Cardiac damage staging in rheumatic mitral stenosis
E H Lim, R Leow, T Li, W Kong, K K Poh, C H Sia, T C YeoAbstract
Introduction
The prognostic utility of cardiac damage staging classifications (CDSC) have been validated across various forms of valvular heart disease such as aortic stenosis, mitral regurgitation and aortic regurgitation. The utility of the CDSC in rheumatic mitral stenosis (MS) has not been previously studied to our knowledge.
Aims
Our study aims to investigate a modified CDSC based on extra-mitral cardiac damage and its association with clinical outcomes in severe rheumatic MS.
Methods
We retrospectively studied 178 patients diagnosed with isolated severe rheumatic MS defined by mitral valve area ≤ 1.5cm2 by planimetry, continuity equation and pressure half-time methods on transthoracic echocardiography. The following modified 4 stage CDSC was constructed based on features of extra-mitral cardiac damage: stage 0, severe MS alone; stage 1, left atrial (LA) damage (LA enlargement or presence of atrial fibrillation); stage 2, pulmonary hypertension; stage 3, right ventricular dysfunction. Specific definitions are sumarised in attached figure. We studied a composite outcome comprising all-cause mortality and heart failure hospitalisation over a 10-year period from initial echocardiography.
Results
Our cohort had a mean age of 55.0 ± 13.8 years; 119 patients (66.9%) were female and 93 patients (52.2%) were symptomatic at baseline. Across a median follow up of 5.97 years (Interquartile range: 3.80 to 10.0 years) there were 47 (26.4%) deaths, 26 (14.6%) hospitalisations for heart failure and 61 (34.3%) had an event represented by the composite of death and heart failure hospitalisation. As there were relatively few patients in stage 0, clinical outcomes for stages 0 and 1 were analysed as a single group. The mean event-free survival time for the composite outcome of all-cause mortality and heart failure hospitalisation for stages 0 and 1 was 8.26 years (95% confidence interval [CI] 7.51-9.01), while that for stage 2 was 7.31 years (95% CI 6.25-8.36 years) and 6.52 years (95% CI 5.47-7.57) for stage 3 (p = 0.012). Multivariate Cox regression analysis incorporating age, sex, obstructive lung disease and CDSC as co-variates showed that CDSC stage was overall independently associated with the composite outcome (p=0.044), with stage 3 associated with poorer event-free survival (hazard ratio [HR] 2.103, 95% CI 1.138-3.885, p=0.018). Other co-variates in this model which were significant were age (HR 1.055, 95% CI 1.031-1.079, p<0.001) and obstructive lung disease (HR 2.905, 95% CI 1.456-5.797, p=0.002).
Conclusions
A modified CDSC found that more extensive extra-mitral cardiac damage was associated with adverse clinical outcomes in isolated severe rheumatic MS.Cardiac damage in MS