Effects of continuous-flow left ventricular assist devices on cerebral hemodynamics

Continuous-flow left ventricular assist devices (LVADs) reduce peak systolic flow, increase diastolic flow, and eliminate pulsatility of circulation. Altered blood flow may lead to a change in end-organ perfusion. Analysis of the flow dynamics of the arteries of end organs, such as the brain, may indicate whether an organ is perfused sufficiently. The aim of this study is to evaluate and identify the flow pattern changes of carotid (CA) and middle cerebral arteries (MCA) in LVAD patients and to compare with heart failure patients and healthy volunteers. Eighty-nine individuals were included in this cross-sectional study. Participants were divided into three groups: LVAD patients (n = 31), heart failure patients (n = 26), and healthy volunteers (n = 27). Carotid and transcranial Doppler ultrasonography were performed for all study groups for peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility (PI), and resistive (RI) indices of CA and MCA. Flow dynamics were compared between the groups. Doppler ultrasonographic data were analyzed at a median 12 (3-47) months after LVAD implantation. CA-PSV was lower in LVAD group compared with the other two groups (P < .001), MCA-PSV of LVAD and heart failure groups were similar and lower than healthy volunteers (P < .05). The highest values for CA-EDV were found in the LVAD group (P < .05). MCA-EDV values were found to be lowest in heart failure group (P < .05). For PI and RI, in all CA and MCA, the LVAD group had lower indices compared with the other two groups (P < .001). In addition, MCA flow analysis in patients with LVADs was identified for the first time with this study.     

Cerebrovascular events in children on intracorporeal continuous-flow left ventricular assist devices

Continuous-flow intracorporeal left ventricular assist devices (CF-LVAD) are used more frequently in the pediatric population. One of the major complications of CF-LVAD is cerebrovascular events (CVEs). Limited information is available on this complication in pediatric patients. We hereby present our experience on CVEs in children under CF-LVAD support in our institution. A retrospective, single center review of 21 patients younger than 19 years of age who underwent CF-LVAD implantation between June 2014 and September 2018 was performed. Patients on biventricular support and extracorporeal devices were excluded. Cerebrovascular accidents (CVAs)—ischemic or hemorrhagic—were investigated. CVE was confirmed by brain computed tomographic scan. Of 21 pediatric patients, 11 were male. Mean BSA was 1.05 ± 0.41 m² and mean age was 11.05 ± 4.07 years. Dilated cardiomyopathy was the leading cause of heart failure. The patients were implanted with HeartWare hVAD (n = 19), HeartMate II (n = 1), and HeartMate 3 (n = 1). Mean support time was 421 ± 448 (18-1460) days. Target international normalized ratio was between 2.5 and 3.0. Nine (43%) patients underwent transplantation, one patient recovered with subsequent device explantation. Four (17%) patients were still on support. One patient (5%) died in the early postoperative period and six (28%) patients died on VAD support after a mean duration of 194 days. There were overall five cerebral hemorrhagic strokes in four patients (0.2 events per patient-year). CVA occurred between 250 and 1320 days (mean 600 days). No ischemic stroke was documented. Only one (20%) patient died after hemorrhagic stroke; the other three patients recovered and were discharged from the hospital with minor sequelae. Incidence of CVE in children on CF-LVAD is relatively low compared with adults on VAD and severity of stroke is milder than adult population.     

Differential impact on post-transplant outcomes between pulsatile- and continuous-flow left ventricular assist devices

Ventura PA, Alharethi R, Budge D, Reid BB, Horne BD, Mason NO, Stoker S, Caine WT, Rasmusson B, Doty J, Clayson SE, Kfoury AG. Differential impact on post‐transplant outcomes between pulsatile‐ and continuous‐flow left ventricular assist devices.
Clin Transplant 2011: 25: E390–E395. © 2011 John Wiley & Sons A/S. Abstract: Background: The HeartMate II (HMII) left ventricular assist device (LVAD) has proven reliable and durable and has become the preferred choice for bridge to transplant therapy (BTT) when compared with the pulsatile HeartMate XVE (XVE). In this study, we compared the post‐transplant (PTx) outcomes between XVE and HMII using a large national data registry. Methods: The Organ Procurement and Transplantation Network (OPTN)/United Network for Organ Sharing (UNOS) Thoracic Registry database was queried for all patients implanted with either an XVE or an HMII as BTT during 2004–2009. Statistical analysis between XVE and HMII were performed using Kaplan–Meier survival analysis and Cox regression analyses. Results: A total of 673 patients were implanted with the XVE and 484 with HMII. When adjusted for age, gender, ethnicity, intra‐aortic balloon pump, ventilator, inotropes, dialysis, body mass index, creatinine, bilirubin, transfusion, pulmonary capillary wedge, and pulmonary arterial pressures, the HMII had similar one‐ and three‐yr survival (hazard ratio = 0.95, CI = 0.64, 1.42) and rejection‐free survival PTx compared to XVE. The XVE group had more early incidences of allograft rejection (AR) and hospitalization for infection (HI). Conclusions: Compared to XVE, patients with HMII have similar one‐ and three‐yr survival after heart transplantation with less risk of early graft rejection and significant infection. With a strong shift toward use of continuous‐flow LVADs, PTx outcomes are expected to continue to improve.     

Off-pump insertion of continuous flow left ventricular assist devices

BACKGROUND AND AIM OF THE STUDY: Traditional left ventricular assist device (LVAD) implantation requires extensive dissection and use of cardiopulmonary bypass (CPB). Potential adverse effects of CPB in very ill end-stage heart failure patients include right ventricular dysfunction, end-organ injury, and bleeding. We sought to evaluate the feasibility and outcome of LVAD insertion without CPB. METHODS: The Jarvik 2000 is an axial-flow pump newly involved in a phase I clinical trial in status I patients as a bridge to transplantation. Seven patients received this pump through thoracotomy or sternotomy with or without the use of CPB. RESULTS: All patients had NYHA class IV heart failure with end-organ dysfunction requiring inotropic therapy. Two were in cardiogenic shock, necessitating full CPB support. Five patients had the Jarvik implanted off-CPB. The off-CPB patients were associated with decreased length of surgery, mechanical ventilation, blood transfusions, inotropic support, and hospital stay including rehabilitation. Nearly all of the patients had complete resolution of liver and kidney dysfunction. CONCLUSION: We have demonstrated that off-CPB insertion of axial flow LVADs is feasible, safe, and potentially advantageous. Although we are encouraged by the perioperative simplicity of this strategy, we acknowledge that additional implants and comparisons of outcomes with traditional pulsatile and continuous flow device techniques will be necessary to advocate its widespread adoption.