Mitral valve-in-ring (MViR) procedures performed via transseptal access show lower-than-expected 30-day mortality rates, making this a reasonable alternative for high-surgical-risk patients, according to late-breaking trial results presented Wednesday at Transcatheter Valve Therapies 2021 in Miami Beach, Florida.
Mayra Guerrero, MD, of the Mayo Clinic, presented an overview of contemporary TMVR outcomes with the SAPIEN 3 and SAPIEN 3 Ultra THVs (Edwards Lifesciences).
Repeat mitral valve surgery after mitral repair may be needed in up to one fourth of the patients, approximately 20,000 patients per year based on current U.S. volume. The operative mortality of repeat mitral surgery after mitral repair is high: 11.1% based on a 2018 study of 1,096 patients in the Society of Thoracic Surgeons (STS) database and 12% based on a 2017 study of 1,627 patients from the Medicare database.
Guerrero added that mitral valve annuloplasty rings may serve as a landing zone for TMVR for patients who need repeat mitral surgery.
The procedural volume and number of sites performing MViR has increased over time, from 34 patients at 25 sites in 2015 to 88 patients in 64 sites in 2020.
Guerrero and colleagues retrospectively analyzed data from the Society of Thoracic Surgeons (STS)/American College of Cardiology Transcatheter Valve Therapy (TVT) Registry.
A total of 341 patients underwent MViR procedures at 128 sites (median number of MViR cases per site, 2) between July 2015 and December 2020 and were included in the TVT registry, which does not include patients treated in clinical trials are not included in the TVT registry. Outcomes at 30 days were evaluated.
Of these patients, 49% were female, their mean STS score was 9.22±6.96, and 77% had and New York Heart Association (NYHA) class III or IV heart failure. A majority of patients had moderate to severe mitral regurgitation (78.2%) and moderate to severe tricuspid insufficiency (56.3%), and nearly half had mitral stenosis (49.3%).
Most of the analyzed patients (91%) underwent MViR via transfemoral or transseptal approach. Most patients received valves 26 mm (46.3%) or 29 mm (37.2%) in size.
Nearly 1 in 5 patients (19.1%) did not require an intensive care unit stay, and study patients’ mean length of hospital stay was 3 days. Most patients (80.7%) were discharged home after the procedure.
At 30 days, the all-cause mortality rate was 10%, 5.1% of patients had a new requirement for dialysis, and 5.1% needed mitral valve re-intervention. Mitral valve regurgitation improved from nearly 80% having moderate, moderate-to-severe or severe regurgitation to less than 10% at discharge and 30 days.
Mean mitral valve area increased from 1.96 cm2 at baseline to 2.16 cm2 at discharge, but fell back to 1.97 cm2 at 30 days. Mean gradient fell from 8.24 mmHg at baseline to 7.2 mmHg at discharge but rose back to 7.8 mmHg at 30 days. For the larger-sized implanted valves, mean valve area was generally larger and mean gradient was generally lower.
At 30 days, about 80% of patients had NYHA class I or II heart failure, an increase from 20% at baseline, and mean Kansas City Cardiomyopathy Questionnaire increased from just under 40 at baseline to higher than 60 at 30 days.
Guerrero noted several technical challenges to MViR, including that not all rings provide adequate anchoring or expansion of the THV, incomplete rings have higher risk of THV embolization, and rigid rings have a high risk of THV under-expansion.
The study’s limitations include that it is retrospective, there are currently insufficient data on 1-year outcomes, and that data on type and size of surgical ring were not always recorded.
Guerrero concluded that most MViR procedures are performed via transseptal access in contemporary practice and that these data represent an early experience for most centers. Thirty-day mortality with transseptal access was lower than predicted by patient STS scores. Small rigid rings should be avoided due to high-risk mitral stenosis. Finally, she said, further studies are needed to understand long-term effects, including residual mitral valve gradients and the role of post-dilatation to improve residual gradients).
The statistical analysis of this study was performed by Edwards Lifesciences. The study co-authors had full access to the data.