Bioprosthetic Heart Valve Problems May Lead to Blood Clot, Stroke Risk: Study

Federal health regulators indicate that some bioprosthetic heart valves, which are devices made from animal tissue used for patients with severe aortic valve disease, may not work like they should. 

In a safety communication issued on October 5, the FDA warned that bioprosthetic aortic valve leaflets may not open and close properly. However, it is unknown whether this heart valve problem inhibits the flow of blood through the heart, and the agency indicates that it is looking for more data on the causes of the impaired valve opening and potential side effects.

Bioprosthetic heart valves are used to replace aortic valves between the left ventricle and the aorta, which carries blood to the rest of the body. The replacements are needed when the original valve is diseased, which can lead to a narrow opening, causing restricted blood flow, or when the valve fails to close properly, causing blood to flow backward into the heart.

The devices play a critically important role for the overall health and quality of life for individuals with severe aortic valve disease.

The replacement valves are generally divided into two categories: surgical aortic valve replacements (SAVRs) placed through open heart surgery, and transcatheter aortic valve replacements (TAVRs), which are placed without open heart surgery.

The FDA warns that it has received reports of reduced motion in the three leaflets that make up the bioprosthetic valves. In most cases, the reduced movement was discovered by advanced imaging studies in patients who were not suffering symptoms of abnormal valve function, and the studies showed that there was still acceptable blood flow through the leaflets.

While more reduced leaflet motion has been reported in TAVR devices than SAVR devices, the FDA notes that this could be because most advanced imaging studies have involved TAVR recipients.

“The true rate of reduced leaflet motion for bioprosthetic aortic valves, whether TAVR or SAVR, is currently not known,” the warning indicates. “In the limited available information that FDA has reviewed regarding advanced imaging studies of bioprosthetic aortic valves, reduced leaflet motion was seen in between 10-40% of TAVR patients and about 6-12% of SAVR patients.”

While the cause of the reduced motion is not known, the FDA says that some imaging studies indicate that blood clots may play a factor, and some reduced leaflet motion problems have been resolved using blood thinner treatments.

Currently, the agency says the valves are still considered reasonably safe and effective when used according to approved indications. SAVR devices have been on the market for 30 years, and TAVR devices have been on the market for eight years.

The FDA is working with the American College of Cardiology and the Society of Thoracic Surgeons, as well as bioprosthetic valve manufacturers, in order to design new clinical studies to help determine the causes, and safety, of reduced valve leaflet motion.

The FDA is calling on doctors and patients who have experienced adverse events involving the valves to report the incidents through it’s MedWatch adverse event reporting system.