SURTAVI: TAVR, SAVR Stand Toe-to-Toe in Intermediate-Risk Patients

WASHINGTON, DC — (Updated with commentary) The SURTAVI trial hit its noninferiority end point, making it the second prospective randomized trial to show transcatheter aortic-valve replacement (TAVR) is comparable to surgery in severe aortic-stenosis patients deemed intermediate risk^[1].

Using mostly first-generation Medtronic CoreValve and some newer Evolut R bioprosthesis valves, the primary end point of all-cause death or disabling stroke at 24 months was estimated at 12.6% for TAVR and 14% for surgery (Bayesian analysis posterior probability of noninferiority >0.999).

"The guidelines were just updated and for intermediate-risk, TAVR is now a 2a, but with this data it will need updating and should even get a class 1 indication. These are outstanding data," lead author Dr Michael J Reardon (Methodist DeBakey Heart and Vascular Center, Houston, TX) said to an overflow crowd that began assembling hours in advance of the late-breaking clinical-trial session here at the American College of Cardiology (ACC) 2017 Scientific Sessions.

Commenting to heartwire from Medscape, Reardon said, "The field has already accepted this, the patients have already accepted this, so I think we're going to continue to see an acceleration; 2017 will be the first year where we see more TAVRs done in the US than isolated aortic valves. That's a landmark year."

The findings reinforce the data presented at ACC 2016 from PARTNER 2A, which showed noninferiority for TAVR using the Sapien XT valve (Edwards Lifesciences).

Dr Michael J Reardon

The study, published simultaneously in the New England Journal of Medicine, involved 1746 intermediate-risk patients (mean age 79.8 years) at slightly lower risk than those in PARTNER 2A (mean STS predicted risk of mortality 5.8% vs. 4.4%).

The data were not strong enough, however, for TAVR to claim statistical superiority over surgery, despite a disabling stroke rate strongly favoring TAVR over surgery at 2 years (2.6% vs 4.5%).

Reardon told the crowd that 30-day survival rates were excellent in both groups but that the mortality curves flattened out to near zero after about 4 months and remained there for all patients.

He noted that SURTAVI has by far the best surgical outcomes seen in any of the randomized trials and that "they're unlikely to be matched, much less beaten." Despite this, "TAVR stood toe-to-toe with surgery," with a 2-year all-cause mortality rate of 11.4% vs 11.6% for surgery.

Where TAVR fell decidedly short was in a 30-day rate of new pacemakers four times that for surgery (25.9% vs 6.6%).

Invited panel discussant Dr David Cohen (St Luke's Medical Center, Kansas City, MO) told heartwire that the rate is actually 29% if one factors out patients who already had pacemakers at baseline.

"It's quite a high rate, and one I think most of us would find in current practice to be unacceptably high," he said.

Cohen agreed with Dr Reardon's claim that the newer Evolut R valve, used in only 16% of patients in the study, allows for more precise implantation than the CoreValve and that pacemaker rates have come down. Still, he said, longer follow-up data from this and other trials are needed, given the costs of implantation and the reasonable expectation that these patients will live another 12 to 15 years.

Having a pacemaker did not affect mortality, Reardon noted.

What Patients Want

At 30 days, TAVR had significantly less acute kidney injury stage 2 or 3 (1.7% vs 4.4%), atrial fibrillation (12.9% vs 43.4%), any stroke (3.4% vs 5.6%), need for transfusion (0 units 58.9% vs 87.5%), and superior quality of life, "all the things your patients want," Reardon said.

Conversely, surgery was associated with less life-threatening or major bleeding (9.3% vs 12.2%) and lower rates of residual aortic regurgitation.

Echocardiographic studies showed that the mean aortic-valve gradient was significantly lower (7.8% vs 11.8% at 2 years) and the effective AV orifice area significantly larger (2.2 cm²vs 1.7 cm ²at 2 years) in the TAVR group than in the surgery group at all time points after the procedure.

Dr Richard Chazal

This is important for patients in terms of their ability to exercise, Reardon explained and told heartwire that while not presented, 6-minute-walk scores were better in the TAVR group at 30 days and remained better at 1 year.

"This is very good news as we move toward the younger population," he told the crowd.

Commenting to heartwire , ACC president Dr Richard Chazal (Heart and Vascular Institute, Lee Memorial Health System, Fort Myers, FL) said, "I think it's fascinating that the hemodynamics of this valve appeared superior to the surgically implanted valves and because there's a limited follow-up in this study, one would wonder whether this could have implications long term that could be offset by the increased aortic insufficiency that we've seen in TAVI patients."

He said longer-term trials are needed to determine valve durability but said most patients will likely side with TAVR rather than undergoing a major surgery.

During a press briefing highlighting the study, Dr Roxanna Mehran (Mount Sinai Medical Center, NY, NY) said the Bayesian analysis was important to inform outcomes and bring devices to market earlier, but added, "I want to see the actual 2-year events to ensure that the posterior probability was met."

Other unknowns are the antithrombotics these patients should be on, the durability of the valves, and the importance of stroke.

Dr Valentin Fuster

Session chair Dr Valentin Fuster (Mount Sinai Medical Center, NY, NY) cautioned that as TAVR moves lower down the risk scale cardiologists should not confuse the intermediate-risk results as a green light to treat patients earlier in life.

Two low-risk TAVR trials are currently under way, but Reardon told heartwire that enrollment "may be really, really hard" given the positive results achieved in SURTAVI and PARTNER.

He added, "When we went to the high-risk trial, these were people that surgeons didn't really want to operate on. It was like going to your partner and saying 'Can I switch call days with you?' And he didn't really want his call day switched.

"When we went to intermediate-risk it was kind of like saying, 'Can I take your car and drive to the store and back?' and if he really likes you, he'll give you his car. You get to low-risk and it's kind of like saying, 'Can I sleep with your wife?' No!"

SURTAVI was funded by Medtronic. Reardon reported research grants from Medtronic. Disclosures for the coauthors are listed on the journal website. Cohen reported consultant fees/honoraria from Abbott Vascular, Cardinal Health, Edwards Lifesciences, Medtronic, and St Jude Medical; research grants from Abbott, AstraZeneca, Biomet, Boston Scientific, Cardiovascular Systems, Daiichi-Sankyo, Edwards Lifesciences, Eli Lilly, Medtronic, Merck; and serving on the speaker’s bureau for AstraZeneca. Mehran reports research grants from Abbott Vascular Research, AstraZeneca, AUM Cardiovascular, Bayer Healthcare Pharmaceuticals, Beth Israel Deaconess Medical Center, Bristol-Myers Squibb, CSL Behring, Medtronic, Novartis Pharmaceuticals, OrbusNeich, the Medicines Company, and Watermark Research Partners; and consultant fees/honoraria from AstraZeneca, Boston Scientific, Cardiovascular Systems, Medscape, Merck, Shaghai BraccoSine Pharmaceutical, and the Medicines Company. Chazal and Fuster report no relevant financial relationships.

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