Results of the Post-U.S. Food and Drug Administration-Approval Study With a Continuous Flow Left Ventricular Assist Device as a Bridge to Heart Transplantation: A Prospective Study Using the INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support)

Study Questions:

Are morbidity and mortality rates following implantation of the HeartMate II (HMII) left ventricular assist device (LVAD) comparable to that of other devices implanted in the same era for the bridge to transplant indication?

Methods:

This was a prospective evaluation of the first 169 HMII patients enrolled into the INTERMACS registry following Food and Drug Administration (FDA) approval of the device (April-August 2008). All patients underwent device implant for the bridge to transplant intent. A comparator group of patients (n = 55; prospectively enrolled) in the INTERMACS registry undergoing implant (September 2007-February 2009) of other FDA-approved devices (79% HeartMate XVE, 21% implantable ventricular assist devices) for the same indication was used. The endpoints of interest included survival, adverse events, and quality of life assessed by the EuroQol 5Q-5D visual analog scale.

Results:

The comparator group had a higher percentage of patients in INTERMACS profiles 1-2, and lower percentage of patients in profiles 3-7. Comparator patients also had poorer baseline renal function, a higher AST, and a higher burden of inotrope use preoperatively. Operative (30-day) mortality was 4% in the HMII group versus 11% in the comparator LVAD group. At 6 and 12 months, 90% and 85% of HMII patients were alive versus 79% and 70% in the comparator group, respectively (p < 0.001). Postoperative complications such as bleeding, nonstroke-related neurologic dysfunction, infection, and device replacement were significantly less frequent after HMII implant than after comparator device implant. Both LVAD groups enjoyed an improved quality of life through 12 months post-LVAD implant when compared with baseline measures.

Conclusions:

The post-approval FDA study suggests that the HMII device implant leads to improved outcomes.

Perspective:

Mortality and morbidity following LVAD implant continue to improve as operative technique, device mechanics, and patient selection improve. This study demonstrates very favorable outcomes in bridge to transplant patients implanted with the HMII continuous flow LVAD. The comparator group was sicker on many accounts at baseline, with higher inotrope requirements and greater degrees of end-organ dysfunction. While attempts were made to control for such differences using multivariable Cox regression analysis, comparisons between HMII and the control group should be viewed with some skepticism. Nevertheless, the outcomes following HMII implant in this cohort are excellent, with some of the highest survivals published following LVAD implant to date. Even more importantly, these outcomes have been achieved in a nontrial, ‘real-world’ patient population.

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: Postoperative Complications, United States Food and Drug Administration, Heart-Assist Devices, Device Approval, Heart Failure, United States, Heart Transplantation


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