Transcatheter mitral valve replacement (TMVR) as a potential therapy for patients with symptomatic, severe mitral regurgitation (MR) was the focus of two studies—INTREPID and TENDYNE—presented at Transcatheter Cardiovascular Therapeutics (TCT 2017) meeting on November 1.

In INTREPID, the results of which were also published in the Journal of the American College of Cardiology, researchers enrolled 50 patients with symptomatic MR deemed at high or extreme risk by local heart teams at 14 sites in the U.S., Europe and Australia. Patients underwent TMVR with a new valve system involving a self-expanding nitinol valve with bovine pericardial leaflets that is placed using a transapical delivery system.

Researchers called the principal findings from the study "provocative," noting that the valve was successfully implanted in all but two patients (96%), with reduction in MR to mild or none in all implanted patients. Additionally, the procedure was short (median deployment time of 14 minutes) and reproducible with a minimal learning curve, with no device malfunction or structural valve degeneration occurring acutely or during clinical follow-up (median 173 days). Improvements in symptom status and quality-of-life were also observed in procedural survivors.

"TMVR with the valve was feasible in a population at high-or extreme-risk for conventional mitral valve replacement," researchers said. "Stable valve function was observed longitudinally, and a majority of patients experienced significant improvement in their clinical symptoms and functional class. Further investigations will determine the role of this therapeutic option in a broader population of patients with mitral valve disease compared with both surgical mitral valve replacement and TMVR techniques."

Similarly, findings from TENDYNE suggest that use of the Tendyne Mitral Valve System in patients with severe native valve MR and at high risk for surgical valve replacement may be safe and effective at relieving MR, and improving symptoms.

Researchers deployed the Tendyne mitral valve system in 30 patients (media age 75.6; 83% male) via trans-apical access and secured it in position using an apical tether. The primary one-year performance endpoint was freedom from cardiovascular mortality, stroke and device dysfunction (MR>1, mitral gradient>6mmHg, outflow gradient >20mmHg, paravalvular leak). The safety endpoint was freedom from cardiovascular death, disabling stroke, myocardial infarction, reintervention, life-threatening bleeding and renal failure.

Overall, researchers found the procedure to be safe and effective given the retrievable and repositionable nature of the device, the predictable and well-tolerated deployment, and that there were no procedural deaths or strokes. They also noted encouraging mid-term clinical and echo results, including low one-year mortality (16.7%), durable relief of MR), and improvements in NYHA Class and quality of life.