Marlene Busko

April 07, 2017

SAN DIEGO — Patients with advanced heart disease who received the HeartMate 3 left ventricular assist device had fewer clotting and bleeding events at 6 months than similar patients who received the HeartMate II device, according to a 6-month secondary analysis of data from the MOMENTUM 3 trial (NCT02224755). Both devices are from Abbott (formerly St. Jude Medical).

This demonstrates that the newer HeartMate 3 pump is better "at reducing hemocompatibility-related adverse outcomes" than the previous pump, said investigator Nir Uriel, MD, from the University of Chicago School of Medicine and Medical Center, who presented the findings here at the International Society of Heart and Lung Transplantation 2017 Scientific Sessions. The study was published online in Circulation to coincide with the presentation.

Hemorrhagic and thrombotic hemocompatibility-related adverse events are the Achilles' heel of the interaction between a left ventricular assist system and its biologic circulatory interface," according to Dr Uriel and his colleagues.

To prevent such events, HeartMate 3 has a fully magnetically levitated rotor, wide blood flow passages, and an intrinsic pulse designed to avert pump stasis.

Bleeding and Clotting Events, the Achilles' Heel of LVADs

In their analysis, Dr Uriel's team examined 6-month data from 151 patients who received the HeartMate 3 and 138 patients who received the HeartMate II. Baseline characteristics of the patients were similar in the two groups.

Hemorrhagic events were defined as nonsurgical bleeding (such as gastrointestinal or other bleeding more than 30 days after the device was implanted) or neurologic events (hemorrhagic or ischemic, disabling or nondisabling stroke, or transient ischemic attack or seizures). Pump thrombosis and arterial thromboembolism were considered thromboembolic events.

More patients who received the HeartMate 3 device than received HeartMate II survived 6 months without any adverse hemocompatibility events, which included bleeding and clotting events (69%vs 59%; hazard ratio, 0.62; P = .012).

In addition, in the HeartMate 3 group, there was an absence of pump thrombosis (so the pump worked as it was designed to) and a decrease in nondisabling strokes.

Table. Adverse Events With the Two Devices

Event HeartMate 3 Group, % (n = 151) HeartMate II Group, % (n = 138)
Hemocompatibility 28.0 38.0
Hemorrhagic 15.2 18.1
Thrombotic 7.3 16.7
Hemorrhagic and thrombotic 6.0 3.6


There were significantly fewer medically managed pump thrombosis events with HeartMate 3 group than with HeartMate II (0 vs 5; P = 0.02). And the number of nondisabling strokes was much lower with HeartMate 3 (3 vs 12; P = .026).

The number of surgically managed pump thrombosis events was "dramatically" lower with HeartMate 3 than with HeartMate II (0 vs 12; P < .001), Dr Uriel pointed out.

There were fewer deaths related to hemocompatibility in the HeartMate 3 group than in the HeartMate II group (2 vs 4), and more instances of disabling stroke with HeartMate 3 (9 vs 5), but neither of these differences was significant.

On exploratory multivariable analysis, there was an independent association between survival at 6 months free of any hemocompatibility-related adverse event and the HeartMate 3 pump, being younger, and receiving adequate antithrombotic therapy.

"The quantitative estimate of freedom from hemocompatibility-related adverse events between the two pumps suggests exploratory findings of clinical correlates in the hemostatic management axis that may warrant prospective confirmation," Dr Uriel explained.

Proposed Hemocompatibility Scoring System

During their analysis, Dr Uriel and his colleagues devised a scoring system for hemocompatibility events related to LVADs that would distinguish between disabling and nondisabling stokes.

They assigned mild events (such as one or two nonsurgical bleeding episodes) 1 point, moderate events (such as a nondisabling stroke) 2 points, moderate to severe events (such as surgery to replace the pump) 3 points, and severe events (such as disabling stroke or death) 4 points.

They determined that the cumulative score for the 151 patients in the HeartMate 3 group was lower than that for the 138 patients in the HeartMate II group (101 vs 137; P = .08).

Session cochair Francis Pagani, MD, from the University of Michigan in Ann Arbor, wanted to know why the scoring system distinguishes between disabling and nondisabling stroke.

A disabling stroke is life-changing for a patient, Dr Uriel explained. "I think that it's about time that we create a tier of hierarchical adverse events" related to LVADs that can affect patients' lives. The proposed scoring system would provide a standardized way to compare devices in clinical trials and give clinicians a tool to help patients understand what they can expect from an LVAD.

This analysis does make it clear "that there are important differences in terms of device design, and the technology is available to resolve some of these adverse [hemocompatibility] events," Dr Pagani told Medscape Medical News.

This proposed system to evaluate bleeding and clotting risk related to LVADs "probably needs further validation," including an analysis to see if the scores correlate with quality of life," he noted. However, there is a need for such a tool to measure the impact on quality of life, he pointed out.

A score of the burden of hemocompatibility can "serve to standardize assessment of aggregate patient-level outcomes across various device patterns," Dr Uriel added.

MOMENTUM 3 was sponsored by Abbott. Dr Uriel reports receiving research and consulting support from Abbott. Dr Pagani has disclosed no relevant financial relationships.

International Society of Heart and Lung Transplantation (ISHLT) 2017 Scientific Sessions. Presented April 6, 2017.

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