The FDA is aware of recent reports regarding reduced leaflet motion in some bioprosthetic aortic valves, including both surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR) devices. Importantly, most cases of reduced leaflet motion were discovered by advanced imaging studies in patients without symptoms of abnormal bioprosthetic valve function. Further, these studies have shown that in valves with reduced motion of one or more individual leaflets, there was acceptable forward blood flow through the valve opening without evidence of stenosis.
The definitive cause(s) of reduced leaflet motion in some bioprosthetic aortic valves also is not known. Evidence from imaging studies suggests that blood clot (thrombus) deposits on the leaflets may cause restricted motion. The prevalence of reduced leaflet motion was less in patients receiving therapeutic anticoagulation with warfarin compared with those receiving sub-therapeutic or no anticoagulation and with those receiving dual anti-platelet therapy. In one study, treatment with blood thinning medications (anticoagulants) resulted in the resolution of the leaflet motion abnormalities.
At this time, the FDA believes that bioprosthetic aortic valves remain reasonably safe and effective when used according to their approved indications. This view is supported by the favorable benefit/risk profile observed in SAVR devices in the 30 years they have been on the market and in TAVR devices in the eight years they have been in use.
These reports have raised important questions about bioprosthetic aortic valves. However, limited available data do not allow the FDA to fully characterize the causes, incidence, and short and long-term risks of reduced valve leaflet motion, or to recommend appropriate treatment. The FDA is working with the American College of Cardiology, the Society of Thoracic Surgeons, and the device manufacturers to design clinical studies to fully evaluate reduced valve leaflet motion for all types of bioprosthetic aortic valves.
For patients who have a bioprosthetic aortic valve, additional diagnostic imaging using 3D or 4D CT or TEE may be considered when clinically indicated. If reduced leaflet motion is found, treatment options should be discussed with the team of heart physicians responsible for the patient’s care.
See the FDA Safety Alert
See also Medical Law Perspectives, February 2015 Report: Mending a Broken Heart: Malpractice Risks in Diagnosing and Treating Heart Disease
See also Medical Law Perspectives, February 2014 Report: Congenital Heart Conditions: How Infants, Adults, and Healthcare Providers Handle the Risks
See also Medical Law Perspectives, December 2013 Report: Thicker Than Water: Liability When Blood Clots Cause Injury or Death
See also Medical Law Perspectives, November 2013 Report: Diagnosis and Treatment of Heart Attacks: Liability Issues