Assessment of right ventricular reserve utilizing exercise provocation in systemic sclerosis

Right ventricular (RV) capacity to adapt to increased afterload is the main determinant of outcome in pulmonary hypertension, a common morbidity seen in systemic sclerosis (SSc). We hypothesized that supine bicycle echocardiography (SBE), coupled with RV longitudinal systolic strain (RVLSS), improves detection of limitations in RV reserve in SSc. 56 SSc patients were prospectively studied during SBE with RV functional parameters compared at rest and peak stress. We further dichotomized patients based on resting RV systolic pressure (RVSP) to determine the effects of load on contractile response. Our pooled cohort analysis revealed reduced global RVLSS at rest (-16.2 +/- 3.9%) with normal basal contractility (-25.6 +/- 7.7%) and relative hypokinesis of the midventricular (-14.1 +/- 6.0%) and apical (-8.9 +/- 5.1%) segments. With exercise, global RVLSS increased significantly (p = 0.0005), however despite normal basal contractility at rest, there was no further augmentation with exercise. Mid and apical RVLSS increased with exercise suggestive of RV contractile reserve. In patients with resting RVSP < 35 mmHg, global and segmental RVLSS increased with exercise. In patients with resting RVSP >= 35 mmHg, global and segmental RVLSS did not increase with exercise and there was evidence of exertional RV dilation. Exercise provocation in conjunction with RVLSS identified differential regional contractile response to exercise in SSc patients. We further demonstrate the effect of increased loading conditions on RV contractile response exercise. These findings suggest subclinical impairments in RV reserve in SSc that may be missed by resting noninvasive 2DE-based assessments alone.