Sleep apnoea and unscheduled re-admission in patients undergoing coronary artery bypass surgery

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.

Postoperative Atrial Fibrillation in Adults with Obstructive Sleep Apnea Undergoing Coronary Artery Bypass Grafting in the RICCADSA Cohort

Postoperative atrial fibrillation (POAF) occurs in 20−50% of patients with coronary artery disease (CAD) after coronary artery bypass grafting (CABG). Obstructive sleep apnea (OSA) is also common in adults with CAD, and may contribute to POAF as well to the reoccurrence of AF in patients at long-term. In the current secondary analysis of the Randomized Intervention with Continuous Positive Airway Pressure (CPAP) in Coronary Artery Disease and Obstructive Sleep Apnea (RICCADSA) trial (Trial Registry: ClinicalTrials.gov; No: NCT 00519597), we included 147 patients with CABG, who underwent a home sleep apnea testing, in average 73 ± 30 days after the surgical intervention. POAF was defined as a new-onset AF occurring within the 30 days following the CABG. POAF was observed among 48 (32.7%) patients, occurring within the first week among 45 of those cases. The distribution of the apnea-hypopnea-index (AHI) categories < 5.0 events/h (no-OSA); 5.0−14.9 events/h (mild OSA); 15.0−29.9 events/h (moderate OSA); and ≥30 events/h (severe OSA), was 4.2%, 14.6%, 35.4%, and 45.8%, in the POAF group, and 16.2%, 17.2%, 39.4%, and 27.3%, respectively, in the no-POAF group. In a multivariate logistic regression model, there was a significant risk increase for POAF across the AHI categories, with the highest odds ratio (OR) for severe OSA (OR 6.82, 95% confidence interval 1.31−35.50; p = 0.023) vs. no-OSA, independent of age, sex, and body-mass-index. In the entire cohort, 90% were on β-blockers according to the clinical routines, they all had sinus rhythm on the electrocardiogram at baseline before the study start, and 28 out of 40 patients with moderate to severe OSA (70%) were allocated to CPAP. During a median follow-up period of 67 months, two patients (none with POAF) were hospitalized due to AF. To conclude, severe OSA was significantly associated with POAF in patients with CAD undergoing CABG. However, none of those individuals had an AF-reoccurrence at long term, and whether CPAP should be considered as an add-on treatment to β-blockers in secondary prevention models for OSA patients presenting POAF after CABG requires further studies in larger cohorts.

Cardiac Surgery Outcomes: A Case for Increased Screening and Treatment of Obstructive Sleep Apnea

BACKGROUND

Due to the limited published information on complications that obstructive sleep apnea (OSA) patients experience during and after cardiac surgery, we are investigating OSA as a risk factor for post-operative outcomes.

METHODS

This project utilized the Northern New England Cardiovascular Disease Study Group's data collected between 2011 and 2017 based on the Society of Thoracic Surgeons Adult Cardiac Surgery Database Data Collections form. A retrospective analysis of 1,555 patients with OSA and 10,450 patients without OSA, across 5 medical centers undergoing isolated CABG, isolated valve, combined CABG valve surgery was conducted. We used 1:1 nearest neighbor propensity score matching with no replacement to balance characteristics among patients with and without OSA.

RESULTS

There was a statistically significant increased risk of post-operative pneumonia, increased length of total and post-operative stay, and time to initial extubation. Two outcomes trended towards significance: intra- and post-operative IABP use. Outcomes that failed to show statistical significance included: surgical site infection, atrial fibrillation cerebrovascular accident, permanent pacemaker placement, and blood products given. A chart review conducted on a subset of the study cohort revealed that more than 40% of OSA patients did not receive CPAP or BiPAP therapy post-operatively during their hospitalization.

CONCLUSIONS

Our study aligns with the literature in concluding that OSA has deleterious effects on post-operative outcomes of cardiac surgery patients. Further research to better stratify OSA patients by severity are still needed. Additionally, heightened awareness of the need to screen, diagnose, and properly treat patients for OSA is needed.

Effects of sleep apnea hypopnea syndromes on cardiovascular events: a systematic review and meta-analysis

PURPOSE

Previous studies suggest that sleep apnea hypopnea syndrome (SAHS) is an independent risk factor that contributes to certain cardiovascular events. However, there are studies arguing that patients with SAHS had lower peak troponin levels when suffering cardiovascular events compared to patients without SAHS, which indicates that there may potentially be a protective effect of SAHS. This meta-analysis aimed to assess the impact of SAHS on cardiovascular events.

METHODS

Databases were searched for studies that examined cardiac biomarkers or reported angiographic data when patients with SAHS experienced cardiovascular events. The data about peak cardiac biomarkers and angiographic coronary lesion were extracted and then used to compute the pooled standardized mean difference (SMD) and 95% confidence interval (95% CI).

RESULTS

Among 26 studies included in the meta-analysis, there was not a definite difference between the SAHS group and the control group for troponins (SMD, 0.05; 95% CI, [- 0.16, 0.26]), creatine kinase (SMD, - 0.08; 95% CI, [- 0.38, 0.22]), and CK-MB (SMD, - 0.11; 95% CI, [- 0.51, 0.29]). However, patients with SAHS revealed worse coronary lesion condition grading via both Gensini score (SMD, 0.63; 95% CI, [0.31, 0.95]) and SYNTAX score (SMD, 0.99; 95% CI, [0.31-1.67]).

CONCLUSIONS

Ischemic preconditioning induced by the intermittent hypoxia at the early stage could generate a cardiac protection effect, which would then benefit SAHS patients encountering a major adverse cardiovascular event.

Sleep apnea and diabetes mellitus are independently associated with cardiovascular events and hospitalization for heart failure after coronary artery bypass grafting

The relative and combined effects of sleep apnea with diabetes mellitus (DM) on cardiovascular outcomes in patients undergoing coronary artery bypass grafting (CABG) remain unknown. In this secondary analysis of data from the SABOT study, 1007 patients were reclassified into four groups based on their sleep apnea and DM statuses, yielding 295, 218, 278, and 216 patients in the sleep apnea (+) DM (+), sleep apnea (+) DM (−), sleep apnea (−) DM (+), and sleep apnea (−) DM (−) groups, respectively. After a mean follow-up period of 2.1 years, the crude incidence of major adverse cardiac and cerebrovascular event was 18% in the sleep apnea (+) DM (+), 11% in the sleep apnea (+) DM (−), 13% in the sleep apnea (−) DM (+), and 5% in the sleep apnea (−) DM (−) groups. Using sleep apnea (−) DM (−) as the reference group, a Cox regression analysis indicated that sleep apnea (+) and DM (+) independently predicted MACCEs (adjusted hazard ratio, 3.2; 95% confidence interval, 1.7–6.2; p = 0.005) and hospitalization for heart failure (adjusted hazard ratio, 12.6; 95% confidence interval, 3.0–52.3; p < 0.001). Sleep apnea and DM have independent effects on the prognosis of patients undergoing CABG.

Clinical trial registration: ClinicalTrials.gov identification no. NCT02701504.

Sleep Apnea and Heart

Scientific investigations in the past few decades have supported the important role of sleep in various domains of health. Sleep apnea is a highly prevalent yet underdiagnosed sleep disorder representing a valid cardiovascular risk factor, particularly for hypertension. While several studies have demonstrated the benefits of sleep apnea treatment on subclinical cardiovascular measures, there is a paucity of studies proving reduction of cardiovascular events and mortality. Sufficient and high-quality sleep is also important in the maintenance of cardiovascular health. Future investigations should focus on improving identification of patients at greatest risk of adverse cardiovascular s sequalae of sleep apnea and testing the therapeutic benefit of sleep apnea treatment in this vulnerable group.

Coronary artery bypass grafting in patients with low ejection fraction: what are the risk factors?

BACKGROUND

Left ventricular (LV) dysfunction alone is insufficient as an independent predictor of postoperative complications and mortality in coronary artery bypass graft (CABG) surgery. Our objective was to identify additional independent risk factors in patients with low left ventricle ejection fraction (EF) who underwent CABG.

METHODS

We retrospectively analyzed CABG results of 346 consecutive patients with low EF (≤30%) in a single institution between 2009 and 2015. The primary study endpoint was 30-day all-cause mortality. The secondary endpoints were the development of major adverse cardiac events (MACE) and renal complications after operation. A subgroup of patients underwent additional analyses of the interaction between extents of viable myocardium and postoperative endpoints.

RESULTS

The analysis showed that preoperative hemodynamic instability (AOR=4.57; 95% CI: 1.53-13.7, P=0.007) and serum creatinine >166 µmol/L (AOR=3.46; 95% CI: 1.12-10.7, P=0.031) were independent predictors of 30-day death. Both urgent and emergency operations were predictors for MACE (P=0.038; P=0.005) and renal complications (P=0.004; P=0.007). Pre-existing diabetes mellitus increased the likelihood of renal complications (P=0.020). In the sub-analysis of patients with viable myocardium, the mortality was significantly lower with predicted mortality (P=0.014).

CONCLUSIONS

Patients with significant LV dysfunction undergoing isolated CABG have fair short-term survival even with EF less than 30%. Hemodynamic instability prior to operation and preoperative kidney dysfunction are strong predictors of mortality in patients with low EF. Favorable coronary targets, meticulous operative techniques, and optimal surgical timing before hemodynamic deterioration occurs are essential to minimize the risk of revascularization complications and early postoperative mortality.

Watch-PAT versus level III device in diagnosing sleep disordered breathing in first myocardial infarction

BACKGROUND

Watch-PAT 200, a novel portable sleep device worn on the wrist, has been validated against polysomnography. Although sleep disordered breathing (SDB) screening is recommended in patients with cardiovascular disease, no study has reported a comparison of results from Watch-PAT 200 and level III portable devices.

METHODS

Patients (n = 140) admitted with a first ST-segment elevation myocardial infarction (STEMI) participated in a hospital-based sleep study using the Watch-PAT 200 and a level III portable device (Embletta Gold) simultaneously within five days of admission. SDB was defined as an apnea-hypopnea index (AHI) of >15 events/h.

RESULTS

The left ventricular ejection fraction was normal (≥50%), impaired (30%-49%) and poor (<30%) in 66 (47.1%), 71 (50.7%), and three (2.2%) patients, respectively. Among 116 patients with a successful paired sleep study, the prevalence of SDB was 53.5% (Watch-PAT 200) and 51.7% (Embletta Gold). The agreement of AHI measured by the two devices was moderately good, with an intra-class correlation value of 0.72 (95% confidence interval, 0.62-0.80; P < .01). Agreement between the two devices in diagnosing at least mild (AHI ≥5), moderate-to-severe (AHI ≥15) and severe (AHI ≥30) SDB was 78% (kappa 0.47; P < .01), 77% (kappa 0.55; P < .01) and 80% (kappa 0.49; P < .01), respectively. At a 15-month follow-up, SDB status based on the two devices was associated with the occurrence of adverse cardiovascular events in 48.3% and 44.8%, respectively (P = .56).

CONCLUSION

We found a high prevalence of SDB in patients presenting with a first STEMI. Agreement between two portable sleep devices was moderately good.

The association of obstructive sleep apnea and renal outcomes-a systematic review and meta-analysis

BACKGROUND

The aim of this systematic review and meta-analysis was to summarize the association of obstructive sleep apnea (OSA) with renal outcome.

METHODS

Our study followed the PRISMA guidelines. Two independent reviewers searched for relevant articles in the databases of Pubmed, the Web of Science and CENTRAL, and conducted study selection and quality assessment. A random-effect model was used to estimate the effects.

RESULTS

total of 1240 articles were initially identified (Pubmed = 568, Web of Science = 640, CENTRAL = 32). After removal of duplicate articles (n = 415) and irrelevant articles (n = 788), 37 were selected for full-text review, and 18 were finally included in the analysis. Overall, patients diagnosed with OSA were found to have a higher odds ratio (OR) of a poorer renal outcome, with a pooled OR of 1.77 (95% C.I.: 1.37–2.29). The significant association between OSA and a poorer renal outcome was not affected by the medical condition of diabetes mellitus (DM). In addition, we found that OSA was consistently associated with higher albuminuria/proteinuria and a lower estimated glomerular filtration rate (eGFR), with a pooled OR of 1.84 (95% C.I.: 1.24–2.73) and 1.60 (95% C.I.: 1.19–2.16), respectively. A greater OSA severity was also found to be related to a higher OR, with a mild group OR of 1.45 (95% C.I.: 1.19–1.77) and a moderate and severe group OR of 2.39 (95% C.I.: 1.96–2.90).

CONCLUSIONS

Our study demonstrated that OSA is significantly associated with poorer renal function.

Screening for Obstructive Sleep Apnea in the Assessment of Coronary Risk

There is increasing awareness that health screening may prevent some acute coronary events. Yet, obstructive sleep apnea (OSA) is seldom screened for and its relation with coronary risk markers is not well established. Consecutive adults (n = 696) enrolled in a cardiovascular health screening program were approached to determine the feasibility of incorporating OSA screening. Screening included questionnaires and a home-based sleep study. High-sensitivity C-reactive protein was the primary coronary risk marker, and other laboratory- and exercise treadmill-based markers were also reported. Two thirds of the participants (66%) agreed to undergo OSA screening and most (78%) successfully completed the sleep study. The prevalence of OSA (apnea-hypopnea index ≥15/hour) was 38.0%. The Berlin Questionnaire (53%) and Epworth Sleepiness Scale (26%) had low sensitivity in identifying OSA. After full adjustment for age, gender, body mass index, hypertension, and diabetes mellitus, OSA remained an independent predictor of serum levels of high-sensitivity C-reactive protein (relative mean difference 1.29, 95% CI 1.03 to 1.62; p = 0.025), triglyceride (relative mean difference 1.15, 95% CI 1.03 to 1.28; p = 0.014), and exercise time (mean difference -26.4 seconds; 95% CI -51.6 to -1.2; p = 0.04). The INTERHEART Risk Score analysis suggested more participants with (31%) than without (14%, p <0.001) OSA will develop future cardiovascular events. In conclusion, based on the acceptance for OSA screening, high prevalence of OSA and independent associations between OSA and coronary risk markers, incorporation of sleep studies into cardiovascular health screening programs appears feasible.

Obstructive Sleep Apnea Increases the Perioperative Risk of Cardiac Valve Replacement Surgery: A Prospective Single-Center Study

STUDY OBJECTIVES

Sleep apnea is common in patients referred for cardiac valve replacement (CVR). We aimed to determine the association of obstructive sleep apnea (OSA) and central sleep apnea (CSA) with perioperative events in CVR surgery in patients with rheumatic valvular heart disease (RVHD).

METHODS

Between April 2010 and April 2014, 290 patients with RVHD undergoing CVR were screened for sleep apnea 1 to 7 days before CVR. Baseline medications, cardiac function, sleep parameters, perioperative events, and related risk factors were evaluated.

RESULTS

OSA patients had longer duration of intensive care unit (ICU) stay and mechanical ventilation compared with no sleep-disordered breathing and CSA patients. Patients with CSA had a higher rate of pacemaker use and higher first dose of dobutamine in ICU. NYHA Class and the presence of OSA were independently associated with overall worsening of postoperative recovery (ICU stay ≥ 25 h). Age, NYHA class, and the presence of OSA were independently associated with postoperative respiratory insufficiency (mechanical ventilation ≥ 20 h). Preoperative atrial fibrillation, pulmonary hypertension, and OSA were independently associated with postoperative pacemaker use.

CONCLUSIONS

RVHD patients with OSA have an increased incidence of perioperative adverse events. OSA was independently associated with overall postoperative recovery, respiratory insufficiency, and higher rate of postoperative pacemaker use, while CSA was not associated with postoperative events.