10 November 2019
Surgery has historically offered the best hope for preventing stroke or heart failure in patients with aortic stenosis, a serious condition where aortic valve opening narrows, restricting blood flow from the heart to the main artery. New clinical trial data from a team led by Michael Mack, at Baylor Scott and White Health Heart Hospital in Plano, Texas, now indicate that a minimally invasive procedure known as ‘transcatheter aortic valve replacement’ (TAVR) may offer a simpler and more effective alternative for most patients.
People with severe stenosis have dangerous constriction of the aorta valve, which prevents it from fully opening to let blood through. Surgical replacement of the aortic valve is the standard solution for repairing such damage and preventing cardiovascular complications. TAVR was developed as a treatment alternative for patients who are likely to fare poorly in surgery, and entails the use of a catheter to deliver an expandable valve that can directly unblock the aorta valve without the need for complete replacement. The new valve is similar to a stent, and once it expands inside the valve, it takes over blood flow regulation.
Today, TAVR is commonly performed even in patients at low risk for surgical complications, but it has remained unclear how well this approach stacks up against conventional surgical replacement. Mack and colleagues embarked on the Placement of Aortic Transcatheter Valves PARTNER 3 clinical trial to answer this question. They enrolled a cohort of low-surgical risk patients with severe aortic stenosis, of whom 496 underwent TAVR and 454 received valve-replacement surgery, and then monitored both sets of patients over the course of a year.
Strikingly, the researchers found that the risk of death, stroke, or hospitalization during that period was reduced by nearly half in the TAVR patients relative to those who underwent surgery. This minimally invasive procedure also offered better outcomes in the shorter term, with a considerably lower risk of death, stroke or other complications even within the first 30 days after treatment. This increased benefit from TAVR was apparent despite the fact that patients receiving surgery in this trial generally fared very well, with fewer than 3 percent experiencing death or stroke after a year.
Mack and colleagues caution that this study is still too short to draw a decisive conclusion on the suitability of TAVR for all patients, and that they will be monitoring this cohort for at least a decade to track the durability of the implanted valves. Nevertheless, the findings from PARTNER3 are very encouraging, and suggest that this less aggressive treatment strategy could potentially offer a superior approach for treating a broader population of aortic stenosis patients.
- Mack, M.J., Leon, M.B., Thourani, V.H., Makkar, R., Kodali, S.K. et al. Transcatheter aortic-valve replacement with a balloon-expandable valve in low-risk patients. New England Journal of Medicine380, 1695–1705 (2019). | article