Effect of mitral valve replacement on left ventricular function in subjects with severe rheumatic mitral regurgitation.
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Date
2019
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Abstract
Background. The outcome in patients with severe mitral regurgitation (MR) and impaired
ejection fraction (EF) is poorly described in the developing world where rheumatic heart
disease is endemic.
Objective. This study describes the effects of mitral valve replacement (MVR) on left
ventricular (LV) function in patients with rheumatic MR.
Methods. This is a retrospective analysis of all subjects with severe rheumatic MR
undergoing MVR over a 9 year period (2005-2013). Clinical and echocardiographic
parameters were recorded pre-operatively, at 2 weeks, 6 weeks to 3 months and 6 months to
2 years following MVR.
Results. Of 132 patients included in the study, 66% (n=87) were NYHA class III-IV, 38%
(n=50) presented with clinical features of heart failure and 14% (n=19) had atrial fibrillation
prior to MVR. The echocardiogram showed increased end systolic diameter (ESD,
39.9±7.2mm), left atrial size (LA, 61.2±12.6mm), and pulmonary artery systolic pressures
(PASP, 59.5mmHg, IQR 45-80mmHg). Pre-operatively, 28% (n=37) of subjects had
impaired LV function (EF <60%). At 6 months to 2 years following MVR (n=93), 1% of
subjects were NYHA III-IV, 1% were in heart failure, and 7.6% had atrial fibrillation. Paired
analysis of 83 patients with complete datasets revealed that the EF was >55% in 87% (n=72)
pre-operatively, the number of patients with EF >55% dropped to 20% (n=17) at 2 weeks
postoperatively (p<0.001, 95% CI 0.02-0.09) and thereafter an EF > 55% was recorded in
60% (n=53) at the 6 months to 2 year follow up (p<0.001, 95% CI 0.1-0.5). After feeding all
clinical and echocardiographic variables into a predictive model only the ESD emerged as a
significant predictor of postoperative LV dysfunction (EF< 50%) both on uni- and
multivariate analysis.
Conclusion. Most subjects with severe rheumatic MR who were subjected to surgery had
advanced disease with heart failure, indicating that preoperatively, impairment of LV
function was a frequent finding. The preoperative ESD was the only predictor of
postoperative LV dysfunction. This study calls for careful clinical assessment with regular
imaging and early referral for surgery in subjects with severe MR according to established
guidelines in order to ensure preservation of ventricular function.
Description
Masters Degree. University of KwaZulu-Natal, Durban.