Design Concepts and Preclinical Results of a Miniaturized HeartWare Platform: The MVAD System.

Over the past 10 years, ventricular assist devices (VADs) have gained increased acceptance as a treatment therapy for advanced stages of heart failure. Continuous-flow VADs have become the gold standard, with over 4000 patients enrolled into the Interagency Registry for Mechanical Assisted Circulatory Support (INTERMACS).1 In the past, device reliability and device-related adverse events inhibited adoption of long-term mechanical circulatory support. However, current advances in VAD technology have improved patient outcomes, and the 2-year survival rate with continuous-flow VADS for destination therapy patients is 70%.1 As long-term support becomes more prevalent, next-generation devices must not only enable wider application of the therapy but also enhance patient quality of life. Ventricular assist device miniaturization may offer several important benefits. By reducing the required thoracic space and pump footprint, patients with a smaller body habitus (<1.2 m2) may become candidates for device implantation.2 A miniature device may also promote minimally invasive surgical techniques that reduce the surgical trauma associated with sternotomy and cardiopulmonary bypass, resulting in lower associated adverse events and faster recovery times.3 The MVAD pump does not require the creation of a pump pocket, which may reduce invasiveness of surgery, length of stay, and complications such as bleeding, hematoma, and infections. In addition, device miniaturization and ease of implantation may ultimately lead to a paradigm shift in clinical practice, resulting in the treatment of a less ill cohort of patients.4 The MVAD System is a miniature VAD designed to provide circulatory assistance to patients diagnosed with end-stage, refractory heart failure. The pump size is significantly smaller than devices currently on the US market with a displacement volume of 20 mL and a weight of just 78 g. In comparison, the Thoratec HeartMate II Pump and HVAD Pump weigh 290 and 160 g, respectively.5,6 A size comparison of the HVAD Pump and MVAD Pump are shown in Figure ​Figure1.1. In addition, the MVAD System peripheral equipment was designed after extensive field research with patients, caregivers, emergency responders, VAD coordinators, cardiologists, and surgeons. Usability and human factor testing were conducted to determine the most ergonomic, safe, and intuitive design. Miniaturization of the pump design as well as simplification of the user experience through user-friendly patient peripherals are 2 important steps toward improving patient quality of life. FIGURE 1 Size comparison of the MVAD Pump—The HeartWare HVAD Pump (right) weighs 160 g compared with the MVAD Pump (left), which weighs 78 g.