Cardiopulmonary Exercise Testing and Exercise Stress Echocardiography in Degenerative Mitral Regurgitation: An Exploratory Analysis of Functional and Left Ventricular Outcomes After Surgery.

backgroundSurgical correction of severe degenerative Mitral Regurgitation (DMR) is indicated in the presence of symptoms and signs of left ventricular (LV) dysfunction. However, conventional clinical and resting echocardiographic parameters may underestimate myocardial impairment. Cardiopulmonary exercise testing (CPET) and exercise stress echocardiography (ESE) may provide a more complete functional and haemodynamic assessment.

objectivesTo characterize preoperative CPET and ESE findings in patients with severe DMR and to explore, in a hypothesis-generating analysis, their association with early functional and left ventricular outcomes after surgery.

methodsWe included patients with severe DMR who underwent CPET and ESE before surgery. Functional improvement was defined as an improvement of at least one NYHA class from the preoperative baseline to early follow-up. LV function was evaluated as the continuous change in LVEF from discharge to early follow-up (Delta LVEF = follow-up LVEF - discharge LVEF). Baseline parameters were compared between patients who did and did not improve functionally. Random forest analyses were used only as an exploratory secondary analysis to assess whether baseline variables showed any non-linear signal of association with the outcomes and to document the instability of variable-importance rankings. RESULTS AND

conclusionsWe included 60 patients, of whom 72% were in NYHA class II and all had preserved LV function. At CPET, rest and peak oxygen uptake were 6 +/- 1.5 and 17.2 +/- 5 mL/kg/min, respectively; the VE/VCO