[Clinical assessment of pulmonary hypertension in collagen diseases]

The occurrence of pulmonary hypertension (PH) has been reported in association with collagen diseases. Because of its grave consequences it is of greatest importance to make an early diagnosis of PH and initiate adequate treatment. For this purpose we have carried out right heart catheterization study to determine pulmonary arterial pressure (PAP), pulmonary vascular resistance (PVR), and cardiac index in thirty-four consecutive patients with collagen diseases including cases of mixed connective tissue disease (MCTD). We also compared the hemodynamic data with clinical pictures and the results of non-invasive cardiopulmonary tests which were done before catheterization study. Pulmonary hypertension as defined by the mean PAP of greater than 20 mmHg was observed in 11 of the 34 cases. PH was observed in five of 6 cases with MCTD and six of 17 cases with PSS including 2 cases with overlapping SLE and PM. The frequencies of positive anti-nRNP antibody, serositis, Raynaud's phenomenon and muscle involvement were significantly higher in cases with PH than in cases without PH. Catheterization study was most useful for diagnosis of cases with mean PAP of less than 25 mmHg, whereas echocardiographic study identified all cases with mean PAP of greater than 25 mmHg. No significant correlation was observed between mean PAP and vital capacity, total lung capacity or diffusion capacity measured as the percent of predicted normal values, which suggests that vascular abnormalities play a more significant role in the pathogenesis of PH than pulmonary fibrosis in collagen diseases.