August 6, 2015 — The U.S. Food and Drug Administration (FDA) is alerting healthcare providers, patients and caregivers about serious adverse events associated with left ventricular assist devices (LVADs). 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. The agency is also aware of bleeding complications associated with both devices.
Implantable LVADs help the left ventricle circulate blood throughout the body in patients with advanced heart failure. The devices consist of a blood pump, power pack and controller. The blood pump is implanted inside a patient’s body and attached to the heart’s left ventricle and to the aorta. The power pack and controller are connected to the blood pump and carried by the patient outside the body.
The FDA has received reports and information from a variety of sources indicating an increase in the rate of pump thrombosis events in patients implanted with the HeartMate II. Information also shows that patients are experiencing pump thrombosis events earlier than observed during the clinical trials conducted to support the product’s approvals in 2008 (bridge-to-transplant) and 2010 (destination therapy).
In regards to the HeartWare HVAD, the FDA is aware of recently reported results from a clinical trial designed to evaluate the safety and effectivness of the device when used for the DT indication. Investigators reported 28.7 percent of HVAD patients experienced one or more strokes over two years, compared to 12.1 percent among patients implanted with the control device (HeartMate II).
Both devices have raised concerns about bleeding complications through adverse event reports and information from a variety of sources. The cause of bleeding complications is not fully understood, but is likely due to many different factors. One possible factor may be modification to blood thinning (anticoagulation) therapy in an attempt to lower the risks of pump thrombosis and embolic stroke.
The FDA recommends the following actions for healthcare providers:
Perform a thorough clinical evaluation, assessing the benefit-risk profile of each patient in determining the most appropriate treatment plan and, if necessary, selecting a device;
Consider the risks for pump thrombosis, stroke and bleeding when determining the appropriate therapy for individual patients; and
Review the current device labeling prior to making treatment decisions if you are considering using either of these devices.
Return all explanted LVAD devices and components to their respective manufacturer. In the case of LVAD-related pump thrombosis and other adverse events, manufacturer evaluation of the affected device is critical to better understand the reasons for these adverse events.
The FDA has been working with Thoratec to better understand and explain the increased incidence of pump thrombosis. On Aug. 5, 2014, the FDA approved updated labeling for the HeartMate II that includes the risk of pump thrombosis. Thoratec is currently conducting a prospective, multi-center, non-randomized study designed to assess the incidence of HeartMate II pump thrombosis and to identify the risk factors associated with pump thrombosis events.
Thoratec was purchased by St. Jude Medical in July 2015.
Regarding the HeartWare HVAD, the FDA is concerned about the reported stroke rates, but at this time believes the benefits of using the device continue to outweigh the risk for the currently approved BTT indication. The agency also believes it is appropriate to continue the clinical investigation of this device in the DT population with the careful monitoring procedures currently in place. HeartWare is also currently conducting a prospective, randomized, controlled, un-blinded, multi-center study to assess whether optimal blood pressure management can help lower the incidence of stroke in DT patients implanted with an HVAD.
For more information: www.fda.gov
July 14, 2025 
