PracticeUpdate Cardiology June 2019

EDITOR’S PICKS 6

A Fully Magnetically Levitated Left Ventricular Assist Device The New England Journal of Medicine Take-home message • Patients with advanced heart failure were randomized to receive a fully magnetically levitated centrifugal-flow left ventricular assist device or a mechanical-bearing axial-flow left ventricular assist device as either a bridge to transplantation or destination therapy. At 2 years, 76.9% of patients in the centrifugal-flow pump group were alive and free from disabling stroke or reoperation compared with 64.8% in the axial-flow pump group (P < .001 for superiority). In addition, patients in the centrifugal-flow pump group had a lower rate of pump replacement at 2 years compared with patients in the axial-flow pump group. • The use of a fully magnetically levitated centrifugal-flow left ventricular assist device in patients with advanced heart failure was associated with improved survival outcomes and less need for pump replacement than an axial-flow device. COMMENT By Clyde W. Yancy MD, MSc, MACC, FAHA, MACP, FHFSA and Jayson R. Baman MD " Our evolving expectation of a less complicated application of mechanical circulatory support brings this technology to more patients and offers hope to the desperately ill patient with advanced heart failure. "

Abstract BACKGROUND In two interim analyses of this trial, patients with advanced heart failure who were treated with a fully magnetically levitated cen- trifugal-flow left ventricular assist device were less likely to have pump thrombosis or nondis- abling stroke than were patients treated with

F or 50 years, cardiovascular investigators have been in pur- suit of capable means of mechanical circulatory support (ie, left ventricular assist device, or LVAD therapy) for the failing heart. The dire outcomes associated with heart failure in the early years fueled the rush to invention, whereas the ongoing need for mechanical support strategies for NYHA class IV heart fail- ure in the contemporary era (despite effective, evidence-based medical therapy) has sustained the need for iterative product development. LVADs have been historically bioengineered as axial-flow devices, but adverse events, particularly pump thrombosis, drive line infection, gastrointestinal bleeding due to mechanical disruptions in coagulation profiles, and stroke, have been significant and costly challenges. These events, especially pump thrombosis, have proven to carry grave prognoses. Yet, the need remains acute, and, when all goes well, the remarkable stabilization of the heart failure syndrome and subsequent evi- dence-based improvement in morbidity and mortality compared with medical therapy has positioned LVAD therapy as a realistic but imperfect treatment option for heart failure. The technology has evolved from large-format, pulsatile, mechanical devices that limited portability to smaller, electronic, non-pulsatile devices that were more patient friendly but abruptly challenged our understanding of physiology. Is there a true need for pulsatile blood flow? The most recent iteration of LVAD technology incorporates a magnetically levitated, friction-free pump with no blood-pump interface and a pump that restores (modest) circulatory pulsatility. The MOMENTUM 3 trial tested this latest third-generation pump against second-generation pumps. The early 6-month and then later 2-year data were heralded as breakthrough findings. We now

have the final report. The authors report superiority of the Heart- Mate 3 device with regard to the primary endpoint of survival free of disabling stroke and reoperation (HR, 0.84; P < .001) and the secondary endpoint of the necessity of pump replacement within 2 years (HR, 0.21; P < .001). Remarkably, the HeartMate 3 device was associated with a 90% reduction in cases of pump thrombosis (70 cases vs 7 cases; HR, 0.08; P < .001). This was in conjunction with reduced rates of cerebrovascular events (HR, 0.42; P < .001) and bleeding events (HR, 0.64; P < .001). We are now able to arguably assert that optimal use of these third-generation pumps has eradicated the most compelling complication of pump thrombosis and has largely reduced the worrisome risk of stroke. There is a need for more research. The authors report the still high rates of drive line infections, there remains a need for devel- opment of best-quality practices, and easier pumps to implant are needed. However, we have reached a pause moment in the care of patients with advanced heart failure. Our evolving expectation of a less complicated application of mechanical circulatory support brings this technology to more patients and offers hope to the desperately ill patient with advanced heart failure. For those of us who provide care for these patients, this technology reliably answers questions raised 50 years ago. The journey continues, but it has been nicely rewarded.

Dr. Baman is an Internal Medicine Resident at Northwestern University in Chicago, Illinois.

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