Transcatheter implantation of the Tendyne mitral valve replacement device for treatment of mitral regurgitation in patients at prohibitive surgical risk because of severe mitral annular calcification showed considerable promise in a small feasibility study,, reported at the virtual annual meeting of the European Association of Percutaneous Cardiovascular Interventions.
There is a huge unmet need for safe and effective therapies for severe mitral annular calcification (MAC).
“Severe MAC often precludes surgical treatment, and there’s a poor prognosis in patients with MAC and mitral regurgitation when untreated, with 2-year survival of about 60% in some studies,” noted Dr. Sorajja, a cardiologist at the Minneapolis Heart Institute Foundation.
Attempts at repurposing transcatheter aortic valves for use in the mitral location have been largely unsatisfactory, he added.
The 6-month outcomes in the 11 patients who received the Tendyne device in the multicenter U.S. feasibility study featured low rates of mortality and nonfatal adverse events, elimination of mitral regurgitation, marked improvement on quality of life measures, and a mean gradient of 4.1 mm Hg. The acute procedural outcomes were encouraging as well.
“We had technical success in 11 of 11 patients, no procedural mortality or left ventricular outflow tract obstruction, no valve embolization or malposition, and no conversion to open heart surgery,” he said.
There was one death caused by mesenteric ischemia 16 days post Tendyne implantation. One patient experienced a nondisabling stroke at day 4. Two patients developed new-onset atrial fibrillation, one of whom cardioverted to sinus rhythm. And one patient had a moderate paravalvular leak that resolved with placement of a plug at 3 months. There were no MIs.
At baseline, 9 of 11 patients were New York Heart Association functional class III and the others were class II. At 6 months, six patients were class I, four were class II, and one was class III. The average score on the Kansas City Cardiomyopathy Questionnaire improved from 45.9 at baseline to 65.5 at 1 month, 77.4 at 3 months, and 70.3 at 6 months.
This was a highly selected study population with a Society of Thoracic Surgery Predicted Risk of Mortality score of 9.03%. Part of the screening process for study participation involved preprocedural CT imaging with simulated device overlay in order to identify candidates who were likely to have an optimal device fit.
Discussant, was impressed by how well this simulation resembled the actual results as depicted in side-by-side pre- and postprocedural CT images presented by Dr. Sorajja.
“What really surprised me was the correlation between preprocedural simulation data and the actual CT scan after the procedure. This trial shows that the simulation works, and also that Tendyne is a great alternative to aortic valve-in-MAC for these very-high-risk patients,” said Dr. Maisano, professor of cardiac surgery at the University of Zürich and a pioneer of catheter-based mitral and tricuspid interventions.
Earlier this year the Tendyne device was approved in Europe for patients with mitral regurgitation who aren’t candidates for surgical valve replacement or transcatheter mitral valve repair. The approval does not, however, extend to MAC. The Abbott device remains investigational in the United States, where the pivotal SUMMIT trial is underway. In one arm of the trial, patients with mitral regurgitation are being randomized to the investigational Tendyne device or to Abbott’s MitraClip, which is approved for that indication. In the other arm, patients with severe MAC at prohibitive surgical risk will get the Tendyne device. Results are expected in 2020.
Dr. Sorajja reported receiving research grants from and serving as a consultant to Abbott, the feasibility study sponsor, as well as to several other medical device companies, as did Dr. Maisano.