Shelley Wood

May 23, 2014

PARIS, FRANCE — Some of the longest follow-up for the first transcatheter aortic-valve implantations (TAVI) ever performed confirm earlier observations that the biggest threat to survival in TAVI-implanted patients remains their comorbidities and not problems related to their valves, regardless of valve type. More surprising, some of the procedural issues that preoccupy interventionalists and surgeons today did not emerge as important in this longer-term follow-up.

Presenting three- and five-year data from the UK TAVI registry in a press conference here at EuroPCR 2014 , Dr Neil Moat (Royal Brompton Hospital, London, UK) pointed to what he called "biphasic" survival curves. In the first few months after valve implantation, there is a steep drop in survival, he noted. Thereafter, the curve becomes significantly less steep, mirroring the survival curves typically seen in older patients who have undergone surgical valve replacement.

"In the first six months, you have quite a dramatic attrition of patients, then mortality falls to about 6% of patients per year," he said. "What this is telling us is that patients undergoing TAVI are not dying of TAVI-related factors."

The UK TAVI registry contains prospectively collected data from 100% of all consecutive transcatheter aortic-valve replacement (TAVR) patients treated since January 1, 2007. The current analysis includes 870 early patients whose mortality status was ascertained in July 2013.

In all, 62% of TAVR-treated patients were alive at three years, while just under half—48.4%—were still alive at five years.

Dr Neil Moat [Source: EuroPCR]

In multivariable analyses, the strongest baseline predictor of mortality at three years was creatinine >200 µg/mmol, followed by presence of atrial fibrillation, chronic obstructive pulmonary disease (COPD), or a high EuroSCORE (>18.5).

Of note, device- or procedure-related characteristics that typically get a lot of attention at interventional meetings were not significant predictors of late survival. For example, 12.7% of patients still alive at three years had had moderate/severe aortic regurgitation at the time of their procedure, compared with 14.9% of patients who'd died, but the difference was not statistically significant. Likewise, permanent pacemaker implantation had been performed in 16.2% of patients still alive at follow-up and in 19.3% of patients who died, again a nonsignificant difference.

Not surprisingly, more transfemorally treated patients were alive at three years than patients treated via a nontransfemoral procedure (64.3% vs 55.7%, p=0.017).

Roughly the same number of patients received the Edwards Sapien device in the early days of the TAVI registry (410) as received the Medtronic CoreValve (452). By three years, 40.7% of Sapien-treated patients had died, compared with 35.4% of CoreValve-treated patients (p=0.078).

"CoreValve had a trend toward better survival, but I wouldn't want to overinterpret that," Moat cautioned. These are preliminary data, he stressed, but added, "There is a trend there that needs looking at" when the registry has more patients, with more follow-up.

One of the theories put forward in other sessions at EuroPCR is that the higher pacemaker-implantation rate with CoreValve might, in fact, help bump up survival rates with this device.

"It's an interesting hypothesis," Moat said. "But I don't think we have any data to support that hypothesis, either here or in any other study. I think if there were an effect of early pacemaker implantation it would be in this first [six-month] phase. Some people are concerned that the early attrition is sudden death because of late heart block occurring two, three, or four months after the procedure. So if you are having pacemakers implanted more frequently, you are being protected from that, but I think our data strongly suggest that pacemaker implant does not affect long-term survival."

Moat disclosed being a consultant for Medtronic.

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