By Will Boggs MD
NEW YORK (Reuters Health) - Pulmonary hypertension is associated with increased mortality in patients undergoing transcatheter mitral-valve repair (TMVr) for severe mitral regurgitation, according to a retrospective study.
"Pulmonary hypertension is highly prevalent in patients with mitral regurgitation undergoing transcatheter mitral-valve repair, with over 70% of patients (having) some degree of pulmonary hypertension, yet even mild elevation of mean pulmonary-artery pressure is associated with adverse clinical outcomes," Dr. Sammy Elmariah of Massachusetts General Hospital, Harvard Medical School, in Boston, told Reuters Health by email.
Dr. Elmariah and colleagues used data from the Society of Thoracic Surgery/American College of Cardiology (STS/ACC) Transcatheter Valve Therapy (TVT) registry to evaluate the link between pulmonary hypertension and clinical outcomes after TMVr using the MitraClip system in more than 4,000 patients with mitral regurgitation.
The analysis included 1,103 patients with no pulmonary hypertension (group 1), 1,399 with mild pulmonary hypertension (mean pulmonary-artery pressure, or mPAP, of 25-34 mm Hg), 1,011 with moderate pulmonary hypertension (mPAP, 35-44 mm Hg), and 558 with severe pulmonary hypertension (mPAP, 45 mm Hg or higher).
The STS predicted risk of mortality score for mitral-valve repair increased significantly with increasing degree of pulmonary hypertension, and more severe pulmonary hypertension was associated with lower Kansas City Cardiomyopathy Questionnaire scores and shorter 6-minute walk test distances before TMVr.
At 30 days, the overall rate of the composite of mortality and heart failure readmission was 5.7%, with progressively higher rates with worse pulmonary hypertension: 3.4% in group 1, 5.7% in group 2, 6.4% in group 3, and 9.0% in group 4.
All-cause 30-day mortality was progressively higher across pulmonary hypertension groups (from 1.5% in group 1 to 4.3% in group 4, P=0.004), the researchers report in JAMA Cardiology, online November 20.
More-severe pulmonary hypertension was not independently associated with increased risk of hospitalization for heart failure at six months, but it was associated with persistent New York Heart Association (NYHA) functional class III to class IV after TMVr.
At one year, the overall rate of mortality and heart-failure readmission was 33.6%, with significantly higher rates associated with worse pulmonary hypertension: 27.8% in group 1, 32.4% in group 2, 36.0% in group 3, and 45.2% in group 4 (P<0.001).
Worse pulmonary hypertension was also associated with significantly higher one-year mortality (from 16.3% in group 1 to 27.8% in group 4) and with higher rates of readmission for heart failure at one year (from 17.7% in group 1 to 27.9% in group 4).
The association of severe pulmonary hypertension with increased rates of the composite endpoint at one year persisted after multivariable adjustment for potential confounders and when modeled in a continuous manner.
"Our study clearly demonstrates significant improvements in NYHA functional class after TMVr, even in the subset of patients with severe pulmonary hypertension," Dr. Elmariah said. "Furthermore, we found that TMVr in patients with pulmonary hypertension is safe and effective. It is, therefore, imperative that TMVr not be withheld from patients with severe mitral regurgitation on the basis of pulmonary hypertension."
"Current management guidelines for management of mitral regurgitation suggest that mitral-valve repair may be considered in patients with severe pulmonary hypertension, yet our study suggests that even mild elevations in pulmonary artery pressure are associated with poor outcomes after TMVr," he said. "Further efforts are therefore needed to determine whether mitral-valve intervention at lower pulmonary-artery-pressure thresholds will result in improved patient outcomes."
JAMA Cardiol 2019.