While the gold standard for treating severe symptomatic aortic stenosis remains open aortic valve replacement (AVR), the surgery is not an option for many very ill, elderly patients. For these individuals, a new, less-invasive treatment known as transcatheter aortic valve replacement, or TAVR, received Food and Drug Administration approval last year and has been shown to reduce mortality by an absolute difference of 20 percent over medical therapy alone at one year.
TAVR provides a treatment option for relieving aortic stenosis in both high-risk patients and those who are deemed inoperable. A team of Stanford cardiologists and cardiovascular surgeons have collaborated on and performed nearly 300 TAVR procedures during the past five years, initially as part of the PARTNER Trial, a randomized, multi-center clinical trial, and now on a routine commercial basis. A second trial is currently ongoing in which the team is randomizing moderate risk aortic stenosis patients to either TAVR with the second generation SAPIEN-XT or open surgical AVR.
"Many of these patients were too sick or too old to even consider a surgical option, but now we can offer them something with reasonable risk, which extends life and improves their sense of well-being and functional capacity," says Craig Miller, MD, Stanford's principal investigator in the PARTNER I and PARTNER II trials.
Less invasive repair
When performing TAVR, the valve is crimped down onto a catheter-based delivery system and then inserted into the body transfemorally, transapically or directly through the ascending aorta. Once delivered to the site of the patient's obstructed valve, the new valve is expanded with a balloon and immediately functions in place of the patient's native valve, allowing relief of the obstruction and symptomatic improvement.
"The main advantage of TAVR is the fact that it's less invasive," says William Fearon, MD, Associate Professor, Cardiovascular Medicine. "We avoid the sternotomy and cardiopulmonary bypass, which allows for a quicker recovery." But there are risks. Patients undergoing TAVR suffered a major stroke rate of 3.8 percent, compared to 2.1 percent for those undergoing the open surgery. They also had more vascular complications, but significantly less bleeding.