PARIS – Five-year hemodynamic results of the first randomized trial of transcatheter versus surgical aortic valve replacement in low-surgical-risk patients with severe aortic stenosis showed continued superior valve performance in the TAVR group, Lars Sondergaard, MD, reported at the annual congress of the European Association of Percutaneous Cardiovascular Interventions.

“The durability results are very encouraging. We can’t see that the TAVR patients are doing worse. So I think this is setting the scene to try to move forward in patients at low risk and also in younger patients,” declared Dr. Sondergaard, professor of cardiology at the University of Copenhagen.

He presented an update from the Nordic Aortic Valve Intervention (NOTION) trial, a prospective, multicenter, randomized, all-comers clinical trial in which 280 patients with symptomatic severe aortic stenosis at low surgical risk were assigned to surgical aortic valve replacement (SAVR) or to TAVR with the self-expanding CoreValve. Their mean age was 79 years, with an average Society of Thoracic Surgeons projected risk of mortality score of 3%. Eighty-two percent of participants had an STS score below 4%. Roughly 40% of TAVR patients got the first-generation CoreValve in the 26-mm size, 40% received the 29-mm version, and the rest got the 31-mm CoreValve.

With 94% compliance with follow-up through 4 years post procedure, the primary clinical endpoint – a composite of all-cause mortality, MI, and stroke – had occurred in 29.1% of the TAVR group and was similar at 30.2% in the SAVR group. The all-cause mortality rate was 20% in the TAVR group, compared with 23% in the SAVR cohort, a nonsignificant difference.

Among patients in the lowest-surgical-risk and youngest subgroup – those aged 70-75 with a Society of Thoracic Surgeons risk score below 4% – the composite primary endpoint rate at 4 years was 15.6% with TAVR compared with 27.2% with SAVR. However, only 62 NOTION participants fell into this category, so the between-group difference, while sizable, didn’t achieve statistical significance, according to Dr. Sondergaard.

There was a trade-off between the two valve replacement strategies with regard to procedural complications. The rate of new-onset atrial fibrillation was far higher in the SAVR group: 59.4% at 1 year and 60.2% at 4 years of follow-up, compared with 21.2% and 24.5% at 1 and 4 years, respectively, in the TAVR group.

On the other hand, 38% of the TAVR patients got a new pacemaker within the first year of follow-up, compared with only 2.4% in the SAVR group. At 4 years, 43.7% of the TAVR group had a pacemaker, versus 9% of the SAVR group.

Turning to the hemodynamic data, the cardiologist noted that the effective orifice area in the TAVR group went from 0.71 cm² at baseline to 1.66 at 1 year and remained steady thereafter at 1.67 cm² through 5 years. The TAVR group’s mean gradient improved from 45.4 mm Hg at baseline to 8.6 mm Hg at 1 year and 7.9 mm Hg at 5 years. These outcomes were significantly better than in the SAVR group, where the effective orifice area went from 0.74 cm² at baseline to 1.32 at 1 year and 1.24 cm² at 5 years, while the mean gradient fell from 44.9 mm Hg to 12.5 at 1 year and 13.6 mm Hg at 5 years.

Moderate hemodynamic structural valve deterioration was significantly more common in the SAVR group: 20.7% at 5 years, compared with 2.9% in the TAVR patients. The opposite was true with regard to moderate paravalvular leak, which occurred in 20.9% of the TAVI group but only 1.5% of SAVR patients.

Late complications were rare following either procedure. There were no cases of valve thrombosis through 5 years. The incidence of endocarditis at 5 years was 4.3% in the TAVR patients and similar at 5.9% in the SAVR group.

Discussant Samer Mansour, MD, of the University of Montreal, remarked that the rate of new pacemaker implantation following TAVR seemed extraordinarily high.

“This was early days,” Dr. Sondergaard explained. “We had a lower threshold for putting in a pacemaker and we put the valves in a little deeper.”

About half of new pacemaker recipients didn’t use the device after the first year, he added. Also, neither getting a new pacemaker nor moderate paravalvular leak was associated with increased mortality in the TAVR group.

Dr. Mansour observed that subtle but real differences in mortality probably wouldn’t show up in a 280-patient trial. Dr. Sondergaard concurred.

“We designed the NOTION trial in 2008-2009. Knowing what we know now, we should have had a larger study, but at that time TAVR volume wasn’t that big and it wasn’t realistic as a Nordic trial to include 1,000 patients. This was the best we could do,” he said.

Follow-up in the NOTION study will continue out to 10 years.

The study is funded by Medtronic. Dr. Sondergaard reported serving as a consultant to and receiving research grant support from the company.

bjancin@frontlinemedcom.com

First trial of TAVR vs. SAVR in low-risk patients