Review of and Updates on Hypertension in Obstructive Sleep Apnea

Abstract

Obstructive sleep apnea (OSA) is a prevalent sleep disorder as is hypertension (HTN) in the 21st century with the rising incidence of obesity. Numerous studies have shown a strong association of OSA with cardiovascular morbidity and mortality. There is overwhelming evidence supporting the relationship between OSA and hypertension (HTN). The pathophysiology of HTN in OSA is complex and dependent on various factors such as sympathetic tone, renin-angiotensin-aldosterone system, endothelial dysfunction, and altered baroreceptor reflexes. The treatment of OSA is multifactorial ranging from CPAP to oral appliances to lifestyle modifications to antihypertensive drugs. OSA and HTN both need prompt diagnosis and treatment to help address the growing cardiovascular morbidity and mortality due to these two entities.

Prevalence of obstructive sleep apnea in primary care patients with hypertension

“…The most important finding of this study was that 64.5% of patients had AHI ≥ 22, which fulfills the diagnostic criteria for moderate or severe OSA in patients with hypertension . This prevalence is much higher than in a recent study that estimated the prevalence of with hypertension to be 30%‐50%. One possible reason for the high prevalence of OSA in PC patients with hypertension is that we might have missed patients with hypertension who do not have obvious signs and symptoms of OSA in the PC setting until now.…”

“…Hypertension and obstructive sleep apnea (OSA) are both common conditions in the general population. Recent studies have estimated 30%‐50% of patients with hypertension have OSA which might be underestimated, though the prevalence in the PC setting is unclear …”

Blood pressure profile and nocturnal oxygen desaturation

“…It results both from the activation of carotid body chemoreceptors triggered by episodic hypoxemia and the generalized stress induced by sleep structure disruption, and contributes to catecholamine surge and baroreceptor sensitivity impairment . Recurrent intermittent hypoxia and subsequent reoxygenation, which resembles the ischemia‐reperfusion cycle, promote the release of reactive oxygen species, cytokines, and vasoactive mediators that cause endothelial injury and dysfunction . Moreover, upregulation of the atrial natriuretic peptide and renin‐angiotensin‐aldosterone systems, which occurs in response to intrapleural pressure swings and increase of renin levels, can determine body fluid redistribution .…”

“…The individual susceptibility to symptoms and systemic sequelae suggests the need to define improved disease measurements that may be useful to better characterize patients’ subgroups and understand the variability in treatment response . In the beginning of the era of “individualized precision medicine,” the joined knowledge of patient features, BP patterns, pathophysiological mechanisms causing and maintaining hypertension, tolerability of pharmacological and pressure therapies and their distinctive effects on nocturnal and diurnal BP, and BP variability profiles would be of high value to develop practicable single or combined therapeutic interventions to obtain tangible improvements in hard cardiovascular outcomes …”

Obstructive Sleep Apnoea: A Risk Factor for Hypertension

“…Various cross-sectional and longitudinal studies suggest an association between OSA and hypertension 15,16,17 . Also, resistant, chronic and longstanding hypertension is purportedly caused by untreated or underdiagnosed OSA 18,19 .…”