Lack correlation between FVC/DLC index and pulmonary hypertension in non sclerodermic patients

Abstract

Introduction: There are some evidences that in patients with systemic sclerosis the ratio between Forced Vital Capacity (FVC) and diffusing capacity of carbon monoxide (DLCO) could be, with others data, a good predictor of Pulmonary Hypertension (PH) when it is higher than 1.5. The aims of this study was to evaluate if also in patients without scleroderma this index could be used. Methods: Patients afferent to Pulmonary Hypertension ambulatory of University of Foggia with suspect of PH, underwent to spirometry and DLCO test before right heart catheterization (RHC), FVC%/DLCO% was then calculated. In accord with the results of RHC, sensibility and specificity was then calculated. Results: 71 patients were enrolled and according Mean Pulmonary Arterial Pressure (PAPm) divided in two groups: 27 were PH negative (PAPm= 18,96 ± 4,78 mmHg) while 44 were PH positive (PAPm= 40,43 ± 14,18). Patients were matched for age, sex and BMI. Any difference rose between FVC%/DLCO% in two groups (1,71±0,69 vs 2,20±1,16; p=0,27). Even if there was a slight correlation between FVC%/DLCO% with PAPm and Cardiac Index (IC) the results were not significant (R=0.21; p 0.35; R=-32; p=0.2 respectively). At cut-off value of 1.5 this index was quite sensible (0.72) and very low specific (0.22). Conclusion: In patients without systemic sclerosis, FVC%/DLCO% cannot be used routinely to screening patients with suspect Pulmonary Hypertension.