Use of an Intrapericardial, Continuous-Flow, Centrifugal Pump in Patients Awaiting Heart Transplantation
Are outcomes in heart failure patients supported with the HeartWare ventricular assist device (HVAD) for the bridge to transplant (BTT) indication similar to that of contemporaneous commercially available devices?
This was a prospective multicenter, historical controlled study of transplant-eligible patients implanted with the investigational HVAD, a centrifugal flow VAD placed intrapericardially into the left ventricular apex. Historical controls implanted for BTT indications were derived from INTERMACS (the Interagency Registry for Mechanical Assisted Circulatory Support), a database of all US patients implanted with Food and Drug Administration-approved durable VADs. The primary outcome was the proportion of device “successes,” defined as survival on the original device, survival to transplant, or explant for recovery at 180 days. Kaplan-Meier survival analyses employed censoring for transplant, myocardial recovery, withdrawal/loss to follow-up.
There were 140 patients implanted with the HVAD, and 499 historical controls. Groups were similar except that controls were more likely to be of lower INTERMACS profiles with worse renal function. There were 88 (63%) patients still on HVAD support at 180 days, with six (4.3%) deaths and seven (5%) device exchanges. Device “success” occurred in 90.7% in the HVAD group and 90.1% in the controls (p < 0.001 for noninferiority, p > 0.05 for superiority). Kaplan-Meier survivals at 180 and 360 days were 94% and 86% for the HVAD and 90% and 85% for controls, respectively (p = 0.61). HVAD patients had significant improvements in 6-minute walk distance and quality-of-life measures. Rates of stroke, infection, right ventricular failure, and device replacement were similar to that of other published LVAD studies.
The HVAD was noninferior to commercially available VADs for the bridge to transplant indication, and had a favorable event profile.
Given the evolution of device technology and coincident improvements in outcome since the mechanical support field’s inception, it is important to examine the safety profile of new devices. Given the era of INTERMACS controls selected, this study was primarily a comparison of the HVAD to that of currently used continuous flow mechanical support. We can also assume that a vast majority of the other comparative VADs were HeartMate II models, the number one implanted continuous flow device in the world. While both devices are of continuous flow design, each has their own weaknesses and benefits from both a patient and surgical perspective. While a major study limitation is lack of a true, single device ‘control,’ this study provides reassurance that the HVAD will bridge eligible patients to transplant with a similar success profile as currently approved technology. Similar studies are needed for nontransplant-eligible patients.
Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Cardiac Surgery and Heart Failure, Acute Heart Failure, Heart Transplant, Mechanical Circulatory Support
Keywords: Heart-Assist Devices, Heart Failure, Survival Analysis, Heart Transplantation
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