Echocardiography as an outcome measure in scleroderma-related pulmonary arterial hypertension: a systematic literature analysis by the EPOSS group.

Objective: To assess the validation status of echocardiography with continuous Doppler (echo-Doppler) as an outcome measure in pulmonary arterial hypertension associated with systemic sclerosis (PAH-SSc).
Methods: Structured literature review on full-text English articles was performed using the PubMed and Cochrane databases. Assessment of validation of echo-Doppler was based on the OMERACT filter criteria with the domains truth (face, content, construct, and criterion validity), discrimination, and feasibility.
Results: Out of 35 studies eligible for analysis, only 5 included well defined PAH-SSc subgroups (World Health Organization criteria). Echo was considered as having face validity based on expert opinion and high number of studies using echo for evaluation of patients with SSc. Echo was considered partially validated with respect to criterion validity based on significant correlations between echo measures and right-heart catheterization in patients with SSc at risk of PAH/PH. However, echo was found to lack specificity (lack of content validity), since measurements of echo pulmonary pressure may be influenced by left-heart disease and interstitial lung disease. Data from general populations of patients with scleroderma indicate that evaluation of pulmonary artery pressure by echo might not be available in all PAH-SSc patients because of technical factors. No studies enabling evaluation of the discriminant capacity over time and treatment of echo in PAH-SSc could be identified.
Conclusion: Further studies are needed to fully validate echo-Doppler as an outcome measure in PAH-SSc. These studies would include cross-sectional analysis of baseline measures and longitudinal data of placebo and verum groups in randomized controlled trials of patients with PAH-SSc.