Assessing right ventricular pulmonary circulation reserve during exercise challenge in patients with heart failure and severely depressed right heart function at rest

Background: Right ventricular (RV) dysfunction at rest has a significant prognostic role in heart failure (HF) syndrome and its combination with pulmonary artery systolic pressure (PASP) is useful for risk stratification. Different response to exercise of echo-derived tricuspid annular systolic excursion (TAPSE), as RV function indicator, and PASP may provide further clinical stratification in a population of HF patients with advanced bi-ventricular disease and depressed RV function. Aim: We aimed to assessed RV-pulmonary circulation functional response to maximal exercise in a population of HF patients with severe RV systolic impairment (TAPSE<16 mm) and to explore the association between right heart functional capacity and exercise capacity as evaluated by cardiopulmonary exercise testing (CPET) parameters combined with echo. Methods: 39 HFrEF patients (mean age 64 y, male 82%, ischemic etiology 64%, LVEF 33±10%, NYHA class I, II, III, IV 20, 21, 42,17 %, mean TAPSE 13±2 mm, PASP 43±19 mmHg) underwent a maximal symptoms-limited CPET on a tiltable cycle ergometer using an incremental personalized ramp protocol and stress echo. Results: Study population as divided in two groups according to the presence RV functional reserve increase of TAPSE at peak exercise >20%). Despite similar left ventricular (LV) function and RV systolic impairment at rest, patients with impaired RV reserve (Group B) showed lower exercise capacity (peak VO2, peak O2 pulse), associated with more advanced cardiac remodeling and more severe degree of mitral regurgitation (MR) both at rest and during exercise. Conclusions: In HF patients an impaired RV function at rest may not invariably lead to an unfavorable RV adaptive response to exercise. Testing the degree of RV functional reserve and RV-pulmonary circulation coupling during exercise can be useful even in the most advanced stages of disease to unmask different clinical phenotypes and, very likely, different levels of risk.