Evaluation of right ventricular performance and impact of continuous positive airway pressure therapy in patients with obstructive sleep apnea living at high altitude

Abstract

Obstructive sleep apnea syndrome (OSAS) can lead to alterations in right ventricular (RV) performance and pulmonary vascular haemodynamics. Additionally, altitude-related hypoxia is associated with pulmonary vasoconstriction, and the effect of high-altitude on the pulmonary circulation in OSAS patients can be further altered. We sought to assess alterations in RV morphology and function in OSAS patients living at high altitude by way of 2-dimensional speckle tracking echocardiography (2D-STE), real-time 3- dimensional echocardiography (RT-3DE) and cardiac biomarkers. We also evaluate the impact of continuous positive airway pressure (CPAP) treatment on RV performance. Seventy-one patients with newly diagnosed OSAS and thirty-one controls were included in this study. All individuals were assessed for cardiac biomarkers as well as underwent 2D-STE and RT-3DE. Forty-five OSAS patients underwent CPAP therapy for at least 24 weeks and were studied before and after CPAP treatment. RT-3DE was used to measure RV volume, and calculate RV 3D ejection fraction (3D RVEF). Peak systolic strain was determined. Cardiac biomarkers, including C-reactive protein (CRP), N-terminal pro-B-type natriuretic peptide, and cardiac troponin T were also measured. Right atrium volume index, RV volume, RV volume index, systolic pulmonary artery pressure (sPAP), pulmonary vascular resistance (PVR) and level of serum CRP were significantly higher in OSAS group, while OSAS patients showed lower 3D RVEF and RV longitudinal strains. Compared to the patients with sPAP < 40 mmHg, RV longitudinal strains in patients with sPAP ≥ 40 mmHg were lower. Both RV global longitudinal strain and sPAP were associated with apnea–hypopnea index. Patients treated with 6 months of CPAP therapy had significant improvement in RV geometry and performance. RV structural abnormalities and RV function impairments were observed in OSAS patients living at moderate high altitude compared to control highlanders. The reversibility of these changes after application of CPAP were further confirmed.

The impact of continuous positive airway pressure on cardiac mechanics: Findings from a meta‐analysis of echocardiographic studies

“…These findings may be related to differences in baseline characteristics of the population study, such as obesity, BP and glucose regulation, as well as duration of CPAP therapy (hours per night, total duration of therapy during follow‐up) and compliance to therapy. Of note, our meta‐analysis shows that LVEF significantly increased after CPAP therapy; this parameter was in the normal range independently of OSA severity in the majority of studies 18–24 and LVEF deterioration from mild, to moderate, and severe OSA was only reported by Hammerstingl and coworkers 17 These authors reported that LVEF improved in patients with moderate and severe OSA, but not in mild OSA; in other studies, LVEF values before and after CPAP treatment have been reported in the OSA group as a whole 19,21 …”

Association of Pulmonary Artery Pulsatility Index With Adverse Cardiovascular Events Across a Hospital-Based Sample

“…There are growing data supporting the increase in RV dysfunction among patients with obesity 26,27 and in patients with obstructive sleep apnea, although initiation of continuous positive airway pressure has been demonstrated to improve RV structure and function in the latter. 28–30 In addition, we observed that the presence of moderate-or-greater tricuspid regurgitation was associated with a lower PAPi. Significant tricuspid regurgitation leads to RV dilation through increased diastolic volume, and progressive RV dilation/dysfunction and a lower cardiac output in these patients have been shown to be associated with mortality.…”

Obstructive Sleep Apnea and Sleep Structure Assessed in Polysomnography and Right Ventricular Strain Parameters

“…Chu et al showed that six-month CPAP therapy caused a significant increase of global and longitudinal strain. Moreover, they observed a decrease of AHI and duration of desaturation <90% [30].…”