The Utility of Cardiopulmonary Stress Testing with Pulmonary Arterial Catheterization in Systemic Sclerosis Patients with Unexplained Dyspnea.

Abstract

RATIONALE: The utility of cardiopulmonary exercise testing with pulmonary artery catheterization (CPET/PAC) as a diagnostic modality in patients with systemic sclerosis (SSc) and unexplained dyspnea has not been studied. METHODS: Retrospective chart review of SSc patients referred over five years for CPET/PAC after initial evaluation (pulmonary function testing, thoracic CT scan, and echocardiography) failed to demonstrate a clear etiology of dyspnea and raised a question of exercise−induced pulmonary hypertension (EIPH). RESULTS: Twenty patients with systemic sclerosis [9 (53%) limited, 6 (35%) diffuse, 2 (12%) overlap 3 not characterized] were referred for CPET/PAC during the study period. Nine (45%) patients had mean pulmonary arterial pressure greater than 30mmHg with exercise: four resulting from left ventricular dysfunction (LVDysfunction) and five from EIPH. The etiology of dyspnea was diagnosed in 17/20 (85%) patients and was evenly distributed between ventilatory limitation (n=5), deconditioning (n = 5), EIPH (n=4), LVdysfunction (n=3), and other (1 normal, 2 nonspecific cardiovascular limit). In one patient with mild EIPH, CPET analysis determined that exercise intolerance was actually secondary to a ventilatory limitation. CPET/PAC testing resulted in a change in therapy in 80% (16/20) of patients. No diagnostic test performed prior to CPET/PAC predicted the etiology of dyspnea eventually determined by CPET/PAC. However, a peak exercise A−a gradient > 16mmHg performed well as a screening test to differentiate EIPH from LVdysfunction in the absence of pulmonary artery catheter data (AUC 0.85, sensitivity 100%, specificity 60%). CONCLUSION: CPET/PAC is a useful modality in systemic sclerosis patients who have multiple potential etiologies of dyspnea: defining an etiology in 85% of patients and leading to a change in treatment in 80% of patients. This abstract is funded by: None. Am J Respir Crit Care Med 179;2009:A4130 Internet address: www.atsjournals.org Online Abstracts Issue