Obstructive Sleep Apnea and Acute Coronary Syndromes: Etiology, Risk, and Management

Abstract

Obstructive sleep apnea (OSA) is characterized by upper airway collapse and airflow reduction despite respiratory effort, resulting in intermittent hypoxia and arousals, leading to a cascade of hemodynamic, autonomic, inflammatory, and metabolic effects, responsible for its adverse cardiovascular effect. OSA is an independent risk factor for cardiovascular disease, and its prevalence in patients presenting with acute coronary syndromes is up to 69%. Furthermore, OSA has been associated with increased risk of adverse events after an acute coronary syndrome. Continuous positive airway pressure is considered the mainstay of treatment of OSA and has been shown to reduce the risk of cardiovascular events. However, the proper time to start treatment in the acute setting is unknown. A prospective randomized clinical trial is currently underway to answer this question.

Cardiovascular autonomic dysfunctions and sleep disorders

“…Increased sympathetic outflow due to increased peripheral chemoreflex sensitivity and reduced BRS seems to have a prominent role in the aetiology of OSA-related hypertension [6,[53][54][55]. The OSA-related sympathethic-vagal imbalance together with mechanical consequences of apnoea has also been implicated in other harmful events, whose risk is increased in patients with OSA, like cardiac arrhythmias, acute coronary syndromes and sudden cardiac death [58][59][60][61][62]. The latter is more likely to occur during sleeping hours (from midnight to six a.m.) in OSA patients, which is the period with the lowest risk of sudden cardiac death in individuals without sleep apnoea and in the general population, showing its peak from six a.m. to noon [58].…”

Obstructive sleep apnea: one more target in cardiac rehabilitation

“…Recent data also reported that OSA prevalence is up to 69% in patients presenting with acute coronary syndromes [21]. Furthermore, OSA has been associated with increased risk of adverse events after an acute coronary syndrome and in patients with established ischemic heart disease [21,22].…”

“…Furthermore, OSA has been associated with increased risk of adverse events after an acute coronary syndrome and in patients with established ischemic heart disease [21,22]. In a case-control study including 192 patients with acute myocardial infarction (63 patients without OSA, 52 untreated patients with OSA and 71 OSA patients treated with CPAP), over a 6-year followup, the risk of recurrent myocardial infarction and revascularization procedures was lower in treated than untreated OSA and similar to non-OSA patients [23].…”

“…In a cross-sectional analysis of the Sleep Heart Health Study in 566 subjects undergoing continuous electrographic monitoring, atrial fibrillation occurred in 5% of those with severe sleep apnea and only in 1% of those without sleep apnea [27]. Other studies reported that OSA was present in 49% of patients referred for electrical cardioversion, while untreated (14) Up to 80% of patients with resistant hypertension (15) 30% of patients with coronary artery disease (21) Up to 70% in patients presenting with acute coronary syndrome (21) Up to 33% of patients with heart failure (25) Up to 70% of patients with acute stroke/TIA (26) 50% of patients with atrial fibrillation requiring cardioversion (28) 33% of patients with lone atrial fibrillation (28) OSA was associated with a significantly higher recurrence rate following cardioversion [28].…”

Rehabilitation of Cardiovascular Disorders and Sleep Apnea

“…[16][17][18][19] Several studies have shown that OSA is an independent risk factor for development of hypertension and has a dose-response relationship between severity of OSA and incidence of hypertension. 18,20,21 SDB is also estimated to have a prevalence of 30% to 69% in patients with coronary artery disease (CAD) [22][23][24] and 50% to 70% in patients with systolic HF. 25,26 However, fewer data are available in HF with preserved ejection fraction (EF) than in those with reduced EF.…”