B.2. What are the main types of LVAD, and how do they compare in terms of morbidity and mortality following implantation?
Answer:
The two main types of implanted LVADs include (1) axial flow (HeartMate 2; HM2) and (2) centrifugal flow (Heartmate 3 [HM3] and HeartWare HVAD). Table 6.1 lists their key differences. The axial flow device (HM 2) has largely been replaced by the centrifugal device (HM 3) based on the Momentum 3 trial which demonstrated that patients with the HeartMate 3 had improved survival and less disabling stroke or reoperation to replace or remove a malfunctioning device at 2 years, as well frequent pump removal. In 2021, Medtronic stopped the sale and distribution of the HeartWare HVAD given the risk of mortality and neurologic adverse events in patients using the device.
Table 6.1: Key Differences Between the HeartWare, HeartMate 2, and HeartMate 3 Centrifugal Continuous-Flow LVADs
| HeartMate 2 | HeartMate 3 | HeartWarea | |
|---|---|---|---|
| Pump properties | Axial flow, requires thoraco-peritoneal placement | Fully magnetically levitated rotor; wide blood flow gaps to decrease shear stress | Both passive magnetic and hydrodynamic thrust to provide contact-free rotation of wide blade impeller |
| Pump speed | 8,800-10,000 rpm | 5,000-9,000 rpm | 2,400-3,200 rpm |
| Artificial pulse | N/A | Automatically on; rotor speed changes every 2 s produced by increase and decrease of speed of 2,000 rpm | Rotor speed decreases by 200 rpm for 2 s and increases by 200 rpm for 1 s above set speed with one cycle per minute |
| Regulatory approval | FDA approved for BTT (2008) and DT (2010) | FDA approved for BTT (2017) and DT (2018) | FDA approved for BTT (2012) and DT (2017), stopped sales in 2021 |
BTT, bridge to transplantation; DT, destination therapy; FDA, U.S. Food and Drug Administration; LVAD, left ventricular assist device; rpm, rotations per minute.
References
- Mehra MR, Uriel N, Naka Y, et al. A fully magnetically levitated left ventricular assist device—final report. N Engl J Med. 2019;380:1618-1627.