ACC.16: TAVR with the Sapien XT valve is non-inferior to surgery at two years

CHICAGO – After two years, intermediate-risk patients with severe, symptomatic aortic stenosis who underwent transcatheter aortic valve replacement (TAVR) with the Sapien XT valve had similar rates of all-cause mortality or disabling stroke compared with those who underwent surgical aortic valve replacement.

A subgroup analysis of the randomized trial that only included patients who underwent transfemoral access of the valve found that TAVR using the Sapien XT significantly reduced all-cause mortality or stroke.

Study author Craig R. Smith, MD, of Columbia University Medical Center in New York, presented the results in a late-breaking session at the ACC scientific session on April 2. The findings were simultaneously published online in the New England Journal of Medicine.

Edwards Lifesciences, which manufactures the Sapien XT, supported the study. The company funded the trial and participated in the selection of trial sites, the collection of data and data monitoring.

Smith noted that in the PARTNER I trial, TAVR with the first-generation Sapien valve was found to be superior to surgery in patients with symptomatic aortic stenosis who were not candidates for surgery and was non-inferior to surgery in high-risk patients.

In this trial, known as PARTNER 2A, the researchers enrolled 2,032 patients with severe aortic stenosis and cardiac symptoms at 57 centers in the U.S. and Canada between December 2011 and November 2013. They used the Society of Thoracic Surgeons (STS) risk model to estimate the risk of death 30 days after surgery. Patients were included if they had a 4 percent to 8 percent risk. They could also be included if their risk was less than 4 percent but they had coexisting conditions that the model didn’t take into account.

Patients were randomized in a 1:1 ratio to undergo surgery or TAVR with the Sapien XT. All patients received 81 mg of aspirin and at least 300 mg of clopidogrel before the procedure and heparin during the procedure. After the procedure, they continued taking aspirin indefinitely and clopidogrel for at least one month.

Of the patients, 76.3 percent were deemed to be suitable for transfemoral placement. The mean STS score was 5.8 percent in each group: 6.7 percent of patients had an STS score of less than 4 percent; 81.3 percent had an STS score between 4 percent and 8 percent; and 12 percent had an STS score of greater than 8 percent.

The surgery and TAVR groups were well-balanced at baseline. The mean age was approximately 81 years old, while approximately 54 percent of patients were males.

After two years, the rate of all-cause mortality or disabling stroke was 19.3 percent in the TAVR group and 21.1 percent in the surgery group. At 30 days, the rates were 6.1 percent and 8 percent, respectively.

In the TAVR group, the two-year rates were 16.7 percent for all-cause mortality, 10.1 percent for cardiovascular mortality, 9.5 percent for all-stroke, 6.2 percent for disabling stroke, 3.7 percent for transient ischemic attack. The corresponding rates for the surgery group were 18 percent, 11.3 percent, 8.9 percent, 6.4 percent and 2.3 percent. None of the differences were statistically significant.

However, at two years, patients in the surgery group had significantly more life-threatening or disabling bleeding events (47 percent vs. 17.3 percent), stage III acute kidney injury (6.2 percent vs. 3.8 percent) and new atrial fibrillation (29.3 percent versus 11.3 percent).

Meanwhile, patients in the TAVR group had significantly more major vascular complications (8.6 percent vs. 5.5 percent) at two years.

The researchers cited a few limitations of the study, including that a larger number of patients withdrew after scheduling to undergo surgery. In addition, the Sapien XT valve has already been replaced by the Sapien 3 valve, which the FDA approved in June 2015 for high-risk patients with severe aortic stenosis.

In addition, they did not use multislice CT to assess aortic annulus dimensions for appropriate valve sizing. Finally, the long-term durability of bioprosthetic transcatheter valves have not been studied, although a previous trial found the valves did not deteriorate after five years.