Heart failure patients treated with Medtronic's HeartWare HVAD had a higher risk of major neurological adverse events (NAEs) than their counterparts who received Abbott’s HeartMate 3 Left Ventricular Assist System, according to an analysis of registry data published in the journal Circulation.
The study of 6,025 recipients of centrifugal-flow left ventricular assist devices (CF-LVAD) found 16.4% of HVAD patients had a major NAE such as a transient ischemic attack, compared to 6.4% of the HeartMate 3 cohort.
- Publication of the registry data comes weeks after Medtronic pulled HeartWare from the market in response to "a growing body of observational clinical comparisons" that link it to a higher rate of NAEs than rival devices.
HeartWare has been the subject of three Class I recalls in 2021 over issues including delayed or stalled restarts. While the recalls ratcheted up the pressure, Medtronic remained publicly committed to the device until revealing a new problem at the start of June. The evidence of a higher rate of NAEs was the death knell for HVAD.
Yet, while the evidence of NAEs was the headline reason for the withdrawal of HVAD, details of what Medtronic had learnt about the link between its device and the adverse events were limited. Late last month, physicians from institutions including Johns Hopkins University School of Medicine published an analysis that shed some light on the risks posed by HVAD.
The paper looked at the rates of major NAEs, namely ischemic and hemorrhagic cerebrovascular accidents and transient ischemic attack (ICVA, HCVA and TIA), in CF-LVAD patients in the Interagency Registry for Mechanically Assisted Circulatory Support. The study population was evenly split between recipients of HVAD and HeartMate 3 but NAEs were unevenly distributed.
After a median of nine months of follow up, 6.4% of recipients of HeartMate 3 had suffered a major NAE. That compared to a 16.4% rate of NAEs after a median of 12 months of follow up in the HVAD analysis. The difference was underpinned by divergent rates of all three adverse events defined as major NAEs. HVAD was linked to statistically higher rates of ICVA, HCVA and TIA.
It is unclear why HVAD is associated with a higher rate of major NAEs. While HVAD is no longer on the market, Sung-Min Cho, assistant professor of neurology at Johns Hopkins and co-author of the study, plans to seek an explanation for the increased risk.
"Hopefully, those observations will inform future device design, advanced heart failure management and device selection, and most of all, yield safer LVAD systems to support seriously ill patients," Cho said in a statement.
At the same time, the rates of major NAEs associated with Abbott's device shows there is room for improvement. In the registry, 3.4% of recipients of HeartMate 3 suffered ICVA, while 2.0% and 1.0% respectively had HCVA and TIA.
FDA in a June 3 alert told healthcare providers to stop implanting end-stage heart failure patients with Medtronic's HVAD and advised them to use Abbott's HeartMate 3 as an alternative product. Medtronic has been coordinating with Abbott to ensure patients who require the device have that option.