The Effect of Primary Airway Therapy on Blood Pressure in Excessively Sleepy Patients With Obstructive Sleep Apnoea: a Retrospective Analysis of the ANDANTE Data

Introduction

Obstructive sleep apnoea (OSA) is one of the most common noncommunicable types of disease, it affects about 1 billion people across the world. Left untreated, it causes apnoeas and hypopnoeas to fragment sleep, with frequent arousal from sleep and intermittent hypoxia associated with increased work of breathing. Frequently, it leads to excessive daytime sleepiness, as measured subjectively by the Epworth Sleepiness Scale, or, objectively, by the multiple sleep latency test (MSLT) or the maintenance of wakefulness test (MWT). OSA can lead to sustained high sympathetic tone at night, which in the long-term may impact on the cardiovascular risk.

With optimised primary airway treatment, normal breathing at night resumes and patients experience a restoration of normal sleep architecture, with little or no further sleep fragmentation due to the underlying sleep disordered breathing. Daytime symptoms and quality of life typically improve with primary airway treatment, and long-term cardiovascular risks follows.

Data from the ANDANTE collaboration have recently shown that the effect of primary airway patency treatment in patients with obstructive sleep apnoea on the blood pressure control differs according to whether patients with OSA have normal blood pressure, controlled or uncontrolled hypertension. Furthermore, the high prevalence of OSA in the general population, frequently diagnosed randomly (e.g., screening prior to elective surgery) in otherwise asymptomatic patients raises the question whether symptoms, like sleepiness, that are associated with the syndrome predict outcomes on the cardiovascular system.

There are clinically relevant implications in who should and who should not be treated with OSA, particularly in the cohort of mild/moderate and asymptomatic patients with OSA, as recently discussed in the Baveno, and the modified Baveno classification. Furthermore, a proportion of patients with OSA who are adherent to primary airway therapy remain symptomatic, as measured by the Epworth Sleepiness Scale, a phenomenon that has been labelled residual excessive daytime sleepiness. The cardiovascular risk associated with patients who are excessively sleepy at baseline, and who remain so, is unclear.