TAVR Survival Surpasses SAVR in Low-Risk Patients: Meta-analysis

Patrice Wendling

September 17, 2019

In a new study, use of transcatheter rather than surgical aortic valve replacement (TAVR/SAVR) reduced the risk of early death in low-risk patients with severe aortic stenosis, calling into question whether TAVR should be the preferred option.

In the pooled analysis of 4 randomized trials involving 2887 patients at low surgical risk, the 1-year risks with TAVR and SAVR for all-cause death were 2.1% vs 3.5% (relative risk [RR], 0.61; 95% CI, 0.39 - 0.96) and were 1.6% vs 2.9% for cardiovascular death (RR, 0.55; 95% CI, 0.33 - 0.90).

The magnitude of relative risk reduction was similar in the recently reported pivotal PARTNER 3 and Evolut Low Risk trials, which were included in this study along with the 2015 NOTION trial and a post-hoc SURTAVI analysis. The four trials have shown TAVR is noninferior or superior to SAVR on composite primary endpoints that included mortality; however, none were adequately powered to detect mortality differences in and of themselves, the authors reported in the September 24 issue of the Journal of the American College of Cardiology.

"What our study adds is that it truly does suggest that over the study period, over the first year, there is a clear survival advantage with TAVR over SAVR, which I think is a substantial observation that hopefully will impact clinical decision making," senior author Sammy Elmariah, MD, MPH, Massachusetts General Hospital, Harvard Medical School, Boston, told theheart.org | Medscape Cardiology.

"The one clear unknown that everyone points to is valve durability," he observed. "We certainly know based on the currently available data that at least out to 5 years, there does not seem to be any appreciable difference in valve durability in regard to TAVR vs SAVR. Having said that, especially as we start talking about younger patients in their 60s and early 70s, the 10-year endpoint is important. So certainly those data will be quite informative as they are published from both of the pivotal trials."

Commenting on the study to theheart.org | Medscape Cardiology, Lars Sondergaard, MD, DMSc, Rigshospitalet, University of Copenhagen, Denmark, said, "I fully agree that the mortality benefit is an important finding from the meta-analysis," but cautioned that physicians may wrongly regard the study as a case to expand the indications for TAVR.

"Let's say these patients are going to live for 25 years and not 5 years. You have to ask yourself, how important is it to have a mortality measure at 1 year," he said. "I don't think that is going to justify expanding TAVR to what most people would regard as the next step, the patient at younger age and longer life expectancy."

He noted that the patients in the four trials were still elderly (average age 75.4 years) with a short life expectancy. The trials, particularly PARTNER 3, also selected patients with a low risk for suboptimal outcomes after TAVR by excluding those not suitable for safe transfemoral access or with heavy aortic calcification, left ventricle outflow tract calcification, bicuspid valves, or low takeoff of the coronary arteries.

"So you pick the very best patients and say we are doing as good or better than surgical patients, but these findings do not apply to all-comer patients at low surgical risk," said Sondergaard, who coauthored an editorial with Giulia Costa, MD, University of Copenhagen, that accompanies the paper.

The editorialists point out that while valve-in-valve TAVR is an option for failing bioprosthetic valves, it may increase the risk of patient–prosthesis mismatch and may prevent critical access to the coronary arteries later on, if used for transcatheter valves with supra-annular positioned leaflets. As to the use of TAVR in bicuspid valves, outcomes have improved but potential long-term issues, such as more paravalvular leak and aneurysm of the ascending aorta, need investigation before using TAVR in patients with a long life expectancy, they write.

In the meta-analysis, patients treated with TAVR, compared with SAVR, had double the risk of moderate/severe paravalvular leak (3.6% vs 1.7%; RR, 2.16; 95% CI, 1.03 - 4.54) and more than three times the risk of permanent pacemaker implantation (17.4% vs 5.5%; RR, 3.85; 95% CI, 1.73 - 8.58).

On the other hand, SAVR was associated with much higher rates of new/worsening atrial fibrillation (39.4% vs 10%; RR, 0.27; 95% CI, 0.20 - 0.32), life-threatening/disabling bleeding (11.2% vs 3.9%; RR, 0.37; 95% CI, 0.24 - 0.55), and acute kidney injury stage 2/3 (2.9% vs 0.7%; RR, 0.26; 95% CI, 0.13 - 0.52).

"Most providers, I would expect, do raise the concept that there are higher degrees of paravalvular leak and also a higher likelihood patients will need pacemakers after TAVR, but I would be surprised to hear that many are really delving into the conversation in enough detail to start to discuss the long-term implications of these short-term complications," Elmariah said. "To be frank, we don't raise that issue because we don't fully understand it."

TAVR has been associated with fewer early strokes than SAVR in recent trials but rates were not significantly different in the current study (3% vs 4.2%; RR, 0.68; 95% CI, 0.43 - 1.07). The finding was surprising, but there are "differences in neurological adjudication of these events among the different trials, and so potentially that is raising some noise that unfortunately we can't overcome in this analysis," Elmariah said.

Heart Team: A Must-Have

Azeem Latib, MD, Montefiore Medical Center, New York City, who was not involved in the study, said the overall results are not that surprising but should be used responsibly in terms of their application to younger TAVR patients, particularly given the lack of long-term data and uncertainty regarding valve durability.

"If you take the same surgical valve and implant it in a 30-year-old compared to a 70-year-old, the durability is very different," he told theheart.org | Medscape Cardiology. "In the 30-year-old, it may only last 6 to 8 years and in the 70-year-old, it may last 10 to 15 years. There are a number of reasons for that that we don't completely understand, but it's probably due to an accelerated degeneration process, accelerated calcification, that happens in younger patients."

Commenting further, Latib said, "This just reiterates for me the importance of the heart team. I'm a TAVR operator and am doing more low-risk patients since these studies and the FDA approved the indication, but every patient that I do I really individualize the decision and speak with the patient through the heart team. Me and my cardiac surgeon meet the patient together and go through whether that patient would be a good candidate for TAVR or not."

Elmariah said that "the heart team, hopefully, will be the mechanism by which the overexpansion of TAVR will be prevented," and now that TAVR has been associated with improved survival in the study, "it is equally important that all patients undergoing evaluation for AVR also have a conversation about the feasibility and appropriateness of TAVR in their situation. For example, for a patient in their mid-70s to undergo an SAVR without a conversation about TAVR is a disservice to that patient."

Asked whether that is still happening, Elmariah replied, "I think it absolutely happens because unfortunately I think the concept of the heart team has been instilled inside the TAVR workflows, but has not actually been mandated within the SAVR workflows. So a patient can be referred directly to a surgeon, undergo SAVR, without ever having met a physician that performs TAVR and without ever understanding that there is an alternative strategy that has been found to have quite favorable results," he said. "So I think strengthening the 'heart team' concept and having it more universally applied to anyone undergoing AVR is the optimal strategy to improve patient outcomes."

Latib, who is Montefiore's medical director of structural heart interventions, said this is a politically and financially charged issue that cuts both ways. He suggested that cardiac surgery and interventional cardiology departments should be replaced by a single structural heart department where both specialities work with a unified budget.

"There's no longer, 'Whose patient is this, who is going to get the income on this patient, which department will be more financially rewarded.' Let's do what's best for the patient, and everyone — including the patient — benefits from that," he said.

Elmariah reports research grants from Edwards Lifesciences and Svelte Medical and consulting fees from Medtronic and AstraZeneca. Sondergaard reports receiving consultant fees and institutional research grants from Abbott, Boston Scientific, Edwards Lifesciences, Medtronic, and Symetis. Costa has disclosed no relevant financial relationships. Latib reports consulting for Medtronic, Abbott, and Edwards Lifesciences.

J Am Coll Cardiol. Published online September 2019. Abstract, Editorial

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