Continuous-Flow Ventricular Assist Devices

The continuous-flow ventricular assist device (CF-VAD) is an effective therapy for patients with advanced (stage D) heart failure. In 2019, 3198 primary left ventricular assist devices were implanted in the United States, which is the largest annual volume in history. There are two main types of CF-VADs (axial-flow and centrifugal-flow pumps). Currently, there are three CF-VADs approved by the Food and Drug Administration as bridge-to-transplant and destination therapy—the HeartMate II (Abbott, Abbott Park, IL), the HVAD (Medtronic, Minneapolis, MN), and the HeartMate 3 (Abbott). In this chapter, the current trends and basic principle of CF-VADs are discussed. The pump descriptions, history, hemocompatibility, and adverse events (AEs) focusing of hemocompatibility-related AEs of four axial-flow and three centrifugal-flow pumps are also discussed. Hemocompatibility-related AEs include stroke, von Willebrand syndrome, bleeding, and pump thrombosis. These are multifactorial AEs, but they are closely related to pump characteristics, such as the streamlined inside of the pump, or supraphysiological shear stress caused by the high rotational speed of CF-VADs. Some of the major AEs were unexpected until installation of the CF-VADs, and many studies have been conducted to learn how to overcome those events. As the pump technology is developed, we observe better clinical outcomes with better pumps, but many complications still exist, and the high complication rate is a major limitation of CF-VAD therapy.