Transcatheter Aortic-Valve Implantation for Patients Not Suitable for Surgery

Patients with untreated aortic stenosis have a high mortality rate (50% in the first 2 years after emergence of symptoms). Survival rates are improved in patients who undergo surgical replacement of the aortic valve. However, 30% of patients with severe symptomatic aortic stenosis are at high surgical risk due to advanced age, left ventricular dysfunction, or multiple coexisting conditions. For those patients, a less invasive procedure may offer a viable alternative. Transcatheter aortic-valve implantation (TAVI) has been performed since 2002. In TAVI a bioprosthetic valve is inserted through a catheter and implanted within the diseased native aortic valve. Recent clinical studies have found that the rate of death from any cause within 1 year among patients treated with TAVI was approximately 25%. However, all of the studies to date have been observational registry studies, with no standardization of end point definitions. Researchers recently conducted the PARTNER (Placement of Aortic Transcatheter Valves) trial, a multicenter, randomized clinical trial that compared TAVI with standard therapy in high-risk patients with severe aortic stenosis. PARTNER included a prespecified cohort of patients who were not candidates for surgery. The researchers reported the outcomes with TAVI compared with standard therapy among the patients in the PARTNER trial who were not candidates for surgery online in the New England Journal of Medicine [2010;10.1056/NEJMoa1008232]. The study enrolled 358 patients who were not suitable candidates for surgery at 21 sites (17 in the United States). The patients were randomly assigned to standard therapy (n=179), including balloon aortic valvuloplasty, or TAVI (n=179) of a balloon-expandable bovine pericardial valve. Death from any cause was the primary end point. The researchers defined the rate of the hierarchical composite of death from any cause or repeat hospitalization as the coprimary end point. Secondary end points included the rate of death from cardiovascular causes, New York Heart Association (NYHA) functional class, rate of repeat hospitalization due to valve-related or procedure-related causes, valve performance assessed by echocardiography, and rates of myocardial infarction, stroke, acute kidney injury, vascular complications, and bleeding. Patients were followed for a minimum of 1 year (median follow-up, 1.6 years; maximum, 2.8 years). Baseline characteristics in the 2 groups were well balanced, and the overall population was at high risk. Of the patients in the TAVI group, 3.4% (n=6) did not receive a transcatheter heart valve. At 1 year, the rate of death from any cause was 30.7% with TAVI and 50.7% with standard therapy (hazard ratio with TAVI, 0.55; 95% confidence interval [CI], 0.40-0.74; P<.001). In the TAVI group, the rate of death from cardiovascular causes was 20.5% compared with 44.6% in the standard therapy group (hazard ratio, 0.39; 95% CI, 0.27-0.56; P<.001). The superiority of TAVI with respect to the coprimary end point was confirmed by the Finkelstein-Schoenfeld analysis (P<.001), and the rate of the nonhierarchical composite of death from any cause or repeat hospitalization was 42.5% with TAVI and 71.6% with standard therapy (hazard ratio, 0.46; 95% CI, 0.35-0.59; P<.001). At 30 days and 1 year, major strokes were observed more frequently in the TAVI group compared with the standard therapy group (5.0% vs 1.1%, P=.06, and 7.8% vs 3.9%, P=.18, respectively). However, the rate of the composite of major stroke or death from any cause at 1 year was significantly lower in the TAVI group than in the standard therapy group (33.0% vs 51.3%; hazard ratio, 0.58; 95% CI, 0.43-0.78; P<.001). At 1 year, among survivors, the rate of cardiac symptoms according to NYHA class was lower among patients in the TAVI group compared with those in the standard therapy group (25.2% vs 58.0% in class III or IV; P<.001). In conclusion, the researchers said, “in patients with severe aortic stenosis who were not suitable candidates for surgery, TAVI, as compared with standard therapy, significantly reduced the rates of death from any cause, the composite end point of death from any cause or repeat hospitalization, and cardiac symptoms, despite the higher incidence of major strokes and major vascular events.”