Pulmonary Artery Dimensions as a Prognosticator of Transplant-Free Survival in Scleroderma Interstitial Lung Disease.

Background: Systemic sclerosis is a chronic debilitating autoimmune disease characterized by endothelial dysfunction and multi-organ fibrosis. Interstitial lung disease, a common manifestation of SSc, is termed scleroderma-related interstitial lung disease (SSc-ILD) and along with pulmonary hypertension contributes to a majority of deaths in SSc. SSc-ILD patients frequently develop pulmonary hypertension, which prognosticates a poorer outcome. We investigated pulmonary artery dimensions as an outcome predictor in patients with SSc-ILD.

Methods: A retrospective chart review abstracting data from SSc-ILD patients evaluated at a large tertiary care center was performed. HRCT imaging was reviewed and pulmonary artery (PA) and ascending aorta (Ao) diameters were measured for calculation of the PA:Ao ratio. Additionally, demographics, vital signs, spirometric parameters, comorbidities, and mean pulmonary artery pressures were collected when available. Outcome analysis with lung transplant or death events within 4 years based on pulmonary artery size as well as PA:Ao ratio was performed.

Results: 70 SSc-ILD patients were identified. Mean pulmonary artery diameter and PA:Ao ratio was 31.17 and 1.07 mm, respectively. Patients with a pulmonary artery diameter ≥32 mm had higher risk of lung transplantation or death (p < 0.001) within 4 years. Patients with a PA:Ao ratio ≥1.1 also had higher risk of lung transplantation or death (p < 0.001) within 4 years. Unadjusted outcomes analyses also identified PA:Ao ratio ≥1.1 as an independent outcome predictor (hazard ratio 3.30, p < 0.001).

Conclusions/clinical Implications: In SSc-ILD patients, a PA:Ao ratio ≥1.1 is associated with higher risk of lung transplant or death. These data suggest that PA:Ao dimension may be used for prognostication in SSc-ILD.