The emerging role of the contractile and vascular reserves in pulmonary arterial hypertension

We read with great interest the recent article by Sharma et al. [1] on the evaluation of right ventricular (RV) reserve in pulmonary arterial hypertension (PAH) by the dobutamine stress test. Their work highlights the potential clinical value of the RV systolic reserve into the evaluation of PAH patients beyond resting measurements. Sharma et al. [1] reported that RV contractile reserve (tricuspid annular plane systolic excursion (TAPSE) and tricuspid annulus systolic myocardial velocity ( S ′)) is markedly attenuated in PAH patients and correlates with exercise capacity. Although the merit of the work is in assessing RV contractile reserve by direct functional parameters, there are some topics that deserve discussion. Patients with PAH exhibit markedly diminished RV contractile reserve and pulmonary arterial vascular reserve