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WASHINGTON -- Two implantable left ventricular assist devices (LVADs) -- the Heart Mate II by Thoratec Corporation and HeartWare by HeartWare -- have been linked to serious adverse events, according to the FDA.
"These adverse events include an increased rate of pump thrombosis (blood clots inside the pump) with Thoratec's HeartMate II and a high rate of stroke with the HeartWare HVAD since approval of the devices. We are also aware of bleeding complications associated with both devices," according to the safety communication from the agency.
HeartMate II was initially approved in 2008 for use as a bridge to transplant for patients at risk of imminent death due to nonreversible left ventricular heart failure, and then in 2010 its indication was expanded to include use as destination therapy for patients who are not candidates to receive donor hearts. The HeartWare system was approved in 2012, but only for use as a bridge to transplant (BTT).
The FDA said it received reports of pump thrombosis in patients implanted with the HeartMate II -- a risk that was also reported in clinical trials of the device -- but noted that "patients are experiencing pump thrombosis events earlier than observed during the clinical trials . For example, two analyses in the scientific literature reported the confirmed (after explant) HeartMate II pump thrombosis rate as high as 8.4% of implanted devices at 3 months (Starling et al. 2013) and 6% of implanted devices at 6 months (Kirklin et al. 2014)."
This is compared with 1.6% of implanted devices at one year during the HeartMate II BTT clinical trial and 3.8% of implanted devices at 2 years during its destination therapy clinical trial.
In the case of the HeartWare product, the FDA said it was issuing the safety warning after reviewing results from a clinical trial of the device for destination therapy. In that study, researchers "reported 28.7% of HVAD patients experienced one or more strokes over 2 years, compared with 12.1% among patients implanted with the control device (HeartMate II)."
Additionally, the FDA said it had received reports of bleeding events related to both devices, but added that the exact cause has not been fully elucidated, although it may be related to anticoagulation therapy used with the devices.
The FDA is advising physicians to take extra precautions before implanting either of the devices, including assessing the risk-benefit profile of each patient. Additionally, the FDA is asking that all explanted devices and components be returned to the manufacturers.
The agency said it has been working with both manufacturers and it has approved new labeling for HeartMate II, which includes information about the pump thrombosis risk.
In the case of HeartWare, the FDA said it still believes the benefit of the device outweighs the risk of stroke when the pump is used for bridge to transplant. It noted that the company is currently conducting a prospective, randomized, controlled, unblinded, multicenter study to assess whether optimal blood pressure management can help patients implanted with the company's system.