Relation of Obstructive Sleep Apnea in Patients With a Coronary Chronic Total Occlusion to Coronary Collaterals and Mortality

Sleep Disorders and Coronary Artery Disease

A sufficient amount and quality sleep is vital components for maintaining optimal physical wellbeing, cognition, and cardiovascular health. Normal sleep provides us with a low physiological stress that promotes overall cardiovascular health. Sleep disorders are common, and often goes undiagnosed. Patients with sleep disorders, commonly suffer from poor quality of life due to the poor quality of their sleep. They are associated with adverse effects on cardiovascular health, such as coronary artery disease. Sleep disorders discussed in this review article include sleep-disordered breathing (obstructive sleep apnea and central sleep apnea), insomnia and restless leg syndrome. Sleep disorders primarily have four acute adverse cardiovascular consequences. First, intermittent hypoxemia-reoxygenation in arterial blood along with PCO 2 fluctuation; second is excessive arousals; third, decreased parasympathetic and increased sympathetic tone; fourth being the large pressure swings in the intrathoracic cavity. This review focuses on classifications, and prevalence of the three major classes of sleep disorders, and the evidence to date on the association between these sleep disorders and coronary artery disease.

Influence of Obstructive Sleep Apnoea Severity on Coronary Collateral Recruitment During Coronary Occlusion

PURPOSE

Obstructive sleep apnoea (OSA) which results in hypoxia may affect the ability to recruit coronary collaterals. The aim of this study was to determine whether the severity of OSA affects collateral recruitment in patients with total coronary occlusions.

METHODS

Patients with total coronary artery occlusion were reviewed. Records from the sleep investigation laboratory were reviewed to identify those patients who had undergone diagnostic polysomnography. Robust coronary collaterals were those with Rentrop grade 2 or 3 collaterals.

RESULTS

Sixty-four patients with a total coronary occlusion had polysomnography performed, of whom 60 patients had OSA. Thirty-two patients (53.3%) had poor collaterals, whilst 28 (46.7%) had robust collaterals. Twenty-four (40%) patients had mild OSA, 10 (16.7%) had moderate OSA and 26 (43.3%) had severe OSA. Patients with robust collaterals were more likely to be males (96.4% vs 74.3%, p < 0.05) and have a history of hypercholesterolaemia (88.9% vs 51.6%, p < 0.01). Patients with robust collaterals had a lower apnoea-hypopnoea index (13.6 vs 45.5, p < 0.05), a higher MinS_aO₂ (85.4% vs 79.8%, p < 0.05), less time S_aO₂ < 90% (0 min vs 30.4 min, p < 0.05) and lower oxygen desaturation index (6.9 vs 26.8, p < 0.05). Those with moderate OSA had a higher mean Rentrop grade (1.6 ± 0.3) than those with mild OSA (1.5 ± 1.1) and severe OSA (0.6 ± 0.2).

CONCLUSION

The presence of more severe OSA is associated with poorer coronary collateral recruitment in patients with total coronary artery occlusion. The effect of treatment of OSA on subsequent ability to recruit collaterals and other cardioprotective mechanisms requires further research.

Influence of Obstructive Sleep Apnoea on Outcomes in Patients With ST Elevation Myocardial Infarction (STEMI): the Role of the Coronary Collateral Circulation

BACKGROUND

Obstructive sleep apnoea (OSA) occurs frequently in patients with coronary artery disease, with associated intermittent hypoxia a possible stimulus for coronary collateral recruitment through ischaemic preconditioning. We sought to determine whether OSA affects recruitment of coronary collaterals and prognosis of patients presenting with ST elevation myocardial infarction (STEMI).

METHODS

Patients with a STEMI undergoing percutaneous coronary intervention (PCI) from July 2010 to December 2019 were reviewed. Electronic medical records were accessed to determine documented patient history of OSA. Patients with robust collaterals were defined as Rentrop grade 2 or 3.

RESULTS

1,863 patients were included, of which 143 (7.7%) patients had documented evidence of OSA in their health record. Patients with OSA had a higher body mass index (BMI) (30.2 kg/m² vs 27 kg/m², p<0.0001), greater rate of hypertension (61.1% vs 45.1%, p<0.0001), hypercholesterolaemia (47.4% vs 38.4%, p<0.05) and diabetes mellitus (22.6% vs 15.9%, p<0.05). Patients with OSA were more likely to have robust coronary collaterals (OR: 2.2 [95% CI: 1.5-3.2]) and a lower rate of left ventricular (LV) impairment (50.7% vs 63.1%, p<0.01), a higher LV ejection fraction (50.3% vs 46.7%, p<0.0001) and a lower peak troponin-I level (26,452 ng/L vs 39,469 ng/L, p<0.01). There were no differences in rates of in-hospital or longer term mortality, in patients with OSA compared to those without.

CONCLUSIONS

Patients with documented OSA presenting with STEMI appear to have more robust coronary collaterals observed on angiography which likely mediates lower myocardial necrosis. Broader implications of this finding on treatment require further investigation.