Current status of third-generation implantable left ventricular assist devices in Japan, Duraheart and HeartWare

Abstract

Recently, left ventricular assist devices (LVADs) have become a viable therapeutic approach as a bridge to cardiac transplantation, as well as destination therapy or as part of the bridge to recovery. In Japan, paracorporeal pneumatic devices are the only choice for such therapy, as implantable LVADs are not yet generally available due to device lag, which represents a serious problem in this field. Clinical trials of four different continuous-flow pumps, both axial and centrifugal flow types, were completed at about the same time, and two of those devices, DuraHeart and EVAHEART, have already been approved for use in Japan. Thus, reports of advanced treatment for severe heart failure with these devices are expected. The DuraHeart (Terumo Heart, Ann Arbor, MI, USA) and another device named the HeartWare (HeartWare Inc, Miami Lakes, FL, USA) are so-called third-generation devices, as they have achieved miniaturization and improvements in performance from the use of magnetic levitation. Based on our experiences from both clinical research and experimental use, we herein discuss the DuraHeart and HeartWare devices, with a focus on the clinical outcomes and management strategies. Because of the long waiting period for heart transplantation in Japan, these two devices are considered to have important roles in the near future for the treatment of severe heart failure, and a comprehensive strategy for LVAD therapy including such third-generation implantable devices is expected.

Design and Implementation of a Novel Passive Magnetically Levitated Nutation Blood Pump for the Ventricular-Assist Device

“…The maximum difference of F z of the simulated and numerical results is 0.206 N and 0.215 N, respectively, when the gap is 1 mm. The maximum deviation between the simulated and numerical results is approximately 4.2% when the gap is 1 mm, which indicates that the numerical data are consistent with the simulations, showing the general validity of Equation (5). Figure 9a shows the velocity vectors at 1450 rpm and a 5 L/min flow rate throughout the pump.…”

“…Currently, because of some tricky problems in cardiac transplantation, such as implantation, the long-term management of transplant-related complications, and a serious lack of heart donors, one of the most effective measures for treating end-stage heart failure is the ventricular-assist device (VAD) [1], [2]. Most of the VADs in a clinical setting are designed as centrifugal blood pumps or axial flow blood pumps, such as HeartWare HVAD [3], HeartMate III [4], Terumo Dura-Heart [5], and Berlin Heart [6]. However, the advantages and disadvantages of centrifugal versus axial flow blood pumps are still in dispute.…”

In Vitro Thrombogenesis Resulting from Decreased Shear Rate and Blood Coagulability

“…Mechanical circulatory support devices are useful for treating patients with severe heart failure (1). Centrifugal blood pumps can be used as mechanical circulatory support devices for implantable artificial hearts (2–4), percutaneous cardiopulmonary support (PCPS) (5–7), and extracorporeal membrane oxygenation (ECMO) (8–10). In developing these centrifugal pumps, it is important that they are blood compatible in terms of antithrombogenicity or blood trauma.…”

Impeller (straight blade) design variations and their influence on the performance of a centrifugal blood pump

“…In the Kyoto-NTN blood pump, the rotor comprises 16 straight blades, 8 and in the DuraHeart, the impeller consists of seven straight vanes. 9 Based on the experience derived from conventional pumps, the spiral-profile blades process a greater hydraulic efficiency than straight blades. Unfortunately, for small-scale blood pumps, the spiral-profile blades in a shrouded impeller are even more difficult and costlier to produce.…”

“…In addition, the impeller flow passage in a shrouded impeller usually lies in the middle of the impeller, such as in the DuraHeart pump. 9 However, in the HeartMate 3, the flow passage is located near the impeller bottom (this side is away from the inlet port), 10 whereas in the UltraMag, the passage is situated near the impeller top (this side is close to the inlet port). 11 The underlying influence of the flow passage position acting on the pump remains unclear.…”