Transcatheter aortic valve replacement (TAVR) procedures had a high rate of success and low risk of death or disabling stroke at 30 days in patients with a bicuspid, or two-leaflet, aortic valve, according to research presented at the American College of Cardiology's Annual Scientific Session Together with World Congress of Cardiology (ACC.20/WCC).
TAVR is a procedure in which operators thread surgical equipment to the aorta through an artery in the chest or groin to replace a patient's malfunctioning valve with an artificial one. The procedure has become increasingly popular in recent years as a less-invasive alternative to open-heart valve replacement surgery. However, few studies have examined its safety in patients with a bicuspid valve, a condition affecting roughly 2-5% of people in which two of the three flaps in the aortic valve are fused together.
A bicuspid valve is more likely to become narrowed or leaky, known as stenosis. Valve replacement, either through TAVR or open-heart surgery, is the main treatment option available for people with severe aortic stenosis, which causes fatigue and other symptoms and raises the risk of other heart problems when left untreated. The new study is the first to prospectively examine TAVR's safety for treating severe aortic stenosis in relatively young, healthy patients--in whom open-heart surgery would pose a low risk--who have a bicuspid valve. It also is one of the first studies involving such patients in which doctors used a newer self-expanding artificial valve.
"TAVR with a self-expanding prosthesis is a very viable and safe procedure in low-risk bicuspid patients and achieved excellent early results," said Basel Ramlawi, MD, cardiothoracic surgeon at Valley Health System in Virginia and the study's co-principal investigator. "Though additional follow-up is necessary to determine long-term outcomes, early results suggest this procedure can be performed successfully in low-risk individuals with a good outcome."
The study prospectively tracked 150 patients who underwent TAVR at 25 medical centers in the U.S. On average, patients were 70 years old and had a Society of Thoracic Surgeons risk score (which reflects the risk of dying during or shortly after open heart surgery) of 1.4%.
Thirty days after their procedure, just 1.3% of patients had died or experienced a disabling stroke, the study's primary safety endpoint. Patients also had an overall device success rate of 95.3%, reflecting a low rate of major complications, ill-fitting valves or the need for additional procedures. The vast majority (99.3%) of patients survived the procedure, 96% showed correct positioning of the valve and 100% had mild or no aortic regurgitation (blood leaking around the valve).
Bicuspid valves can have several different shapes, which are named according to the Sievers classification system. The study found 84.6% of those with a Sievers type 0 valve had trace or no aortic regurgitation and the rest had only mild aortic regurgitation, a high rate of success that Ramlawi said was somewhat unexpected due to the perceived complexity of operating on valves with this shape.
"This is the first study that shows the self-expanding valve works well for patients with both type 1 and type 0 bicuspid valves," Ramlawi said. "The medical community has perceived type 0 bicuspid valves as more challenging to treat, so those data are especially encouraging."
The researchers plan to continue to track outcomes in the patients for 10 years to assess the long-term efficacy of the TAVR-implanted valves. Ramlawi said that the study was limited by the fact that all patients received TAVR, rather than providing a randomized comparison between TAVR and open-heart surgery. In addition, the study was conducted in medical centers that perform a high volume of TAVR procedures, and it is unclear whether a similarly high success rate would be achievable in centers with less TAVR experience.