Impact of obstructive sleep apnea on the occurrence of restenosis after elective percutaneous coronary intervention in ischemic heart disease

Obstructive sleep apnoea and coronary revascularisation outcomes

Obstructive sleep apnoea (OSA) is a chronic sleep disorder characterised by recurrent cyclical episodes of upper airway collapse causing apnoea or hypopnoea. Despite being highly prevalent in patients with cardiovascular conditions, OSA has been a neglected component in cardiovascular practice. Fortunately, in the past few decades, increasing acknowledgement of the vulnerability of cardiac patients to OSA-related stressors and its adverse cardiovascular outcomes has made it a recognised cardiovascular risk factor in practice guidelines. Consequences of OSA include oxidative stress, endothelial dysfunction, autonomic dysfunction, and increased catecholamine release. The perturbations caused by OSA not only provide a clear mechanistic link to cardiovascular disease but also to poor outcomes after coronary revascularisation. This review article focuses on the correlation of OSA to coronary revascularisation outcomes. Our team reported that OSA is present in approximately 50% of patients undergoing coronary revascularisation. Importantly, untreated OSA was found to be an independent predictor of adverse events after both percutaneous coronary intervention and coronary artery bypass grafting. Although randomised trials did not confirm the benefits of OSA treatment in improving cardiovascular outcomes, these early trials were limited by poor treatment adherence. For now, systematic screening for OSA in patients undergoing coronary revascularisation is not indicated. Yet, with the proven benefit of OSA treatment in improving blood pressure control and quality of life, screening for and treatment of OSA is still indicated if patients have reported excessive daytime sleepiness and/or suboptimally controlled hypertension.

Clinical outcomes and plaque characteristics in patients with coronary artery disease and concomitant sleep-disordered breathing treated by continuous positive airway pressure

BACKGROUND

Sleep-disordered breathing (SDB) is a risk factor for recurrent adverse events in patients with coronary artery disease (CAD). However, the prognosis of continuous positive alveolar pressure (CPAP) treatment for SDB with CAD remains unknown.

METHODS

A total of 281 consecutive patients with stable CAD requiring percutaneous coronary intervention (PCI) were included and classified into three groups according to the concomitance of SDB and CPAP treatment (untreated SDB group, n = 61; CPAP-SDB group, n = 24; and non-SDB group, n = 138). The incidence of major adverse cardiac and cerebrovascular events (MACCEs) within a year after PCI was compared between the three groups. The characteristics of the culprit plaques, including macrophage accumulation, were further assessed using optical coherence tomography.

RESULTS

The incidence of MACCEs was significantly different among the three groups (p = 0.037), with the highest incidence in the untreated-SDB group (22.9%) and 8.3% and 10.1% in the CPAP-SDB and non-SDB groups, respectively. The incidence of MACCEs at 1 year was significantly lower in patients with appropriate CPAP use than that in inadequately treated patients with SDB (0.0 vs. 22.5%, p = 0.048). Macrophage accumulation differed significantly among the three groups, with the highest accumulation in the untreated SDB group.

CONCLUSIONS

CPAP treatment for SDB may be associated with a lower incidence of MACCEs following PCI and a lower prevalence of macrophages in the culprit plaques.

Obstructive Sleep Apnea during REM Sleep and Cardiovascular Disease

RATIONALE

Obstructive sleep apnea (OSA) during REM sleep is a common disorder. Data on whether OSA that occurs predominantly during REM sleep is associated with health outcomes are limited.

OBJECTIVES

The present study examined the association between OSA during REM sleep and a composite cardiovascular endpoint in a community sample with and without prevalent cardiovascular disease.

METHODS

Full-montage home polysomnography was conducted as part of the Sleep Heart Health Study. The study cohort was followed for an average of 9.5 years, during which time cardiovascular events were assessed. Only participants with a non-REM apnea-hypopnea index (AHI) of less than 5 events/h were included. A composite cardiovascular endpoint was determined as the occurrence of nonfatal or fatal events, including myocardial infarction, coronary artery revascularization, congestive heart failure, and stroke. Proportional hazards regression was used to derive the adjusted hazards ratios for the composite cardiovascular endpoint.

MEASUREMENTS AND MAIN RESULTS

The sample consisted of 3,265 subjects with a non-REM AHI of less than 5.0 events/h. Using a REM AHI of less than 5.0 events/h as the reference group (n = 1,758), the adjusted hazards ratios for the composite cardiovascular endpoint in those with severe REM OSA (≥30 events/h; n = 180) was 1.35 (95% confidence interval, 0.98-1.85). Stratified analyses demonstrated that the association was most notable in those with prevalent cardiovascular disease and severe OSA during REM sleep with an adjusted hazards ratio of 2.56 (95% confidence interval, 1.46-4.47).

CONCLUSIONS

Severe OSA that occurs primarily during REM sleep is associated with higher incidence of a composite cardiovascular endpoint, but in only those with prevalent cardiovascular disease.

Meta-Analysis of the Effect of Obstructive Sleep Apnea on Cardiovascular Events After Percutaneous Coronary Intervention

Increasing evidence proved that obstructive sleep apnea (OSA) is associated with a variety of diseases, especially cardiovascular diseases. This study systematically reviewed the existing publications to assess the influence of OSA on cardiovascular survival among patients who underwent percutaneous coronary intervention. Eleven eligible publications, including 3,008 participants, were finally evaluated. Eight studies conducted adjustment of risk ratio for potential cardiovascular risk factors, 5 studies defined OSA groups as AHI (apnea hypopnea index) ≥15/hour, whereas the remaining eligible studies used AHI ≥5/hour, AHI ≥10/hour, or AHI ≥30/hour as the criteria. According to the result from 5 studies that use AHI ≥15/hour as OSA group, the existence of OSA could, to some extent, increase the risk of cardiovascular events (risk ratio 1.59, 95% confidence interval 1.22 to 2.06). Meanwhile, hazard ratio was also observed in separate co-morbidities, such as cardiac death, all-cause mortality, stroke, target lesion revascularization, non-fatal myocardial infarction, hospitalization for heart failure, and recurrence of acute coronary syndrome, regardless if the estimates are varied among studies. In conclusion, OSA can independently increase the risk of cardiovascular events, even after adjustment for confounders. Sleep health should be given utmost importance due to its extensive influence on cardiovascular disorders.

Obstructive Sleep Apnea and Cardiovascular Events After Percutaneous Coronary Intervention

BACKGROUND

There is a paucity of data from large cohort studies examining the prognostic significance of obstructive sleep apnea (OSA) in patients with coronary artery disease. We hypothesized that OSA predicts subsequent major adverse cardiac and cerebrovascular events (MACCEs) in patients undergoing percutaneous coronary intervention.

METHODS AND RESULTS

The Sleep and Stent Study was a prospective, multicenter registry of patients successfully treated with percutaneous coronary intervention in 5 countries. Between December 2011 and April 2014, 1748 eligible patients were prospectively enrolled. The 1311 patients who completed a sleep study within 7 days of percutaneous coronary intervention formed the cohort for this analysis. Drug-eluting stents were used in 80.1% and bioresorbable vascular scaffolds in 6.3% of the patients, and OSA, defined as an apnea-hypopnea index of ≥15 events per hour, was found in 45.3%. MACCEs, a composite of cardiovascular mortality, nonfatal myocardial infarction, nonfatal stroke, and unplanned revascularization, occurred in 141 patients during the median follow-up of 1.9 years (interquartile range, 0.8 years). The crude incidence of an MACCEs was higher in the OSA than the non-OSA group (3-year estimate, 18.9% versus 14.0%; p=0.001). Multivariate Cox regression analysis indicated that OSA was a predictor of MACCEs, with an adjusted hazard ratio of 1.57 (95% confidence interval, 1.10-2.24; P=0.013), independently of age, sex, ethnicity, body mass index, diabetes mellitus, and hypertension.

CONCLUSIONS

OSA is independently associated with subsequent MACCEs in patients undergoing percutaneous coronary intervention. Evaluation of therapeutic approaches to mitigate OSA-associated risk is warranted.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01306526.

Prevalence of Undetected Sleep Apnea in Patients Undergoing Cardiovascular Surgery and Impact on Postoperative Outcomes

STUDY OBJECTIVE

We examined the prevalence of obstructive sleep apnea (OSA) among patients undergoing cardiac surgery and its impact on postoperative outcomes.

METHODS

Subjects were recruited from inpatient cardiovascular surgery units at two tertiary care centers. Crystal Monitor 20-H recorded polysomnograms preoperatively. Regression analyses were performed to explore associations between OSA using different apnea-hypopnea index (AHI) cutoffs and postoperative outcomes adjusting for key covariates. Prevalence of postoperative outcomes was compared among groups defined by AHI and left ventricle ejection fraction (LVEF) median cutoffs.

RESULTS

Of 107 participants, the AHI was ≥ 5 in 79 (73.8%), ≥ 10 in 63 (58.9%), ≥ 15 in 51(47.7%), and ≥ 30 in 29 (27.1%). Patients with AHI ≥ 15 had significantly lower LVEF (p < 0.001). Logistic regression analyses with OSA cutoffs as above adjusting for age, gender, race, BMI, and LVEF found no significant increase in odds for any postoperative outcomes. No significant differences were found in %Total sleep time (TST) with SpO2 < 90% between AHI or LVEF groups, or by presence/absence of complications. Patients with any amount of TST with SpO2 < 90% had greater BMI, longer OR tube time, and greater prevalence of prolonged intubation (p = 0.007, 0.035, 0.038, respectively).

CONCLUSIONS

OSA is highly prevalent in patients undergoing cardiovascular surgery. It could not be shown that OSA was significantly associated with adverse postoperative outcomes, but this may have been due to an insufficient number of subjects. AHI ≥ 15 was associated with lower LVEF. Larger samples are required to explore the impact of OSA on key postoperative outcomes that have clinical and economic importance in the care of cardiovascular surgery populations.

COMMENTARY

A commentary on this article appears in this issue on page 1081.

Angiotensin type 1 receptor A1166C gene polymorphism is associated with endothelial dysfunction and in-stent restenosis after percutaneous coronary intervention

BACKGROUND AND PURPOSE

Percutaneous coronary intervention (PCI) has been commonly used in the treatment of ischemic cardiovascular diseases, but the postprocedural in-stent restenosis (ISR) associated with altered endothelial functions has limited the clinical application of it; preventive medication with aspirin and statins has underlying adverse effects despite lowered risk of ISR. The purpose of this study was to investigate the role of angiotensin type 1 receptor (AT1R) A1166C gene polymorphisms in the development of endothelial dysfunction and ISR after PCI.

METHODS

A total of 483 ST-segment elevation myocardial infarction (STEMI) patients undergoing PCI were prospectively genotyped using polymerase chain reaction (PCR) and restriction fragment length polymorphism assay. The demographic, clinical, laboratory and angiographic parameters were recorded peri-procedurally and the patients were followed within 3 years. The flow-mediated dilation (FMD) was used to reflect the short-term changes in endothelial functions among different genotypes. The significance of AT1R gene polymorphisms in the development of ISR was analyzed using univariable and multivariable models.

RESULTS

Amongst 483 patients, the distribution of the AT1R genotypes (AA, AC and CC) was associated with the levels of blood biomarkers of oxidative stress and deteriorated FMD after PCI (P<0.05). In univariable and multivariable logistic regression analysis, it was shown that AT1R CC genotype is strongly associated with the development of restenosis within 3 years after PCI (OR=3.736; P<0.001; calibrated OR=4.104; P<0.001).

CONCLUSION

The CC AT1R genotype was associated with deteriorated endothelial functions in the target vessels of PCI and intermediate to long-term ISR. Our findings contribute to the foundation of genome-based prevention for high risk groups of cardiovascular diseases and pretreatment for the patients undergoing PCI.

Treatment of OSA reduces the risk of repeat revascularization after percutaneous coronary intervention

BACKGROUND

The impact of OSA treatment with CPAP on percutaneous coronary intervention (PCI) outcomes remains largely unknown.

METHODS

Between 2002 and 2012, we identified 390 patients with OSA who had undergone PCI. OSA was diagnosed through in-laboratory sleep studies and defined by an apnea-hypopnea index ≥ 5 events/h. The cohort was divided into three groups: (1) moderate-severe OSA successfully treated with CPAP (n = 128), (2) untreated moderate-severe OSA (n = 167), and (3) untreated mild OSA (n = 95). Main outcomes included repeat revascularization, major adverse cardiac events (MACEs) (ie, death, nonfatal myocardial infarction, repeat revascularization), and major adverse cardiac or cerebrovascular events (MACCEs). The median follow-up period was 4.8 years (interquartile range, 3.0-7.1).

RESULTS

The untreated moderate-severe OSA group had a higher incidence of repeat revascularization than the treated moderate-severe OSA group (25.1% vs 14.1%, P = .019). There were no differences in mortality (P = .64), MACE (P = .33), and MACCE (P = .76) among the groups. In multivariate analysis adjusted for potential confounders, untreated moderate-severe OSA was associated with increased risk of repeat revascularization (hazard ratio, 2.13; 95% CI, 1.19-3.81; P = .011).

CONCLUSIONS

Untreated moderate-severe OSA was independently associated with a significant increased risk of repeat revascularization after PCI. CPAP treatment reduced this risk.

Positive airway pressure in patients with coronary artery disease and obstructive sleep apnea syndrome

AIMS

We designed a prospective nonrandomized study aiming at assessing the impact of continuous positive airway pressure (CPAP) after a new diagnosis of obstructive sleep apnea syndrome (OSAS) in patients with coronary artery disease (CAD).

METHODS

Consecutive patients referred to coronary angiography underwent an overnight sleep study during their hospital stay. Among those with angiographically confirmed CAD and a new diagnosis of moderate or severe OSAS, we compared the 3-year major adverse cardiac or cerebrovascular event (MACCE)-free survival stratified by CPAP at discharge.

RESULTS

Of 496 patients undergoing an overnight sleep study, 129 had angiographically confirmed CAD and presented with moderate or severe OSAS. The incidence of 3-year MACCE was significantly lower in the CPAP-treated group (n = 17) than in the untreated group (n = 112; 12 vs. 44%, P = 0.02). After adjusting for differences in baseline characteristics, CPAP was significantly associated with a decreased risk of MACCE [adjusted hazard ratio 0.18, 95% confidence interval (CI) 0.04-0.78, P = 0.02]. Among men, CPAP was associated with a significant 3-year risk reduction in MACCE (adjusted hazard ratio 0.12, 95% CI 0.02-0.87, P = 0.04), whereas no significant benefit of CPAP was seen in women (adjusted hazard ratio 2.1, 95% CI 0.10-41.6, P = 0.63). The statistical interaction between CPAP and sex trended to be significant (adjusted P for interaction = 0.10).

CONCLUSION

In patients with OSAS and CAD, the initiation of CPAP is associated with a significant reduction in MACCE compared with patients left untreated.

Symptoms of disturbed sleep predict major adverse cardiac events after percutaneous coronary intervention

BACKGROUND

Disturbed sleep is associated with atherosclerosis in native coronary arteries and may be associated with adverse cardiac events after percutaneous coronary intervention (PCI). We sought to determine the association between symptoms of disturbed sleep and adverse cardiovascular events after PCI.

METHODS

Outpatients who were stable after successful PCI were assessed for symptoms of disturbed sleep with 10 true/false questions. Follow-up was performed at least 4 years after PCI. The primary outcome was a composite of death, myocardial infarction (MI), and repeated revascularization.

RESULTS

Three hundred eighty-eight patients (mean age, 66 ± 11 years) reported on average 3.1 ± 2.1 sleep disturbance symptoms. Follow-up was performed on average 4.4 years after the incident PCI. The primary outcome occurred in 25% of patients. An association was seen between the number of sleep disturbance symptoms and the occurrence of the primary end point. Patients with zero symptoms had a 4-year event rate of 12% compared with a 67% event rate for those with 9 symptoms. On multivariable analysis, sleep symptoms, diabetes mellitus, and the number of diseased coronary vessels were independently associated with the primary end point. Each additional sleep symptom was associated with a hazard ratio (HR) of 1.2 (P = 0.001). The results were driven primarily by the association between symptoms of disturbed sleep and the need for repeated revascularization (repeated PCI HR, 1.9; P = 0.003; coronary artery bypass grafting (CABG) HR, 1.5; P = 0.001).

CONCLUSIONS

Symptoms of disturbed sleep were associated with increased risk of long-term adverse cardiovascular outcomes after successful PCI.

Obstructive sleep apnea and cardiovascular disease in blacks: a call to action from the Association of Black Cardiologists

Obstructive sleep apnea (OSA) has emerged as a new and important risk factor for cardiovascular disease (CVD). Over the last decade, epidemiologic and clinical research has consistently supported the association of OSA with increased cardiovascular (CV) morbidity and mortality. Such evidence prompted the American Heart Association to issue a scientific statement describing the need to recognize OSA as an important target for therapy in reducing CV risk. Emerging facts suggest that marked racial differences exist in the association of OSA with CVD. Although both conditions are more prevalent in blacks, almost all National Institutes of Health-funded research projects evaluating the relationship between OSA and CV risk have been conducted in predominantly white populations. There is an urgent need for research studies investigating the CV impact of OSA among high-risk minorities, especially blacks. This article first examines the evidence supporting the association between OSA and CVD and reviews the influence of ethnic/racial differences on this association. Public health implications of OSA and future directions, especially regarding minority populations, are discussed.

Obstructive sleep apnea syndrome (OSAS) and hypertension: pathogenic mechanisms and possible therapeutic approaches

Obstructive sleep apnea syndrome (OSAS), a chronic condition characterized by collapse of the pharynx during sleep, has been increasingly recognized as a health issue of growing importance over the last decade. Recently emerging evidence suggests that there is a causal link between OSAS and hypertension, and hypertension represents an independent risk factor in OSAS patients. However, the pathophysiological basis for patients with OSAS having an increased risk for hypertension remains to be elucidated. The main acute physiological outcomes of OSAS are intermittent hypoxia, intrapleural pressure changes, and arousal from sleep, which might induce endothelial dysfunction, sympathetic activation, renin-angiotensin-aldosterone system activation, lipid metabolism dysfunction, and increased oxidative stress. This brief review focuses on the current understanding of the complex association between OSAS and hypertension.

Cardiac response to chronic intermittent hypoxia with a transition from adaptation to maladaptation: the role of hydrogen peroxide

Obstructive sleep apnea (OSA) is a highly prevalent respiratory disorder of sleep, and associated with chronic intermittent hypoxia (CIH). Experimental evidence indicates that CIH is a unique physiological state with potentially “adaptive” and “maladaptive” consequences for cardio-respiratory homeostasis. CIH is also a critical element accounting for most of cardiovascular complications of OSA. Cardiac response to CIH is time-dependent, showing a transition from cardiac compensative (such as hypertrophy) to decompensating changes (such as failure). CIH-provoked mild and transient oxidative stress can induce adaptation, but severe and persistent oxidative stress may provoke maladaptation. Hydrogen peroxide as one of major reactive oxygen species plays an important role in the transition of adaptive to maladaptive response to OSA-associated CIH. This may account for the fact that although oxidative stress has been recognized as a driver of cardiac disease progression, clinical interventions with antioxidants have had little or no impact on heart disease and progression. Here we focus on the role of hydrogen peroxide in CIH and OSA, trying to outline the potential of antioxidative therapy in preventing CIH-induced cardiac damage.

Sleep-disordered breathing and cardiovascular disorders

Compelling data demonstrate a strong association between sleep-disordered breathing (SDB) and cardiovascular disorders. The association is most consistent between obstructive sleep apnea (OSA) and hypertension. Epidemiologic and clinic-based studies provide evidence for an etiological role of OSA in hypertension, independent of obesity. Furthermore, several studies suggest amelioration of hypertension with therapy for sleep apnea. Emerging data also suggest a role for OSA in causing coronary artery disease. This association is bolstered by evidence suggesting that continuous positive airway pressure (CPAP) therapy improves early signs of atherosclerosis and may impede progression to clinically important cardiovascular disease. SDB (both OSA and central sleep apnea) is frequently observed in patients with heart failure. OSA may be a risk factor for incident heart failure. The current data do not provide consistent evidence for whether treatment of SDB will improve survival or other end points in patients with heart failure, and larger trials are currently underway to better elucidate that relationship. Substantial evidence also links SDB to an increased risk of various arrhythmias. Treatment of SDB with CPAP appears to significantly attenuate that risk. Finally, several studies suggest SDB as a risk factor for stroke. Whether treatment of SDB reduces stroke risk, however, remains to be determined. In conclusion, persuasive data provide evidence for an association, probably causal, between sleep-disordered breathing and several cardiovascular disorders. Large randomized controlled trials will further help confirm the association and elucidate the cardiovascular benefits of SDB therapy.

[Cardiac effects of obstructive sleep apnea]

Sleep disordered breathing, especially obstructive sleep apnea, are common in cardiovascular disease. Negative hemodynamic effects are mediated by nocturnal ischemia and intrathoracal pressure swings. Therefore "therapy resistant" arterial hypertension and congestive heart failure, as well as atrial fibrillation or sleep associated bradycardia are suggestive of sleep disordered breathing. Further on, clinical course of coronary artery disease seems to be influenced by nocturnal breathing disorders. Application of continuous positive airway pressure (CPAP) is effective in most of the patients and attenuates cardiodepressive hemodynamic effects of obstructive sleep apnea.

NFATc3 contributes to intermittent hypoxia-induced arterial remodeling in mice

Sleep apnea (SA) is defined as intermittent respiratory arrest during sleep and affects up to 20% of the adult population. SA is also associated with an increased incidence of hypertension and peripheral vascular disease. Exposing rodents to intermittent hypoxia during sleep mimics the cyclical hypoxia/normoxia of SA. We have previously shown that in mice and rats intermittent hypoxia induces ET-1 upregulation and systemic hypertension. Furthermore, intermittent hypoxia (IH) in mice increases nuclear factor of activated T cells isoform 3 (NFATc3) transcriptional activity in aorta and mesenteric arteries, whereas the calcineurin/NFAT inhibitor cyclosporin A prevents IH-induced hypertension. More importantly, NFATc3 knockout (KO) mice do not develop IH-induced hypertension. The goals of this study were to determine the role of NFATc3 in IH-induced arterial remodeling and whether IH-induced NFATc3 activation is mediated by ET-1. Oral administration of both a dual (bosentan) and a selective endothelin receptor type A antagonist (PD155080) during 2 days of IH exposure attenuated NFAT activation in aorta and mesenteric arteries. Rho kinase inhibition with fasudil also prevented IH-induced NFAT activation. Mesenteric artery cross-sectional wall thickness was increased by IH in wild-type (WT) and vehicle-treated mice but not in bosentan-treated and NFATc3 KO mice. The arterial remodeling in mesenteric arteries after IH was characterized by increased expression of the hypertrophic NFATc3 target smooth muscle-alpha-actin in WT but not in KO mice. These results indicate that ET-1 is an upstream activator of NFATc3 during intermittent hypoxia, contributing to the resultant hypertension and increased wall thickness.