Outcomes with severe MAC
After screening for MR 3+ or greater, severe mitral stenosis, or moderate MR plus mitral stenosis, 103 eligible patients were treated with the Tendyne device. The median MAC volume of the cohort was 4000 mm3, with a maximum of 38,000 mm3.
Patients averaged 78 years old, 44.7% male, 55.3% had a frailty score of 2 or greater, 73.8% were in NYHA class III or greater, and 29.1% had been hospitalized within the prior 12 months for heart failure. Grade III or IV MR severity was present in 89%, with MR being primary in 90.3% of patients, and 10.7% had severe mitral stenosis.
Tendyne procedure survival was 98.1%, technical success was 94.2%, and valves were implanted in all patients. Emergency surgery or other intervention was required in 5.8%.
As co-presenter of the SUMMIT results, Vinod Thourani, MD, of the Piedmont Heart Institute in Atlanta, said at 30 days there was 6.8% all-cause mortality, all of it cardiovascular. There was one disabling stroke, one MI, no device thrombosis, and 21.4% major bleeding.
“At 1 month, there was less than grade 1 mitral regurgitation in all patients,” he reported, vs. 89% grade 3+/4+ at baseline. “At 1 month, it was an improvement in the NYHA classification to almost 70% in class I or II, which was improved from baseline of 26% in NYHA class I or II.”
Hemodynamic parameters all showed improvement, with a reduction in LVEF, LVEDV, and mitral valve gradient and increases in CO and forward stroke volume. There was no significant increase in LVOT gradient.
There was a small improvement in the KCCQ quality of life score from a baseline score of 49.2 to 52.3 at 30 days. “We’re expecting the KCCQ overall score to improve on 1 year follow up since the patients [are] still recovering from their thoracotomy incision,” Dr. Thourani predicted.
The primary endpoint will be evaluated at 1 year post procedure, he said at the meeting, sponsored by the Cardiovascular Research Foundation.
No good option
Designated discussant Joanna Chikwe, MD, chair of cardiac surgery at Cedars-Sinai Medical Center in Los Angeles, first thanked the presenters for their trial, saying, “What an absolute pleasure to be a mitral surgeon at a meeting where you’re presenting a solution for something that we find incredibly challenging. There’s no good transcatheter option for MAC. There’s no great surgical option for MAC.”
She noted the small size of the MAC cohort and asked what drove failure in patient screening, starting with 474 patients, identifying 120 who would be eligible, and enrolling 103 in the MAC cohort. The presenters identified neo-LVOT, the residual LVOT created after implanting the mitral valve prosthesis. Screening also eliminated patients with a too large or too small annulus.
Dr. Thourani said in Europe, surgeons have used anterior leaflet splitting before Tendyne, which may help to expand the population of eligible patients, but no leaflet modification was allowed in the SUMMIT trial.
Dr. Chikwe then pointed to the six deaths in the MAC arm and 11 deaths in the roll-in arm and asked about the mechanism of these deaths. “Was it [that] the 22% major bleeding is transapical? Really the Achilles heel of this procedure? Is this something that could become a transcatheter device?”
“We call it a transcatheter procedure, but it’s very much a surgical procedure,” Dr. Rogers answered. “And, you know, despite having great experienced sites...many surgeons don’t deal with the apex very much.” Furthermore, catheter insertion can lead to bleeding complications.
He noted that the roll-in patients were the first one or two cases at each site, and there have been improvements with site experience. The apical pads assist in hemostasis. He said the current design of the Tendyne catheter-delivered valve does not allow it to be adapted to a transfemoral transseptal approach.
Dr. Rogers is a consultant to and co-national principal investigator of the SUMMIT Pivotal Trial for Abbott. He is a consultant to Boston Scientific and a consultant/equity holder in Laminar. Dr. Thourani has received grant/research support from Abbott Vascular, Artivion, AtriCure, Boston Scientific, Croivalve, Edwards Lifesciences, JenaValve, Medtronic, and Trisol; consultant fees/honoraria from Abbott Vascular, Artivion, AtriCure, Boston Scientific, Croivalve, and Edwards Lifesciences; and has an executive role/ownership interest in DASI Simulations. Dr. Chikwe reports no relevant financial relationships. The SUMMIT trial was sponsored by Abbott.
A version of this article first appeared on Medscape.com.