Sleep Apnea-Specific Nocturnal Blood Pressure Surge to Determine Cardiovascular Risks and Therapeutic Benefits in Patients with Obstructive Sleep Apnea

点击翻译按钮获取中文摘要

Abstract Obstructive sleep apnea (OSA) is a common sleep disorder associated with an increased risk of cardiovascular (CV) disease. However, it remains uncertain whether treatment of OSA improves CV outcomes given the lack of evidence from recent clinical trials. We hypothesize that characterizing repetitive nighttime blood pressure (BP) surges following sleep apnea events improves risk stratification in OSA and helps identify those who benefit most from therapy. OSA is a major risk factor for nocturnal hypertension, a well-established prognostic marker for adverse CV outcomes, including mortality. Therefore, it is plausible that nocturnal hypertension acts as a mediator between OSA and CV morbidity and mortality. However, continuous BP is not currently quantified in clinical sleep studies for OSA evaluation, while the conventional ambulatory BP monitoring device that intermittently measures BP is unable to capture BP surges associated with sleep apnea events. To capture sleep apnea-specific episodic BP increase, we will use a recently validated finger-cuff-based beat-to-beat BP device to monitor nocturnal BP during polysomnography (PSG). In this time-sensitive ancillary study, we propose to examine the extent to which sleep apnea-specific BP increase is associated with an increased risk for CV outcomes (Aim 1, cross-sectional study); and whether individuals with higher sleep apnea-specific BP surges respond more favorably to continuous positive airway pressure (CPAP) therapy in terms of reduction in CV risks (Aim 2, prospective study). In addition, we will examine the race-specific differences between White and African American in the degree of sleep apnea-specific BP increase and whether the associations examined in Aims 1 and 2 are modified by race (Aim 3). To achieve these aims, we will leverage the infrastructure and resources of the ongoing NHLBI sponsored parent study at the Brigham and Women's Hospital (N~160) in which novel PSG- derived physiological metrics are being investigated to evaluate their utilities for predicting CV responses to 12- week CPAP therapy in people with OSA. We will add continuous beat-to-beat BP monitoring to PSG recording performed at the baseline study of the parent study. The primary CV outcome will be left ventricular strain by speckle tracking echocardiography, which is a sensitive marker for subclinical mechanical left ventricular dysfunction. Secondary CV outcomes will include other conventional echocardiographic measures of structural and functional remodeling, electrocardiographic marker of left atrial electrical remodeling and arterial stiffness by pulse wave velocity. We will also recruit additional African Americans to have sufficient statistical power in Aim 3. The major innovation of this proposal is the incorporation of the continuously measured nocturnal BP and other PSG-derived physiological measurements into the clinical decision making. Our study design allows for race-specific investigation with the goal of better understanding the mechanisms linking OSA to the existing CV health disparity in African Americans.