UK TAVI at Two Years Highlight Sapien, Corevalve Performance

Shelley Wood

October 20, 2011

October 19, 2011 (London, United Kingdom) — Two-year outcomes with the two types of transcatheter valves used in the UK Transcatheter Aortic Valve Implantation (UK TAVI) registry are "encouraging," say the authors of a new study, although they point out that deaths within the first year remain high [1].

UK TAVI results, published online October 19, 2011 in the Journal of the American College of Cardiology, represent some of the largest numbers with two-year follow-up to date and come within weeks of an expected announcement from the FDA on the first TAVI device to be reviewed by the agency for the US market, the Sapien (Edwards Lifesciences).

The new paper reports outcomes with both the Sapien and the CoreValve (Medtronic)--both of which are approved for use in the UK--and covers 877 TAVI procedures performed at 25 centers between January 2007 and December 2009, with survival tracked out to December 2010. Two-year outcomes are reported for 213 patients.

No Mortality Differences Between Devices

According to Dr Neil Moat (Royal Brompton Hospital, London, UK) and colleagues, mortality rates were no different between the two valve types at 30 days, one year, and two years, with patients demonstrating significant declines in survival between 30 days and one year, regardless of which device they received.

Differences between CoreValve and Sapien

End point CoreValve (%) Sapien (%) p
30-d mortality 5.8 8.5 0.11
1-y mortality 21.7 20.6 0.68
2-y mortality 23.9 28.3 0.14
Moderate/severe aortic regurgitation 17.3 9.6 0.001
Conversion to surgery 0 1.5 0.01*
Pacemaker implantation 24.4 7.4 <0.001
Repeat procedure 1.6 0 0.02*

*Fisher's exact test

Mortality rates at all time points were significantly lower among patients treated via a transfemoral route as compared with patients whose TAVI was implanted by nontransfemoral routes (>85% transapical).

Differences Between Transfemoral and Nontransfemoral

End point Transfemoral Nontransfemoral p
30-d mortality 5.5 10.7 0.006
1-y mortality 18.5 27.7 0.002
2-y mortality 22.5 36.7 <0.001

Nontransfemoral implantation, however, was not an independent predictor of mortality and likely reflected the higher risk of the patients treated this way.

What's to Be Gleaned From UK TAVI?

Speaking with heartwire , Moat emphasized that the registry results, particularly the shorter-term mortality findings, echo those of other registries, including the SOURCE, FRANCE, German, and Italian registries. The UK registry, he pointed out, is notable for the completeness of its data set, which includes every patient treated in the UK over this period, with results for both approved devices, and 100% mortality data--a point also highlighted in an accompanying editorial by Dr Alec Vahanian (Hôpital Bichat, Paris, France) [2].

Discussing their findings, Moat and colleagues zero in on the "survival attrition" within the first year.

"What is clear in TAVI is that we can take a high-risk population and have a lot of patients alive 30 days after the procedure, but there is a very large attrition between 30 days and one year and that's a feature of this registry, and that's a feature of PARTNER A," Moat told heartwire .

"One of the things this registry shows us is we need to understand what is happening between one month and one year, and can we identify the patient population, the 15% of patients who died, and figure out who they are and whether we can do something different to reduce that risk?"

That may mean not treating those patients at all or doing something differently to improve outcomes between one and 12 months, he said. One of the things much discussed at the recent London Valve meeting was the fact that many of these older, sicker patients undergo a TAVI procedure and then are sent home, often some distance from their treatment center.

"So could we improve their survival with more aggressive medical management over that 12-month period? That's one of the things we need to find out," Moat said.

Other Differences Between Devices

The UK TAVI results also showed significant differences between the two types of devices in rates of moderate/severe aortic regurgitation (AR), rates of pacemaker use (a well-documented phenomenon with the self-expanding CoreValve), rates of repeat procedures, and rates of conversion to surgery.

The postimplant paravalvular AR numbers are particularly striking, since this problem--virtually unheard of with surgical valve replacement--is emerging as an important predictor of worse outcomes. Indeed, in these UK TAVI results, moderate/severe AR was one of only three independent predictors of mortality at one year (along with presence of chronic obstructive pulmonary disease and LVEF <30%).

But as Moat stressed to heartwire , while rates of moderate or severe AR were nearly two times higher in CoreValve-treated patients, mortality rates were nearly identical at all time points.

"This may point to problems in measuring AR or the nature of the AR possibly being different between devices," Moat observed.

"I think the message from this is that the patient shouldn't be allowed to leave the lab with moderate or severe AR," he said. "Even moderate paravalvular AR is very important, and we must improve on the devices and our implantation techniques to [reduce] this." Even now, he adds, "there are a number of maneuvers that you can do in the lab to reduce the amount of aortic regurgitation, and the message from the paper is: you must do this."

While the data is not provided in the paper, Moat noted that rates of paravalvular aortic regurgitation declined in UK TAVI as operators became better at the procedures.