Hemodynamic Responses to Exercise and Predictors of Exercise Capacity in Mitral Stenosis: Exercise Catheterization...

Although a mitral valve area (MVA) of <1.5 cm² is a major indication for intervention in mitral stenosis (MS), patients in this group may exhibit wide variability in exercise tolerance.

The aim of this study was to assess hemodynamic changes during exercise in patients with severe MS using exercise cardiac catheterization.

This prospective study enrolled 30 patients with MVA <1.5 cm² who underwent exercise catheterization using a supine bicycle between 2021 and 2024. Measurements from 30 MS patients were compared with those from 17 control participants without evidence of heart failure (noncardiac dyspnea [NCD] group). Exercise capacity was quantified by peak oxygen consumption (Vo₂).

At peak exercise, mean pulmonary artery wedge pressure was markedly higher in the MS group. Peak Vo₂ was significantly lower in MS than in NCD patients (14.2 mL/kg/min vs 16.5 mL/kg/min; P = 0.027), while the arteriovenous oxygen difference was higher in the MS group (9.6 mL/dL vs 7.1 mL/dL; P < 0.001). Although the cardiac index did not significantly differ between the 2 groups at rest, it was significantly lower in the MS group at peak exercise (5.7 L/min/m² vs 9.4 L/min/m²; P < 0.001). In the MS group, the parameters associated with peak Vo₂ were left ventricular global longitudinal strain, stroke volume index, and MVA, as calculated by the continuity equation, but not planimetry MVA or pressure gradient.

Patients with MVA <1.5 cm² exhibited limited exercise tolerance compared with those with NCD. Left ventricular global longitudinal strain and resting stroke volume index emerged as key parameters associated with exercise tolerance among MS patients.