HeartMate® VE LVAS design enhancements and its impact on device reliability1

OBJECTIVE: The HeartMate VE left ventricular assist system (LVAS) has supported more than 2300 patients and has been shown to be effective for bridge to cardiac transplantation and has demonstrated improved outcomes in survival as a destination therapy. Improvements in device durability are needed as bridge to transplant times increase and as we move into the era of LVAD as destination therapy. The purpose of this study is to determine if design enhancements to the HeartMate LVAS have improved device reliability and durability. METHODS: A retrospective analysis of serious mechanical failures was performed in 1865 devices (1458 VE, 407 XVE). The analysis of data included devices used to support patients from September 1998 for bridge to transplantation and destination therapy. Serious mechanical failures were defined as inflow valve dysfunction, percutaneous lead breaks, diaphragm fractures or punctures, bearing failures, outflow graft erosion and pump disconnects. RESULTS: Median device duration for the VE was 97 days (max 1206 days), and 85 days (max 517 days) for the XVE. A total of 134 serious mechanical failures occurred and included inflow valve dysfunction (5.3% VE, 2.4% XVE) (P = 0.853) percutaneous lead breaks (1.9% VE, 0% XVE) (P < 0.001) diaphragm fractures (0.1% VE, 0% XVE) (P = 0.134) outflow graft erosion (0.2% VE, 0% XVE) (P = 0.1096), pump disconnects (0.1% VE, 0% XVE) (P = 0.1336) and bearing failures (0.6% VE, 0.2% XVE) (P = 0.5538). Of the XVEs 97% were free of serious mechanical failures at 6 months and 82% at 1 year compared to 92 and 73% for the VE, respectively. The 6-month difference between the devices was statistically significant (P = 0.0063) and there was no statistically significant difference at 1 year (P = 0.1492). CONCLUSIONS: Preliminary experience with the HeartMate XVE LVAS demonstrated a significant reduction in percutaneous lead breaks. Early trends indicate positive impact of recent design modifications on XVE performance. These design modifications may improve device durability and reliability, which is crucial as we enter the era of LVADs as an alternative to medical therapy.