Persistent Mitral Regurgitation After TAVR Bodes Ill in Some

By David Douglas

February 26, 2020

NEW YORK (Reuters Health) - Patients with low-flow, low-gradient aortic stenosis (LFLG-AS) who don't show improvement in mitral regurgitation following transcatheter aortic-valve replacement (TAVR) face an increased risk of mortality, according to a substudy of a multicenter registry.

"Some degree of mitral regurgitation, usually of functional origin, is common in LFLG-AS patients and improves in a significant proportion after TAVR. However, the lack of improvement is associated with poorer outcomes," said Dr. Josep Rodes-Cabau of Laval University, in Quebec, Canada, told Reuters Health by email.

Patients with LFLG-AS are known to have higher perioperative mortality and worse long-term outcomes than those with high-gradient AS and/or preserved left ventricular ejection fraction (LVEF), Dr. Rodes-Cabau, and colleagues note in JACC: Cardiovascular Interventions. The impact of mitral regurgitation has remained unclear.

To investigate, the researchers identified 308 TAVI-candidates with LFLG-AS in the True or Pseudo-Severe Aortic Stenosis-Transcatheter Aortic Valve Implantation (TOPAS-TAVI) registry. At baseline, 118 (38.3%) had mild mitral regurgitation (MR) and 115 (37.3%) had moderate-to-severe MR.

A total of 138 (44.8%) patients died after a median follow-up of two years. Baseline moderate-or-greater MR had no effect on mortality.

At one year, MR improved in 44.3% of patients and remained unchanged or worsened in 55.7%. Lack of improvement was associated with higher risks of all-cause mortality (hazard ratio, 2.02) and cardiac mortality (HR, 3.03), both statistically significant findings. This was also true of hospitalization overall and rehospitalization for cardiac causes.

A higher baseline left-ventricular end-diastolic diameter and a higher increase in LVEF were independent predictors of MR improvement.

"These patients may benefit from a closer follow-up within the year following TAVR, and an intervention targeting the mitral valve may be considered if significant mitral regurgitation persists," Dr. Rodes-Cabau said.

Dr. Colin M. Barker, director of Interventional Cardiology at the Vanderbilt Heart and Vascular Institute, in Nashville, Tennessee, told Reuters Health by email, "This is a small, but very interesting registry. The authors showed that in patients with LFLG-AS and concomitant significant MR treated with TAVR, the MR in over half of these patients remained the same of got worse. This group, (with) significant MR after TAVR, had a higher risk of mortality, re-hospitalizations and complications from congestive heart failure."

"These data need to be reproduced in an adjudicated prospective study, but are still very compelling," said Dr. Barker, who was not involved in the study. "The opportunities in this population are twofold: 1. Determine which patients will not have an improvement in the MR after TAVR, and 2. Clarifying the appropriate patients, timing and modality for a beneficial mitral valve intervention. Clinically, these remain very challenging patients to manage."

In an accompanying editorial, Dr. Martin J. Swaans of St. Antonius hospital, in Nieuwegein, the Netherlands, says the findings show "there is still hope for a special category of TAVR patients with concomitant mitral a valve dysfunction and poor ventricular performance, especially in the presence of functional mitral regurgitation."

Dr. Swaans added in an email to Reuters Health that TAVR has expanded "mainly in two directions: more and more patients with lower risk are treated with TAVR, and on the other hand, more and more complex patients receive this treatment. The border between to treat or not to treat is difficult to draw; and challenging cases with multiple-valve affectation and poor ventricle may create doubts."

SOURCE: https://bit.ly/39SJZEn and https://bit.ly/2Pfw8jB JACC: Cardiovascular Interventions, online February 12, 2020.

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