The frequency of pulmonary hypertension in patients with sarcoidosis

Introduction: Sarcoidosis-associated pulmonary hypertension is an important complication with significant morbidity and high mortality. Its etiology is multifactorial and there are few studies about its frequency. The aim of our study is to determine the frequency of pulmonary hypertension in sarcoidosis and to investigate its relationship with easily accessible tests for early diagnosis. Method: 106 sarcoidosis patients who were followed in the Interstitial Lung Diseases Polyclinic of Istanbul University, Istanbul Faculty of Medicine, Department of Chest Diseases between 1996-2020 were included in our study. Age, gender, smoking anamnesis, occupational and environmental exposures, additional diseases, medications used, sarcoidosis stages, current complaints, follow-up periods, treatments and durations they received for sarcoidosis, body mass indexes and functional capacities were recorded. Data were recorded by performing respiratory function test, diffusion capacity measurement and 6-minute walking test in all patients. Patients were evaluated by transthoracic echocardiography and right heart catheterization was performed in patients with high suspected PH (EthicNo:2020/56). Results: 106 sarcoidosis patients were included in the study. 78 (73.6%) of the cases were female and 38 (26.4%) were male. Their mean age was 49.5 ± 10.4 (23-72)/year, and the mean age at diagnosis was 42.6 ± 9.8 (18-69)/year. Recurrence was detected in 20 patients (18.9%) during the follow-up period, and 58 patients (54.7%) had previously received treatment for sarcoidosis. The mean duration of treatment was 27.6 ± 37.7/month. Looking at the stages of sarcoidosis, 84.9% of the cases were stage II and III. Mean forced expiratory volume in 1 second (FEV1) 2434.3 ± 827 mL (830-5300 mL), forced vital capacity (FVC) 3177.2 ± 1230 mL (1260-6710 mL), diffusing capacity (DLCO) 82.9 ± 16.2 mmol/(min*kPa), the 6-minute walking distance was 423.6 ± 79/m. Right heart catheterization in cases with TRV 2.9 m/s on echocardiography revealed pre-capillary pulmonary hypertension at a rate of 2.83% (n=3). The EF value was significantly lower in the group with TRV ≥ 2.9 m/s than the group with TRV < 2.9 m/s (p = 0.037). Again, although fatigue was significantly higher in this group (p = 0.04), no significant difference was observed between the groups in terms of other symptoms. İn Spearman correlation analysis; positive correlation between increased sPAP measured at TTE (Rs = 0.305, p = 0.004), age (Rs = 0.218, p = 0.025), weakness (Rs = 0.283, p = 0.006), shortness of breath (Rs = 0.184, p = 0.059), chest pain (Rs = 0.265, p = 0.06), hypertension (Rs = 0.0226, p = 0.020), and hypothyroidism (Rs = 0.315, p = 0.001) with the presence of PH in sarcoidosis was determined. In functional evaluation, negative correlation was found with FEV1 (mL) (Rs = -0.199, p = 0.041) and FVC (ml) (Rs = -0.201, p = 0.039), while FVC value was found to be 1110.5 ml lower in the group with PH. A positive correlation was found between pulmonary hypertension and DLCO value below 60% (Rs = 0.413, p <0.001) and a negative correlation (Rs = -0.221, p = 0.020) between 6 MWD. 6 MWD was 103.6 m lower in the group with pulmonary hypertension. Conclusion: In our study, the frequency of pulmonary hypertension in patients with sarcoidosis was 2.83%. Negative correlation between FVC (Rs = -0.201, p = 0.039) and 6-minute walking distance (Rs = -0.221, p = 0.020) with the presence of pulmonary hypertension, positive correlation between DLCO rate below 60% and the presence of pulmonary hypertension in sarcoidosis (Rs = -0.221, p = 0.020) = 0.413, p <0.001) was determined. Keywords: 6 minute walking test, diffusing capacity, pulmonary hypertension, sarcoidosis, pulmonary function test