Optimal use of gas transfer values in detecting pulmonary vascular involvement in sarcoidosis

Introduction: Gas transfer abnormalities in sarcoidosis may reflect changes in both interstitium and pulmonary capillary bed given the correlation with both extent of disease and pulmonary vascular resistance. The aim of our study was to evaluate cohort evidence with regards to prevalence of pulmonary vascular involvement as assessed by gas transfer values.Methods: Data were evaluated from 1245 consecutive adults with sarcoidosis between 1/1/2009 and 14/7/2014. Current or ex-smokers were excluded in order to avoid effects on ventilation-perfusion abnormalities. Isolated TLCO reduction was identified when FEV1/FVCu003e70%, FVCu003e80%, TLCu003e80% and TLCO 1.6.Results: 793 patients (340 males) aged 52.1±11.7 years old were studied. Mean values (±SD) of pulmonary function tests parameters were: FEV1:78.7±21.8%, FVC:88.3±21.4%, FEV1/FVC:72.1±11.7%, TLC:84.9±16.9%, RV:88.2±22.7%, TLCO:65.9±20.2% and KCO:84.7±17.4%. Isolated TLCO reduction was found in 167(21.1%) and reduction in TLCO disproportionate to change in lung volume in 139(17.5%) patients. When patients with TLCO reduction disproportionate to change in lung volume were compared with 85 consecutive IPF patients, sarcoidosis patients were found with significant lower KCO (62.1±12.6 vs 74.1±18.7, pu003c0.0001) although FVC (78.4±21.4 vs 60.1±14.7, pu003c0.0001) and TLC (74.6±17.4 vs 56.8±11, pu003c0.0001) were significantly higher and CPI was significantly lower (46.7±16 vs 59.5±10.5, pu003c0.0001).Conclusion: The results highlighted the use of gas transfer values in the evaluation of pulmonary vascular component in patients with sarcoidosis.