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Introduction: On the United States' Organ Transplantation Waitlist, approximately 17 people die each day waiting for an organ. The situation continues to deteriorate as the discrepancy between harvested organs and the number of patients in need is increasing. Static cold storage is the clinical standard method for preserving a harvested organ but is associated with several drawbacks. Machine perfusion of an organ has been shown to improve preservation quality as well as preservation time over static cold storage. While there are machine perfusion devices clinically available, they are costly and limited to specific organs and preservation solutions. This study presents a versatile oxygenating perfusion system (VOPS) that supplies oxygen and pulsatile perfusion. Materials and Methods: Experiments evaluated the system's performance with a human kidney mimicking hydraulic analog using multiple compressed oxygen supply pressures and aqueous solutions with viscosities ranging from 1 to 6.5 cP, which simulated viscosities of commonly used organ preservation solutions. Results and Conclusions: The VOPS produced mean flow rates ranging from 0.6 to 28.2 mL/min and perfusion pressures from 4.8 to 96.8 mmHg, which successfully achieved the desired perfusion parameters for human kidneys. This work provides evidence that the VOPS described herein has the versatility to perfuse organs using many of the clinically available preservation solutions. [ABSTRACT FROM AUTHOR]

Aortic stiffness increases with advancing age, more than doubling during the human life span, and is a robust predictor of cardiovascular disease (CVD) clinical events independent of traditional risk factors. The aorta increases in diameter and length to accommodate growing body size and cardiac output in youth, but in middle and older age the aorta continues to remodel to a larger diameter, thinning the pool of permanent elastin fibers, increasing intramural wall stress and resulting in the transfer of load bearing onto stiffer collagen fibers. Whereas aortic stiffening in early middle age may be a compensatory mechanism to normalize intramural wall stress and therefore theoretically "good" early in the life span, the negative clinical consequences of accelerated aortic stiffening beyond middle age far outweigh any earlier physiological benefit. Indeed, aortic stiffness and the loss of the "windkessel effect" with advancing age result in elevated pulsatile pressure and flow in downstream microvasculature that is associated with subclinical damage to high-flow, low-resistance organs such as brain, kidney, retina, and heart. The mechanisms of aortic stiffness include alterations in extracellular matrix proteins (collagen deposition, elastin fragmentation), increased arterial tone (oxidative stress and inflammation-related reduced vasodilators and augmented vasoconstrictors; enhanced sympathetic activity), arterial calcification, vascular smooth muscle cell stiffness, and extracellular matrix glycosaminoglycans. Given the rapidly aging population of the United States, aortic stiffening will likely contribute to substantial CVD burden over the next 2-3 decades unless new therapeutic targets and interventions are identified to prevent the potential avalanche of clinical sequelae related to age-related aortic stiffness. [ABSTRACT FROM AUTHOR]

Background Ventricular assist devices (VADs) have been used in children on an increasing basis in recent years. One-year survival rates are now >80% in multiple reports. In this report we describe adverse events experienced by children with durable ventricular assist devices, using a national-level registry (PediMACS, a component of INTERMACS) Methods PediMACS is a national registry that contains clinical data on patients who are <19 years of age at the time of VAD implantation. Data collection concludes at the time of VAD explantation. All FDA-approved devices are included. PediMACS was launched on September 1, 2012, and this report includes all data from launch until August 2014. Adverse events were coded with a uniform, pre-specified set of definitions. Results This report comprises data from 200 patients with a median age of 11 years (range 11 days to 18 years), and total follow-up of 783 patient-months. The diagnoses were cardiomyopathy ( n = 146, 73%), myocarditis ( n = 17, 9%), congenital heart disease ( n = 35, 18%) and other ( n = 2, 1%). Pulsatile-flow devices were used in 91 patients (45%) and continuous-flow devices in 109 patients (55%). Actuarial survival was 86% at 6 months. There were 418 adverse events reported. The most frequent events were device malfunction ( n = 79), infection ( n = 78), neurologic dysfunction ( n = 52) and bleeding ( n = 68). Together, these accounted for 277 events, 66% of the total. Although 38% of patients had no reported adverse event and 16% of patients had ≥5 adverse events. Adverse events occurred at all time-points after implantation, but were most likely to occur in the first 30 days. For continuous-flow devices, there were broad similarities in adverse event rates between this cohort and historic rates from the INTERMACS population. Conclusions In this study cohort, the overall rate of early adverse events (within 90 days of implantation) was 86.3 events per 100 patient-months, and of late adverse events it was 20.4 events per 100 patient-months. The most common adverse events in recipients of pulsatile VADs were device malfunction, neurologic dysfunction, bleeding and infection. For continuous-flow VADs, the most common adverse events were infection, bleeding, cardiac arrhythmia, neurologic dysfunction and respiratory failure. Compared with an adult INTERMACS cohort, the overall rate and distribution of adverse events appears similar. [ABSTRACT FROM AUTHOR]

Background: Computational fluid dynamics (CFD) is an important tool for predicting cardiovascular device performance. The FDA developed a benchmark nozzle model in which experimental and CFD data were compared, however, the studies were limited by steady flows and Newtonian models., Objective: Newtonian and non-Newtonian blood models will be compared under steady and pulsatile flows to evaluate their influence on hemodynamics in the FDA nozzle., Methods: CFD simulations were validated against the FDA data for steady flow with a Newtonian model. Further simulations were performed using Newtonian and non-Newtonian models under both steady and pulsatile flows., Results: CFD results were within the experimental standard deviations at nearly all locations and Reynolds numbers. The model differences were most evident at Re = 500, in the recirculation regions, and during diastole. The non-Newtonian model predicted blunter upstream velocity profiles, higher velocities in the throat, and differences in the recirculation flow patterns. The non-Newtonian model also predicted a greater pressure drop at Re = 500 with minimal differences observed at higher Reynolds numbers., Conclusions: An improved modeling framework and validation procedure were used to further investigate hemodynamics in geometries relevant to cardiovascular devices and found that accounting for blood's non-Newtonian and pulsatile behavior can lead to large differences in predictions in hemodynamic parameters.

Objectives: To evaluate the association of intertwin differences in umbilical artery pulsatility index (DUAPI) and infant survival in twin-to-twin transfusion syndrome (TTTS)., Methods: Absolute DUAPI was calculated prior to laser surgery. Receiver-operating characteristics (ROC) curve analysis provided an intertwin DUAPI cutoff of 0.4 for the prediction of double twin survival to 30 days of life. Infant survival was compared between women with an intertwin DUAPI <0.4 and ≥0.4 in the whole cohort, in TTTS cases with Quintero stages I/II and in those with Quintero stages III/IV. Regression analyses were performed to evaluate the association of intertwin DUAPI <0.4 and infant survival adjusted for confounders., Results: In total, 349 TTTS cases were included. Double twin survival to 30 days was observed in 67% (234/349) of cases. Significant differences in double twin survival was seen between intertwin DUAPI groups in the whole cohort (76.8 vs. 52.2%; p<0.001), in women with TTTS Quintero stage I or II (77.8 vs. 58.5%; p=0.015) as well as in women with TTTS Quintero stage III or IV (75 vs. 49.5%; p=0.001). Intertwin DUAPI <0.4 conferred a threefold increased chance for double twin survival., Conclusions: Small intertwin DUAPI is associated with increased double infant survival in early and advanced TTTS stages., (© 2021 Walter de Gruyter GmbH, Berlin/Boston.)

Purpose: A credible computational fluid dynamics (CFD) model can play a meaningful role in evaluating the safety and performance of medical devices. A key step towards establishing model credibility is to first validate CFD models with benchmark experimental datasets to minimize model-form errors before applying the credibility assessment process to more complex medical devices. However, validation studies to establish benchmark datasets can be cost prohibitive and difficult to perform. The goal of this initiative sponsored by the U.S. Food and Drug Administration is to generate validation data for a simplified centrifugal pump that mimics blood flow characteristics commonly observed in ventricular assist devices., Methods: The centrifugal blood pump model was made from clear acrylic and included an impeller, with four equally spaced, straight blades, supported by mechanical bearings. Particle Image Velocimetry (PIV) measurements were performed at several locations throughout the pump by three independent laboratories. A standard protocol was developed for the experiments to ensure that the flow conditions were comparable and to minimize systematic errors during PIV image acquisition and processing. Velocity fields were extracted at the pump entrance, blade passage area, back gap region, and at the outlet diffuser regions. A Newtonian blood analog fluid composed of sodium iodide, glycerin, and water was used as the working fluid. Velocity measurements were made for six different pump flow conditions, with the blood-equivalent flow rate ranging between 2.5 and 7 L/min for pump speeds of 2500 and 3500 rpm., Results: Mean intra- and inter-laboratory variabilities in velocity were ~ 10% at the majority of the measurement locations inside the pump. However, the inter-laboratory variability increased to more than ~ 30% in the exit diffuser region. The variability between the three laboratories for the peak velocity magnitude in the diffuser region ranged from 5 to 25%. The bulk velocity field near the impeller changed proportionally with the rotational speed but was relatively unaffected by the pump flow rate. In contrast, flow in the exit diffuser region was sensitive to both the flow rate and the rotational speed. Specifically, at 3500 rpm, the exit jet tilted toward the inner wall of the diffuser at a flow rate of 2.5 L/min, but the jet tilted towards the outer wall when the flow rate was 7 L/min., Conclusions: Inter-laboratory experimental mean velocity data (and the corresponding variance) were obtained for the FDA pump model and are available for download at https://nciphub.org/wiki/FDA&#95;CFD . Experimental datasets from the inter-laboratory characterization of benchmark flow models, including the blood pump model presented herein and our previous nozzle model, can be used for validating future CFD studies and to collaboratively develop guidelines on best practices for verification, validation, uncertainty quantification, and credibility assessment of CFD simulations in the evaluation of medical devices (e.g. ASME V&V 40 standards working group).

The Food and Drug Administration (FDA) is issuing a final order to reclassify intra-aortic balloon and control system (IABP) devices when indicated for acute coronary syndrome, cardiac and non-cardiac surgery, or complications of heart failure, a preamendments class III device, into class II (special controls), and to require the filing of a premarket approval application (PMA) or a notice of completion of a product development protocol (PDP) for IABPs when indicated for septic shock or pulsatile flow generation.

Objectives: The present study compared the interval until device exchange or death from pump-related failure in patients with pulsatile versus continuous flow left ventricular assist devices., Methods: Data from Interagency Registry for Mechanically Assisted Circulatory Support (June 23, 2006, to March 31, 2011) compared the durability of implanted pulsatile and continuous flow left ventricular assist devices. The durability issues included pump replacement for infection, thrombosis-hemolysis, driveline failure, or pump drive unit failure, and death from driveline or pump drive unit failure., Results: A total of 3302 left ventricular assist devices were implanted (486 pulsatile, 2816 continuous flow) and 98 pump exchanges or deaths from durability issues (46 pulsatile, 52 continuous flow; 3% of implants). The interval to device issue was greater for the continuous flow than for the pulsatile devices (P < .001). A comparisons of the causes for pump exchange or pump-related death showed (1) greater freedom from pump failure in the continuous flow compared with the pulsatile left ventricular assist devices (10 events/2816 continuous flow implants vs 39 events/486 pulsatile implants; P < .0001); (2) similar exchange or pump-related death for driveline failure (1/486 pulsatile vs 7/2816 continuous flow; P = .82); (3) similar exchange or pump-related death for thrombosis-hemolysis (2/486 pulsatile vs 28/2816 continuous flow; P = .25); and (4) fewer exchanges or pump-related deaths from infection in continuous flow left ventricular assist devices (4/486 pulsatile vs 7/2816 continuous flow; P = .034). Competing outcomes analysis corroborated this finding, with 54% of continuous flow versus 23% of pulsatile patients alive and receiving support at 12 months after implantation., Conclusions: The Analysis of Interagency Registry for Mechanically Assisted Circulatory Support data showed greater durability for continuous flow than for pulsatile left ventricular assist devices. Even longer durations of support can be expected if pump durability continues to improve., (Published by Mosby, Inc.)

Objectives: Aortic stiffness, a hallmark of vascular aging, is an independent risk factor of cardiovascular disease and all-cause mortality. The association of aortic stiffness with aortic calcification in middle-aged general population remains unknown although studies in patients with end-stage renal disease or elderly subjects suggest that aortic calcification is an important determinant of aortic stiffness. The goal of this study was to examine the association of aortic calcification and stiffness in multi-ethnic population-based samples of relatively young men., Methods: We examined the association in 906 men aged 40-49 (81 Black Americans, 276 Japanese Americans, 258 White Americans and 291 Koreans). Aortic stiffness was measured as carotid-femoral pulse wave velocity (cfPWV) using an automated waveform analyzer. Aortic calcification from aortic arch to iliac bifurcation was evaluated using electron-beam computed tomography., Results: Aortic calcium score was calculated and was categorized into four groups: zero (n=303), 1-100 (n=411), 101-300 (n=110), and 401+ (n=82). Aortic calcification category had a significant positive association with cfPWV after adjusting for age, race, and mean arterial pressure (mean (standard error) of cfPWV (cm/s) from the lowest to highest categories: 836 (10), 850 (9), 877 (17) and 941 (19), P for trend <0.001). The significant positive association remained after further adjusting for other cardiovascular risk factors. The significant positive association was also observed in each race group., Conclusions: The results suggest that aortic calcification can be one mechanism for aortic stiffness and that the association of aortic calcification with stiffness starts as early as the 40s., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Background and Objectives: Brachial artery measures of BP are associated with increasing degrees of proteinuria. Whether central measures of BP or vascular stiffness are associated with increased risk of proteinuria in patients with chronic kidney disease (CKD) is unknown., Design, Setting, Participants, & Measurements: Measurements of central and brachial artery BP, and aortic pulse wave velocity (PWV) were performed in a cross-sectional cohort of patients with CKD (n = 2144) from the Chronic Renal Insufficiency Cohort (CRIC) study to determine factors which predict increased risk of proteinuria. Multivariate analysis stratified by diabetes included age, ethnicity, gender, estimated glomerular filtration rate (GFR), waistline, smoking, heart rate, and medications to evaluate the relationship of hemodynamic factors and proteinuria., Results: Brachial artery systolic BP (SBP) was important as an explanatory factor for variations in proteinuria among both diabetics (R(2) = 0.40, P < 0.0001) and non diabetics (R(2) = 0.38, P < 0.001). Measures of peripheral pulse pressure (PP), central SBP, and central pulse pressure added little to the explained variation in proteinuria beyond brachial artery SBP, whereas PWV as a measure of vascular stiffness incrementally accounted for a significant portion of variation in proteinuria beyond that explained by brachial artery SBP in diabetics (R(2) = 0.42, P < 0.001) but not non diabetics., Conclusions: Brachial artery SBP and PWV are both associated with variations in proteinuria in patients with CKD.

Objective: Although left ventricular assist devices (LVADs) are associated with excellent outcomes in patients with end-stage heart failure, there are conflicting reports on posttransplant survival in these patients. Furthermore, prior studies with pulsatile LVADs have shown that transplantation, either early (<6 weeks) or late (>6 months) after LVAD implantation, adversely affected post-cardiac transplant survival. We sought to determine factors related to posttransplant survival in patients supported with continuous-flow LVADs., Methods: The HeartMate II LVAD (Thoratec Corporation, Pleasanton, Calif) was implanted in 468 patients as a bridge to transplant at 36 centers in a multicenter trial. Patients who underwent transplantation after support were stratified by demographics: gender, age, etiology, body mass index, duration of device support, and by adverse events during support. The median age was 54 years (range 18-73 years); 43% had ischemic etiology, and 18% were women. Survival was determined at the specific intervals of 30 days and 1 year after transplantation., Results: Of 468 patients, 250 (53%) underwent cardiac transplant after a median duration of LVAD support of 151 days (longest: 3.2 years), 106 (23%) died, 12 (2.6%) recovered ventricular function and the device was removed, and 100 (21%) were still receiving LVAD support. The overall 30-day and 1-year posttransplant survivals were 97% and 87%. There were no significant differences in survival based on demographic factors or LVAD duration of less than 30 days, 30 to 90 days, 90 to 180 days, and more than 180 days. Patients requiring more than 2 units of packed red blood cells in 24 hours during LVAD support had a statistically significant decreased 1-year survival (82% vs 94%) when compared with patients who did not require more than 2 units of packed red blood cells in 24 hours during LVAD support (P = .03). There was a trend for slightly lower survival at 1 year in patients with percutaneous lead infections during LVAD support versus no infection (75% vs 89%; P = .07)., Conclusions: Post-cardiac transplant survival in patients supported with continuous-flow devices such as the HeartMate II LVAD is equivalent to that with conventional transplantation. Furthermore, posttransplant survival is not influenced by the duration of LVAD support. The improved durability and reduced short- and long-term morbidity associated with the HeartMate II LVAD has reduced the need for urgent cardiac transplantation, which may have adversely influenced survival in the pulsatile LVAD era. This information may have significant implications for changing the current United Network for Organ Sharing criteria regarding listing of heart transplant candidates., (2010 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Background: Aortic pulse wave velocity (PWV) is a measure of arterial stiffness and has proved useful in predicting cardiovascular morbidity and mortality in several populations of patients, including the healthy elderly, hypertensives and those with end-stage renal disease receiving hemodialysis. Little data exist characterizing aortic stiffness in patients with chronic kidney disease (CKD) who are not receiving dialysis, and in particular the effect of reduced kidney function on aortic PWV., Methods: We performed measurements of aortic PWV in a cross-sectional cohort of participants enrolled in the Chronic Renal Insufficiency Cohort (CRIC) study to determine factors which predict increased aortic PWV in CKD., Results: PWV measurements were obtained in 2,564 participants. The tertiles of aortic PWV (adjusted for waist circumference) were <7.7 m/s, 7.7-10.2 m/s, and >10.2 m/s with an overall mean (+/- s.d.) value of 9.48 +/- 3.03 m/s (95% confidence interval = 9.35-9.61 m/s). Multivariable regression identified significant independent positive associations of age, blood glucose concentrations, race, waist circumference, mean arterial blood pressure, gender, and presence of diabetes with aortic PWV and a significant negative association with the level of kidney function., Conclusions: The large size of this unique cohort, and the targeted enrollment of CKD participants provides an ideal situation to study the role of reduced kidney function as a determinant of arterial stiffness. Arterial stiffness may be a significant component of the enhanced cardiovascular risk associated with kidney failure.

Purpose of Review: The purpose of this article is to describe the current use of pulsatile kidney perfusion during organ preservation and the effects on kidney allograft outcomes and utilization., Recent Findings: As of spring 2008, there were 75 629 candidates on the kidney waiting list in the USA according to United Network for Organ Sharing data. In 2006, a total of 1815 deceased donor expanded criteria donors kidneys were transplanted, and approximately 80% of those kidneys had cold ischemic time of over 12 h. The utilization of kidney pulsatile perfusion varies extensively throughout the USA with rates of 7-12% in our institution., Summary: Data on the use of pulsatile hypothermic perfusion for kidneys during organ preservation are limited and mostly retrospective. Most authors agree that pulsatile perfusion is safe and leads to a decrease in delayed graft function, especially for marginal kidneys from extended criteria or deceased donors. The long-term effects of delayed graft function on graft survival remain to be seen. With the recent large-sampled international prospective randomized trial recently completed, we may see more kidneys pulsatile perfused. This may lead to an increase in the utilization of otherwise discarded kidneys, though these data are difficult to extrapolate.

Background and Objectives: Higher phosphorus levels are associated with cardiovascular disease (CVD) events and mortality. Whether vascular stiffness may be responsible is unknown., Design, Setting, Participants, & Measurements: This study examined the cross-sectional associations of serum phosphorus with ankle brachial index (ABI), pulse pressure, and large and small artery elasticity by radial artery waveform analysis among 1370 individuals (440 with moderate chronic kidney disease) who did not have clinical CVD and participated in the Multi-Ethnic Study of Atherosclerosis., Results: Fifty-nine (4%) individuals had high ABI (>1.30), a marker of peripheral arterial stiffness. Participants with phosphorus levels >4 mg/dl had greater than four-fold risk for high ABI compared with participants with phosphate levels <3 mg/dl (relative risk 4.6; 95% confidence interval 1.6 to 13.2; P = 0.01) after adjustment for demographics, traditional CVD risk factors, and kidney function. Higher phosphorus levels were also associated with greater pulse pressure and lesser large and small artery elasticity in unadjusted models, but these associations were attenuated after adjustment., Conclusions: Higher phosphorus levels are strongly associated with high ABI but not pulse pressure or large or small artery elasticity. If confirmed in future studies, then the association of higher phosphorus concentrations with CVD events may be partially mediated through peripheral arterial stiffness.

Children with heart failure unresponsive to medical therapy are left with few options for survival. Pulsatile paracorporeal ventricular assist devices are life-saving options for such patients, allowing for bridge to transplantation or cardiac recovery. From March 1997 to July 2004, 12 patients underwent implantation of Thoratec biventricular assist devices (BVADs) for refractory heart failure. Mean age was 14.9 (range 7-20) and mean BSA was 1.7 (range 1.1-1.9). Indications for support included end-stage cardiomyopathy (n=10), myocarditis (n=1), and postcardiotomy heart failure (n=1). Preimplant variables included 50% of patients requiring mechanical ventilation (mean 4.2 days), hyperbilirubinemia in 58%, and acute renal failure in 50%. Mean duration of support was 64.5 (range 2-175) days. Overall survival was 83%, with nine patients successfully bridged to transplantation (75%). One patient exhibited recovery allowing for device explantation, and two patients died while on BVADs. Complications included bleeding requiring reoperation in 25% (n=3), stroke in 8% (n=1), driveline infections in 17% (n=2), and device malfunction in one patient. Pulsatile paracorporeal BVADs can be used successfully in children and adolescents with heart failure. These results warrant consideration of using available miniaturized technology in the United States for the support of smaller children with intractable biventricular failure.

A prototype design of a portable, pulsatile, perfusion preservation device based on a novel application of fluidics technology was tested to evaluate its ability to oxygenate preservation solution and to examine the relationship between organ resistance, perfusion pressure, and perfusion flow characteristics. The effects of organ resistance on pulse rate, perfusion pressure, and perfusion flow were modeled. Interstitial PO2 in canine hearts stored at 4 degrees C for 12 hours in the fluidics device (n = 5) and in static hypothermic storage (n = 5) was also compared. Increasing outflow resistance did not have an effect on operating frequency of the fluidics actuator. Perfusion pressure rose as outflow resistance was increased, and the flow of preservation solution decreased proportionately. The PO2 of the preservation solution increased to 300 mm Hg in two hours and reached a plateau that exceeded 400 mm Hg within six hours. The aortic flow profile during pulsatile perfusion resembled a square wave function with a mean pulse duration of 0.30 +/- 0.05 seconds. Oxygen delivery by the fluidics perfusion device exceeded the oxygen requirements of the hypothermically preserved organs at all resistance levels. Initial interstitial PO2 in the hearts of both groups was greater than 150 mm Hg. In perfused hearts, PO2 declined 30% by the 12th hour, whereas complete depletion of oxygen was noted in the static storage group within six hours. The fluidics organ perfusion/transport apparatus weighs less than 18 kg, uses no electrical power, and can operate continuously for 10 to 12 hours expending 780 L of oxygen.

Background: Ventricular assist device (VAD) support with pulsatile first generation pumps is a well-established therapy for bridging to transplantation. Shortcomings of this technology include limited applicability to small patients, noise, and high incidence of infection and pump malfunction. A second generation of pumps, spearheaded by the axial flow MicroMed DeBakey VAD, is in clinical trials and potentially will address these shortcomings., Methods and Results: Between November 13, 1998 and May 7, 2002, 150 patients worldwide underwent placement of the Micromed DeBakey VAD as a bridge to transplantation. Prospectively acquired data including demographics, adverse events and outcomes was collected. Follow up is 100% with 30.4 patient-years of cumulative support time. Mean age was 48+/-4 years and 18% were female. Twenty-three percent had prior sternotomy. Preoperatively, 25% were on balloon pump support, 20% had renal insufficiency, and 40% were on at least two inotropes with a mean cardiac index of 1.8 L/min/m2. Mean support time was 75+/-81 days. Linearized rates (events/patient-year) were: reoperation for bleeding 2.03, hemolysis 0.61, device infection 0.16, thromboembolic event 0.61, pump thrombus 0.61, and pump failure 0.13. Eight-two patients (55%) were either bridged to transplantation, recovery or are ongoing and 68 (45%) have died. Several patients have been supported as outpatients., Conclusions: This initial experience suggests that bridging to transplantation can be successfully approached with a small and quiet axial flow pump that provides low incidence of device infection and pump failure. The incidence of pump thrombus and thromboembolism is being addressed by incorporation of heparin coating to all device surfaces.

Context: Kidney preservation has been performed by either ice (static) or machine pulsatile perfusion. Ice storage is simple, with only 1 methodology. Machine perfusion, on the other hand, is accomplished using multiple methodologies. This article delineates the different methodologies of pumping centers throughout the country., Objective: Pulsatile machine perfusion is again being viewed as the preservation method of choice for kidneys from non-heart-beating cadaver donors and cadaver kidneys from marginal donors. To develop indices to predict the viability of cadaver kidneys for transplant, a review of the organ procurement organizations, specific perfusion techniques, and a comparison of the delayed graft function and graft survival rates were considered., Methods: A survey, asking for specifics on perfusion parameters, pulsatile machine perfusion experience, and criteria for perfusion implementation and graft survival results, was mailed to all organ procurement organizations in the United States., Results: Of the 44 centers that responded to the survey, 12 used pulsatile machine perfusion (11 used the Waters perfusion machine), 6 pumped marginal cadaver kidneys, and the remaining 6 pumped all cadaver kidneys. Minimum perfusion criteria, pulse rates, perfusate composition, pressures, renal resistance, and renal pressure and flow were considered. Vasodilators and other machine additives were used to improve flow. The variance in each center's number of cadaver kidneys pumped each year, as well as the differences in pump times, was noted., Conclusion: Twelve centers use pulsatile machine perfusion. A variety of techniques are used to perform pulsatile machine perfusion, but 11 of 12 have less delayed graft function than those programs employing ice storage preservation.

Pulsatile lavage is an effective means of irrigation for grossly contaminated wounds. Pulse lavage was first used by oral surgeons in the U.S. Army during the war in Vietnam, and U.S. military investigators pioneered its early development and scientifically validated its efficacy. Modern pulse lavage units are ideally suited for military use because they enable first- and second-echelon medical personnel (including nonphysicians) to rapidly and effectively decontaminate combat wounds with minimal logistic burden. Pulse lavage units should become standard issue in all combat medical supply canisters or Authorized Medical Allowance blocks, and medical personnel should be trained in their use.

A small axial flow ventricular assist device (VAD) measuring 3 inches long and 1 inch in diameter is in development. The pump consists of a spinning inducer/ impeller, a flow straightener (FLS), and a diffuser enclosed in a cylindrical flow tube. The impeller has rod-shaped permanent magnets embedded within its 6 blades and is activated magnetically by the motor stator which is positioned outside the flow tube. At the completion of a previous study, the FLS was identified as a thrombogenic area. The aim of the present study was to evaluate the thrombogenicity of redesigned FLSs (swept-back and bulbous types), compared with standard type (STD) FLS. A total of 15 pumps (STD, n = 7; swept-back, n = 4; and bulbous, n = 4) were sequentially implanted into 4 calves paracorporeally in a short-term ex vivo test. The STD and bulbous FLSs experienced thrombus formation, but the swept-back FLS was thrombus free during a 48 h screening test.

This report has presented evidence to support a disease-modifying role for corticosteroids in rheumatoid arthritis. It would appear that the efficacy of these agents in retarding the destructive course of rheumatoid disease has been substantially underestimated. Consideration for more liberal use of corticosteroids in the management of rheumatoid arthritis is warranted. Further study on new approaches to corticosteroid delivery is proposed.