (54%), and specific immunosuppressive agents (27%). Operative therapy included aortofemoral bypass grafting (n = 4), infrainguinal bypass grafting (n = 14), embolectomy (n = 4), and primary amputation (n = 7). Overall 5-year limb salvage rate was 70% in patients undergoing bypass surgery. Comparison of surgical with nonsurgical patients showed no significant differences in baseline risk factors, serologic disorders, or anatomic location of vascular disease. Multivariate analysis revealed that rest pain and lack of immunosuppression were significantly predictive of need for revascularization or amputation (P <.05)., Conclusion: Patients with RD should receive treatment on the basis of standard criteria for limb ischemia, in that surgical revascularization outcomes are satisfactory. Immunosuppressive agents may confer a protective effect against progression of PVOD.

Purpose: The role of prophylactic vena cava filters (VCF) in patients with cancer is debated. Although VCF are often placed in patients with cancer after recurrence of venous thromboembolic events (VTE), identification of this subset of patients has not been well-defined. This study was undertaken to assess factors associated with increased risk for recurrent VTE., Methods: All patients with a history of thromboembolism or malignant disease and who required a VCF because of failure of or contraindication to anticoagulation therapy were abstracted from the Michigan Filter Registry. Univariate analysis of potential risk factors for recurrent VTE and logistic regression models were used to identify associations between these variables and recurrent VTE., Results: Ninety-nine patients (49 men, 50 women) with a mean age of 58 years were included in the study. New metastases occurred in 55% of patients, and 12% of patients had a history of VTE before cancer diagnosis. Corticosteroid agents were used during therapy in 48% of patients. Acute VTE was present in 52% of patients at cancer diagnosis, and in 34% of patients VTE was associated with new metastases. Recurrent VTE occurred in 40% of patients, and significant risk factors included presence of new metastases (odds ratio [OR], 3.3; 95% confidence interval [CI], 1.16-9.09; P =.02) and history of VTE (OR, 10.6; CI, 1.98-57.2; P =.006). Whereas a single episode of neutropenia did not reach significance (OR, 1.1; CI, 0.97-1.35; P =.11), multiple neutropenic episodes were significantly associated with recurrent VTE (P =.04). Smoking, hormone replacement therapy, decreased mobility, post-surgical state, and obesity were not independently associated with increased risk. Mean survival in this series was 30 months, and was significantly worse in patients with VTE at cancer diagnosis and with inability to tolerate anticoagulant therapy in conjunction with VCF., Conclusion: Patients with malignant disease may be at increased risk for recurrent VTE after development of new metastases or multiple episodes of neutropenia, especially those patients with a history of VTE. VCF may be a reasonable alternative to long-term anticoagulation therapy in this subgroup of patients at high risk patients, provided their quality of life is reasonable.

Chlorophyll-fluorescence and infrared gas analyser measurements show saturation of photosynthetic electron flow and CO(2) uptake at generally lower irradiances in Hymenophyllum tunbrigense than in H. wilsonii, but with wide variation in both species (63-189 micromol m(-2) s(-1) PPFD in H. tunbrigense, 129-552 micro mol m(-2) s(-1) PPFD in H. wilsonii), probably related to both site and season. Non-photochemical quenching (at 400 micromol m(-2) s(-1) PPFD) ranged from 2.1 to 8.1, with no significant difference between the species. Pressure-volume curves from thermocouple-psychrometer measurements give full-turgor osmotic potentials of approx. -1.4 MPa in both species, and indicate low apoplast fractions and high cell-wall elastic moduli. Leaves of H. tunbrigense recovered within 24 h from up to 7 d desiccation at water potentials ranging from -40 MPa (74 % relative humidity, RH) to -220 MPa (20 % RH); after 15 or 30 d, desiccation recovery was slower and less complete, and leaves were severely damaged at the highest and lowest humidities. Hymenophyllum wilsonii recovered well from up to 30 d desiccation at -114 and -220 MPa, but at -40 MPa it showed signs of damage after 15 d, and was severely damaged or killed after 30 d. Results are discussed in relation to the ecological and geographical distributions of the two species, and to the adaptive strategies of filmy ferns in general.

Objective: This study sought to identify risk factors associated with an unfavorable outcome after elective abdominal aortic aneurysm (AAA) repair in patients with chronic obstructive pulmonary disease (COPD)., Methods: The clinical records of 158 patients who underwent elective open AAA repair with COPD determined from preadmission International Classification of Diseases-ninth revision codes during a 12-year period at the University of Michigan were reviewed. Patients with uncomplicated outcomes (group I) were compared with those with unfavorable postoperative outcomes (group II). The unfavorable outcomes were defined as myocardial infarction, acute renal failure, worsening respiratory insufficiency necessitating tracheostomy, or death within 30 days of surgery. Logistic regression analyses of variables that were identified as being statistically significant in the univariate analysis were used to develop a predictive model of these events., Results: Group I included 133 patients (77 men, 56 women) with a mean age of 70.1 years, and group II included 25 patients (13 men, 12 women) with a mean age of 71.4 years. Preoperative factors statistically related (P =.002) to an unfavorable outcome in group II patients included: suboptimal COPD management (fewer prescribed inhalers), lower hematocrit, preoperative renal insufficiency, and coronary artery disease. Importantly, abnormal preoperative spirometry and arterial blood gases were not predictive of a poor outcome. Univariate analysis also revealed increased hospital (25 versus 13 days; P =.0001) and intensive care unit (14 versus 4 days; P =.001) length of stays and a greater need for prolonged ventilation (8 versus 1 day; P =.039) for group II patients compared with group I patients. The 30-day mortality rate in the entire experience was 3.2% (5/158). No specific variables associated with mortality were identified., Conclusion: Fewer prescribed inhalers, lower hematocrit, renal insufficiency, and coronary artery disease are preoperative factors associated with unfavorable outcomes after open elective surgical repair of AAA in patients with COPD. Intensive management of these factors may reduce the hazards of AAA operations in these patients. COPD alone should not be considered a deterrent to the surgical treatment of AAAs.

Background: The use of animals in medical research raises both ethical and economic concerns. Validated in vitro models allow extensive device testing prior to in vivo studies which limits the numbers of animals required to reach conclusions regarding efficacy and safety., Materials and Methods: In vitro studies were conducted in a vena caval simulator (ECU) to evaluate characteristics of filter performance: ability to capture emboli, resistance to vertical movement from lateral forces, resistance to vertical movement from mass impact, and ability to maintain caval flow. These tests are used to select candidate filters for in vivo studies. In vivo filter studies are conducted in an ovine model with filters placed into the vena cava from a jugular or femoral vein approach. At intervals, the animals are sacrificed and both cava and device are evaluated for thrombogenicity, thrombus resolution, and mechanical integrity. Radiographs, intravascular ultrasound, and histology are used to determine outcome., Results: During the 6-year period from 1993 to 1999, 11 vena caval filter types were evaluated. In each case, it was possible to select a single prototype for in vivo study on the basis of four tests. An investigational device was developed that was comparable to the marketed devices with respect to clot capture (P = 0.001), superior to the Greenfield in resistance to movement (P = 0.001), and superior to the VenaTech and Simon Nitinol relative to volume loading (P = 0.01). Problems with metal fatigue prevented clinical development., Conclusion: An integrative system of in vitro and in vivo studies allows efficient evaluation of IVC filters and identifies design characteristics associated with clinical functioning. Evaluation over time is essential to determine safety as well as efficacy.

Background: The objective of this study was to determine the likelihood of mortality after abdominal aortic aneurysm (AAA) repair in patients with thoracic or thoracoabdominal aortic dissection., Methods: Fourteen patients (11 men, three women) with known thoracic or thoracoabdominal aortic dissections underwent elective AAA repair from 1986 to 2001, including three patients with acute dissections (less than 14 days) and 11 patients with chronic dissections (14 days or longer). All 14 patients had type III aortic dissections. Stent graft exclusion of the aortic dissection was performed in one patient before AAA repair. Preoperative patient characteristics, intraoperative events, perioperative complications, and 30-day and 1-year mortality rates were assessed., Results: Elective AAA repair in the setting of thoracic or thoracoabdominal aortic dissection in this series was associated with no 30-day mortality and a 1-year mortality rate of 7.1%. Furthermore, preoperative patient characteristics, intraoperative events, and perioperative complications did not appear to be associated with late, 1-year, mortality., Conclusion: Elective AAA repair in the setting of acute or chronic aortic dissection is associated with mortality rates similar to those generally attributed to elective AAA repair without accompanying aortic dissection. Nevertheless, the conduct of the operation is usually complex, especially in the setting of an acute aortic dissection.

Hypothesis: Surgical compression stockings measurably improve venous physiologic mechanisms, and stocking brands do not differ from one another., Methods: Eleven patients, (8 men and 3 women [mean age, 53 years]), were included. Six patients had primary venous insufficiency and 5 patients had secondary venous insufficiency; 5 patients were in CEAP class 4 and 6 were in CEAP class 5. Patients were randomly assigned to a sequence of 4 brands of knee-high, open-toe, 30- to 40-mm Hg stockings. Each patient wore a stocking for a 1-month equilibration period, then a different stocking monthly for 4 months in a row. Air plethysmography examinations were performed with and without stockings before and after each month of wear. Patients filled out a daily stocking record log and a monthly satisfaction survey. Stockings underwent compression testing after use., Results: Stockings controlled reflux better than they improved calf muscle pump function. With stockings on, patients in CEAP 4 benefited more than those in CEAP 5 in decreasing reflux, while patients in CEAP 5 benefited more than those in CEAP 4 in improving calf muscle pump function. Changes in residual volume fraction were improved in patients in CEAP 5 wearing stockings but not in patients in CEAP 4. Patients with primary disease had greater volumes of reflux and calf ejection than with secondary disease. There were no hemodynamic differences between stocking brands but there were differences in patient compliance and acceptance., Conclusions: Surgical support stockings seem to be more effective in controlling reflux than in improving calf muscle pump function. All stocking brands function equally as measured by air plethysmography.

Purpose: This study tested the hypothesis that a subset of secondary infrainguinal arterial reconstructions show prohibitive failure rates., Methods: Records of 79 consecutive patients, 44 men and 35 women, with a mean age of 60 years, who underwent secondary infrainguinal bypass from 1992 to 2000 at the University of Michigan Hospital, were reviewed. Data were analyzed with life-table analysis, logistic regression, and descriptive statistics., Results: Secondary infrainguinal reconstructions were performed in patients who had undergone earlier ipsilateral bypasses once (n = 35) or twice (n = 44). Among the prior procedures, 68% (n = 54) were done at an institution other than the authors'. Comorbidities included coronary artery disease (72%), tobacco use (77%), and diabetes mellitus (34%), but no patient had hemodialysis-dependent renal failure. Disabling claudication, with average ankle brachial index of 0.48, had been the indication for the primary operation in 77% of cases. Femoral-popliteal bypass was the primary procedure in 67%, with a prosthetic graft used in 62%. The mean patency duration of these earlier bypasses was 25 months. The indication for the final bypass was rest pain or tissue loss in 51% of patients, with an average ankle brachial index of 0.37. The most common procedure was a femoral-distal bypass with autologous vein (63%). Mean patency duration of the secondary bypasses was 30 months. Graft failure within 30 days of operation occurred in 22 patients (28%), and amputation was necessitated in 86% of these patients. The presence of rest pain or tissue loss, when accompanied with a history of early prior graft thrombosis in female patients, correlated with worse mean patency rates, recurrent graft failure (P

Purpose: Duplex ultrasound scanning (US) is the accepted standard means of diagnosis for lower-extremity suprageniculate deep venous thrombosis (LE-DVT). Computed tomographic venography (CTV) has been proposed as an alternative modality for diagnosis of LE-DVT in patients with suspected pulmonary embolism (PE). This study compared CTV with US as a means of diagnosing acute LE-DVT., Methods: A retrospective review of US and CTV scans from 136 patients with suspected PE who underwent both studies to exclude acute LE-DVT at a single institution was performed. Studies were reviewed and coded in a blinded manner. US was considered to be the reference test. Direct costs of each study were determined by using commercial software., Results: The sensitivity and specificity rates of CTV were 71% and 93%, respectively. The positive predictive value, negative predictive value, and accuracy rates of CTV were 53%, 97%, and 90%, respectively. DVT localization was the same in eight of 10 cases in which the results of both US and CTV were positive. CTV costs and charges per study were greater than those of US by $46.88 and $602.00, respectively., Conclusion: CTV is specific, but has a lower sensitivity rate and positive predictive value for the diagnosis of acute LE-DVT compared with US. Additionally, CTV is more costly than US scanning. Because of the lower sensitivity rate and positive predictive value and the increased cost of CTV, US remains the screening study of choice in cases of suspected acute LE-DVT.

Introduction: Questions regarding which patients require prophylaxis for thromboembolism, what methods should be used and the appropriate duration of treatment remain unanswered., Methods and Materials: A retrospective review from a single academic medical center was undertaken to evaluate prophylactic strategies. Multiple sources of data were used to identify patients who were prophylaxed and those who developed deep vein thrombosis or pulmonary embolism. These data were analyzed to determine factors associated with successful prophylaxis including age, type of prophylaxis and admitting services., Results: A total of 22,030 patients were admitted of whom 7520 (36%) received prophylaxis and there were 523 thromboembolic events. Pneumatic compression devices and antiembolic stockings had the lowest incidence of failure, 2.2% and 3.2% respectively. There were significant differences in the rates of prophylaxis used by the five admitting services, being highest in surgery (40.8%) and lowest in gynecology (11.4%). However, these groups had the lowest incidence of venous thromboembolism (4.3%, 2.3%). Both of these groups used pneumatic compression as the method of choice (64.3% and 65.2%)., Conclusions: Thromboembolism prophylaxis reduces the incidence of DVT and PE, however, our study demonstrates the variable effectiveness of each method in different types of patients. Our data suggest that patient risk of DVT should be individually assessed and an appropriate method of prophylaxis should be applied when warranted.

Purpose: The five pneumatic compression devices (PCDs) that are marketed provide mechanical protection from deep venous thrombosis (DVT). They differ with respect to patterns of compression and the length of the sleeve. Evidence linking differences to clinical outcomes is lacking. Our purpose was twofold: to evaluate each of the marketed PCDs with respect to effectiveness, compliance, and patient and nursing satisfaction and to determine whether there is a clinical basis for the selection of one device over another., Methods: Each of the marketed devices was used exclusively for a 4-week period. Patients participated in an evaluation including venous duplex ultrasound scan, DVT risk assessment, and device evaluation. Vascular laboratory records were used to document DVT. Compliance was measured by meters installed on all pumps. A ranking matrix was stratified by compression pattern: rapid graduated sequential compression, graduated compression, and intermittent compression, and each device was rated by patients and nurses., Results: The PCDs were used in 1350 cases with a DVT rate of 3.5% ranging from 2% to 9.8% depending on the method of compression. Patients with DVT were older (58 vs 54 years), had better compliance (67% vs 50%), and had more compression days (11 vs 7.2). When thigh-length sleeves were used, a greater proportion of DVT occurred in the proximal segments (71%) as compared with the number of proximal DVT when the calf-length devices were used (52%; P =.21). Devices W, X, and Y had comparable rates of DVT, which were lower than those for V and Z. Compression device W, [correction] with calf and thigh sleeves, achieved the best overall ranking largely because of high scores for patient and nurse satisfaction., Conclusion: Our data appear at odds with commonly held beliefs. We were unable to show a difference in DVT incidence based on the length of the device or the method of compression. Randomized studies are needed to confirm our findings and evaluate hypotheses derived from this study.

Objective: The hypothesis to be tested was that diminished bioavailable nitric oxide (NO) affects matrix metalloproteinase (MMP) expression and activation in vascular smooth muscle cells (SMCs)., Methods: Cultivated rat aortic SMCs (RA-SMCs) were exposed to increasing concentrations of L-N-monomethyl arginine (L-NMMA), a nonselective inhibitor of NO synthase, in the presence of proinflammatory cytokines (50 ng/mL interleukin [IL]-1beta, 50 ng/mL interferon-gamma, and 30 microg/mL lipopolysaccharide). Nitrite and nitrate, two of the final end products of NO metabolism, were measured in media collected at 48 hours with the use of the Saville assay (n = 4). MMP activity was measured with 1% gelatin zymography (n = 4). In separate experiments in which 2 ng/mL of IL-1beta and L-NMMA was used, MMP protein and messenger RNA (mRNA) levels were determined with Western blot analysis (n = 3) and semiquantitative reverse transcriptase-polymerase chain reaction (n = 3), respectively. Data were analyzed with nonparametric analysis of variance., Results: Increasing concentrations of the NO synthase inhibitor L-NMMA caused a dose-dependent decrease (P <.05) in nitrite and nitrate production by RA-SMCs after cytokine exposure. Zymography documented an early dosedependent increase (P <.05 compared with cytokines alone) in 92-kd MMP activity, with no significant changes in 72-kd MMP activity after treatment with L-NMMA (P >.05 compared with cytokines alone). Reverse transcriptase-polymerase chain reaction and Western blot analysis revealed that the addition of L-NMMA to IL-1beta-stimulated RA-SMCs led to significant increases in MMP-9 mRNA (n = 3, P <.01 for 1.0 mmol/L L-NMMA) and MMP-9 protein levels (n = 3, P <.05), respectively. No differences in MMP-2 mRNA or protein levels were demonstrated., Conclusions: Inhibition of cytokine-induced NO expression in RA-SMCs is associated with a selective, dose-dependent increase in MMP-9 expression and synthesis. These findings suggest that alterations in local NO synthesis may influence MMP-9-dependent vessel wall damage.

Purpose: This study determined whether there is an association between psychological and socioeconomic characteristics and the long-term outcome of operative treatment for patients with sensory neurogenic thoracic outlet syndrome (N-TOS)., Methods: Clinical records, preoperative psychological testing results, and long-term follow-up questionnaire data were reviewed for consecutive patients who underwent surgery for N-TOS from 1990 to 1999. Multivariate logistic regression models were developed as a means of identifying independent risk factors for postoperative disability., Results: Operative decompression of the brachial plexus via a supraclavicular approach was performed for upper extremity pain and paresthesia with no mortality and minimal morbidity in 170 patients. After an average follow-up period of 47 months, 65% of patients reported improved symptoms, and 64% of patients were satisfied with their operative outcome. However, 35% of patients remained on medication, and 18% of patients were disabled. Preoperative factors associated with persistent disability include major depression (odds ratio [OR], 15.7; P =.02), not being married (OR, 7.9; P =.04), and having less than a high school education (OR, 8.1; P =.09)., Conclusion: Operative decompression was beneficial for most patients. Psychological and social factors, including depression, marital status, and education, are associated with self-reported disability. The impact of the preoperative treatment of depression on the outcome of TOS decompression should be studied prospectively.

Background: Patients with venous thromboembolic disease are treated with anticoagulation or vena cava filter placement to prevent pulmonary embolism. A recent report suggested that filter placement may increase the risk of recurrent deep venous thrombosis (DVT) and prompted a review of our experience., Methods: Prospectively collected data on 2109 consecutive patients receiving filters were evaluated for recurrent thromboembolism, vena cava occlusion, or venous stasis ulceration. Outcomes were stratified and analyzed according to the use of anticoagulants at the time of insertion and at follow-up. Incidence rates were also compared with reports in the literature., Results: Of 1191 patients with DVT at filter placement, complete follow-up data at a mean of 9 years were available for 465. Recurrent DVT was found in 12% of the 241 patients who were given anticoagulants and 15% of the 224 who were not (P >.05). We also failed to find a significant association between the use of anticoagulation and the incidence of pulmonary embolism (2%), stasis ulceration (2%), and vena cava occlusion (0.0)., Conclusions: Recurrent DVT in patients with existing thromboembolic disease is not an unexpected event, which, in our experience, is not associated with anticoagulant or filter use. Anticoagulation should be used when possible to treat existing DVT to reduce thrombus progression and potentially to reduce subsequent complications but does not seem to reduce the rate of recurrent DVT. Rates of recurrent thromboembolism were consistently less than the 20% to 50% reported in the literature.

Objective: The percutaneous steel Greenfield filter (PSGF) is similar in appearance to the titanium Greenfield filter (TGF) but differs in the length and orientation of the attachment hooks and in the over-the-wire delivery system. Because these differences improve ease of insertion and attachment, they may affect patient outcomes and physician practices. The purpose of this study was to evaluate the performance of the PSGF relative to the TGF and to determine whether there had been a change in physician practices., Methods: The Michigan Filter Registry contains data for a prospective cohort of 2188 patients with Greenfield filters. Procedural and long-term outcomes for patients with a PSGF were abstracted. These events were compared with rates for Registry patients who had a TGF. Trends for indication for placement, delivery route, and filter location were also compared with published series., Results: Since 1995, 600 PSGFs have been placed in 599 patients. A 1-year mortality rate of 42% left 349 patients available for annual follow-up, and studies were completed for 231 (66%). Periprocedural events occurred in 2.5% of cases with associated morbidity in 1.5%. The rate of new pulmonary embolism was 2.6%, and vena caval patency was 98.3%. The combined rate of new venous thromboembolic events was 12.5%. Left-sided femoral vein placements increased to 20%, and the major indication for filter placement has become prophylaxis (46%)., Conclusions: The PSGF is similar to the TGF with respect to patient outcomes, and it provides decreased rates of asymmetry along with excellent fixation. The flexible carrier system has allowed more frequent access through the left femoral vein. The ease of use and favorable patient outcomes have resulted in more frequent placement for prophylactic indications.

Purpose: To compare the five vena caval filters marketed in the United States and one investigational vena caval filter and to determine whether there is an association between their design and their in vivo function., Methods: Four of each type of filter--Simon Nitinol (SN), Bird's Nest (BN), Vena Tech (VT), Greenfield stainless steel (PSGF), Greenfield titanium (TGF), and the investigational stent cone filter (NGF)--were studied for 60 days in 12 sheep. Radiographic and pathologic outcomes to be assessed included clot capture and resolution, vena caval penetration, position of the filter, thrombogenicity, and vessel wall reaction., Results: Filters differed with respect to the number of clot-trapping levels and the interdependence of the legs. All devices were successfully placed. Intentionally embolized clot was captured. One VT and two SN filters migrated in response to clot capture. Resolution of thrombus was variable, and related to the design of the device. Fibrin webbing was widely present with the VT, BN, and SN filters but limited in the others. The VT and NGF filters demonstrated the most stable filter base diameter., Conclusions: The performance of vena caval filters differs with respect to clot resolution and mechanical stability. Interdependent filter limbs and single-stage conical capture sites appear to result in more favorable performance in in vivo studies.

Background: The identification of trauma patients at risk for the development of deep venous thrombosis (DVT) at the time of admission remains difficult. The purpose of this study is to validate the risk assessment profile (RAP) score to stratify patients for DVT prophylaxis., Methods: All patients admitted from November 1998 thru May 1999 were evaluated for enrollment. We prospectively assigned patients as low risk or high risk for DVT using the RAP score. High-risk patients received both pharmacologic and mechanical prophylaxis. Low-risk patients received none. Surveillance duplex Doppler scans were performed each week of hospitalization or if symptoms developed. Hospital charges for prophylaxis were used to determine the savings in the low-risk group. Statistical differences between the risk groups for each factor of the RAP and development of DVT were determined by the chi-squared test, with significance at a probability value of less than .05., Results: There were 102 high-risk (64%) and 58 low-risk (36%) individuals studied. Eleven of the high-risk group (10.8%) experienced the development of DVT (asymptomatic, 64%). None of the low-risk group was diagnosed with DVT. Five of the 16 RAP factors were statistically significant for DVT. Eliminating prophylaxis and Doppler scans in low-risk patients resulted in a total savings of $18,908 in hospital charges., Conclusions: The RAP score correctly identified trauma patients at increased risk for the development of DVT. Despite prophylaxis, the high-risk group warrants surveillance scans. Withholding prophylaxis in low-risk patients can reduce hospital charges without risk.

In the mosses Racomitrium lanuginosum, Anomodon viticulosus and Rhytidiadelphus loreus, after a few days air dry, F:(v)/F:(m) reached, within the first minute of remoistening in the dark, two-thirds or more of the value attained after 40 min. A fast initial phase of recovery was completed within 10-20 min after which further change was slow. Initial recovery of Phi(PSII) in the light was somewhat slower, but was generally substantially complete within a similar time. Remoistening with 0.3 mM cycloheximide (CHX) or 3 mM dithiothreitol (DTT) made little difference to this short-term (40 min) recovery of either F:(v)/F:(m) or Phi(PSII); 3 mM chloramphenicol (CMP) had little effect on recovery of F:(v)/F:(m), but resulted in substantial (though not total) depression of Phi(PSII) and (14)CO(2) uptake. Effects of the protein-synthesis inhibitors and DTT were much more clearly apparent in longer-term experiments (>20 h) but only in the light. In the dark, the three inhibitors had at most only slight effects over periods of 60-100 h. In the light, CMP-treated samples of all three species showed a progressive decline of dark-adapted F:(v)/F:(m), falling to zero within 1-5 d (possibly due to blocking of the turnover of the D1 protein of PSII) and accelerated by DTT. CHX-treated samples showed a similar but slower decline. In the shade-adapted and relatively desiccation-sensitive Rhytidiadelphus loreus, slow recovery of F:(v)/F:(m) continued in the dark even in the presence of CMP and CHX for much of the 142 h of the experiment. The results indicate that in desiccation-tolerant bryophytes recovery of photosynthesis after periods of a few days air dry requires only limited chloroplast protein synthesis and is substantially independent of protein synthesis in the cytoplasm.

Prophylaxis for venous thromboembolism is an area that has received intense study in certain conditions, but less than adequate coverage in other areas. In considering who needs prophylaxis, patients are categorized into levels of risk. Clinical venous thromboembolism can be correlated to these levels of risk. Methods of prophylaxis include pharmacologic, mechanical, and combinations of these. Each category of surgical and medical patient requires specific types of prophylaxis. In certain orthopedic indications, the length of prophylaxis outlasts the inpatient hospital stay and may be as long as 1 month after discharge. Even with the best prophylaxis today, the incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE) is decreased by only approximately 70% to 80%. Further developments should allow for greater declines in the rates of venous thromboembolism, with its subsequent short-term consequence of pulmonary embolism and lower extremity morbidity and long-term consequence of the disabling syndrome of chronic venous insufficiency (CVI).

Indications for placement of a vena caval filter reflect the perception of efficacy and safety of these devices. The traditional indications include contraindications to or complications of anticoagulation. Over time, physicians have expanded these indications to include prophylactic placement in patients at high risk of pulmonary embolism. The decision to place a filter should be made only after weighing the risks and benefit in each situation. Long-term outcomes should be carefully evaluated.

Complications from the use of vena caval filters are rare but can occur at placement, during other procedures, or late in follow-up. Placement problems such as bleeding from the insertion site or embolism from thrombus manipulation are largely avoidable. Technical difficulties with introduction, positioning, or misplacement have been minimized by use of flexible carriers and guidewires. However, later insertion of guidewires without fluoroscopy for line changes can lead to problems of entrapment. Filter capture of emboli can result in further thrombus propagation at that site or in filter obstruction. Management of these events requires adequate visualization to determine whether to use lytic therapy or a second filter. Late complications include filter strut fracture in 0.05% of cases and filter penetration, of even rarer functional significance. Pain that can be attributed to the filter has been found only in a single case of pelvic misplacement. The limited consequences of mechanical changes in the filter argue strongly against unnecessary interventions, which frequently result in an increase in morbidity.

Objective: The purpose of this study was to describe outcomes for patients with trauma who had vena caval filters placed in the absence of venous thromboembolic disease (group P) and compare them with outcomes for patients with trauma who had filters placed after either deep venous thrombosis or pulmonary embolism (group T)., Design: The study is a case series of consecutive patients who received vena caval filters after traumatic injury. Data were collected prospectively at the time of filter placement from reports of diagnostic studies obtained for clinical indications and during the annual follow-up examinations. Event rate findings are based on objective tests. Data were obtained from the Michigan Vena Cava Filter Registry., Results: Filters were placed in 385 patients with trauma; 249 of these filters were prophylactic (group P). Event rates were similar in the two groups. New pulmonary embolism was diagnosed in 1.5% of the patients in group P and 2% of the patients in group T. Caval occlusion rates were 3.5% for group P and 2.3% for group T. In all, 15.6% of the patients in group P had deep venous thrombosis or pulmonary embolism after placement. The frequencies of lower extremity swelling and use of support hose were higher in group T than in group P (43% vs 25% and 25% vs 3.5%, respectively; P <.005). Outcomes were comparable in the two groups with respect to mechanical stability of the filter., Conclusions: The prophylactic indication for vena caval filter placement in patients with trauma is associated with a low incidence of adverse outcomes while providing protection from fatal pulmonary embolism. The current challenge is to limit the number of unnecessary placements through improved methods of risk stratification.

Purpose: This study was undertaken to determine the clinical outcomes for patients with Greenfield filters placed in the suprarenal (SR) inferior vena cava (IVC)., Methods: We collected data prospectively from annual follow-up evaluations of patients with filters. Patients underwent venous color-flow duplex examinations of the IVC and lower extremities, abdominal radiographs, and physical assessment. The outcomes for those patients with filters in the SR IVC were compared with the outcomes previously reported and with the outcomes for patients with filters in the infrarenal cava., Results: SR placement accounted for 7.6% (148/1932) of all filter placements. Follow-up data were available for 73 placements, or 49%. No cases of renal dysfunction were related to filter placement. The rate of recurrent pulmonary embolism (PE) was 8%, and the rate of long-term caval occlusion was 2.7%. These rates did not differ statistically from the rates for patients with infrarenal filters (P > .05). Male patients tended to be older by 15 years, to have more recurrent PE, and to experience more filter migration (6 vs 2 mm). Failure of SR filters to prevent PE was associated statistically with the primary indication for placement. Recurrent PE was the indication in 5 of 6 patients who sustained PE after SR filter placement (P = .007). Filter limb fracture was seen only with the stainless-steel Greenfield filter., Conclusion: Greenfield filters placed above the renal vein provide protection from PE with a minimal risk of occlusion. Twenty-five years of experience with Greenfield filters shows that they are safe and effective both in young female patients of child-bearing potential and in all patients with appropriate indications for SR placement.

Purpose: To examine and elucidate the mechanisms for apparent "penetration" by Greenfield vena caval filters., Methods: Two filters were placed in the inferior venae cavae (IVC) of four immature sheep and followed with cavography for 1 year. Two animals underwent computed tomography (CT) and laparoscopic examination. At necropsy, the vena cava and adjacent structures of all four animals were examined grossly and histologically., Results: Based upon cavography and CT imaging, all filters appeared to penetrate the vena cava at 12 months. However, at laparoscopy, no hooks or limbs were exposed, and the pericaval tissues remained intact; each hook or limb was within the adventitia or encapsulated in scar tissue. Histology of the tissue at the hook sites revealed remodeling of the intimal surface of the IVC and thinning of the adventitia., Conclusions: Based upon these data, we hypothesize that the vena cava gradually adapts by medial and adventitial thinning and myointimal remodeling to the radial force exerted by a filter. This process allows increase in the filter base diameter while maintaining the integrity of the cava and protecting adjacent structures.