At 1 year, TAVR patients who receive a self-expanding valve have survival similar to that observed in those implanted with a balloon-expandable device, according to updated results of the randomized CHOICE trial published in the August 18, 2015, issue of the Journal of the American College of Cardiology.

However, the trial had limited statistical power and additional studies are needed to evaluate the relative safety and efficacy of the devices over long-term follow-up, caution Mohamed Abdel-Wahab, MD, of the Segeberger Kliniken (Bad Segeberg, Germany), and colleagues. 

The investigators randomized 241 high-risk patients (mean age 81.5 years) with symptomatic severe aortic stenosis who were anatomically suitable for either device to transfemoral TAVR with the balloon-expandable Sapien XT (Edwards Lifesciences; n = 121) or the self-expanding CoreValve (Medtronic; n = 120). The procedures were performed by highly experienced operators at 5 German centers between March 2012 and December 2013. Device size was selected based largely on 3-D multidetector CT measurements of the annulus.

The mean logistic EuroSCORE was 21.8, and 80.9% of patients were in NYHA functional class III or IV. The treatment arms were well matched except that there were more men in the balloon-expandable group (P = .02). 

Previously reported 30-day results of the trial showed that device success, the primary endpoint, was higher with the balloon-expandable compared with the self-expanding valve (95.9% vs 77.5%; P < .001), with the advantage driven by lower rates of more-than-mild regurgitation and need for more than 1 valve. Cardiovascular mortality and bleeding and vascular complications were similar between the groups, although a new permanent pacemaker was more frequently needed in the self-expanding device arm.

All-Cause, Cardiovascular Mortality Similar at 1 Year

At 1 year, there were no differences between treatment groups in rates of all-cause and cardiovascular death, stroke, repeat hospitalization for heart failure, and MACCE (MI, cardiac or vascular surgery, and stroke). Improvement by at least 1 NYHA functional class and quality-of-life scores were also similar. Need for new permanent pacemaker implantation remained higher in the self-expanding valve group (table 1).

The same pattern was seen in a landmark analysis of selected events occurring between 30 days and 1 year.

Echocardiographic follow-up was performed at 1 year in 89.6% of survivors. Similar to observations from postprocedural and 30-day assessments, patients in the balloon-expandable group were less likely to have more-than-mild paravalvular regurgitation (1.1% vs 12.1%; P = .005) and overall paravalvular regurgitation (1.1% vs 13.1%; P = .02). Among 177 patients with paired evaluations at discharge and 1 year, regurgitation improved in 20.3%, remained unchanged in 59.4%, and worsened in 20.3%, with no differences between device groups (P = .98).

In contrast, the median transvalvular gradient remained slightly higher in the balloon-expandable group compared with the self-expanding group at 1 year (9 mm Hg vs 8 mm Hg; P = .004). Four patients in the balloon-expandable arm had elevations of mean gradient and reductions of valve area during follow-up, although the gradient normalized with anticoagulant therapy in all cases, suggesting a thrombotic etiology.

Valve dysfunction, as defined by the Valve Academic Research Consortium, occurred less often in the balloon-expandable group than in the self-expanding group (2.6% vs 11.7%; P = .009), although there was no difference in the combined efficacy endpoint (P = .22).

Outcomes Unaffected by Differences in Device Performance

Many prior retrospective studies have compared the 2 valve types, with most showing an advantage for the balloon-expandable device in terms of paravalvular leak, Josep Rodés-Cabau, MD, of Laval University (Quebec City, Canada), told TCTMD in a telephone interview. But because the studies were all subject to selection bias, it was important to confirm the findings in a randomized trial such as CHOICE, he said.

“It is interesting to see that despite differences in device performance, including more leaks in the CoreValve group, this did not translate into higher mortality rates, even for cardiovascular death,” Dr. Rodés-Cabau said. “We are learning that maybe in some patients the leaks are not so important, or perhaps that accurate evaluation of these leaks is not so easy. 

“It is also intriguing that while in the CoreValve US Pivotal Trial, aortic regurgitation declined over time, on the whole that was not the case in the current study,” Dr. Rodés-Cabau commented. On the other hand, the final transvalvular gradients in CHOICE were lower in the CoreValve than in the Sapien group, he noted.

Thrombosis Signal with Sapien?

The valve thrombosis associated with Sapien XT was an unexpected finding, Dr. Rodés-Cabau said. While infrequent—only 4 cases—it will require validation in future studies, he commented. Nonetheless, in an earlier systematic review, the vast majority of thrombosis cases occurred in patients with a balloon-expandable valve. Ongoing trials are exploring use of anticoagulants vs antiplatelets after TAVR, he reported, “so we will see if that makes a difference.”

In an accompanying editorial, Giuseppe Bruschi, MD, and Federico De Marco, MD, PhD, of Niguarda Ca’ Granda Hospital (Milan, Italy), also point to the relatively high incidence of stroke, especially in the balloon-expandable group. “This is in accord with the finding of a higher number of possible valve thromboses in the same group…, potentially casting suspicion of an association between the 2 events,” they say.

According to Dr. Rodés-Cabau, it is reassuring that despite some clear differences in performance between the valves, there is no difference in hard endpoints. Asked if that will motivate more centers to use both devices, he offered a word of caution: “Be careful, because it will be difficult for low-volume centers to obtain the same results as larger-volume centers if they start using different valve types. That said, it is good to have 2 platforms available in order to deal with different types of anatomies and patients.

Sources:
1. Abdel-Wahab M, Neumann F-J, Mehilli J, et al. 1-Year outcomes after transcatheter aortic valve replacement with balloon-expandable versus self-expandable valves: results from the CHOICE randomized clinical trial. J Am Coll Cardiol. 2015;66:791-800.
2. Bruschi G, De Marco F. The choice will be tailored TAVR therapy: “the talent is in the choices [editorial].” J Am Coll Cardiol. 2015;66:801-803.

Related Stories:

• CHOICE Trial, TVT Registry Shed Light on Evolving TAVR Outcomes, Risks
• Belgian Registry Reports Similar 3-Year Survival for Sapien, CoreValve in Transfemoral TAVR
• TAVR With the CoreValve Device Superior to Surgery at 1 Year