Percutaneous repair or surgery for mitral regurgitation.

BACKGROUND: Mitral-valve repair can be accomplished with an investigational procedure that involves the percutaneous implantation of a clip that grasps and approximates the edges of the mitral leaflets at the origin of the regurgitant jet. METHODS: We randomly assigned 279 patients with moderately severe or severe (grade 3+ or 4+) mitral regurgitation in a 2:1 ratio to undergo either percutaneous repair or conventional surgery for repair or replacement of the mitral valve. The primary composite end point for efficacy was freedom from death, from surgery for mitral-valve dysfunction, and from grade 3+ or 4+ mitral regurgitation at 12 months. The primary safety end point was a composite of major adverse events within 30 days. RESULTS: At 12 months, the rates of the primary end point for efficacy were 55% in the percutaneous-repair group and 73% in the surgery group (P=0.007). The respective rates of the components of the primary end point were as follows: death, 6% in each group; surgery for mitral-valve dysfunction, 20% versus 2%; and grade 3+ or 4+ mitral regurgitation, 21% versus 20%. Major adverse events occurred in 15% of patients in the percutaneous-repair group and 48% of patients in the surgery group at 30 days (P<0.001). At 12 months, both groups had improved left ventricular size, New York Heart Association functional class, and quality-of-life measures, as compared with baseline. CONCLUSIONS: Although percutaneous repair was less effective at reducing mitral regurgitation than conventional surgery, the procedure was associated with superior safety and similar improvements in clinical outcomes. (Funded by Abbott Vascular; EVEREST II ClinicalTrials.gov number, NCT00209274.).

Stroke and mortality rates after off-pump vs. pump-assisted/no-clamp coronary artery bypass grafting.

BACKGROUND: Ascending aorta manipulation during on-pump coronary artery bypass grafting (CABG) surgery can release embolic matter and may cause stroke. Strategies for lowering the stroke rate associated with coronary artery bypass grafting surgery include off-pump surgery without cardiopulmonary bypass and pump-assisted surgery with minimal aortic manipulation (i.e., without aortic cross-clamping). We examined whether one approach is superior to the other in reducing stroke and perioperative mortality rates. METHODS: We reviewed consecutive elective, urgent, and emergency off-pump/no-bypass and pump-assisted/no-clamp coronary artery bypass grafting procedures performed by a single surgeon at our institution from June 2011 through October 2017. RESULTS: Of 570 patients analyzed, 395 (69.3%) underwent off-pump/no-bypass surgery, 43 (7.5%) underwent pump-assisted/no-clamp surgery, and 132 (23.2%) transitioned mid-procedure from off-pump/no-bypass to pump-assisted/no-clamp surgery. Patients who were >70 years old, were female, or had diabetes, cardiomegaly, or a history of myocardial infarction or congestive heart failure were more likely to undergo pump-assisted/no-clamp surgery or the combined technique. None of the pump-assisted/no-clamp patients had a stroke, versus 0.3% of the off-pump/no-bypass patients and 0.8% of the combination patients. Stroke and in-hospital mortality rates did not differ by technique. CONCLUSIONS: A hybrid strategy incorporating off-pump, pump-assisted, and combined off-pump/pump-assisted techniques achieved very low stroke rates in patients undergoing coronary revascularization. Perioperative mortality was similar for all three techniques. Avoiding aortic clamping may be crucial for decreasing CABG-related stroke rates. Off-pump/no-bypass surgery had no significant advantage over the pump-assisted/no-clamp or combined techniques in reducing the stroke rate after coronary artery bypass grafting surgery.

The influence of preoperative dialysis on survival after continuous-flow left ventricular assist device implantation.

OBJECTIVES: Dialysis is considered a contraindication to continuous-flow left ventricular assist device (CF-LVAD) implantation. We evaluated clinical outcomes and survival in carefully selected, low-risk patients with renal failure who required dialysis before CF-LVAD implantation. METHODS: We extracted medical record data of patients who underwent CF-LVAD placement at our centre between 1 January 2006 and 31 August 2017, with 2 clinical scenarios: those who required long-term (>14 days) dialysis and those who required short-term (≤14 days) dialysis immediately before implantation. Demographic, clinical and intraoperative characteristics and survival outcomes were assessed. RESULTS: Of 621 patients who underwent CF-LVAD implantation during the study period, 31 underwent dialysis beforehand. Of these, 17 required long-term dialysis (13 haemodialysis, 4 peritoneal dialysis), and 14 underwent short-term haemodialysis. Compared with the long-term dialysis patients, the short-term dialysis patients were more likely to be Interagency Registry for Mechanically Assisted Circulatory Support profile 1-2 (92.9% vs 70.6%; P < 0.001), to have needed preoperative mechanical circulatory support (78.6% vs 70.6%; P < 0.01) and to have higher in-hospital mortality (85.7% vs 29.4%; P = 0.01). Patients stable on long-term dialysis had acceptable overall survival and markedly better 6-month and 1-year survival than those with short-term dialysis before implantation (64.7% vs 14.3% and 58.8% vs 7.1%, respectively; P < 0.001). CONCLUSIONS: Carefully selected patients who are stable on long-term dialysis have acceptable survival rates after CF-LVAD implantation. Patients with acute renal failure had much poorer outcomes than those with chronic end-stage renal disease.

Mechanical Cardiac Support With an Implantable Direct Cardiac Compression Device: Proof of Concept.

PURPOSE: We examined the hemodynamic effects of a new, implantable, direct cardiac assist device in an ovine heart failure model. DESCRIPTION: The device, which encompasses both left and right ventricles, is inserted through the pericardial apex and self-expands to encompass the heart without suturing. The intact pericardium anchors the device in place. The device has 2 concentric chamber layers: an internal chamber layer filled with fluid to conform to the heart and an external chamber layer filled with air that provides external compression and negative pressure to aid relaxation. EVALUATION: The device was implanted in 7 sheep with heart failure induced by microsphere embolization. Cardiac performance was assessed for 6 to 8 hours. The cardiac assist device provided cardiac systolic and diastolic assistance, as shown by pressure tracings of the left ventricle and aorta, pulmonary artery flow, and +dP/dt. Central venous pressure decreased during cardiac assistance. No anatomic damage was noted postmortem. CONCLUSIONS: Systolic and diastolic cardiac assistance can be achieved with this device that compresses and relaxes in synchrony with the native cardiac cycle.

Continuous-Flow Left Ventricular Assist Device Explantation After More Than 5 Years of Circulatory Support and Ventricular Reconditioning.

Continuous-flow left ventricular assist devices have proved to be effective, durable, life-saving tools in patients with end-stage heart failure. However, because of the risks associated with mechanical circulatory support (including stroke, infection, gastrointestinal bleeding, and device malfunction), the optimal goal of device therapy is myocardial recovery and device removal. Ventricular reconditioning and pump explantation after continuous-flow support have been reported; however, little is known about variables that govern the pace and degree of myocardial response in patients who experience such recovery. We describe our long-term pump-weaning strategy for a 25-year-old man who had a continuous-flow device implanted and then needed more than 5 years of support from it before developing cardiac reserve sufficient to enable pump explantation. To our knowledge, this is the longest period of uninterrupted continuous-flow device support to end in successful pump deactivation and a return to medical therapy. This case highlights the importance of actively and persistently pursuing a device-weaning strategy in all patients who need left ventricular assist device therapy.

Ten-Year Survival With a Continuous-Flow Left Ventricular Assist Device and Aortic Valve Closure.

We report the long-term survival of a 46-year-old man supported with a HeartMate II continuous-flow left ventricular assist device after complex repair of a bicuspid aortic valve, anomalous left main coronary artery, and dilated aorta. He has been maintained on an anticoagulation regimen of warfarin and low-dose aspirin without problems for 10 years, during which he has worked continuously and productively. Device flow has been kept at 10,000 rpm. Possible contributors to this long-term success include proper alignment of the device inflow cannula, pericardial patch closure of the left ventricular outflow tract, and, notably, the remarkable freedom from mechanical failure of the continuous-flow left ventricular assist device. Whether the higher flow rate produced by the pericardial patch closure contributes to pump longevity is unknown and merits further investigation.

Heterotopic Cardiac Transplantation: Long-term Results and Fate of the Native Heart.

BACKGROUND: The long-term results of heterotopic cardiac transplantation have not been well defined. Patient survival rates and the fate of the native heart remain unclear. METHODS: This study is a retrospective review of all 46 heterotopic cardiac transplantations performed at a single institution, the Texas Heart Institute in Houston, Texas, between 1982 and 2017. Four patients who underwent heterotopic transplantation as an emergency procedure for cardiogenic shock were excluded. Three of the procedures were repeat transplantations in patients who had previously undergone heterotopic transplantation; the 3 repeat transplantations were excluded, but the original procedures were not. Follow-up was 100% complete for mortality and 77% complete (30 of 39 patients) for assessment of preoperative indication for surgery and postoperative cardiac function. RESULTS: For the 39 patients, the 1-year, 5-year, and 10-year survival rates were 69%, 36%, and 21%, respectively. One patient remains alive 25 years after the transplantation procedure. The most frequent indication for heterotopic transplantation was pulmonary vascular resistance greater than 4 Wood units (n = 11), followed by weight greater than 112.5 kg (n = 7). In most patients, native heart left ventricular ejection fraction stabilized over time to between 10% and 30%. Sinus rhythm was preserved in 87% (26 of 30) of native hearts at long-term follow-up. CONCLUSIONS: Heterotopic cardiac transplantation is an acceptable procedure that should be considered for obese patients (especially those heavier than 112.5 kg) and patients with elevated pulmonary vascular resistance (especially those with pulmonary vascular resistance >4.0 Wood units). After heterotopic transplantation, native cardiac function appears to stabilize, and there is potential for native heart recovery.

Low Incidence of Pump-Related Infections in Jarvik 2000 Ventricular Assist Device Recipients with a Subcostal Driveline Exit Site.

Driveline infection has been a persistent problem with mechanical cardiac assist devices. The reported incidence of infection has been low in patients who receive a Jarvik 2000 continuous-flow left ventricular assist device when a skull-pedestal driveline exit site is used. We evaluated whether this is also true when a subcostal driveline exit site is used. We reviewed baseline demographic variables, postimplantation vital signs, laboratory values, and culture results in patients who underwent Jarvik 2000 implantation at our center from April 2000 through October 2009, including follow-up through June 2014. All patients had a subcostal driveline exit site. We defined device-related infection as a positive blood or wound culture associated with a medical or surgical device intervention. Event and time-to-event rates were calculated. Eighty-one patients received 89 Jarvik 2000 devices, all as bridges to transplantation. The median support duration was 69 days (interquartile range, 27-153 d; range, 2-2,249 d). Five superficial driveline infections and one incision-site infection occurred (0.002 events per patient-year of support). The median time from pump implantation to onset of driveline infection was 30 days; the incision-related infection occurred at 44 days. The Jarvik 2000 has a low incidence of infection when implanted with use of a subcostal driveline exit site. The incidence of pump infections is particularly low. Using a subcostal driveline exit site may be as effective in preventing infections as using a skull-pedestal driveline exit site. We detail our findings in this report.

Recommendations of the National Heart, Lung, and Blood Institute Working Group on Future Direction in Cardiac Surgery.

New surgical procedures, imaging modalities, and medical devices have improved therapy for many patients and made treatment possible for others who have had few options in the past. In February 2004, the National Heart, Lung, and Blood Institute's (NHLBI) Advisory Council proposed that the institute evaluate the status and future directions in cardiac surgery. In response to this recommendation, the NHLBI convened a working group of cardiac surgeons on May 7 and 8, 2004, to assess the state of cardiac surgery research, identify critical gaps in current knowledge, determine areas of opportunity, and obtain specific recommendations for future research activities. The working group discussed surgical revascularization, novel surgical approaches, valvular research directions, biotechnology and cell-based therapy, heart failure, imaging modalities, and barriers to clinical research and presents its recommendations here.

Myocardial perfusion as assessed by positron emission tomography during long-term mechanical circulatory support.

Although mechanical circulatory support (MCS) can improve myocardial function in patients with advanced heart failure, its effects on relative myocardial perfusion are unclear. Using positron emission tomographic imaging techniques, the authors assessed relative myocardial perfusion in patients with ischemic or idiopathic cardiomyopathy who were receiving chronic MCS with a left ventricular assist device (pulsatile HeartMate [n = 2] [Thoratec Corporation, Pleasanton, CA] or nonpulsatile Jarvik 2000 [n = 4] [Jarvik Heart, Inc., New York, NY]). Relative myocardial perfusion was compared at lower and higher levels of MCS (50 vs. 100 - 110 ejections/min for the HeartMate and 8000 vs. 12,000 rpm for the Jarvik 2000). The size and severity of perfusion defects at rest and after dipyridamole stress were measured objectively and subjectively by computer algorithms and visual inspection, respectively. Relative myocardial perfusion increased > 5% from baseline in only one of six patients when MCS was increased. No change in relative myocardial perfusion of > 5% was seen in any of the other five patients, even after subsequent dipyridamole stress positron emission tomographic imaging. These pilot study findings suggest that the decreased metabolic requirements induced by ventricular unloading correspondingly decreased blood flow requirements to physiologically inactive myocardium.

Successful ventricular remodeling with coronary artery bypass grafting and mitral valve repair in a patient with severe heart failure.

Left ventricular remodeling is becoming a frequent treatment for severe heart failure, but its use in combination with other surgical techniques is controversial. We report a case in which left ventricular remodeling was combined with coronary artery bypass grafting and mitral valve repair to treat a patient with severely depressed ejection fraction, mitral insufficiency, coronary artery disease, and a recent history of myocardial infarction. Cardiac function improved after the combined treatment. This case suggests that left ventricular remodeling can be used safely and effectively in conjunction with other surgical techniques.

Surgical approach to continuous-flow left ventricular assist device explantation: A comparison of outcomes.

OBJECTIVE: Ventricular reconditioning and device weaning in select patients with continuous-flow left ventricular assist devices (CF LVADs) has been shown to be feasible. However, little is known regarding the outcomes associated with different surgical methods of device removal. We examined the effect of surgical explantation approach on early and late outcomes. METHODS: We retrospectively reviewed data from all patients who underwent successful ventricular weaning and CF LVAD explantation at our center. Patients were stratified by surgical approach. Descriptive univariate statistics, multivariate regression, and survival analyses were performed. Patients were censored by transplant, device reimplantation, or end of follow-up. RESULTS: Twenty-seven patients were identified who underwent successful removal of a CF LVAD (25 HeartMate II, 2 HeartWare) after 532 ± 424 days of support (range, 42-1937 days). Four approaches were used that vary primarily in the degree of retained pump material: complete pump removal with plug ventriculotomy closure (n = 13; 48%), pump housing explant with ligation of the inflow and outflow grafts (n = 7; 26%), ligation of the outflow graft and driveline transection (n = 5; 19%), and driveline transection alone (n = 2; 7%). Mean overall postexplant survival was 1286 ± 947 days (range, 143-3072 days). Overall time-to-event and survival analyses showed no significant association between surgical approach and postoperative length of stay (P = .7), stroke (P = .12), reoperation (P = .4), or survival (P = .12). CONCLUSIONS: For patients who receive device therapy, pump deactivation and removal represents a favorable outcome. All methods are feasible and produce similar early and late survival and clinical outcomes.

Identification of hibernating myocardium with quantitative intravenous myocardial contrast echocardiography: comparison with dobutamine echocardiography and thallium-201 scintigraphy.

BACKGROUND: There are currently no data on the accuracy of intravenous myocardial contrast echocardiography (MCE) in detecting myocardial hibernation in man and its comparative accuracy to dobutamine echocardiography (DE) or thallium 201 (Tl(201)) scintigraphy. METHODS AND RESULTS: Twenty patients with coronary artery disease and ventricular dysfunction underwent MCE 1 to 5 days before bypass surgery and repeat echocardiography at 3 to 4 months. Patients also underwent DE (n=18) and rest-redistribution Tl(201) tomography (n=16) before revascularization. MCE was performed using continuous Optison infusion (12 to 16 cc/h) with intermittent pulse inversion harmonics and incremental triggering (1:1 to 1:8). Myocardial contrast intensity (MCI) replenishment curves were constructed to derive quantitative MCE indices of blood velocity and flow. Recovery of function occurred in 38% of dysfunctional segments. MCE parameters of perfusion in hibernating myocardium were similar to segments with normal function and higher than dysfunctional myocardium without recovery of function (P<0.001). The best MCE parameter for predicting functional recovery was Peak MCIxbeta, an index of myocardial blood flow (area under the curve, 0.83). MCE parameters were higher in segments with contractile reserve and Tl(201) uptake > or =60% (P<0.05) and identified viable segments without contractile reserve by DE. The sensitivity of Peak MCIxbeta >1.5 dB/s for recovery of function was 90% and was similar to Tl(201) scintigraphy (92%) and any contractile reserve (80%); specificity was higher than for Tl(201) and DE (63%, 45%, and 54%, respectively; P<0.05). CONCLUSIONS: MCE with intravenous contrast identifies myocardial hibernation in humans. Prediction of viable myocardium with MCE is best using quantification of myocardial blood flow and provides improved accuracy compared with DE and Tl(201) scintigraphy.

Microvascular structural correlates of myocardial contrast echocardiography in patients with coronary artery disease and left ventricular dysfunction: implications for the assessment of myocardial hibernation.

BACKGROUND: Myocardial contrast echocardiography (MCE) has been used to evaluate myocardial viability. There are no data, however, on the pathological determinants of myocardial perfusion by MCE in humans and the implications of such determinants. METHODS AND RESULTS: MCE was performed in 20 patients with coronary artery disease and ventricular dysfunction within 24 hours before myocardial biopsy at surgery using a continuous Optison infusion (12 to 16 cc/h), with intermittent pulse inversion harmonics and incremental triggering. Peak myocardial contrast intensity (MCI) and the rate of increase in MCI (beta) were quantitated. Thirty-six transmural myocardial biopsies (2 per patient) were obtained by transesophageal echocardiography. Total microvascular (<100 microm) density, capillary density and area, arteriolar and venular density, and percent collagen content were quantitated with immunohistochemistry. Peak MCI correlated with microvascular density (r=0.59, P<0.001) and capillary area (r=0.64, P<0.001) and inversely correlated with percent collagen content (r=-0.45, P=<0.01). The best relation was observed when the ratio of peak MCI in the 2 biopsied segments in each patient was compared with the ratio of microvascular density and capillary area (r=0.84 and 0.87, respectively; P<0.001). A significant overlap in microvascular density was seen between segments with and without recovery of function. The new MCE indices of blood velocity (beta) and flow (peak MCIxbeta) better identified recovery of function compared with microvascular density and the sole use of peak MCI. CONCLUSIONS: Microvascular integrity is a significant determinant of maximal MCI in humans. MCE indices of blood velocity and flow are important parameters that predict recovery of function after revascularization.

Active interstitial remodeling: an important process in the hibernating human myocardium.

OBJECTIVES: The purpose of this study is to investigate the morphologic characteristics of the cardiac interstitium in the hibernating human myocardium and evaluate whether active remodeling is present and is an important determinant of functional recovery. BACKGROUND: Myocardial hibernation is associated with structural myocardial changes, which involve both the cardiomyocytes and the cardiac interstitium. METHODS: We evaluated 15 patients with coronary disease with two-dimensional echocardiography and thallium-201 ((201)Tl) tomography before coronary bypass surgery. During surgery, transmural myocardial biopsies were performed guided by transesophageal echocardiography. Myocardial biopsies were stained immunohistochemically to investigate fibroblast phenotype and examine evidence of active remodeling in the heart. RESULTS: Among the 29 biopsied segments included in the study, 24 showed evidence of systolic dysfunction. The majority of dysfunctional segments (86.4%) were viable ((201)Tl uptake > or = 60%). After revascularization, 12 dysfunctional segments recovered function as assessed with an echocardiogram three months after bypass surgery. Interstitial fibroblasts expressing the embryonal isoform of smooth muscle myosin heavy chain (SMemb) were noted in dysfunctional segments, predominantly located in border areas adjacent to viable myocardial tissue. Segments with recovery had higher SMemb expression (0.46 +/- 0.16% [n = 12] vs. 0.10 +/- 0.02% [n = 12]; p < 0.05) and a higher ratio of alpha-smooth muscle actin to collagen (0.14 +/- 0.026 [n = 12] vs. 0.07 +/- 0.01 [n = 12]; p < 0.05) compared with segments without recovery, indicating fibroblast activation and higher cellularity of the fibrotic areas. In addition, interstitial deposition of the matricellular protein tenascin, a marker of active remodeling, was higher in hibernating segments than in segments with persistent dysfunction (p < 0.05), suggesting an active continuous fibrotic process. Multiple logistic regression demonstrated a significant independent association between SMemb expression and functional recovery (p < 0.01). CONCLUSIONS: Fibroblast activation and expression of SMemb and tenascin provide evidence of continuous remodeling in the cardiac interstitium of the hibernating myocardium, an important predictor of recovery of function after revascularization.

Gastrointestinal bleeding from arteriovenous malformations in patients supported by the Jarvik 2000 axial-flow left ventricular assist device.

The long-term effects of axial-flow mechanical circulatory support in humans are unclear. We report 3 cases of chronic gastrointestinal bleeding after implantation of a Jarvik 2000 axial-flow left ventricular assist device. The bleeding was refractory to aggressive management and in 2 cases resolved only after orthotopic cardiac transplantation.

Evaluation of myocardial function in patients with end-stage heart failure during support with the Jarvik 2000 left ventricular assist device.

In 2 patients with the Jarvik 2000 left ventricular assist device (LVAD), we assessed left ventricular systolic function through pressure-volume loops and E(max) at the beginning and end of the support period to potentially predict the possibility of pump removal without transplantation. Immediately before LVAD implantation and explantation, pressure and volume measurements were made with catheters and echocardiography, respectively, the E(max) being calculated from the slope of the pressure-volume loops, and the left ventricular ejection fraction (LVEF) being estimated by echocardiography. Transplantation was performed after 14 and 62 days, respectively, during which the LVEF increased by 75% (from 12% to 21%) in Patient 1 and remained unchanged (from 16% to 18%) in Patient 2, whereas the E(max) increased from 0.63 and 0.42 mm Hg/ml, respectively, to 1.31 and 1.07 mm Hg/ml, reflecting a 107% and 155% improvement. In these 2 cases, the E(max) was a more reliable indicator of intrinsic myocardial contractility than was the LVEF.

Vascular thrombosis during support with continuous flow ventricular assist devices: correlation with computerized flow simulations.

Continuous flow pumps are increasingly used to treat severe heart failure. These pumps alter flow physiology by lowering pulsatility in the arterial circulation. In patients with peripheral stenosis, continuous flow pumps may lead to thrombosis of peripheral vessels, possibly predisposing to vascular thrombosis in areas of non-flow-limiting stenosis. The authors performed a computerized flow modeling simulation to analyze the effects of altered hemodynamics in a stenotic area. Drawing on previous clinical experience, we modeled a stenotic area in the common carotid artery. Computerized flow modeling revealed blood stagnation zones with low shear stress and velocity adjacent to the stenotic area during nonpulsatile flow. Such stagnation was not present during pulsatile flow. These results indicate a mechanism by which altered physiologic flow may accelerate occlusion of arterial conduits in patients with preexisting stenosis. This finding may be important for patients with continuous flow devices who have peripheral vascular disease; therefore, further study is warranted.

Orthotopic cardiac transplantation 30 months after successful dynamic cardiomyoplasty.

Reports of cardiac transplantation after successful cardiomyoplasty are rare. We report the case of a 63-year-old man with intractable heart failure who underwent successful orthotopic cardiac transplantation 30 months after dynamic cardiomyoplasty.

Continuous axial-flow left ventricular assist device (Jarvik 2000) maintains kidney and liver perfusion for up to 6 months.

BACKGROUND: The Jarvik 2000 axial flow left ventricular assist device (LVAD), under development for the past decade, has the potential to support patients temporarily until cardiac transplantation or as a permanent circulatory support, without the size limitations of other implantable systems. METHODS: To assess its ability to perfuse the kidneys and liver, we monitored renal and hepatic function in 10 patients who received the Jarvik 2000 LVAD as a bridge to transplantation. Left ventricular assistance was maintained for up to 214 days (> 6 months), and renal and hepatic function were monitored at least weekly. RESULTS: Renal function before LVAD implantation in these patients was normal in 7 (creatinine, < 1.5) and moderately impaired in 3 (creatinine, 1.2 to 2.0). Hepatic function was normal in 7 patients before LVAD implantation (total bilirubin< 1.2; serum glutamic-oxaloacetic transaminase (SGOT), < 40; serum glutamic-pyruvic transaminase (SGPT), < 50) and normal at the time of transplantation in all 10 patients. Of the 3 patients with abnormal hepatic function before LVAD implantation, 1 patient had also had moderate renal dysfunction. CONCLUSIONS: Despite reduced pulsatility, the Jarvik 2000 LVAD improves or maintains excellent renal and hepatic function during periods of circulatory assistance in patients awaiting transplantation.