Successful TMVR hinges on operator experience

The odds of a successful and effective transcatheter mitral valve repair (TMVR) for the treatment of mitral regurgitation (MR) increase alongside an operator’s level of experience, a study published in the Journal of the American College of Cardiology has found.

Adnan K. Chhatriwalla, MD, of Saint Luke’s Mid America Heart Institute, and colleagues examined the effect of experience on TMVR outcomes in a group of nearly 15,000 patients who underwent the procedure at 290 unique sites. The authors said TMVR has a favorable safety profile and has been reported to be successful in as many as 90% of post-market registries, but procedural success can vary.

“As a relatively complex procedure, TMVR requires close collaboration among multidisciplinary specialists for patient selection and technical performance, and indeed, prior studies have demonstrated that procedural outcomes of TMVR improve with increasing institutional experience,” Chhatriwalla and co-authors wrote in JACC. “However, few data are available regarding the level of individual operator experience necessary to optimize clinical outcomes of TMVR.”

The team used data from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry to examine cumulative operator case experience and its relationship to procedural success, time and complications. They included 14,923 total cases performed by 562 operators, who they grouped into tertiles based on procedural experience (low: 1-25 cases; intermediate: 25-60 cases; high: 50-plus cases).

The study’s primary outcome was 1+ or better (“optimal”) or 2+ or better (“acceptable”) MR without surgery or mortality. Optimal procedural success increased across tertiles of operator experience, ranging from 63.9% to 68.4% to 75.1% for low-, intermediate- and high-level physicians, respectively. Acceptable procedural success also increased with experience, though gaps between tertiles were smaller (91.4%, 92.4% and 93.8%, respectively).

Chhatriwalla et al. said procedural time and procedural complications both decreased in conjunction with increasing operator experience. They reported that visual inflection points in the learning curves for procedural time, success and complications were obvious after around 50 cases, with continued improvement through 200 cases.

In a related editorial comment, Charles D. Resor, MD, MSc, of Tufts Medical Center in Boston, said Chhatriwalla and colleagues’ results are strong due to their large sample size and access to short-term echocardiographic and clinical data. Limitations included site-reported outcomes, a lack of information on echocardiographer experience and a small percentage of functional MR cases.

Resor said the researchers’ findings should be approached cautiously—as should any causal inferences found in observational data—but called the study an impressive one that “offers an important window into the effect of more operator experience on a technically challenging procedure.”

“In a reaction to a ‘less is more’ culture of minimalist aesthetics in the 1950s, Robert Venturi famously declared, ‘More is more. Less is a bore,’” Resor wrote. “With regard to TMVR volume and outcomes, more is indeed more: more nuance with patient selection, more experience for the operator and echocardiographer and more process familiarity for the institution, leading to more high-quality outcomes.”