Pulmonary hypertension as estimated by Doppler echocardiography in adolescent and adult patients with cystic fibrosis and their relationship with clinical, lung function and sleep findings

Abstract

Background: In cystic fibrosis (CF) patients, end stage of pulmonary disease is characterized by pulmonary hypertension (PH), hypoxemia, decrease in exercise tolerance, and sleep quality.

Objective: To evaluate the association between clinical, lung function, sleep quality, and polysomnographic variables with PH in CF patients aged 16 years or older.

Methods: In a cross-sectional study, 51 clinically stable CF patients underwent a clinical evaluation, an overnight polysomnography and answered sleep questionnaires (Pittsburgh Sleep Quality Index and Epworth sleepiness scale). Also, CF patients had their pulmonary function, 6-minute walk test (6MWT) and echocardiography assessed.

Results: Fifty-one CF patients participated in the study; 47% were female. The mean age was 25.1 ± 8.8 years. Pulmonary artery systolic pressure (PASP) was greater than 35 mm Hg in 11 (27.5%) patients. Variables associated with PASP>35 mm Hg in univariate analysis were Shwachman-Kulczycki clinical score, forced expiratory volume in 1 second % of predicted, Pseudomonas aeruginosa in sputum culture, at-rest peripheral capillary oxygen saturation (SpO₂ ), SpO₂ at end of 6MWT and time of oxygen desaturation <90% during sleep. These variables were included in the binary logistic regression. The independent variable associated with the PASP > 35 mm Hg was at-rest SpO₂ (OR = 10.8, CI 95% 1.7-67.3, P = .011). The cuttoff SpO₂ < 94% had the sensitivity = 7/11 = 64%, specificity = 40/40 = 100%, positive predicted values = 7/7 = 100% and negative predicted values = 40/44 = 91% to the diagnosis of PH.

Conclusion: the present study showed a high rate of PH in adolescent and adult CF patients. At-rest SpO₂ was associated with PH.

Keywords: cystic fibrosis; doppler echocardiography; polysomnography; pulmonary hypertension.