麻豆传媒

WASHINGTON -- Head-to-head comparison of transcatheter aortic valve implantation (TAVI) devices favored the second-generation Sapien XT over CoreValve, although the trial was criticized on several fronts.

The balloon-expandable valve came in with a 96% rate of technical success compared with 76% using the self-expanding CoreValve valve (relative risk 1.24, P<0.001), , of the Universities of Kiel and Hamburg in Bad Segeberg, Germany, reported here at the American College of Cardiology meeting.

That primary composite endpoint included successful vascular access, deployment, and delivery system retrieval as well as correct positioning but was driven by fewer cases of moderate or severe aortic regurgitation (4.1% versus 18.3%, P<0.001) and less use of more than one valve (0.8% versus 5.8%, P=0.03) with Sapien XT.

Also, in the Sapien XT arm fewer patients required a new permanent pacemaker (17.3% versus 37.6%, P=0.001) in the , released simultaneously online in the Journal of the American Medical Association.

The results in 241 high-risk patients with severe aortic stenosis at five German centers, came a day after the high-risk cohort from the U.S. pivotal trial with CoreValve was presented at the meeting.

The device cut all-cause mortality by an absolute 5% at 1 year compared with surgical valve replacement in that trial, spurring comments of "absolutely fantastic" and "a giant leap forward for TAVR" by the discussant panel at the session.

The survival advantage is likely to shift the balance of clinical decision-making further toward TAVI (also called TAVR) for the roughly 20% of valve patients considered high risk for surgery, predicted .

Patients already prefer any option that will spare opening their chest -- particularly if sternotomy is involved -- and this will give them one more incentive, Tomaselli, of Johns Hopkins and a past president of the American Heart Association, said in an interview.

A Good Comparison?

But the findings also spurred indirect comparisons between devices, in part because the first generation Sapien device had only shown noninferior mortality risk to surgery in the .

"Comparisons between CoreValve and PARTNER are difficult but undoubtedly happening already," noted , of Northwestern University in Chicago and also a past president of the AHA.

Results can't be assumed to generalize from the first generation available in the U.S. to the newer iteration used in Germany, although similar properties might support some extrapolation, he told 麻豆传媒.

Moreover, CHOICE didn't focus on the endpoints that really matter to practice, Tomaselli argued.

"In my opinion, the CHOICE trial is not going to be the final arbiter about which valve one uses in the setting of TAVR," Tomaselli said. "It's not definitive ... because the trial was set up in a way to generally favor the balloon-expanded valve and not the self-expanded valve."

Paravalvular leak was reported only out to 30 days in CHOICE, but in the CoreValve pivotal trial was shown to fall to little or no regurgitation by 1 year in three-quarters of patients with moderate to severe leaks initially, presumably because the device continued to expand over time.

Less leak with Sapien goes against what would have been expected from prior studies, , a cardiac surgeon at Christiana Care in Newark, Del., told 麻豆传媒.

Mortality and stroke were the more important issues, , of Mount Sinai Medical Center in New York City, told reporters at a press conference in discussing the CoreValve data he presented.

"I'm not sure I'm ready to sign off ... that we've done that head-to-head comparison in a way that mimics exactly the way we graded postoperative regurgitation, for example," Adams cautioned, urging a close look at the "fine print."

CHOICE wasn't powered for the former and was based on just a handful of events for the latter (seven with Sapien XT versus three with CoreValve, 5.8% versus 2.6%, P=0.33).

It's not clear how the endpoint the trial was powered for -- device success -- relates to long-term survival, , and , both of the Cleveland Clinic, cautioned in an editorial accompanying the JAMA paper.

There were no significant differences in 30-day cardiovascular mortality, bleeding and vascular complications, or overall safety on the composite of all-cause mortality, major stroke, and other serious complications.

Open Questions

No one questioned the higher rate of pacemaker implantation with CoreValve, though opinions varied widely on how key that risk was.

Study discussant , of Mount Sinai School of Medicine in New York City, called it just a "cosmetic" issue, whereas Bonow called it a concern and the editorialists deemed it "an important consideration," particularly as the field moves toward lower surgical risk patients.

The CoreValve trial aimed for a population estimated at a 15% or higher risk of dying within 30 days if they got surgical valve replacement but ended up with a population with an average 7% predicted risk, lower than the 11% in the PARTNER high-risk cohort.

"It seems this is more an intermediate-risk than high-risk population," , a thoracic surgeon in the Baylor Healthcare System in Plano, Texas, cautioned as a discussant on the CoreValve trial.

Further efforts to understand how patient characteristics play into the risks and benefits of TAVI and its long-term outcomes are "imperative," Tuzcu and Kapadia concluded.

"Additional rigorous randomized trials like the CHOICE trial will provide the quality of evidence necessary to ensure optimal use and optimal patient outcomes from TAVR."

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