Correlação entre a função do ventrículo direito e a capacidade de difusão do monóxido de carbono (DLCO) na esclerose sistêmica: estudo transversal

Abstract

Correlation between right ventricular function and diffusing capacity for carbon monoxide (DLCO) in systemic sclerosis: a cross-sectional study. [Rheumatology Residency Final Paper]. Rheumatology Service, Professor Edgard Santos University Hospital (HUPES/UFBA), 2025. Introduction: Systemic sclerosis (SSc) is an autoimmune disease characterized by vasculopathy and fibrosis of multiple organs, in which cardiopulmonary involvement is a major determinant of prognosis. Assessment of right ventricular (RV) function by transthoracic echocardiography (TTE) and evaluation of the diffusing capacity for carbon monoxide (DLCO) may help identify early functional abnormalities along the heart–lung axis. Objectives: To correlate echocardiographic measures of RV function with pulmonary function parameters and the presence of interstitial lung disease (ILD) in patients with SSc, and to explore the relationship between RV dysfunction and peripheral vasculopathy phenotypes.Methods: Cross-sectional study including adults with SSc followed at a tertiary care center, classified according to the 2013 ACR/EULAR criteria. Standardized clinical data, TTE, pulmonary function tests and high-resolution computed tomography (HRCT) of the chest for ILD detection were obtained. On TTE, RV systolic function was assessed using tricuspid annular plane systolic excursion (TAPSE), estimated pulmonary artery systolic pressure (PASP) and the TAPSE/PASP ratio. Descriptive and exploratory analyses were performed, with comparisons between groups and assessment of associations between echocardiographic and pulmonary function parameters. Results: Of 103 patients initially evaluated, 71 composed the analytical sample after application of inclusion criteria, and the effective number of observations varied across analyses according to exam availability. Overt RV systolic dysfunction was infrequent, whereas elevated PASP values were observed in a relevant proportion of patients. Higher TAPSE values were associated with better-preserved DLCO, whereas higher PASP was accompanied by lower DLCO. The TAPSE/PASP ratio showed a consistent association with DLCO and was lower in patients with ILD on HRCT, who also presented higher PASP, suggesting worse RV–pulmonary arterial coupling in this subgroup. No clear association was identified between RV echocardiographic parameters and peripheral vasculopathy phenotypes such as pitting scars, digital ulcers or amputations. Conclusion: In patients with SSc, the TAPSE/PASP ratio behaved as an integrated marker of the cardiopulmonary axis, simultaneously reflecting RV function, pulmonary pressure load and impairment of gas transfer, particularly in the presence of ILD. These findings suggest that the routine incorporation of TAPSE/PASP into TTE interpretation, together with pulmonary function and HRCT assessment, may contribute to more refined risk stratification in SSc. Keywords: Systemic Sclerosis; Right Ventricle; TAPSE/PASP; DLCO; Interstitial Lung Disease; Echocardiography.