Multicenter clinical evaluation of the HeartMate vented electric left ventricular assist system in patients awaiting heart transplantation

AbstractBackground: Despite advances in heart transplantation and mechanical circulatory support, mortality among transplant candidates remains high. Better ways are needed to ensure the survival of transplant candidates both inside and outside the hospital. Methods: In a prospective, multicenter clinical trial conducted at 24 centers in the United States, 280 transplant candidates (232 men, 48 women; median age, 55 years; range, 11-72 years) unresponsive to inotropic drugs, intra-aortic balloon counterpulsation, or both, were treated with the HeartMate Vented Electric Left Ventricular Assist System (VE LVAS). A cohort of 48 patients (40 men, 8 women; median age, 50 years; range, 21-67 years) not supported with an LVAS served as a historical control group. Outcomes were measured in terms of laboratory data (hemodynamic, hematologic, and biochemical), adverse events, New York Heart Association functional class, and survival. Results: The VE LVAS–treated and non–VE LVAS–treated (control) groups were similar in terms of age, sex, and distribution of patients by diagnosis (ischemic cardiomyopathy, idiopathic cardiomyopathy, and subacute myocardial infarction). VE LVAS support lasted an average of 112 days (range, < 1-691 days), with 54 patients supported for > 180 days. Mean VE LVAS flow (expressed as pump index) throughout support was 2.8 L · min–1 · m–2. Median total bilirubin values decreased from 1.2 mg/dL at baseline to 0.7 mg/dL (P =.0001); median creatinine values decreased from 1.5 mg/dL at baseline to 1.1 mg/dL (P =.0001). VE LVAS–related adverse events included bleeding in 31 patients (11%), infection in 113 (40%), neurologic dysfunction in 14 (5%), and thromboembolic events in 17 (6%). A total of 160 (58%) patients were enrolled in a hospital release program. Twenty-nine percent of the VE LVAS-treated patients (82/280) died before receiving a transplant, compared with 67% of controls (32/48) (P <.001). Conversely, 71% of the VE LVAS–treated patients (198/280) survived: 67% (188/280) ultimately received a heart transplant, and 4% (10/280) had the device removed electively. One-year post-transplant survival of VE LVAS–treated patients was significantly better than that of controls (84% [158/188] vs 63% [10/16]; log rank analysis P =.0197). Conclusion: The HeartMate VE LVAS provides adequate hemodynamic support, has an acceptably low incidence of adverse effects, and improves survival in heart transplant candidates both inside and outside the hospital. The studies of the HeartMate LVAS (both pneumatic and electric) for Food and Drug Administration approval are the only studies with a valid control group to show a survival benefit for cardiac transplantation

Predicting Left Ventricular Assist Device Outcomes Utilizing the Stanford Integrated Psychosocial Assessment for Transplant Measure

Objective: Durable mechanical circulatory support is a proven therapy to extend survival for patients with end-stage heart failure (HF). The International Society for Heart and Lung Transplantation guidelines recommend a detailed psychosocial assessment when selecting candidates for durable mechanical circulatory support. Currently, there are no formally validated psychosocial evaluation tools for left ventricular assist device (LVAD) candidacy. The Stanford Integrated Psychosocial Assessment for Transplantation (SIPAT) uses a multidisciplinary algorithm to evaluate the impact of pre-transplant risk factors on post-transplant outcomes. Emerging literature suggests that the SIPAT might be useful for assessing psychosocial risk factors for LVAD outcomes. Methods: A total of 268 consecutive patients (median age 66 years, 84.6% male) with terminal HF were evaluated before LVAD implantation with a SIPAT assessment. Key outcomes included readmission and mortality rates at 30 days and two years. Results: After screening, 234 subjects met the inclusion criteria and were analyzed. The Patient Readiness subscale of the SIPAT was statistically significant in predicting two-year mortality (B = .167, P \u3c .001; Nagelkerke r2 = .106). Scores on the SIPAT did not correlate to 30-day readmission, 30-day mortality, or two-year readmission rates. Discussion: In this study, only the Patient Readiness score was associated with mortality at two-years post-implantation. This research elucidates the potential longer-term impact of psychosocial factors on LVAD outcomes and the SIPAT’s utility in evaluating LVAD candidacy

A 20-year experience with urgent percutaneous cardiopulmonary bypass for salvage of potential survivors of refractory cardiovascular collapse

In-hospital cardiac arrest or refractory shock carries a high mortality despite the use of advanced resuscitative measures. We have implemented an in-hospital, nurse-based, continuously available, percutaneous, venoarterial cardiopulmonary bypass system, also known as extracorporeal life support (ECLS), as an adjunct to resuscitation when initial measures are ineffective.In 1986, a system for the rapid initiation of ECLS, was created in which trained critical care nurses primed an ECLS circuit and in-house physicians percutaneously placed required cannulas. From a prospective registry, we assessed long-term survival (LTS) (≥30 days, cardiopulmonary support weaned), short-term survival (<30 days, CPS weaned), or death on CPS.One hundred fifty patients (age, 57 ± 17 years) were urgently started on CPS for cardiac arrest (n = 127; witnessed, n = 124; unwitnessed, n = 3) and refractory shock (n = 23). Sixty-nine patients were weaned from CPS, and 81 could not be weaned. Overall, 39 (26.0%) patients achieved LTS with a subsequent Kaplan–Meier median survival of 9.5 years. Duration of CPS was 32 ± 38 hours for LTS and 21 ± 38 hours for non-LTS. LTS occurred in 29 (23.4%) of 124 patients started on CPS for witnessed cardiac arrest and 11 (47.8%) of 23 for refractory shock ( < .05). Among patients with CPS initiated in the cardiac catheterization laboratory, LTS was seen in 24 (50.0%) of 48 versus 15 (14.7%) of 102 in patients with CPS initiated in other locations ( < .001). Cardiopulmonary resuscitation times greater than or equal to 30 minutes were associated with lower LTS ( < .05). The most common cause of death during CPS was refractory cardiac dysfunction (39.5%), and the most common cause associated with short-term survival was neurologic/pulmonary dysfunction (53.6%). Seven patients were bridged to a left ventricular assist device, and 1 subsequently underwent heart transplantation. Multivariate analysis revealed only cardiac catheterization laboratory site of initiation as a significant independent predictor of LTS ( < .01). When dividing the 20-year experience in tertiles, recent recipients have had more common prearrest insertion. Rates of long-term survival have not changed.Of patients started on CPS, 46% were weaned, and 26.0% were long-time survivors. Rapid initiation of CPS permits LTS for some inpatients with cardiovascular collapse when initial advanced resuscitation fails. Strategies to improve end-organ function associated with use of CPS should lead to greater LTS. This practical application of inexpensive available technology should be more widely used

Fellowship award in cardiovascular perfusion: Perfusion Techniques of Profound Hypothermia and Circulatory Arrest for Pulmonary Thromboendarterectomy

One hundred ninety-five patients with the diagnosis of chronic pulmonary thromboembolic pulmonary hypertension have been operated on utilizing a standardized protocol involving profound hypothermia and circulatory arrest. A small subgroup, nine, were identified preoperatively as having heparin-associated thrombocytopenia (HAT). This challenging subgroup of patients was treated during heparin exposure with an investigational, “platelet disaggregating” agent, Iloprost. The surgical procedure of pulmonary thromboendarterectomy requires multiple periods of circulatory arrest under profound hypothermia. Perfusion management of this procedure involves cerebral and myocardial protection, cooling, reperfusion at hypothermia and rewarming, treatment with Iloprost when appropriate, and methods of hemodilution

Perfusion Techniques of Profound Hypothermia and Circulatory Arrest for Pulmonary Thromboendarterectomy

One hundred ninety-five patients with the diagnosis of chronic pulmonary thromboembolic pulmonary hypertension have been operated on utilizing a standardized protocol involving profound hypothermia and circulatory arrest. A small subgroup, nine, were identified preoperatively as having heparinassociated thrombocytopenia (HAT). This challenging subgroup of patients was treated during heparin exposure with an investigational, “platelet disaggregating” agent, Iloprost. The surgical procedure of pulmonary thromboendarterectomy requires multiple periods of circulatory arrest under profound hypothermia. Perfusion management of this procedure involves cerebral and myocardial protection, cooling, reperfusion at hypothermia, and rewarming; treatment with Iloprost when appropriate; and methods of hemodilution

Non-physiologic closing of bi-leaflet mechanical heart prostheses requires a new tri-leaflet valve design

Mechanical heart valve prostheses are based on older designs without changes during the last 40 years. Today, there is an unmet need for less thrombogenic mechanical prostheses. Analysis of the relationship between flow characteristics and thromboembolic complications is possible using numerical and biomolecular flow studies that have shown that the reverse rather than the forward flow is responsible for local platelet activation and thrombosis. After peak flow, leaflets experience flow deceleration and the leaflets are still widely open when the flow becomes zero. The closure of the valve starts with the onset of reverse flow. Therefore, the valve closes extremely fast with most of the leaflet traveling angle occurring in <10 ms with excessively high reverse flow velocities. The pivoting spaces, so-called “Hot Spots” should be eliminated to prevent pathologic shear stress that result in thrombosis. A novel tri-leaflet valve combines favorable hemodynamics with the durability of mechanical heart valve. This valve closes within 60 ms, much slower than bi-leaflet valves and similar to the closing mode of a tissue valve. Micro-particle image velocimetry did not show critical regions of flow stagnation and zones of excessive shear in the pivoting region suggesting low potential for thrombogenic events that should allow to avoid long-term anticoagulation.ISSN:0167-527

Non-physiologic closing of bi-leaflet mechanical heart prostheses requires a new tri-leaflet valve design

Mechanical heart valve prostheses are based on older designs without changes during the last 40 years. Today, there is an unmet need for less thrombogenic mechanical prostheses. Analysis of the relationship between flow characteristics and thromboembolic complications is possible using numerical and biomolecular flow studies that have shown that the reverse rather than the forward flow is responsible for local platelet activation and thrombosis. After peak flow, leaflets experience flow deceleration and the leaflets are still widely open when the flow becomes zero. The closure of the valve starts with the onset of reverse flow. Therefore, the valve closes extremely fast with most of the leaflet traveling angle occurring in <10 ms with excessively high reverse flow velocities. The pivoting spaces, so-called "Hot Spots" should be eliminated to prevent pathologic shear stress that result in thrombosis. A novel tri-leaflet valve combines favorable hemodynamics with the durability of mechanical heart valve. This valve closes within 60 ms, much slower than bi-leaflet valves and similar to the closing mode of a tissue valve. Micro-particle image velocimetry did not show critical regions of flow stagnation and zones of excessive shear in the pivoting region suggesting low potential for thrombogenic events that should allow to avoid long-term anticoagulation.status: publishe