Impact of right ventricular reserve on exercise capacity and survival in patients with pulmonary hypertension

Abstract

AimsPulmonary hypertension is a clinical syndrome characterized by a progressive increase in pulmonary vascular resistance leading to right ventricular failure and death. Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are key subgroups of this disorder with comparable clinical and pathological findings. Resting pulmonary haemodynamics correlate only moderately with functional parameters and do not predict prognosis in these patients sufficiently accurately. We therefore correlated exercise haemodynamics with peak oxygen uptake (peakVO 2 ) and determined their prognostic significance. Methods and resultsThirty-six consecutive patients (21 female, 54 + 15 years) with PAH (n ¼ 21) or inoperable CTEPH were studied. The mean follow-up period was 1709 + 837 days. All patients underwent right heart catheterization at rest and during exercise, and cardiopulmonary exercise testing. Patients had severe pulmonary hypertension at rest (mean pulmonary artery pressure 46 + 11 mmHg, cardiac index 2.2 + 0.6 L/min/m 2 , pulmonary vascular resistance 861 + 330 dynes/s/cm 5 ). Exercise cardiac index correlated with peakVO 2 (r ¼ 0.59, P , 0.001) and was the only independent predictor of peakVO 2 on multivariate stepwise linear regression analyses (P , 0.001). PeakVO 2 was the strongest predictor of survival (x 2 ¼ 14.5, P ¼ 0.003). Among haemodynamic variables, only exercise cardiac index (x 2 ¼ 5.6, P ¼ 0.018) and the slope of the pressure/flow relationship (x 2 ¼ 4.1, P ¼ 0.04) were significant prognostic indicators. ConclusionThe ability of the right ventricle to increase the cardiac index during exercise is an important determinant of exercise capacity in patients with pulmonary hypertension. It also predicts prognosis and might therefore be useful in the clinical assessment of these patients.--

2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension

“…Patients with PAH show a typical pattern with a low end-tidal partial pressure of carbon dioxide ( pCO 2 ), high ventilator equivalents for carbon dioxide (VE/ VCO 2 ), low oxygen pulse (VO 2 /HR) and low peak oxygen uptake ( peak VO 2 ) [121]. Several variables determined by CPET provide prognostic information, although peak VO 2 is most widely used for therapeutic decision making [106,[122][123][124][125]. The diagnostic and prognostic information provided by CPET add to that provided by the 6MWT [122].…”

Right ventricular reserve in a piglet model of chronic pulmonary hypertension

“…Secondly, the study highlights that contractile reserve could be more useful than resting parameters for risk stratification. In a recent study, BLUMBERG et al [31] showed that CI at peak exercise was more strongly associated with outcome than resting parameters. In the present study, CI was increased in the PH group after dobutamine infusion, but to a lesser extent compared with controls.…”

Dobutamine stress for evaluation of right ventricular reserve in pulmonary arterial hypertension

“…Even though patients with PAH may present with mild-to-moderate ventilation/perfusion mismatch abnormalities, the main determinant of exercise capacity is right ventricular function (and cardiac output) [31]. In PAH, exercise capacity is dependent on the ability of the RV to respond to the increase in cardiac output required for the metabolic requirements of exercise [32]. Thus, it is perceivable that measures of RV contractile reserve may, therefore, be coupled with exercise capacity.…”