Why is this study important?
Treatment options for high-surgical risk patients with significant mitral regurgitation or with severe mitral annular calcification are unmet clinical needs.
History of Tendyne Transcatheter Mitral Valve Replacement (TMVR) System
The first Tendyne TMVR was implanted in 2014. Since then, more than 1500 patients have been treated with Tendyne TMVR system worldwide. The device was granted CE mark approval in early 2020.
Tendyne TM Roll-in arm for early experience
These were the very first or second patients treated at clinical sites, totaling 100 patients included in the Roll-in arm that did not have severe mitral annular calcification. 2/3 of the patients had secondary mitral regurgitation. Technical success was 94%, and 97% of patients had Tendyne TM TMVR implanted successfully. 3 pts underwent emergency surgery, and one pt suffered from stroke. All-cause mortality was 11% at 30 days and 27% at 1 year. Major Bleeding was reported in 32.4% of patients by 1 yr. Two patients required tether retention to optimize valve position by 1 year. Significant improvements in NYHA class and KCCQ score were seen by 1 year, as well as 96.5% of patients having none or mild mitral regurgitation at 1 yr. Favorable left ventricle remodeling with increased cardiac output and forward stroke volume was observed in paired echo assessments.
Mitral Annular Calcification (MAC) cohort
474 patients were screened but ~75% (354 patients) were not eligible, primarily for insufficient neo-LVOT, annular dimensions outside of treatable range, and interaction with the inner valve frame. 103
patients were treated. The majority (89%) had grade III or IV mitral regurgitation, and 10.7% had severe mitral stenosis. Procedural success was 98%, and technical success was 94%. 6 patients required emergency procedure intervention, and 2.9% required cardiopulmonary bypass. At 30 days, major bleeding was 21.4%, 6.8% mortality, and 2% needed mitral reintervention. 98.9% of patients had trace or no mitral regurgitation at one month with improvement in NYHA class, although minimal improvements in KCCQs were observed at 1 month. Paired echo assessments showed a slight decrease in LVEF with increase in cardiac output and forward stroke volume with no significant increase in LVOT gradient at one month.
Tendyne TM TMVR system is one of the very few TMVR systems leading the field of TMVR. Still, it is only available in transapical system.
Wah Wah Htun, MD interviewed Dr. Jason Rogers, one of the National Primary Investigators and Steering Committee co-chair of SUMMIT Tendyne trial.
How much does transapical approach impact the overall usability and efficacy of the device?
The transapical approach is a surgical approach and is more invasive than a transseptal transfemoral approach. However, the current transapical delivery system allows Tendyne to offer a wide range of valve sizes to match specific patient anatomy. Also, the apical approach and use of the tether for anchoring allow the valve to be repositioned or even retrieved during the procedure, which is an important safety feature. Current transfemoral systems do not allow the valve to be repositioned or recaptured once it is fully deployed.
In the Roll-In arm (patients without MAC), are there any screen failures of patients due to insufficient neo-LVOT or annular dimension outside of treatable range?
Yes, in the Roll-In arm, the two most common reasons for an anatomic exclusion are insufficient neo-LVOT area or annular dimensions outside the treatable range.
When do you foresee this TMVR to be commercially approved in the USA?
The mitral annular calcification (MAC) arm of the trial is fully enrolled, and this will be the first to be submitted for consideration of FDA approval. Hopefully, we will have approval to allow Tendyne treatment of MAC patients soon which is a major unmet clinical need. The non-MAC arms of the trial are still enrolling.
In summary, Tendyne TMVR system is one step closer to getting FDA approval for MAC cohort of patients with significant mitral valve disease. High screen failure due to anatomical reasons is still the main roadblock that needs to be overcome.
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