PURPOSE: Recent data show that there is an unpredictably high prevalence of “inappropriate“ pulmonary responses to exercise among patients with systemic sclerosis (SSc). However, no consensus exists as to which threshold of pulmonary artery systolic pressure (PASP) can be considered diagnostically relevant. The present study was undertaken to gain insights into the determinants and clinical significance of PASP increase during exercise in SSc patients.
METHODS: The study enrolled 172 consecutive SSc patients in NYHA class I-II with a peak tricuspid regurgitant jet velocity at echocardiography not greater than 3 m/sec and 88 control subjects. Echocardiography was performed at rest and at the end of a maximal exercise test.
RESULTS: SSc patients showed a higher exercise PASP than control subjects (36.9.±8.7 vs 25.9±3.3 mmHg, p=0.00008). The response to effort was exaggerated in the presence of moderate interstitial lung fibrosis (39.7±9.3 vs 36.0±8.4 mmHg, p=0.016) or subclinical left ventricular diastolic dysfunction (42.3±5.8 vs 37.0±8.6 mmHg, p=0.015). In control subjects, PASP values were normally distributed at rest and during exercise. In SSc patients, the distribution was normal at rest and bimodal during exercise, with a second peak at 52.2 mmHg including 13% of the total SSc population. Patients in this subgroup showed abnormalities of right ventricular diastolic function at rest and a blunted increase in right ventricular systolic function during exercise.
CONCLUSION: Exercise echocardiography may identify a subset of SSc patients with an inappropriate increase in PASP during exercise and with early signs of right ventricular dysfunction.
CLINICAL IMPLICATIONS: An abnormal pulmonary vascular reserve in SSc patients might be related to the presence of mild to moderate interstitial lung disease or to subclinical LV diastolic dysfunction. However, exercise echocardiography may disclose abnormalities of the pulmonary circulation in a small subset of patients with normal PASP at baseline. It is still unknown whether these patients are really at risk of future development of PAH.
DISCLOSURE: Michele D’ Alto, No Financial Disclosure Information; No Product/Research Disclosure Information