Right ventricular global work efficiency: A reliable non-invasive estimate of right ventricular contractility

Abstract

Background: Right ventricular (RV) myocardial work (RVMW) recently emerged as a non-invasive alternative for the assessment of RV contractility. However, none of the prior studies assessed its variations under different haemodynamic conditions. We aimed to evaluate the variations of the components of RVMW in heart failure (HF) patients with pulmonary hypertension (PH) undergoing a reversibility test.

Methods: Consecutive HF patients with reduced ejection fraction who underwent right heart catheterization and echocardiography at our institution were prospectively enrolled. Patients with PH and augmented pulmonary vascular resistance who achieved normalization of pulmonary pressures after the reversibility test using vasodilators underwent a second echocardiographic assessment under the same haemodynamic conditions. Four components of RVMW were analysed: (1) RV global work index (mmHg%); (2) RV global constructive work (mmHg%); (3) RV global wasted work (RVGWW) (mmHg%); (4) RV global work efficiency (RVGWE) (%).

Results: One hundred two patients were enrolled (53 with PH and 49 without). Global RVMW was higher in patients with PH, due to a significantly higher RVGWW [81 (55-119) mmHg% vs. 49 (28-72) mmHg%; P = 0.013], while RVGWE was similar between the two groups (80 ± 10% vs. 82 ± 12%; P = 0.332). In patients with PH, 27/52 (51.9%) had combined PH, while 25/52 (48.1%) had isolated post-capillary PH. A reversibility test was performed in 26/27 (96.2%) patients with combined PH and pulmonary pressure normalization was observed in 16/26 (61.5%) subjects. In patients with PH normalization, RVGWE remained almost unchanged (from 82.8 ± 6.9% to 85.3 ± 6.6%; P = 0.596), while RVGWW significantly decreased [from 60 (49-90) mmHg% to 41 (31-53) mmHg%; P = 0.027]. Among all the echocardiographic and haemodynamic parameters adopted for assessing RV function, RVGWE was the least variable during the reversibility test (mean variation 3 ± 10%).

Conclusions: RVGWE is comparable between HF patients with and without PH and remains stable across different haemodynamic conditions. This consistency suggests that it can be a reliable parameter for assessing RV contractility. Larger studies are needed to confirm this hypothesis and to test its prognostic significance.

Keywords: heart failure; myocardial work; pulmonary hypertension; reversibility test; right ventricle.