Exhaled nitric oxide levels in patients with pulmonary hypertension

Abstract

Introduction: Pulmonary hypertension (PH) is a chronic, progressive disease with a high morbidity and mortality. Its pathobiology involves interacting pathways of prostacyclin (PGI2), endothelin, and nitric oxide (NO). There are few studies which evaluated exhale NO levels in patients with PH. Aim of this study was to investigate the levels of exhaled NO in PH patients. Methods: Patients who were followed in Istanbul Faculty of Medicine, Pulmonary Hypertension Outpatient Clinic were enrolled in this study. Exhaled NO levels of patients with PH were compared to age and gender matched healthy controls. Results: Data of 38 patients with PH (28 females, 10 males, age:54.5±16.3years) were compared to 80 healthy controls (55 females, 25 males, age:49.8±14.4years). Etiologies of PH were pulmonary arterial hypertension (PAH, n=24) and chronic thromboembolic pulmonary hypertension (CTEPH, n=14). NYHA functional class of the patients were mostly II (68.4%). Thirteen of them (41.9%) were given PH specific treatment (prostacyclin derivatives, endothelin receptor antagonists, phosphodiesterase inhibitors). Estimated systolic pulmonary arterial pressure (PAP) by transthoracic echocardiography was 64.9±28.2mmHg and TAPSE was 1.88±0.48. ProBNP measured 1169.2±2858.9pg/ml. Right heart catheterization revealed systolic PAP 87.1±39.4mmHg, mean PAP 55.9±25.4mmHg, PVR 7.9±5.3wood. Exhaled NO levels were lower in patients with PH than healthy controls (16.7±6.8ppb vs 19.8±7.7ppb, p=0.036). Exhaled NO levels were not different between patients with PAH and CTEPH (16.7±6 vs 16.7±7.7, p=0.458). Conclusions: Our study showed a significant reduction in exhaled NO levels in PH patients.