麻豆传媒

WASHINGTON -- Using the CoreValve and Evolut R devices, transcatheter aortic valve replacement (TAVR) was deemed non-inferior to surgery in the lowest-risk randomized dataset yet, according to the SURTAVI trial presented here -- but the story is not that simple.

Although death and disabling strokes occurred at similar rates between groups by 24 months (12.6% for TAVR versus 14.0% for surgery, posterior probability of noninferiority>0.999), the complications after TAVR were more likely to be major vascular complications (6.0% versus 1.1%, 95% CI for difference 3.2-6.7) and need for pacemaker implantation (25.9% versus 6.6%, 95% CI for difference 15.9-22.7).

That 26% pacer rate is "not surprising but still a concern," said , of The Heart Hospital Baylor Plano, Texas -- who was not involved in SURTAVI -- to 麻豆传媒.

Furthermore, 1-year rates of residual moderate-to-severe paravalvular regurgitation were higher for the TAVR group as well (5.3% for TAVR versus 0.6% for surgery, 95% CI for difference 2.8-6.8)

The SURTAVI trial results were reported as a late-breaking clinical trial during the opening session of the American College of Cardiology meeting here and published simultaneously online in the New England Journal of Medicine.

At 30 days, aortic valve reintervention was numerically more likely among TAVR recipients (0.9% versus 0.2%, 95% CI for difference -0.1 to 1.4). The gap widened over time and became statistically significant as observed by , of Houston's Methodist DeBakey Heart and Vascular Center, and colleagues at 12 months (2.1% versus 0.5%, 95% CI for difference 0.4-2.7) and at 24 months (2.8% versus 0.7%, 95% CI for difference 0.7-3.5).

Similarly, TAVR recipients were more likely to be hospitalized for aortic valve-related disease at 24 months (13.2% versus 9.7%, 95% CI for difference 0.1-7.0).

Reardon's group claimed both non-inferiority and superiority of TAVR in terms of echocardiography: By 12 months, TAVR resulted in lower mean gradients (8.29 mmHg versus 11.70 mm Hg) and larger aortic valve areas (2.15 cm² versus 1.76 cm²).

"Clearly, this is a relatively short follow up for a valve trial and is difficult to acknowledge the real long-term clinical significance of these findings. Considering the true low-risk patient population and younger patients with aortic stenosis for whom device durability is key, valve hemodynamics and reintervention rates matter," said , of University of Washington Medical Center, who was not involved in the study.

“There is a need for long term assessment and evaluation of valve hemodynamics, structural valve degeneration, and need for reintervention. For the younger lower-risk population, a 10-year follow-up is surely required. Two or even 5 years of follow-up is not enough,” Dvir emphasized.

Yet the most surprising result of SURTAVI didn't come from the TAVR group at all: it was the 0.38 observed-to-expected rate of 30-day surgical mortality, which Reardon's group called "one of the lowest" reported in randomized studies to date.

"We attribute this result to the best practices of our cardiac surgical teams, which underscores the importance of the similar 30-day rates of death in the TAVR group and the surgery group (2.2% and 1.7%, respectively)," they wrote.

Asked for comment, the lead author emphasized the numerical benefit, rather than the non-inferior finding of the trial. "At 2 years, even though the data started with the best surgery we've ever seen, TAVR with CoreValve and Evolut R achieved numerically better results, which is incredible," said Reardon via a Medtronic spokesperson in an email to 麻豆传媒.

"The data for SURTAVI is excellent -- if this was a surgical valve, it would be approved by the FDA very quickly, so I anticipate that intermediate-risk approval for the self-expanding CoreValve and Evolut R valves will come rapidly. It's one more minimally-invasive tool for physicians to use in this patient population as an alternative to open-heart surgery that will help save lives."

"The new guidelines do recommend TAVR with high-risk now, and that TAVR is a suitable treatment alternative for patients at intermediate surgical risk. With this data, I expect the next set of guidelines to list TAVR as a recommendation on par with surgery for the intermediate risk patient and not just an alternative," the email continued.

“I assume that these results should support an indication to use self-expanding transcatheter heart valve platform in the intermediate-risk population in the US,” Dvir agreed.

“I believe that SURTAVI will be considered in several years as a turning point in which the community will start to consider SAVR and TAVR for lower-risk patients as platforms that should be more patient-oriented than related to a certain age cutoff or surgical risk.”

“Some would be disappointed by the SURTAVI results, not being able to show a clear superiority for TAVR. For me, the clear and dramatic finding is that both approaches were very successful — 11.5% all-cause mortality for each within 24 months. These are fantastic outcomes for both SAVR and TAVR when you consider patients’ age — almost 80 years in average. Not dramatically different from expected survival of an average octogenarian person without aortic stenosis,” he continued.

Dvir noticed that for the subgroup of patients with STS scores under 4%, there was a trend for superiority for TAVR over sugery for the composite endpoint at 1 year (3.8% vs. 7.2%). “That finding cannot be extrapolated to true low-risk patient population but is still an interesting signal,” he commented.

The SURTAVI investigators enrolled 1,746 patients, of whom 1,660 were randomized to TAVR (n=864) or surgery (n=796). Mean age was 79.8 years and average STS-PROM score 4.5% (notably lower than the 5.8% average in PARTNER IIA).

Those who got TAVR mostly got the CoreValve (84%) and the rest got the Evolut R. Transfemoral access was preferred and patients given DAPT with aspirin and clopidogrel for 3 months, followed by monotherapy. Reardon and colleagues forbade the use of embolic protection in the trial.

Both procedures were associated with their own unique set of complications within 30 days. For surgery, these were: acute kidney injury stage 2 or 3 (4.4% versus 1.7%, 95% CI for difference -4.4 to -1.0), atrial fibrillation (43.4% versus 12.9%, 95% CI for difference -34.7 to -26.4), a greater transfusion requirement (no transfusion for 58.9% versus 87.5%, 95% CI for difference 24.4-32.5), and cardiogenic shock (3.8% versus 1.1%, 95% CI for difference -4.2 to -1.1).

One-year rates of residual moderate-to-severe paravalvular regurgitation were higher for TAVR (5.3% versus 0.6%, 95% CI for difference 2.8-6.8).

There was no structural deterioration of the implanted valves over 2-year follow-up. Both TAVR and surgery groups had Kansas City Cardiomyopathy Questionnaire scores around 60 at baseline that jumped to 80 by 12 months (the TAVR group showed a rapid improvement within 30 days, whereas the surgery group improved more slowly).

“Our study has several limitations,” Reardon’s group conceded. “A relatively high frequency of unplanned withdrawals occurred in the surgery group, primarily because of the withdrawal of patient consent after randomization. We could not identify differences in baseline demographic characteristics among the patients who underwent the assigned surgery and those who did not.”

“We also recognized that long-term follow-up is needed, since a 24-month end-point analysis provides incomplete information about the life cycle of TAVR as compared with surgical bioprostheses.”

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