Left Ventricular Device Research Articles

Usefulness of the Six-Minute Walk Test After Continuous Axial Flow Left Ventricular Device Implantation to Predict Survival

The goal of this study was to describe the predictors and significance of poor exercise tolerance after left ventricular assist device (LVAD) implantation. Despite LVAD therapy, some patients continue to exhibit exercise intolerance. The predictors and outcomes of these patients are unknown. A retrospective review of 65 LVAD recipients who performed 6-minute walk tests was conducted. Patients walking <300 m were considered to have poor exercise tolerance. Twenty patients exhibited poor exercise tolerance (221 ± 45 m), compared to 45 patients with better exercise tolerance (406 ± 76 m). Postoperatively, poor performers were not easily identified by functional symptoms alone, because 42% of these patients reported New York Heart Association functional class I or II symptoms. Preoperative New York Heart Association class, inotrope therapy, and intra-aortic balloon pump use were similar between the 2 groups. Multivariate analysis using all adequately powered (n >50) univariate predictors identified diabetes mellitus (odds ratio 10.493, p = 0.003) and elevated 1-month right atrial pressure (odds ratio 2.985 for every 5 mm Hg, p = 0.003) as significant predictors of poor performance (<300 m; area under the curve 0.85). The poorly performing group had increased mortality (p = 0.011), with 21% increased risk for overall mortality for every 10 m short of 300 m (fitted Cox model: hazard ratio 1.211, p = 0.0001). The distance walked in meters in a postoperative 6-minute walk test was the strongest predictor of late post-LVAD mortality (p = 0.0002). In conclusion, despite similar severity of heart failure preoperatively, some LVAD recipients may have persistent exercise intolerance postoperatively as assessed by the 6-minute walk test that is independently associated with subsequent reduced survival.

A Pulsatile Control Algorithm of Continuous-Flow Pump for Heart Recovery

The intra-aorta pump is a novel continuous flow (CF) left ventricular (LV) device. According to literatures, the pulsatile flow LV device can provide superior LV unloading and circulatory support compared with CF LV assist devices at the same level of ventricular assist device flow. Therefore, a pulsatile control algorithm for the intra-aorta pump is designed. It can regulate the pump to generate pulsatile arterial pressure (AP) and blood flow. A mathematic model of the cardiovascular-pump system is used to verify the feasibility of the control strategy in the presence of LV failure. The surplus hemodynamic energy (SHE), pulsatile ratio (PR), and pulsatile attenuation index (PAI) are used to evaluate the pulsatility of AP and blood flow. The SHE is 8,012.0 ergs/cm(3) by using the pulsatile control strategy (PCS) compared with 5,630.0 ergs/cm(3) by failing heart without support. The PR is 0.302 in the PCS vs. 0.315 in failing heart without support. Meanwhile, the PAI is 85.9% in the PCS compared with 69.7% in failing heart without support. The results demonstrate that the presented control strategy can maintain the pulsatility of AP and blood flow. Moreover, the pulsatile controller provides notably LV unloading. To test the response of the controller to the change of blood demand of patients, another simulation is conducted. In this simulation, the peripheral resistance is reduced to mimic the status of a slight physical active; the Emax is increased to simulate the ventricular contractility recovery. The simulation results demonstrate that the proposed control strategy can automatically regulate the pump in response to the change of the parameters of the circulatory system. To test the dynamic character of the intra-aorta pump, an in vitro experiment is conducted on an in vitro experiment rig. The experimental results demonstrate that the intra-aorta pump can achieve the pulsatile pump speed calculated by the pulsatile controller. The PCS is feasible for the intra-aorta pump. As a key feature, the proposed control strategy provides adequate perfusion in response to the change of blood demands of patients, while restoring the pulsatility of AP and blood flow.

What is the evidence for IABP in STEMI with and without cardiogenic shock?

Intraaortic balloon pump (IABP) is the most widely used left ventricular support device in a variety of indications. This review focuses on the current literature and discusses the evidence of IABP in ST-elevation myocardial infarction (STEMI) with and without cardiogenic shock. In high-risk STEMI patients without cardiogenic shock several randomized clinical trials have been performed. The majority of the studies could not demonstrate an efficacy benefit for IABP as adjunctive therapy in comparison to standard treatment alone. Hence, recent meta-analyses could not reveal diverging mortality rates at a higher incidence of stroke and major bleedings with IABP use independent of the type of reperfusion therapy. IABP in STEMI patients with cardiogenic shock is recommended according to current American College of Cardiology/American Heart Association (AHA/ACC) and European Society of Cardiology (ESC) guidelines. In recent meta-analyses, IABP in cardiogenic shock complicated by STEMI has been shown to be associated with decreased mortality. However, these beneficial effects are limited to patients treated with thrombolysis, whereas in patients undergoing mechanical revascularization IABP therapy is associated with an increase in mortality. Nevertheless, these data only arise from prospective and retrospective cohort studies, as up to date only one very small randomized clinical trial has been completed. In summary, in high-risk STEMI patients without cardiogenic shock, current data do not support the use of IABP and should only be considered as a standby and bailout strategy if patients develop haemodynamic instability. Current data on IABP in patients with cardiogenic shock complicated by STEMI are scarce and highly limited due to the nonrandomized design of previous trials. However, according to current AHA/ACC and ESC guidelines its use is recommended. Although recent meta-analyses challenge current AHA/ACC/ESC guidelines, adequately powered randomized studies are needed to elucidate the role of IABP in patients with acute myocardial infarction complicated by cardiogenic shock.

Percutaneous left ventricular partitioning in patients with chronic heart failure and a prior anterior myocardial infarction: Results of the PercutAneous Ventricular RestorAtion in Chronic Heart failUre PaTiEnts Trial

The aim of this study was to assess the feasibility, safety, and preliminary efficacy of a novel percutaneous left ventricular partitioning device (VPD) in patients with chronic heart failure (HF) and a prior anterior myocardial infarction. Anterior myocardial infarction is frequently followed by left ventricular remodeling, HF, and increased long-term morbidity and mortality. Thirty-nine patients were enrolled in a multinational, nonrandomized, longitudinal investigation. The primary end point was an assessment of safety, defined as the successful delivery and deployment of the VPD and absence of device-related major adverse cardiac events over 6 months. Secondary (exploratory) efficacy end points included changes in hemodynamics and functional status and were assessed serially throughout the study. Ventricular partitioning device placement was not attempted in 5 (13%) of 39 subjects. The device was safely and successfully implanted in 31 (91%) of the remaining 34 patients or 79% of all enrolled patients. The 6-month rate of device-related major adverse cardiac event occurred in 5 (13%) of 39 enrolled subjects and 5 (15%) of 34 treated subjects, with 1 additional event occurring between 6 and 12 months. For patients discharged with the device to 12 months (n = 28), New York Heart Association class (2.5 ± 0.6 to 1.3 ± 0.6, P < .001) and quality-of-life scores (38.6 ± 6.1 to 28.4 ± 4.4, P < .002) improved significantly; however, the 6-minute hall walk distance (358.5 ± 20.4 m to 374.7 ± 25.6 m, P nonsignificant) only trended toward improvement. The left VPD appears to be relatively safe and potentially effective in the treatment for patients with HF and a prior anterior myocardial infarction. However, these limited results suggest the need for further evaluation in a larger randomized controlled trial.

Pump it up with an LVAD left ventricular assist device

Pump it up with an LVAD left ventricular assist device

31 Pump-Related Infections (PRI) after Implantation of Continuous-Flow Left Ventricular Devices (CF LVADs): Analysis of 2900 Patients from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS)

31 Pump-Related Infections (PRI) after Implantation of Continuous-Flow Left Ventricular Devices (CF LVADs): Analysis of 2900 Patients from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS)

780 Impaired 6 Minute Walk Test after Continuos Axial Flow Left Ventricular Device Implantation Is Associated with Reduced Survival

Despite left ventricular assist device (LVAD) therapy 20-30% of patients with stage D heart failure continue to exhibit exercise intolerance. The six minute walk test (6MWT) can objectively identify these patients. This study aims to describe predictors and outcomes of patients with poor exercise tolerance after LVAD implantation.

Experimental and numeric investigation of Impella pumps as cavopulmonary assistance for a failing Fontan

This study sought to evaluate the performance of microaxial ventricular assist devices for the purposes of supporting failing Fontan physiology by decreasing central venous pressure. Three Abiomed Impella pumps (Abiomed, Inc, Danvers, Mass) were evaluated in a mock circulatory system of the Fontan circuit. The local response of pressures and flows to pump function was assessed as a function of pump speed and pulmonary vascular resistance at a high baseline central venous pressure. For one device, subsequent modeling studies were conducted using a lumped parameter model of the single ventricle circuit. The left ventricular devices (Impella 2.5, 5.0) were shown to be suboptimal as single device solutions for cavopulmonary support. The small area of these devices relative to vessel diameter led to significant flow recirculation without an obstructive separator in place. Furthermore, downstream pressure augmentation adversely affected the pressure in the superior vena cava. The use of 2 devices would be mandatory for successful support. The right-sided device (Impella RP), whose outflow was positioned in the left pulmonary artery, demonstrated decreased flow recirculation and did not impede superior caval venous flow. Although static pressure is still required to drive flow through the opposite lung, numeric modeling demonstrated the potential for modest but significant improvements in lowering the central venous pressure (2-8 mm Hg). Left-sided microaxial pumps are not well suited for cavopulmonary support because of severe flow recirculation and the need for multiple devices. The right-ventricular Impella device provides improved performance by directing flow into the pulmonary artery, resulting in modest decreases in central venous pressure.

Postoperative ICU care of patients suffering from cardiogenic shock at time of left ventricular device placement

Aims: Cardiogenic shock at time of left ventricular assist device (LVAD) placement for treatment of terminal heart failure is related to high incidence of biventricular failure and its sequellae. We studied the catecholamine therapy and ICU complication profile of this specific patient cohort.

Role of FPR1 Formyl Peptide Receptors in the Cardioprotective Actions of Annexin-A1 Against Ischaemia–Reperfusion (I–R) Injury

M. Imran ∗, A. Keogh, E. Kotylar, C. Hayward, P. Macdonald, R. Prichard Heart Transplant Unit, St. Vincent’s Hospital, NSW, Australia Introduction: A high transpulmonary gradient (i.e. >10mmHg) secondary to severe left heart failure is associatedwith increasedmortality after heart transplantation and left ventricular assist device implantation. Endothelin receptor antagonists are useful in certain forms of pulmonary hypertension (PAH), but avoided in PAH due to LHF. In this small studywe assessed the effect of bosentan on right heart haemodynamics in LHF with high TPG. Methods: Four patients with advanced LHF and high TPG-unresponsive to vasodilator challenge with nitroglycerine infusion or inhaled nitric oxide (precluding transplant or LVAD) received bosentan (62.5mg or 125mg BD) supplied on compassionate usage by Actelion Pharmaceuticals Australia. Serial right heart catheterisations were performed. Results: One of four patients had no fall in TPG after six weeks therapy and bosentan was discontinued. Three of four patients showed a good response to bosentan. Patient #1: was on LVAD support, developed a TPG of 16mmHg, falling to <10 on bosentan allowing successful heart transplant at 2 months. Patient #2: three months bosentan therapy resulted in improvement inTPG from20 to 12mmHg, PVR from 421 to 218 dyne s cm−5 and cardiac 2 of the actions of full-length ANX-A1 and activates both formyl peptide receptor (FPR)1 and FPR2. Although their anti-inflammatory effects are largely mediated by FPR2, receptors responsible for ANX-A1-based cardioprotection have not been resolved. In this study, rat isolated hearts were Langendorff-perfused with physiological buffer at constant flow (10mL/min), subjected to global, no-flow 30-min ischaemia followed by 30-min reperfusion. Hearts (n= 6–8 per group) were randomly allocated to treatment during reperfusion with Ac-ANX-A12–26 (0.3 M) in absence or presence of either non-selective FPR1/FPR2 antagonist Boc-2 (10 M), FPR2-selective antagonist Quinc-7 (10 M) or FPR1-selective antagonist Cyclosporin-H (1 M). Upon reperfusion, LV developed pressure (LVDP) was significantly reduced compared to pre-ischaemic baseline, and remained depressed during reperfusion. Lactate dehydrogenase (LDH) release was significantly elevated during reperfusion compared to sham (p= 0.001). In comparison, Ac-ANX-A12–26 treated hearts elicited complete recovery of LVDP by 10min reperfusion (p< 0.01), and LDH release was significantly attenuated (p= 0.005). Interestingly, preservation of LV function and cell viability mediated by Ac-ANXA12–26 were prevented by Boc-2, partially attenuated by Cyclosporin-H, but were unaffected by Quinc-7. Our findings suggest administration of Ac-ANX-A12–26 on reperfusion rescues LV function likely via activation of index from 1.7 to 2.0 l/min/m . He remains under consideration for heart transplant. Patient #3: bosentan for six months resulted inTPGfall from27 to18mmHg,PVRfrom 424 to 300 dyne s cm−5 with improvement in symptoms. Conclusion: Bosentan therapy can diminish disproportionately elevated TPG, secondary to left heart failure, facilitating definitive therapy (LVAD implant or transplant). http://dx.doi.org/10.1016/j.hlc.2012.05.232

Occluding the pulmonary artery to improve detection of patent foramen ovale during ventricular assist device placement

Unrecognized patent foramen ovale (PFO) in patients after left ventricular assist device (VAD) placement could cause significant hypoxemia and paradoxical embolism. We aim to improve the techniques for PFO detection in this patient population before left ventricular device initiation. We evaluated the effects of main pulmonary artery occlusion on patients' hemodynamic and detection of PFO by transesophageal echocardiography (TEE). We compared between the standard and pulmonary artery occlusion technique. Sixty-two patients with ASA physical status class IV were studied. They presented with end-stage heart failure for left VAD placement. All patients received both Valsava maneuver and occlusion of their pulmonary arteries to assess their influence on detection of PFO. Occlusion of the main pulmonary artery consistently increased right atrial to left atrial pressure gradient. The PFO detection rate using TEE was significantly improved from 0% to 10% by this maneuver compared with the Valsava maneuver. Occlusion of the main pulmonary artery is a simple and effective method to improve PFO detection by TEE before left VAD initiation.

TCT-480: Safety and Feasibility of Percutaneous Delivery of a Partial Left Ventricular Support Device (CircuLite® Synergy® Micro-Pump) in a Porcine Model

TCT-480: Safety and Feasibility of Percutaneous Delivery of a Partial Left Ventricular Support Device (CircuLite® Synergy® Micro-Pump) in a Porcine Model

The Impella 2.5 and 5.0 devices for ST-elevation myocardial infarction patients presenting with severe and profound cardiogenic shock: The Academic Medical Center intensive care unit experience*

Cardiogenic shock remains an important therapeutic challenge, with high in-hospital mortality rates. Mechanical circulatory support may be beneficial in these patients. Since the efficacy of the intra-aortic balloon pump seems limited, new percutaneously placed mechanical left ventricular support devices, such as the Impella system, have been developed for this purpose. Our current purpose was to describe our experience with the Impella system in patients with ST-elevation myocardial infarction presenting in profound cardiogenic shock, who were admitted to our intensive care unit for mechanical ventilation. From January 2004 through August 2010, a total of 34 ST-elevation myocardial infarction patients with profound cardiogenic shock were admitted to our intensive care unit and treated with either the Impella 2.5 or the Impella 5.0 device. Baseline and follow-up characteristics were collected retrospectively. Within the study cohort, 25 patients initially received treatment with the Impella 2.5, whereas nine patients received immediate Impella 5.0 support. Eight out of 25 patients in the Impella 2.5 group were upgraded to 5.0 support. After 48 hrs, 14 of 25 patients in the 2.5 group were alive, five of whom had been upgraded. In the 5.0 group, eight out of nine patients were alive. After 30 days, six of 25 patients in the 2.5 group were alive, three of whom had been upgraded. In the 5.0 group, three of nine patients were alive at 30 days. In ST-elevation myocardial infarction patients with severe and profound cardiogenic shock, our initial experience suggests improved survival in patients who received immediate Impella 5.0 treatment, as well as in patients who were upgraded from 2.5 to 5.0 support, when compared to patients who received only Impella 2.5 support.

Hepatitis C in Cardiac Patients Investigation Leads to Opportunities for Improvement in Preventing the Transmission of Bloodborne Pathogens

The setting is a 900 bed teaching institution with a Cardiovascular Center that houses 40 inpatient beds and 8 operating rooms. Approximately 300 cardiac procedures are performed per year, including heart transplants and left ventricular device procedures (LVAD). In 2009 two patients were identified as having acute HCV status post LVAD procedure, with an unexplainable source. There are reports in the literature of iatrogenic acquisition of HCV in patients, therefore an investigation was launched.

Comparison of three different regimens of intermittent inotrope infusions for end stage heart failure

AimsInotrope treatment is often necessary in refractory to optimal management end stage heart failure, when signs of end-organ hypoperfusion appear. The effect of specific inotropes on patient outcome remains controversial. The aim of the study was to compare the effect of levosimendan versus dobutamine, alone or in combination with levosimendan, on the outcome of end-stage heart failure patients, requiring inotropic therapy. Methods and resultsWe studied 63 patients in NYHA class IV, refractory to optimal medical therapy, recently hospitalized for cardiac decompensation and stabilized by an intravenous inotrope. They were randomly assigned to intermittent infusions of either a) dobutamine, 10mg/kg/min, versus b) levosimendan, 0.3mg/kg/min, versus c) dobutamine, 10mg/kg/min+levosimendan 0.2mg/kg/min, each administered weekly, for 6h, over a 6-month period. All patients received amiodarone, 400mg/day, to suppress the proarrhythmic effects of the inotropes. Baseline characteristics of the 3 groups were similar. At 6months, survival free from death or urgent left ventricular device implantation was 80% in the levosimendan, 48% in the dobutamine (P=0.037 versus levosimendan), and 43% in the levosimendan+dobutamine (P=0.009 versus levosimendan) group. At 3months, NYHA class improved significantly in all 3 groups, whereas pulmonary capillary wedge pressure decreased (27±4 to 19±8mmHg, P=0.008) and cardiac index increased (1.5±0.3 to 2.1±0.3l/min/m2, P=0.002) significantly only in patients assigned to levosimendan. ConclusionsIn patients with refractory end-stage heart failure, intermittent administration of levosimendan conferred survival and hemodynamic benefits in comparison to a regimen of intermittent infusions of dobutamine, alone or in combination with levosimendan.

Heart Transplant vs Left Ventricular Assist Device in Heart Transplant-Eligible Patients

Patients listed for heart transplant have a prolonged wait time, with continued deterioration, poor quality of life, and 10% mortality. Although recent bridge to transplant (BTT) studies demonstrated 1-year survival similar to heart transplantation, doubt remains about overall effectiveness as a treatment strategy compared with waiting and implanting a left ventricular device (LVAD) only as a last resort. We evaluated 1-year outcome and effectiveness of LVAD vs heart transplantation. Patients on the heart transplantation list, either receiving an allograft or LVAD for BTT from January 2009 to December 2009 were evaluated. Of 43 patients treated, 1 received both LVAD and an allograft during same admission was removed from the analysis. All patients but one who received an allograft had prior LVAD. Descriptive and univariate (t test) statistics and Kaplan-Meier survival curve were used for analyses. LVAD for BTT was used in 29 patients (51.4±12.8 years, 6.9% women), and 13 (51.1±11.6 years, 15.38% women) underwent heart transplantation. Initial hospital length of stay was 17.5±14.4 days in BTT group and 14.3±4.6 days in heart transplant group (p=0.44) At 1 year, the total number of days spent in the hospital (operation and related complications), including index hospitalization was 11.6±14.3 days/100 days in BTT and 7.9±9.0 days/100 days in heart transplantation (p=0.38). A total of 41% BTT and 46% heart transplant patients had one readmission within 3 months of the index hospitalization. Infection was the most common cause of readmission in both groups. The 1-year survival was similar for both groups (no hospital death in either group; 3 late deaths in the BTT group). One-year outcomes for patients eligible for heart transplantation were similar whether they received an allograft or LVAD for BTT. Heart transplant outcome for patients with LVAD were not adversely affected. Improving outcomes for patients treated with LVAD suggest that current decision models for patients eligible for heart transplantation may need to be reevaluated.

Current State of Ventricular Assist Devices

Left ventricular assist device (LVAD) support is an accepted treatment of patients with end-stage heart failure. The increased applicability and excellent results with LVADs have revolutionized the treatment options available for such patients. Success with LVADs as bridge-to-transplant therapy has led to their successful use as an alternate to a transplant (ie, as destination therapy [DT]). The use of these devices as DT represents a relatively newer but growing indication. Until recently, most patients who have undergone LVAD implantation have been supported by pulsatile devices. Newer continuous-flow (CF) pumps have resulted in superior outcomes, including significantly reduced complication rates with improved durability over first-generation pulsatile design pumps. However, as with all new technology, the newer LVADs have introduced management challenges that were either unimportant or absent with pulsatile LVADs. This article reviews the current state of left ventricular devices, focusing on the CF pumps that currently dominate the field, including clinical outcomes, the physiologic and pathologic effects that are associated with CF pumps, and their unique management issues and complications.

Aortic valve closure associated with HeartMate left ventricular device support: Technical considerations and long-term results

Aortic valve integrity is crucial for optimal left ventricular assist device (LVAD) support. Pre-existing native aortic insufficiency, aortic valve incompetence acquired during support, as well as previously placed prosthetic aortic valves present unique problems for these patients. We reviewed and analyzed data for 28 patients who underwent left ventricular outflow tract closure associated with HeartMate I (n =12) and HeartMate II (n = 16) LVAD insertion or exchange. Indications for valve closure, surgical technique, LVAD function, survival rates and complications were retrospectively analyzed. Survival rates were compared with those of HeartMate LVAD patients (n = 104) who did not undergo aortic valve closure. Indications for closure included native aortic valve insufficiency (10 patients), aortic valve deterioration after prolonged LVAD support (8 patients) and previously placed mechanical (9 patients) or bioprosthetic aortic prostheses (1 patient). There were 2 operative and 5 late deaths (mean 227 days post-operatively). Of the deaths, none were due to aortic valve closure. Actuarial survival was 78% at 1 year and 53% at 3 years, which was statistically better than for our patients with an intact aortic outflow (61% at 1 year, 45% at 3 years; p < 0.05). Five patients had transplants, 1 patient was successfully bridged to recovery, and 15 patients remain on LVAD support. No patient with outflow closure developed regurgitation, embolization or compromised LVAD support. Outflow tract closure in LVAD-supported patients is safe, often necessary and well tolerated.

Nanocomposite Elastomeric Biomaterials for Myocardial Tissue Engineering Using Embryonic Stem Cell‐derived Cardiomyocytes

AbstractRegeneration or repair of the damaged myocardium requires different strategies including engineered constructs for more efficient cell delivery. This study was undertaken to examine the potential of a new nanostructured elastomer to deliver embryonic stem cell‐derived cardiomyocytes (ESC‐CM) to an infarcted area of the myocardium. Engineered materials were biocompatible, mechanically stable, and elastomeric nanocomposites serving as substrates for delivery of ESC‐CM and as a left ventricular support device in myocardial regeneration strategies. Materials investigated were soft and strong poly(aliphatic/aromatic‐ester) multiblock thermoplastic elastomers with poly(ethylene terephthalate) (PET) hard segments and dimerized fatty acid, i.e., dilinoleic acid (DLA) soft segments, respectively, with and without addition of 0.2 wt% TiO2 nanoparticles to form nanocomposites. The PET/DLA‐TiO2 nanocomposite exhibited over 8 MPa tensile strength and 900% elongation at break. Addition of TiO2 nanoparticles significantly altered surface roughness and enhanced adhesion and spreading of ESC‐CM derived from mouse and human embryonic stem cells. The newly developed materials did not affect the functional activity of spontaneously beating hESC‐CM, as demonstrated by unaltered rate of their beating, and the cells continued to demonstrate contractile activity on the materials for more than two months in culture (the longest time tested). Quantitative proliferation and survival assays using fibroblasts confirmed the ability of the new materials to support cells as well as or better than the present commercial‐type thermoplastic elastomer analog. The results indicate that PET/DLA and PET/DLA‐TiO2 are promising candidates for the manufacture of engineered patches to deliver ESC‐CMs.

A structured 3-step approach to evaluate cardiac recovery with continuous flow circulatory support

In contrast to the large body of literature describing cellular recovery during left ventricular asst device (LVAD) support,1,2 most series have described low rates of functional cardiac recovery during LVAD support. The recovery rate in the LVAD working group recovery (LWG) study was 9% (pulsatile devices)3 and in the HeartMate (HM) II axial flow LVAD bridge-to-transplant experience was <3%.4 Weaning of a pulsatile first generation LVAD may be achieved by stopping the device with intermittent hand pumping to prevent pump thrombosis.