Right ventricular reserve in cardiopulmonary disease: a simultaneous hemodynamic and three-dimensional echocardiographic study.

Background: RV reserve has been linked to exercise capacity and prognosis in cardiopulmonary diseases. However, evidence in this setting is limited, due to the complex shape and load dependency of the RV. We sought to study right ventricular (RV) adaptation to exercise by simultaneous three-dimensional echocardiography (3DE) and right heart catheterization (RHC).

Methods: Patients with heart failure with preserved ejection fraction (HFpEF) or pulmonary vascular disease (PVD) underwent simultaneous supine rest/exercise RHC-3DE. They were subdivided based on RV ejection fraction (EF) changes: 1)exhausted RV reserve, RVEF-; 2)preserved RV reserve, RVEF+.

Results: Sixty percent of patients were RVEF-. Distribution of HFpEF/PVD, as well as RV volumes and RVEF at rest were similar in the two groups. Hemodynamic metrics of RV afterload, as well as their exercise-induced changes, were similar in the two groups. During exercise, RV end-diastolic volume increased more in RVEF- than in RVEF+ (29±29 vs 7±25 mL,p<0.05). RV end-systolic volume increased by 21[12;31]mL in RVEF- and decreased by 8[-15;1]mL in RVEF+ (p<0.001). RV-pulmonary artery coupling was lower in RVEF- at peak exercise(p<0.05). Peak RVEF was associated with left ventricular preload (R=0.14,p=0.011). Cardiac output increased less in RVEF- than in RVEF+ (+2.3±2.0 vs +4.0±2.4 L/min,p<0.05). Peak RVEF was associated with oxygen consumption(p<0.01).

Conclusions: Exhausted RV reserve, as evaluated by 3DE, was frequent in HFpEF and PVD, was relatively independent from classical afterload parameters, was associated with RV-pulmonary artery decoupling, RV dilation, enhanced ventricular interdependence, and cardiac limitation to exercise. Intrinsic RV dysfunction may contribute to exhausted RV reserve.