A fully magnetically levitated, centrifugal-flow left ventricular assist device (LVAD) that creates a pulse-like variation in blood flow was associated in a major study with a less frequent need for pump replacement than a previous, axial-flow pump version. The analysis also determined the device was superior with respect to patient survival free of disabling stroke or the need for a second procedure to replace the pump.
The results of the Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy with HeartMate 3 (MOMENTUM 3) trial were published in April in the New England Journal of Medicine.
Duke specialists Carmelo A. Milano, MD, a cardiac surgeon, and Chetan B. Patel, MD, a heart failure cardiologist and medical director of the Duke transplant program, were among the authors. Duke was the leading enrolling center for the trial, which assessed the performance of the device over two years. The study reviewed results for 1,028 patients (516 in a centrifugal-flow pump group, 512 in an axial-flow pump group). Duke cardiologists have extensive experience with the magnetically levitated LVAD, known as HeartMate 3 (Abbott, Abbott Park, IL).
“The results mean that the quality of life for patients with end-stage heart failure (HF) just got a lot better because of the performance of this device,” Milano says. “Patients who are not eligible for transplant but who have advanced HF should be considered for this therapy.” The Duke transplant team treats approximately 100 patients each year who could benefit from the new centrifugal-flow LVAD, Milano adds.
The findings may also offer hope for the 50,000 to 100,000 patients in the nation with terminal HF who are unlikely to be among the 3,000 patients who undergo heart transplantation annually.
“The results offer a lifesaving solution,” Patel says. “Because we are now less worried about thrombosis, we can offer it to a much larger group of patients with greater confidence. The LVAD can now be seen as a truly long-term therapy in select patients.”
Because transplantation remains a limited option, the MOMENTUM results point toward a solution for patients with HF who would not otherwise live long enough for transplant.
“Only a relatively small number of patients can be helped with heart transplantation,” Milano says. “But this LVAD may open the door to allow us to help many more people with terminal HF.”
New LVAD lowers risk of thrombosis
During trials with the previous axial-flow device, HeartMate II (Abbot, Abbot Park, IL), approximately 10% of patients who were implanted developed thrombosis, requiring that the device be surgically removed. Thrombosis-related events forced some patients to undergo hemodialysis for kidney failure. Duke specialists were involved in identifying the thrombosis risk associated with the axial-flow model—a risk that forced specialists to be cautious.
“Here at Duke, we have experienced only one patient who needed to have the HeartMate 3 replaced,” Milano says. “This is far better than the 10% rate of replacement of the older axial flow pumps, mostly for pump thrombosis.”
The HeartMate 3 offers two distinctive features that contributed to improved outcomes in the trial, the study authors note:
- The centrifugal design uses a magnet external to the rotor—a novel configuration likely to influence future LVAD design, says Patel. The design offers more space through which blood cells travel and reduces trauma experienced by the cells.
- An algorithm within the device creates a flow differential—a protocolized pump speed—that alters the flow of circulating blood and creates a washing effect simulating a pulse. “This is felt to be a key factor that reduces the stroke rate by preventing clots from forming,” Milano says.
Heart failure and transplant specialists at Duke have played a central role in the development and testing of LVAD devices. “We were the leading enrollers in the trials that preceded MOMENTUM,” Patel says. “We have one of the busiest, most experienced LVAD programs in the country.”
The specialists have also played a leading role in major published analyses of LVAD development. Since February 2017, Milano has contributed to three New England Journal of Medicine studies analyzing the progress of the devices; in an April 2018 article, Patel and Milano were among the co-authors of a study assessing two-year LVAD outcomes of the magnetically levitated cardiac pump in HF. Duke physicians Joseph G. Rogers, MD, a heart failure cardiologist, and Jacob N. Schroder, MD, a cardiac surgeon, have also contributed to related analyses.
Patel views the LVAD results as another step in the ongoing development of the technology as a permanent solution for patients with HF. “The next evolution must focus on the peripherals of the devices: the controllers and the batteries. From a patient’s perspective, that’s what they see, and that’s what they must manage. Those aspects must become more patient friendly,” Patel says.