Prevalence of extravalvular mitral damage in patients with rheumatic etiology mitral stenosis
Authors: Santos Alfaro H A , Millan Vela J , Jimenez Ruan L , Arias Godinez J A , Fritche Salazar J F , Posada Martinez E L , Ortiz Leon X A , Ruiz Esparza Duenas M E , Rodriguez Zanella H 
Published: January 2025

Abstract

Background
Rheumatic fever is the leading cause of mitral stenosis (MS) worldwide. Clinically significant stenosis if accompanied by symptoms, atrial fibrillation, or pulmonary hypertension merits therapeutic interventions. Extra valvular damage has been shown to be of prognostic value in patients with mitral regurgitation and aortic stenosis. The prevalence and significance of extra valvular damage has not been studied in patients with rheumatic mitral stenosis.

Objective
To describe the prevalence of extra valvular damage in patients with rheumatic mitral stenosis and its relationship with major adverse cardiovascular events.

Methods
We prospectively enrolled patients 18 years and older with rheumatic mitral stenosis and MVA measured by planimetry less than 2 cm². Patients with more than mild mitral regurgitation and aortic stenosis or regurgitation were excluded. Patients were divided in four groups depending on the degree of extra valvular damage. Group 1: mitral stenosis without extra valvular damage, group 2: mitral stenosis with left atrial dilation (left atrial volume &gt;34 ml/m2BSA) or atrial fibrillation, group 3: mitral stenosis with pulmonary vascular involvement (tricuspid regurgitation velocity &gt;2.8 m/s), group 4: mitral stenosis with right ventricular systolic dysfunction (TAPSE &lt;17). Major adverse cardiovascular events included cardiovascular death, all-cause mortality, de novo atrial fibrillation, acute myocardial infarction, stroke, as well as hospitalizations for heart failure.

Results
We included 92 patients age 62 ± 11, 78 female (84%). A high burden of cardiovascular risk factors was found, obesity 60 (66%), atrial fibrillation 68 (63%), hypertension 33 (30%) and type 2 diabetes 24 (26%) with no significant difference between groups (Table 1). Main echocardiographic parameters were as follows: left ventricular fraction of 56% (25-73), left atrial volume 91 ml (32-364), TAPSE 18 mm ± 4.6, systolic pulmonary artery pressure 42 mmHg ± 18, mitral valve area 0.97cm (0.3-1.7). Importantly none of the patients was classified in group 1 (without extra valvular damage). Mitral valve area was lower in patients of group 4 compared to patients with group 2 and 3. Although not statistically significant (p=0.37) a higher numerical number of events occurred in patients with higher burden of extra valvular damage: 18 (50%) in group 4, 16 (47%) and, in group 3, 7 (31%) (Table 2).

Conclusions
Extra valvular damage in patients with rheumatic MS is highly prevalent. None of the patients was classified in group 1, highlighting the high burden of extra valvular damage in patients with mitral stenosis. As the severity of mitral stenosis progress extra valvular damage increases. A higher number of events occurs in patients with increasing extra valvular damage. The study was limited by a small number of patients. Larger studies are needed to establish the prognostic value of extra valvular damage in rheumatic mitral stenosis.
Table 1.
Table 2.