Search

Abstract Background Abdominal aortic aneurysm (AAA) is a prevalent disease which is of significant concern because of the morbidity associated with the continuing expansion of the abdominal aorta and its ultimate rupture. The transient interaction between blood flow and the wall contributes to wall stress which, if it exceeds the failure strength of the dilated arterial wall, will lead to aneurysm rupture. Utilizing a computational approach, the biomechanical environment of virtual AAAs can be evaluated to study the affects of asymmetry and wall thickness on this stress, two parameters that contribute to increased risk of aneurysm rupture. Methods Ten virtual aneurysm models were created with five different asymmetry parameters ranging from β = 0.2 to 1.0 and either a uniform or variable wall thickness to study the flow and wall dynamics by means of fully coupled fluid-structure interaction (FSI) analyses. The AAA wall was designed to have a (i) uniform 1.5 mm thickness or (ii) variable thickness ranging from 0.5 – 1.5 mm extruded normally from the boundary surface of the lumen. These models were meshed with linear hexahedral elements, imported into a commercial finite element code and analyzed under transient flow conditions. The method proposed was then compared with traditional computational solid stress techniques on the basis of peak wall stress predictions and cost of computational effort. Results The results provide quantitative predictions of flow patterns and wall mechanics as well as the effects of aneurysm asymmetry and wall thickness heterogeneity on the estimation of peak wall stress. These parameters affect the magnitude and distribution of Von Mises stresses; varying wall thickness increases the maximum Von Mises stress by 4 times its uniform thickness counterpart. A pre-peak systole retrograde flow was observed in the AAA sac for all models, which is due to the elastic energy stored in the compliant arterial wall and the expansion force of the artery during systole. Conclusion Both wall thickness and geometry asymmetry affect the stress exhibited by a virtual AAA. Our results suggest that an asymmetric AAA with regional variations in wall thickness would be exposed to higher mechanical stresses and an increased risk of rupture than a more fusiform AAA with uniform wall thickness. Therefore, it is important to accurately reproduce vessel geometry and wall thickness in computational predictions of AAA biomechanics.

Background: Musculoskeletal disorders (MSDs) are a leading cause of disability worldwide, with a growing burden across all demographics. With advancements in technology, conversational artificial intelligence (AI) platforms such as ChatGPT (OpenAI, San Francisco, CA) have become instrumental in disseminating health information. This study evaluated the effectiveness of ChatGPT versions 3.5 and 4 in delivering primary prevention information for common MSDs, emphasizing that the study is focused on prevention and not on diagnosis., Methods: This mixed-methods study employed the CLEAR tool to assess the quality of responses from ChatGPT versions in terms of completeness, lack of false information, evidence support, appropriateness, and relevance. Responses were evaluated independently by two expert raters in a blinded manner. Statistical analyses included Wilcoxon signed-rank tests and paired samples t-tests to compare the performance across versions., Results: ChatGPT-3.5 and ChatGPT-4 effectively provided primary prevention information, with overall performance ranging from satisfactory to excellent. Responses for low back pain, fractures, knee osteoarthritis, neck pain, and gout received excellent scores from both versions. Additionally, ChatGPT-4 was better than ChatGPT-3.5 in terms of completeness (p = 0.015), appropriateness (p = 0.007), and relevance (p = 0.036), and ChatGPT-4 performed better across most medical conditions (p = 0.010)., Conclusions: ChatGPT versions 3.5 and 4 are effective tools for disseminating primary prevention information for common MSDs, with ChatGPT-4 showing superior performance. This study underscores the potential of AI in enhancing public health strategies through reliable and accessible health communication. Advanced models such as ChatGPT-4 can effectively contribute to the primary prevention of MSDs by delivering high-quality health information, highlighting the role of AIs in addressing the global burden of chronic diseases. It is important to note that these AI tools are intended for preventive education purposes only and not for diagnostic use. Continuous improvements are necessary to fully harness the potential of AI in preventive medicine. Future studies should explore other AI platforms, languages, and secondary and tertiary prevention measures to maximize the utility of AIs in global health contexts., Competing Interests: Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Yilmaz Muluk et al.)

Background: Low back pain (LBP) is a prevalent healthcare concern that is frequently responsive to conservative treatment. However, it can also stem from severe conditions, marked by 'red flags' (RF) such as malignancy, cauda equina syndrome, fractures, infections, spondyloarthropathies, and aneurysm rupture, which physicians should be vigilant about. Given the increasing reliance on online health information, this study assessed ChatGPT-3.5's (OpenAI, San Francisco, CA, USA) and GoogleBard's (Google, Mountain View, CA, USA) accuracy in responding to RF-related LBP questions and their capacity to discriminate the severity of the condition., Methods: We created 70 questions on RF-related symptoms and diseases following the LBP guidelines. Among them, 58 had a single symptom (SS), and 12 had multiple symptoms (MS) of LBP. Questions were posed to ChatGPT and GoogleBard, and responses were assessed by two authors for accuracy, completeness, and relevance (ACR) using a 5-point rubric criteria., Results: Cohen's kappa values (0.60-0.81) indicated significant agreement among the authors. The average scores for responses ranged from 3.47 to 3.85 for ChatGPT-3.5 and from 3.36 to 3.76 for GoogleBard for 58 SS questions, and from 4.04 to 4.29 for ChatGPT-3.5 and from 3.50 to 3.71 for GoogleBard for 12 MS questions. The ratings for these responses ranged from 'good' to 'excellent'. Most SS responses effectively conveyed the severity of the situation (93.1% for ChatGPT-3.5, 94.8% for GoogleBard), and all MS responses did so. No statistically significant differences were found between ChatGPT-3.5 and GoogleBard scores (p>0.05)., Conclusions: In an era characterized by widespread online health information seeking, artificial intelligence (AI) systems play a vital role in delivering precise medical information. These technologies may hold promise in the field of health information if they continue to improve., Competing Interests: Human subjects: All authors have confirmed that this study did not involve human participants or tissue. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Yilmaz Muluk et al.)

Background Musculoskeletal disorders are a significant global health issue, necessitating advanced management strategies such as intra-articular and extra-articular injections to alleviate pain, inflammation, and mobility challenges. As the adoption of these interventions by physicians grows, the importance of robust safety protocols becomes paramount. This study evaluates the effectiveness of conversational artificial intelligence (AI), particularly versions 3.5 and 4 of Chat Generative Pre-trained Transformer (ChatGPT), in creating patient safety checklists for managing musculoskeletal injections to enhance the preparation of safety documentation. Methodology A quantitative analysis was conducted to evaluate AI-generated safety checklists against a preformed checklist adapted from reputable medical sources. Adherence of the generated checklists to the preformed checklist was calculated and classified. The Wilcoxon signed-rank test was used to assess the performance differences between ChatGPT versions 3.5 and 4. Results ChatGPT-4 showed superior adherence to the preformed checklist compared to ChatGPT-3.5, with both versions classified as very good in safety protocol creation. Although no significant differences were present in the sign-in and sign-out parts of the checklists of both versions, ChatGPT-4 had significantly higher scores in the procedure planning part (p = 0.007), and its overall performance was also higher (p < 0.001). Subsequently, the preformed checklist was revised to incorporate new contributions from ChatGPT. Conclusions ChatGPT, especially version 4, proved effective in generating patient safety checklists for musculoskeletal injections, highlighting the potential of AI to streamline clinical practices. Further enhancements are necessary to fully meet the medical standards., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Yilmaz Muluk et al.)

Objective: The objective of this study is to identify disparities in geographic access to medical oncologists at the time of diagnosis., Data Sources/study Setting: 2014-2016 Pennsylvania Cancer Registry (PCR), 2019 CMS Base Provider Enrollment File (BPEF), 2018 CMS Physician Compare, 2010 Rural-Urban Commuting Area Codes (RUCA), and 2015 Area Deprivation Index (ADI)., Study Design: Spatial regressions were used to estimate associations between geographic access to medical oncologists, measured with an enhanced two-step floating catchment area measure, and demographic characteristics., Data Collection/extraction Methods: Medical oncologists were identified in the 2019 CMS BPEF and merged with the 2018 CMS Physician Compare. Provider addresses were converted to longitude-latitude using OpenCage Geocoder. Newly diagnosed cancer patients in each census tract were identified in the 2014-2016 PCR. Census tracts were classified based on rurality and socioeconomic status using the 2010 RUCA Codes and the 2015 ADI., Principal Findings: Large towns and rural areas were associated with spatial access ratios (SPARs) that were 6.29 lower (95% CI -16.14 to 3.57) and 14.76 lower (95% CI -25.14 to -4.37) respectively relative to urban areas. Being in the fourth ADI quartile (highest disadvantage) was associated with a 12.41 lower SPAR (95% CI -19.50 to -5.33) relative to the first quartile. The observed difference in a census tract's non-White population from the 25th (1.3%) to the 75th percentile (13.7%) was associated with a 13.64 higher SPAR (Coefficient = 1.10, 95% CI 11.89 to 15.29; p < 0.01), roughly equivalent to the disadvantage associated with living in the fourth ADI quartile, where non-White populations are concentrated., Conclusions: Rurality and low socioeconomic status were associated with lower geographic access to oncologists. The negative association between area deprivation and geographic access is of similar magnitude to the positive association between larger non-White populations and access. Policies aimed at increasing geographic access to care should be cognizant of both rurality and socioeconomic status., (© 2022 Health Research and Educational Trust.)

Variability in surgeon prescribing patterns is common in the post-operative period and can be the nidus for dependence and addiction. This project aims to reduce opioid overprescribing at the Veteran's Affairs Pittsburgh Healthcare System (VAPHS). The VAPHS Opioid Stewardship Committee collaborated to create prescribing guidelines for inpatient and outpatient general, thoracic, and vascular surgery procedures. We incorporated bundled order sets into the provider workflow in the electronic medical system and performed a retrospective cohort study comparing opioid prescription patterns for Veterans who underwent any surgical procedure for a three-month period pre- and post- guideline implementation. After implementation of opioid prescribing guidelines, morphine milligram equivalents (MME), quantity of pills prescribed, and days prescribed were statistically significantly reduced for procedures with associated guidelines, including cholecystectomy (MME 140.8 vs. 57.5, p = 0.002; quantity 18.8 vs. 8, p = 0.002; days 5.1 vs. 2.8, p = 0.021), inguinal hernia repair (MME 129.9 vs. 45.3, p = 0.002; quantity 17.3 vs. 6.1, p = 0.002; days 5.0 vs. 2.4, p = 0.002), and umbilical hernia repair (MME 128.8 vs. 53.8, p = 0.002; quantity 17.1 vs. 7.8, p = 0.002; days 5.1 vs. 2.5, p = 0.022). Procedures without associated recommendations also preceded a decrease in overall opioid prescribing. Post-operative opioid prescribing guidelines can steer clinicians toward more conscientious opioid disbursement. There may also be reductions in prescribing opioids for procedures without guidelines as an indirect effect of practice change.

Objective: New formulations and applications of hemostatic adjuncts such as fibrin sealant (FS) to support local hemostasis and sutures continue to be developed. In a pivotal, confirmatory, controlled, prospective, single-blinded, randomized, multicenter phase III clinical trial, the efficacy and safety of FS Grifols during vascular surgeries were evaluated., Methods: Patients undergoing a nonemergency, open, peripheral vascular surgical procedure with moderate arterial bleeding were recruited. In an initial preliminary part of the study, all patients were treated with FS Grifols. In a subsequent primary part, patients were randomized (2:1) to FS Grifols or manual compression (MC). The primary efficacy end point was the proportion of the primary part patients achieving hemostasis by 4 minutes after the start of treatment. Cumulative proportion and time to hemostasis were secondary efficacy end points. Safety end points (in pooled preliminary and primary parts) included adverse events (AEs), vital signs, physical assessments, clinical laboratory tests, viral markers, and immunogenicity., Results: The primary efficacy end point was met by 76.1% of patients (83/109) for the FS Grifols group versus 22.8% of patients (13/57) for the MC group (P < .001). The cumulative proportion of patients at 5, 7, and 10 minutes was 80.7%, 84.4%, and 88.1%, respectively, in the FS Grifols treatment group, and 28.1%, 35.1%, and 45.6% in the MC treatment group (P < .001). The median time to hemostasis was shorter in the FS Grifols group (4 minutes vs ≥10 minutes in the MC group; P < .001). The nature of AEs reported were those expected in the study patient profile. The percentage of patients experiencing treatment-emergent AEs were similar in both the FS Grifols (pooled n = 59 + 109) and MC groups (81.0% and 77.2%, respectively), most recurrent being procedural pain (34.5% and 36.8%, respectively) and pyrexia (11.3% and 10.5%, respectively)., Conclusions: FS Grifols was superior in efficacy and similar in safety to MC as an adjunct local hemostatic agent in patients undergoing open vascular surgeries., (Copyright © 2019 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: The standard of care in the treatment of vascular disease continues to evolve as endovascular therapies develop. Currently, it is unclear how medical malpractice litigation has adapted to the "endovascular era." This retrospective case review is the most comprehensive analysis to date of malpractice actions involving endovascular procedures performed by vascular surgeons (VSs), interventional radiologists (IRs), interventional cardiologists (ICs), and cardiothoracic surgeons (CTSs)., Methods: The legal databases LexisNexis and Westlaw were searched for all published legal cases in the United States involving endovascular procedures. The search was limited to state and federal cases up to and including the year 2016. Keywords included "malpractice," "vascular," "endovascular," "catheter," "catheterization," "stent," "angiogram," "angiography," and "surgery." Cases involving tax revenue, insurance disputes, Social Security Disability, and hospital employment contract disputes were excluded. Data were analyzed using χ 2 test., Results: There were 2115 initial search results identified, and 369 cases were included in final analysis. The rate of endovascular procedure-related lawsuits (per 1000 active physicians in the specialty) was highest for ICs (105.56), whereas rates for VSs and IRs were comparable (18.47 and 16.85, respectively); 93% of the IC cases were related to coronary interventions. Overall, 55% (148/271 classifiable cases) of actions were related to elective procedures. For VSs specifically, 46% (25/54) of cases arose from diagnostic angiography and inferior vena cava filter placement, two relatively minor procedure types. Overall, 83% (176/211 finalized cases) of verdicts favored defendants, with no significant differences across the specialties; 43% (157/368) of total cases involved death of the patient. Among the four specialties, there was a significant (P = .0004) difference in the primary allegation (informed consent, preprocedure negligence, intraprocedure complications, or postprocedure complications) underlying the litigation. For CTSs and VSs, there was a predominance of informed consent and preprocedure negligence allegations (70% [7/10] and 52% [28/54], respectively). Intraprocedure negligence was the most common allegation for IRs (59% [23/39]), whereas allegations were more evenly distributed among ICs., Conclusions: Key issues were identified regarding malpractice litigation involving the specialties that commonly perform endovascular procedures. Despite the increasing number of ICs doing peripheral interventions, a large majority of IC cases were related to coronary treatments. A surprisingly large percentage of VS cases were related to seemingly minor cases. There were significant interspecialty differences in the primary underlying allegations. As the scope of endovascular procedures broadens and deepens, it is important for clinicians to be aware of legal considerations relevant to their practice., (Copyright © 2017 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Objective/background: To examine the role of carotid stenosis (CS) and other independent risk factors of perioperative stroke, following transcatheter aortic valve implantation (TAVI)., Materials and Methods: Using data from the National Inpatient Sample database for analysis, patients who underwent TAVI were identified using the International Classification of Diseases, Ninth Revision, Clinical Modification codes. Various preoperative and perioperative risk factors and their association with perioperative strokes were studied., Results: Data on 7566 patients who underwent a TAVI procedure from 2012 to 2013 were extracted. The average age of the patient population was 81.2 ± 0.32 years. The overall perioperative stroke rate in our patient cohort was 2.79%. Majority (94.6%) of the strokes were ischemic. Multivariate analysis showed the following independent risk factors for perioperative strokes after TAVI: female gender odds ratio (OR) = 2.25 (95% confidence interval [CI], 1.42-3.57), higher van Walraven score OR = 6.6 (95% CI = 3.71-11.73), bilateral CS OR = 4.46 (95% CI = 2.03-9.82), and TAVI with a cardiac procedure done under cardiopulmonary bypass OR = 2.84 (95% CI = 1.57-5.14)., Conclusion: Bilateral carotid disease is a significant risk factor for perioperative strokes following TAVI. Preoperative screening with carotid Doppler to identify high-risk patients appears to be warranted. In addition, patients of female gender were found to have an increased risk for carotid disease.

Objectives: Examine the effectiveness of an advanced pneumatic compression device (APCD) in reducing limb volume (LV), and to evaluate clinician and patient-reported outcomes., Design: Device registry study., Materials and Methods: Data were collected prospectively for 196 lower extremity lymphedema patients prescribed an APCD. Baseline and post-treatment LVs were calculated and clinical outcomes (skin changes, pain, and function) were assessed. Patient-reported outcomes and satisfaction utilizing a pre- and post-treatment survey were also evaluated., Results: 90% of APCD-treated patients experienced a significant reduction in LV with 35% enjoying a reduction >10%. Mean LV reduction was 1,150 mL or 8% (p < .0001). Greater baseline LV and BMI were strong predictors of LV reduction (p < .0001). Clinician assessment indicated that the majority of patients experienced improvement in skin fibrosis and function. Patient-reported outcomes showed a significant increase in ability to control lymphedema through APCD treatment, with an increase in function and a reduction in the interference of pain. 66% were "very satisfied" with the APCD treatment., Conclusion: APCD use is associated with consistent reductions in LV, with favorable patient-reported outcomes. Results demonstrate that reduction in LV and pain, combined with functional improvement and patient satisfaction can be achieved, providing tangible benefit for lower extremity patients., (Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.)

Focal infrarenal aortic stenosis is relatively rare. Traditionally, aortic endarterectomy and aortic bypass surgery have been used to treat these lesions. However, percutaneous transluminal angioplasty and stenting have become well-defined alternatives. A 62-year-old woman presented with bilateral ischemic rest pain. Angiography revealed a mid-infrarenal aortic stenosis adjacent to an enlarged, patent inferior mesenteric artery. Celiac artery and superior mesenteric artery stenoses were also present. The kissing-stent technique is a viable option for ensuring inferior mesenteric artery patency when treating distal aortic lesions by endovascular means in patients with asymptomatic multivessel mesenteric artery disease., (Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: The ideal hemostatic agent for treatment of suture-line bleeding at vascular anastomoses has not yet been established. This study evaluated whether the use of a fibrin sealant containing 500 IU/mL thrombin and synthetic aprotinin (FS; marketed in the United States under the name TISSEEL) is beneficial for treatment of challenging suture-line bleeding at vascular anastomoses of expanded polytetrafluoroethylene (ePTFE) grafts, including those further complicated by concomitant antiplatelet therapies., Methods: Over a 1-year period ending in 2010, ePTFE graft prostheses, including arterio-arterial bypasses and arteriovenous shunts, were placed in 140 patients who experienced suture-line bleeding that required treatment after completion of anastomotic suturing. Across 24 US study sites, 70 patients were randomized and treated with FS and 70 with manual compression (control). The primary end point was the proportion of patients who achieved hemostasis at the study suture line at 4 minutes after start of application of FS or positioning of surgical gauze pads onto the study suture line., Results: There was a statistically significant difference in the comparison of hemostasis rates at the study suture line at 4 minutes between FS (62.9%) and control (31.4%) patients (P < .0001), which was the primary end point. Similarly, hemostasis rates in the subgroup of patients on antiplatelet therapies were 64.7% (FS group) and 28.2% (control group). When analyzed by bleeding severity, the hemostatic advantage of FS over control at 4 minutes was similar (27.8% absolute improvement for moderate bleeding vs 32.8% for severe bleeding). Logistic regression analysis (accounting for gender, age, intervention type, bleeding severity, blood pressure, heparin coating of ePTFE graft, and antiplatelet therapies) found a statistically significant treatment effect in the odds ratio (OR) of meeting the primary end point between treatment groups (OR, 6.73; P < .0001), as well as statistically significant effects for intervention type (OR, 0.25; P = .0055) and bleeding severity (OR, 2.59; P = .0209). The safety profile of FS was excellent as indicated by the lack of any related serious adverse events., Conclusions: The findings from this phase 3 study confirmed that FS is safe and its efficacy is superior to manual compression for hemostasis in patients with peripheral vascular ePTFE grafts. The data also suggest that FS promotes hemostasis independently of the patient's own coagulation system, as shown in a representative population of patients with vascular disease under single- or dual-antiplatelet therapies., (Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Background: The left internal thoracic artery is the ideal conduit for coronary artery revascularization due to superior patency compared with venous grafts. The hemodynamic effects of an arterio-venous fistula on the native in situ internal thoracic artery and the potential for coronary flow steal after revascularization with the internal thoracic artery, are not well-characterized., Methods: Fifteen chronic hemodialysis patients with functioning left upper extremity arterio-venous fistulas were evaluated with the use of transthoracic color Doppler analysis. Flow characteristics of the left and right internal thoracic arteries at baseline, with arterio-venous fistula occluded, and during hemodialysis were recorded. Peak systolic and diastolic velocities for the right and left internal thoracic arteries were calculated for each fistula state (occluded, open, and on-dialysis). One-way analysis of variance was used to compare the different means., Results: Mean flow velocity calculations failed to identify any statistically significant differences between the ipsilateral and contralateral internal thoracic artery in any fistula state. In addition, mean internal thoracic flow velocities were similar between the different fistula states., Conclusions: Changes in arteriovenous fistula flow state did not significantly alter Doppler flow hemodynamics of either the ipsilateral or contralateral in-situ internal thoracic artery. Further studies of the possible effects on internal thoracic arteries used as pedicled coronary grafts may be required.

Objective: The purpose of this study was to delineate the natural history of claudication and determine risk factors for ischemic rest pain (IRP) and ischemic ulceration (IU) among patients with claudication., Methods: We prospectively collected data on 1244 men with claudication during a 15-year period, including demographics, clinical risk factors, and ankle-brachial index (ABI). We followed these patients serially with ABIs, self-reported walking distance (WalkDist), and monitoring for IRP and IU. We used Kaplan-Meier and proportional hazards modeling to find independent predictors of IRP and IU., Results: Mean follow-up was 45 months; statistically valid follow-up could be carried out for as long as 12 years. ABI declined an average of 0.014 per year. WalkDist declined at an average rate of 9.2 yards per year. The cumulative 10-year risks of development of IU and IRP were 23% and 30%, respectively. In multivariate analysis using several clinical risk factors, we found that only DM (relative risk [RR], 1.8) and ABI (RR, 2.2 for 0.1 decrease in ABI) predicted the development of IRP. Similarly, only DM (RR, 3.0) and ABI (RR, 1.9 for 0.1 decrease in ABI) were significant predictors of IU., Conclusion: This large serial study of claudication is, to our knowledge, the longest of its kind. We documented an average rate of ABI decline of 0.014 per year and a decline in WalkDist of 9.2 yards per year. Two clinical factors, ABI and DM, were found to be associated with the development of IRP and IU. Our findings may be useful in predicting the clinical course of claudication.

Objective: Adequate proximal neck length is important for proper endovascular treatment of abdominal aortic aneurysms (AAAs). Placement of endografts in AAAs with relatively short proximal necks may require covering the origin of accessory renal arteries. Exclusion of these arteries carries the theoretical concern of regional renal ischemia associated with loss of parenchyma or worsening hypertension. We reviewed our experience with accessory renal exclusions during endovascular AAA repair to determine the frequency and severity of complications., Methods: Complete records were available for review on 311 of 325 consecutive patients treated with endovascular grafts for AAAs from February 6, 1996, to March 15, 2001. The presence of accessory renal arteries was ascertained from preoperative/intraoperative aortography or from computed tomographic scanning. Sizes of the accessories were measured by using the main renal arteries as a reference. Considerations for excluding the accessory renal arteries were based on the likelihood of successful proximal attachment to healthy aorta, an accessory vessel whose size does not exceed the diameter of the main renal artery, and the absence of renal disease., Results: The mean follow-up was 11.5 months. Fifty-two accessory renal arteries were documented in 37 patients (12%), ranging from 1 to > or =3 per patient. Of these, 26 accessory renal arteries were covered in 24 patients. Patients ranged in age from 57 to 85 years (mean, 74.1 years), with 20 men and 4 women. The Ancure device was used in 23 patients and the Excluder device in one. Of the accessories excluded, 22 originated above the aneurysm and 4 originated directly from the aneurysm itself. There were no perioperative mortalities. One patient died 5 months after surgery from an unrelated condition. There was one type I (distal) endoleak and no type II endoleaks. Five patients (21%) had segmental renal infarction associated with the side of accessory renal artery exclusion. Only one patient with segmental infarction had significant postoperative hypertension that resulted in changes in blood pressure medication. The blood pressure reverted to normal 3 months later. One patient with a stenotic left main renal artery required exclusion of the accessory renal artery for successful proximal attachment. Serum creatinine levels remained unchanged throughout follow-up in all but one patient, in whom progressive postoperative renal failure developed despite normal renal flow scan, presumably from intraoperative manipulation and contrast nephropathy., Conclusion: Exclusion of accessory renal arteries to facilitate endovascular AAA repair appears to be well tolerated. Long-term sequelae seem infrequent and mild.

Objective: The purpose of this study was to delineate the natural history of claudication and determine risk factors for death., Methods: We reviewed the key outcomes (death, revascularization, amputation) in 2777 male patients with claudication identified over 15 years at a Veterans Administration hospital with both clinical and noninvasive criteria. Patients with rest pain or ulcers were excluded. Data were analyzed with life-table and Cox hazard models., Results: The mean follow-up was 47 months. The cohort exhibited a mortality rate of 12% per year, which was significantly (P <.05) more than the age-adjusted US male population. Among the deaths in which the cause was known, 66% were due to heart disease. We examined several baseline risk factors in a multivariate Cox model. Four were significant (P <.01) independent predictors of death: older age (relative risk [RR] = 1.3 per decade), lower ankle-brachial index (RR = 1.2 for 0.2 change), diabetes requiring medication (RR = 1.4), and stroke (RR = 1.4). The model can be used to estimate the mortality rate for specific patients. Surprisingly, a history of angina and myocardial infarction was not a significant predictor. Major and minor amputations had a 10-year cumulative rate less than 10%. Revascularization procedures occurred with a 10-year cumulative rate of 18%., Conclusions: We found a high mortality rate in this large cohort and four independent risk factors that have a large impact on survival. Risk stratification with our model may be useful in determining an overall therapeutic plan for claudicants. A history of angina and myocardial infarction was not a useful predictor of death, suggesting that many patients in our cohort presented with claudication before having coronary artery symptoms. Our data also indicate that claudicants have a low risk of major amputation at 10-year follow-up.

Introduction: Postoperative care after infrarenal abdominal aortic aneurysm (AAA) repair has traditionally involved admission to the intensive care unit (ICU). With the advent of endovascular AAA repair, the management of open procedures has received increased scrutiny. We recently modified our AAA clinical pathway to include selective use of the ICU., Methods: Consecutive elective infrarenal AAA repairs performed by members of the vascular surgery division at a university medical center from 1994 to 1999 were analyzed retrospectively with a computerized database, the Medical Archival Retrieval System. Group I consisted of 245 patients who were treated in the ICU for 1 or more days, and Group II included 69 patients admitted directly to the floor. Ruptured, symptomatic, suprarenal, endovascular, and reoperative repairs were excluded. Outcome variables were compared over the 6-year period., Results: Floor admissions increased over the study period with 0%, 0%, 3.3%, 16.3%, 48.6%, and 43.6% of patients admitted directly to the surgery ward from 1994 to 1999. The average ICU length of stay declined from 4.6 to 1.2 days, whereas the hospital length of stay decreased from 12.5 to 6.8 days from 1994 to 1999. The change in ICU use had no effect on death (2.4% in Group I vs 0% in Group II). Major and minor morbidity was comparable. Hospital charges were significantly lower for patients in Group II., Conclusion: A policy of selective utilization of the ICU after elective infrarenal AAA repair is safe. It can reduce resource use without a negative impact on the quality of care.

Purpose: The purpose of this study was to determine the etiologic factors in the progression of carotid stenosis., Methods: We performed prospective serial duplex scan surveillance of 1470 carotid arteries in 905 asymptomatic patients during a 10-year period, with an average follow-up interval of 29 months and an average of 3.0 scans per carotid artery. Vascular laboratory and hospital records were used to collect risk factor information. The data were analyzed with proportional hazards modeling., Results: We examined several demographic, clinical, and laboratory risk factors that were chosen because of their potential relevance to atherosclerotic disease. These factors were analyzed with univariate proportional hazards modeling, in which time to progression of stenosis was the outcome variable. The six significant predictors (P <.05) were age, sex, systolic pressure, pulse pressure (systolic pressure - diastolic pressure), total cholesterol, and high-density lipoprotein (HDL). All, except HDL, were positive predictors of time to disease progression. With multivariate modeling, only pulse pressure and HDL remained as significant independent predictors of stenosis progression. The risk ratio for a 10-mm Hg rise in pulse pressure was 1.12, and the risk ratio for a 10-mg/dL decrease in HDL was 1.20., Conclusion: In this large cohort of patients who were followed prospectively for carotid stenosis, pulse pressure and HDL were found to be the key risk factors for carotid stenosis progression. The fact that pulse pressure superseded systolic pressure in multivariate modeling may shed light on the biology of carotid plaque progression. Further, our identification of these modifiable risk factors may help in the design of therapeutic trials for the prevention of progression of carotid atherosclerosis.

Purpose: The purpose of this study was to delineate the natural history of the progression of asymptomatic carotid stenosis., Methods: In a 10-year period, 1701 carotid arteries in 1004 patients who were asymptomatic were studied with serial duplex scans (mean follow-up period, 28 months; mean number of scans, 2.9/patient). At each visit, stenoses of the internal carotid artery (ICA) and the external carotid artery (ECA) were categorized as none (0 to 14%), mild (15% to 49%), moderate (50% to 79%), severe (80% to 99%), preocclusive, or occluded. Progression was defined as an increase in ICA stenosis to >/=50% for carotid arteries with a baseline of <50% or as an increase to a higher category of stenosis if the baseline stenosis was >/=50%. The Cox proportional hazards model was used for data analysis., Results: The risk of progression of ICA stenosis increased steadily with time (annualized risk of progression, 9.3%). With multivariate modeling, the four most important variables that affected the progression (P <.02) were baseline ipsilateral ICA stenosis >/=50% (relative risk [RR], 3.34), baseline ipsilateral ECA stenosis >/=50% (RR, 1.51), baseline contralateral ICA stenosis >/=50% (RR, 1.41), and systolic pressure more than 160 mm Hg (RR, 1. 37). Ipsilateral neurologic ischemic events (stroke/transient ischemic attack) occurred in association with 14.0% of the carotid arteries that were studied. The progression of ICA stenosis correlated with these events (P <.001), but baseline ICA stenosis was not a significant predictor., Conclusion: In contrast to recently published studies, we found that the risk of progression of carotid stenosis is substantial and increases steadily with time. Baseline ICA stenosis was the most important predictor of the progression, but baseline ECA stenosis also was identified as an important independent predictor. Contralateral ICA stenosis and systolic hypertension were additional significant predictors. We found further that the progression of ICA stenosis correlated with ischemic neurologic events but not baseline stenosis. The data provide justification for the use of serial duplex scans to follow carotid stenosis and suggest that different follow-up intervals may be appropriate for different patient subgroups.

Purpose: Although saphenous vein is the most reliable conduit for arterial interposition procedures in the coronary circulation, graft thrombosis remains a clinical problem. We hypothesized that an important factor in early graft thrombosis is sudden change in the hemodynamic environment of the vein as it is placed in the coronary circulation., Methods: We used an ex vivo perfusion system to study freshly excised segments of human saphenous vein (HSV) and pig internal jugular vein. For coronary graft (CAVG) simulation, sections of HSV were subjected to arterial pulsatile pressure and flow and twisting and stretching to mimic deformations caused by the beating heart. Using functional and immunohistochemical assays, we investigated the effect of these conditions on expression of tissue factor (TF), an important prothrombotic surface molecule., Results: In each of 11 experiments (6 human, 5 porcine), vein segments from a single donor were subjected to venous conditions (VEN), CAVG perfusion, or no perfusion. Expression of TF was measured as the amount of factor Xa generated per unit area of luminal vein surface. VEN perfusion did not cause a significant change in mean TF expression over nonperfused control values (human: 14.3 +/- 1.5 versus 11.4 +/- 2.3 U/cm2, p = 0.31; pig: 11.6 +/- 1.5 versus 12.5 +/- 1.4 U/cm2, p = 0.70). CAVG perfusion led to significant enhancement of TF expression over VEN perfusion (human: 36.8 +/- 6.2 versus 14.3 +/- 1.5 U/cm2, p < 0.05; pig: 40.0 +/- 9.9 versus 11.6 +/- 1.5 U/cm2, p < 0.05). Immunohistochemical analysis showed positive TF staining on the luminal side of a CAVG-stimulated HSV segment, but not on a VEN-stimulated segment. In four additional studies, HSV segments were subjected to arterial perfusion without twist and stretch to mimic lower extremity arterial interposition grafts. TF expression for lower extremity venous graft perfusion was significantly higher than for VEN perfusion (25.3 +/- 2.5 versus 14.3 +/- 1.5, p < 0.01) but not significantly different from CAVG perfusion., Conclusions: Our studies in a unique perfusion system suggest that exposure of vein to coronary arterial hemodynamic conditions results in elevated expression of the important prothrombotic molecule TF. This phenomenon may contribute to early graft thrombosis.

Purpose: We reviewed our experience with a clinical pathway instituted in December 1993 for all nonurgent abdominal aortic aneurysm (AAA) surgery., Methods: We analyzed a reference group of 49 consecutive pre-pathway AAA patients (group I) and the 44 patients enrolled in the first year of the pathway (group II). On the basis of the interim review of data collected during the first year, pathway modifications were made, and 34 patients enrolled after these modifications (group III) were also analyzed., Results: Comparison of groups I and II showed that institution of the pathway resulted in a marginally significant reduction in mean charges of 14.7% (p = 0.09), and a slight fall in mean length of stay (LOS) (13.8 vs 13.1 days, NS) and mortality rate (4.1% vs 2.3%, NS). For group II, a significant correlate (p < 0.05) of increased charges was fluid overload as diagnosed by chest radiograph. This recognition led to active efforts to reduce perioperative fluid administration. Comparison of groups II and III revealed that the practice modifications led to marked reduction in the incidence of fluid overload (73% vs 24%; p < 0.01), mean charges (30.4% reduction; p < 0.05), mean LOS (13.1 vs 10.2 days; p < 0.05), and median LOS (11 vs 8 days). Multiple regression analysis of all pathway patients showed that preoperative renal insufficiency is a significant predictor of both increased LOS (p < 0.01) and charges (p < 0.01), but that age, sex, and coronary disease were not predictive. Of the postoperative parameters analyzed, important correlates of increased charges were acute renal failure (p < 0.01) and fluid overload (p < 0.01)., Conclusions: Institution of a clinical pathway for AAA repair resulted in significant charge reduction and a slight reduction in stay. Practice modifications based on interim data analysis yielded further significant reductions in charges and LOS, with overall per-patient charge savings (group I vs III) of 40.6% (p < 0.05) and overall LOS reduction of 3.5 days (p < 0.05). The reduction in actual charges was seen despite an overall increase in the hospital rate structure. Comparing groups I, II, and III, we found no indication of increasing mortality rate. Ongoing analysis has identified correlates of increased charges, potentially permitting identification of high-cost subgroups and more focused cost-control efforts. Rather than restricting management, clinical pathways with periodic data analysis may improve quality of care.

Purpose: This report reviews our recent experience with nine patients who had intramural hematoma of the thoracic aorta., Methods: This was a retrospective study of all patients who had intramural hematoma at our institution from 1989 to 1994. Patients who had identifiable intimal flap, tear, or penetrating aortic ulcer were excluded from the study., Results: Among these nine elderly patients (mean age, 76 years), the most common presentation was chest or back pain. Intramural hematoma was diagnosed by a variety of high-resolution imaging techniques. The descending thoracic aorta alone was involved in seven patients, whereas the ascending aorta was affected in the other two patients. One patient had evidence of an aneurysm (5.0 cm diameter) in the region of the hematoma. All patients were initially managed nonsurgically with blood pressure control. Both patients who had ascending aortic involvement had progression of aortic hematoma, which resulted in death in one case and in successful surgery in the other. Six of the seven patients who had descending aortic involvement alone were successfully managed without aortic surgery. The patient who had intramural hematoma and associated aortic aneurysm, however, had severe, recurrent pain and underwent successful aortic replacement. Another patient had recurrent pain associated with hypertension, but was successfully managed nonsurgically with antihypertensive therapy. All eight survivors are doing well at a median follow-up of 19 months., Conclusions: Intramural hematoma appears to be a distinct entity, although overlap with aortic dissection or penetrating aortic ulcer exists. Aggressive control of blood pressure with intensive care unit monitoring has been our initial management. Patients who have involvement of the descending thoracic aorta alone can frequently be managed without surgery in the absence of coexisting aneurysmal dilatation or disease progression. Our experience suggests that a more aggressive approach with early surgery is warranted in patients who have ascending aortic involvement or those who have coexisting aneurysm and intramural hematoma.

Purpose: The purpose of this study was to define the clinical features of aortic aneurysms occurring in heart transplant recipients., Methods: Among the 734 patients who have undergone heart transplantation at our institution over the last 14 years, we have identified 12 patients (1.6% incidence) with aortic aneurysms (9 infrarenal, 3 thoracoabdominal), making this the largest reported series of aortic aneurysms (AA) in heart transplant recipients., Results: For nine of the 12 patients with AA (75%), the indication for transplantation was ischemic cardiomyopathy. This indication accounted for only 42% of the overall transplantation group; our data therefore show that the risk of infrarenal AA disease was higher for patients who underwent transplantation for ischemic cardiomyopathy than for other indications (p = 0.02). In two of the patients with thoracoabdominal AA, chronic dissection was identified as the specific AA cause, whereas all of the other patients in the study had nonspecific "atherosclerotic" AAs. All 12 patients were symptom free at the time of initial discovery of the AAs. Two of the patients with infrarenal AA were diagnosed with AAs before transplantation; for the seven remaining patients with infrarenal AAs, the mean time between transplantation and AA discovery was 5.0 years (range 1.2 to 11.8 years). Serial radiologic studies allowed us to determine the AA expansion rate in seven of the 12 patients. This rate varied from 0 to 2.53 cm/yr (mean 1.20 cm/yr; 1.0 cm/yr for infrarenal AA alone). Five patients with infrarenal AA underwent AA repair as the initial treatment. Three others underwent repair after their AAs significantly expanded under observation. Mean AA diameter at the time of repair was 6.9 cm. All three patients with thoracoabdominal AAs died of acute AA rupture before resection could be done, despite their initial asymptomatic state. AA diameters at time of rupture were 3.5, 6.0, and 11 cm. All of the eight patients with AA treated with surgery are alive and well (median follow-up 18 months). The only complication was acute heart transplant rejection, which occurred 11 days after AA repair in one patient., Conclusions: Our data suggest that AA occurrence is more likely in patients who undergo heart transplantation for ischemic heart disease than for other indications. Careful serial radiologic surveillance is warranted in any heart transplant patient with an AA, because of the apparent potential for more rapid AA expansion in this patient population than in patients who do not undergo transplantation. We conclude that early repair of infrarenal AA is indicated because excellent operative results and low morbidity rates can be achieved. An aggressive approach to thoracoabdominal AAs in this group may also be appropriate because of the apparent propensity to lethal rupture, sometimes at relatively small AA size.

A 32-year-old man with progressive dyspnea and congenital lymphedema was transferred to our hospital for evaluation as a lung transplant candidate with the suspected diagnosis of primary pulmonary hypertension. Evaluation revealed the additional history of previous limb-shortening procedures for the left leg, the presence of syndactyly, long-standing bilateral (left to right) lower extremity varices, as well as soft tissue asymmetry with the left leg and arm larger than the right-sided counterparts. A diagnosis of Klippel-Trénaunay syndrome was made on the basis of these findings. Because of the deep venous malformations known to occur in this syndrome, we sought evidence of recurrent pulmonary emboli as an explanation for the patient's progressive dyspnea, despite negative pulmonary arteriography and ventilation-perfusion scanning results at another institution. Repeat pulmonary arteriography demonstrated evidence of chronic and subacute pulmonary emboli. The patient is presently being treated with warfarin anticoagulation, with plans for placement of a caval filter if anticoagulation alone is insufficient to prevent further embolism. Klippel-Trénaunay syndrome is a rare cause of chronic pulmonary emboli, and this entity should be considered when the characteristic historical and physical findings are present. A case report and review of the syndrome, with particular focus on the aspects relevant to the vascular surgeon, are presented.

Purpose: Although aortic aneurysm (AA) is primarily a disease of older age groups, younger (< 51 years) patients infrequently are admitted requiring AA surgery. We sought to compare the characteristics of these patients with those of a randomly selected group of older patients with AA., Methods: We identified 26 patients with AA (group I) under age 51 (mean age 44.8) treated surgically between 1977 and 1993, after excluding patients with acute aortic dissection, traumatic pseudoaneurysms, and ascending or arch aneurysms, and compared them with 75 randomly selected patients with AA between the ages of 65 and 75 (mean age 70.3) who were surgically treated during the same time period (group II)., Results: Prevalence of hypertension, diabetes, coexisting heart, kidney, or occlusive peripheral vascular disease was similar between the two groups, and familial aneurysm rates and sex distribution did not differ significantly. More patients in group I had symptoms at the time of presentation (46% vs 6.7%, p < 0.001), and they also had larger AAs (6.9 cm vs 6.0 cm, p = 0.01). Definable causes of aneurysmal disease, such as Takayasu's, Cogan's, and Marfan syndromes, were more common among the young patients (23% vs 0%, p = 0.01), but most (77%) young patients did not have an identifiable syndrome associated with their aneurysm disease. Group I had a marked shift toward proximal aneurysms, defined as involvement of juxtarenal, suprarenal, or thoracoabdominal aorta (46% vs 18% in group II, p < 0.01). This difference persisted even when aneurysms associated with the above syndromes were excluded from consideration (p = 0.02). Cigarette smoking was much more common among the young patients (83% vs 51% in group II, p < 0.01). Smoking in group II was associated with more extensive aneurysm disease (p = 0.04)., Conclusions: Aneurysmal disease presenting in the young adult is more likely to be symptomatic and associated with more proximal aortic involvement than aneurysmal disease in older patients. Smoking appears to play an important role in the pathogenesis of aneurysmal disease in the young patient and was associated in our study with more proximal aneurysms among older patients. A subgroup of patients at risk for early and aggressive aneurysm disease is suggested by these data.