Echocardiographic and Cardiopulmonary Phenotypes Related to the Severity of Functional Mitral Regurgitation During Maximal Exercise Testing in Heart Failure

Background: In heart failure (HF) patients the severity of mitral regurgitation (MR) at rest has a well established prognostic value and its increase during exercise further adds to an increased risk. Our goal was to define the relationship between the degree of exercise MR severity with cardiopulmonary and echocardiographic related phenotypes in a cohort of HF patients Methods: 71 HF reduced ejection fraction patients (mean age 6711; male 72%; ischemic etiology 61%; NYHA class I, II, III and IV 13%, 36%, 39% and 12%, mean ejection fraction 339%) underwent cardiopulmonary exercise test (CPET) on tiltable cycle-ergometer combined with echocardiography at rest and during exercise. The population was divided into two groups according to the degree of functional peak MR: no to mild/moderate MR (no MR, MR1 and MR2) vs moderate/severe MR (MR3and MR4). Results: Peak exercise variables no MR (n11) MR 1 (n19) MR 2 (n7) MR3 (n15) MR 4 (n19) P coeff. Anova Pulmonary artery systolic pressure (PASP), mmHg 447 5523 5710 6217 7116 0.005 Cardiac Output, l/min 7.42 6.13 0.015 Cardiac Power Output, Watt 1.750.6 1.30.7 0.018 Oxygen consumption (VO2), ml/kg/min 13.83.4 11.63 0.036 O2 pulse, ml/beat 9.62.2 82.8 0.008 Workload, Watt 7023 549 0.002 VE/VCO2, slope 339 378 0.07 A good correlation (ρ coefficient 0.49) was found between the degree of dynamic MR and PASP at peak exercise. Despite similar echocardiographic profile at rest patients with significant peak MR (MR≥3+) had worse exercise performance (lower peak VO2, O2 pulse and workload) and impaired ventilatory efficiency (higher VE/VCO2 slope). Conclusions: In HF patients the severity of exercise-induced MR is associated with the most unfavorable performance and pulmonary hemodynamic response. A combined approach with CPET and echocardiographic assessment can help to early unmask and target functional MR and its related unfavorable phenotypes.