Regional left ventricular strain recovery after percutaneous mitral balloon valvuloplasty: determinants and prognostic implications.

Abstract

In severe rheumatic mitral stenosis (MS), left ventricular (LV) systolic function is often considered preserved based on ejection fraction. However, longitudinal myocardial mechanics may be impaired and may improve after relief of inflow obstruction. The regional pattern of strain recovery following percutaneous mitral balloon valvuloplasty (PMBV), and its prognostic implications remain uncertain. To characterize global and regional LV strain response following PMBV, identify determinants of limited strain recovery, and evaluate its association with long-term outcomes. In 190 patients with severe symptomatic MS undergoing PMBV, LVGLS was measured by speckle-tracking echocardiography before and within 48 h after intervention. Absence of meaningful recovery was defined as ≤ 15% relative GLS improvement. The secondary endpoint was cardiovascular death or subsequent mitral valve replacement. PMBV significantly increased mitral valve area and reduced transmitral gradients, with concomitant improvement in GLS despite unchanged ejection fraction. Strain recovery demonstrated a distinct basal-to-apical gradient, with the greatest improvement in basal segments. In 29% of patients, absent GLS improvement was observed. Limited recovery was independently associated with larger baseline valve area, reduced leaflet displacement, lower pre-procedural left atrial pressure, and higher post-procedural pulmonary artery pressure. Over 48 months of follow-up, adverse outcomes were independently predicted by age, advanced NYHA class, smaller post-procedural valve area, higher residual gradient, and greater mitral regurgitation severity. Absence of GLS improvement was not associated with long-term events. In severe rheumatic MS, PMBV leads to an immediate improvement in LV longitudinal mechanics, characterized by a distinct basal predominance of recovery. This response appears largely load-mediated and does not independently translate into improved prognosis, which is primarily determined by procedural success and the degree of residual valve obstruction.