Arrhythmia and sleep-disordered breathing in patients undergoing cardiac surgery

Impact of sleep disordered breathing on postoperative atrial fibrillation in patients who underwent cardiac surgery: a meta-analysis

Objective: An increasing number of studies suggest that sleep disordered breathing (SDB) may be associated with postoperative atrial fibrillation (POAF), but these studies present discrepant results. Thus, this meta-analysis aimed to synthesize the data associating SDB with POAF in patients who underwent cardiac surgery.Methods: A literature search was performed in the Scopus, PubMed, Web of Science, EMBASE, CENTRAL, Weipu, Wanfang Data, and China National Knowledge Infrastructure databases before August 2022. Data were extracted, and the strength of the relationship between SDB and the risk of POAF was evaluated using odds ratio (OR) and 95% confidence intervals (CIs). All statistical analysis was carried out using the Stata 12.0 software.Results: A total of 24 studies with 660,685 subjects were included in current meta-analysis. SDB was significantly associated with the risk of POAF in the patients who underwent cardiac surgery (OR = 1.49; 95% CI, 1.30-1.70; p < .001). Next subgroup analysis revealed that such association may be increased in the group with medical equipment-measured SDB (OR = 2.27; 95% CI, 1.59-3.23; p < .001), prospective studies (OR = 2.17; 95% CI, 1.55-3.03; p < .001), patients without a previous history of atrial fibrillation (OR = 2.04; 95% CI, 1.47-2.82; p < .001), and patients who received a coronary artery bypass graft (OR = 2.10; 95% CI, 1.45-3.05; p < .001). No publication bias was identified.Conclusion: The results of meta-analysis support that SDB may be associated with an increased risk of POAF in patients who had undergone cardiac surgery, and these results should be confirmed in more rigorously designed studies.KEY MESSAGESPatients with SDB who underwent cardiac surgery showed increased risk of POAF.The relationship between SDB and POAF should be explained with caution with the consideration of various covariate.The effect of pre-treatment of SDB on POAF should be examined in future.

Ventricular arrhythmia in heart failure patients with reduced ejection fraction and central sleep apnoea

Cheyne–Stokes respiration (CSR) may trigger ventricular arrhythmia in patients with heart failure with reduced ejection fraction (HFrEF) and central sleep apnoea (CSA). This study determined the prevalence and predictors of a high nocturnal ventricular arrhythmia burden in patients with HFrEF and CSA (with and without CSR) and to evaluate the temporal association between CSR and the ventricular arrhythmia burden.

 This cross-sectional ancillary analysis included 239 participants from the SERVE-HF major sub-study who had HFrEF and CSA, and nocturnal ECG from polysomnography. CSR was stratified in ≥20% and <20% of total recording time (TRT). High burden of ventricular arrhythmia was defined as >30 premature ventricular complexes (PVCs) per hour of TRT. A sub-analysis was performed to evaluate the temporal association between CSR and ventricular arrhythmias in sleep stage N2.

 High ventricular arrhythmia burden was observed in 44% of patients. In multivariate logistic regression analysis, male sex, lower systolic blood pressure, non-use of antiarrhythmic medication and CSR ≥20% were significantly associated with PVCs >30·h⁻¹ (OR 5.49, 95% CI 1.51–19.91, p=0.010; OR 0.98, 95% CI 0.97–1.00, p=0.017; OR 5.02, 95% CI 1.51–19.91, p=0.001; and OR 2.22, 95% CI 1.22–4.05, p=0.009; respectively). PVCs occurred more frequently during sleep phases with versus without CSR (median (interquartile range): 64.6 (24.8–145.7) versus 34.6 (4.8–75.2)·h⁻¹ N2 sleep; p=0.006).

 Further mechanistic studies and arrhythmia analysis of major randomised trials evaluating the effect of treating CSR on ventricular arrhythmia burden and arrhythmia-related outcomes are warranted to understand how these data match with the results of the parent SERVE-HF study.

High ventricular arrhythmia burden occurs in 44% of heart failure patients with reduced ejection fraction and central sleep apnoea. Arrhythmia burden is higher in sleep phases with versus without Cheyne–Stokes respiration.https://bit.ly/2QBDamC

Does an undetected obstructive sleep apnea influence the natural course and success of cardiac rehabilitation after cardiac surgery?

BACKGROUND

Obstructive Sleep Apnea (OSA) is common in patients with cardiovascular diseases (CVD) and can negatively impact the course of CVD. However, scarce data are available for patients before or after cardiac surgery (CS) in the context of OSA.

AIM

This study investigated the impact of an undetected OSA on the results of cardiac rehabilitation (CR) in patients after CS.

DESIGN

Observational study over a period of 3 months following CS.

SETTING

The setting of this study was inpatient CR after CS or cardiac interventions.

POPULATION

CS cohort referred to a CR program to an inpatient rehabilitation clinic in Switzerland.

METHODS

In this prospective observational study 256 patients were screened for OSA at the entry of CR via a level III screening device (ApneaLink Air^TM, Resmed, San Diego, CA, USA). They were stratified into two groups: apnea hypopnea index (AHI) >15 or <15/h. A comprehensive assessment was performed at entry and end of CR including six-minute walk test (6-MWT), Functional Independence Measure (FIM), Hospital Anxiety and Depression Scale, MacNewHeart (MNH), STOP-Bang Questionnaire (SBQ) and Epworth Sleepiness Scale (ESS).All patients participated in a comprehensive CR program with a mean duration of approximately 3 weeks. Another OSA screening was performed at the end of the PR program and after 3 months in order to observe the clinical course of OSA.

RESULTS

An AHI>15/h was found in 133 patients (59%) at baseline, 54% after 3 weeks and 43% after 3 months. The AHI>15/h-group was older, had a higher BMI, more frequent hypertension and coronary artery disease, and higher ESS and SBQ scores compared to the AHI<15/h-group. The results of the STOP-Bang and ESS questionnaires showed a statistically significant but weak positive correlation with AHI. However, in both groups ESS did not improve from baseline to the end of CR. A multivariable logistic regression model confirmed age and ESS as independent positive predictors of OSA. No differences were found between both groups according to the results of the 6-MWT, HADS and MNH.

CONCLUSIONS

OSA had a high prevalence in a large CS cohort referred to CR. However, moderate-severe OSA, though symptomatic, had no significant influence on the outcome during CR and on the parameters representing success.

CLINICAL REHABILITATION IMPACT

In our study the improvements during CR after CS were not influenced by the presence of significant OSA which is remarkable since the presence of OSA is thought to be associated with increased rates of cardiovascular adverse events after cardiovascular intervention or CS. This is true at least for the success of CR after CS. The long-term consequences of untreated OSA in CVD remain unclear and are still the subject of current research.

A prospective five-year cohort study of undiagnosed sleep apnea in patients undergoing coronary artery bypass graft surgery

BACKGROUND

We aimed to study prospectively the nature and effect of sleep apnea-hypopnea syndrome (SAHS) in patients undergoing coronary artery bypass graft (CABG) surgery over five years of follow-up.

METHODS

Patients undergoing CABG surgery (N.=145) were assessed longitudinally (baseline, 1 year, and 5 years post-surgery) using the 'STOP-BANG' screen of sleep apnea risk. Additionally, all patients had a preoperative multiple-channel sleep-study, providing acceptable data for an obstructive and central apnea, and desaturation index in 97 patients.

RESULTS

Preoperatively, over half (63%) of patients obtained an apnea-hypopnea index score (combining apnea types) in the moderate-severe range for SAHS, and STOP-BANG threshold score (>3/8) was reached by most (95%) patients. Despite some improvement in 'STOP symptoms' at 1-year follow-up, most patients (98%) remained at risk of SAHS at 5 years post-surgery. There was an underlying and chronic relationship between STOP-BANG score and cardiac symptoms at both baseline and 5-year follow-up. Additionally, SAHS variables were associated with greater incidence of acute postoperative events, and generally with increased length of stay on the intensive care unit.

CONCLUSIONS

We confirm that SAHS is common in CABG-surgery patients, presenting additional clinical challenges and cost implications. The underlying pathophysiology is complex, including upper airway obstruction and cardiorespiratory changes of heart failure. In patients presenting for CABG-surgery, we show chronic susceptibility to SAHS, likely associated with traditional risk factors e.g. obesity but perhaps also with gradual decline in heart function itself. Superimposed on this, there is potential for exacerbated risk of morbidity at the time of CABG surgery itself.

A Review of Current Tools Used for Evaluating the Severity of Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common and heterogeneous disease characterized by episodic collapse within the upper airways, which leads to reduced ventilation and adverse consequences, including hypoxia, hypercapnia, sleep fragmentation, and long-term effects such as cardiovascular comorbidities. The clinical diagnosis of OSA and its severity classification are often determined based on the apnea-hypopnea index (AHI), defining the number of apneic and hypopnea events per hour of sleep. However, the limitations of the AHI to assess disease severity have necessitated the exploration of other metrics for additional information to reflect the complexity of OSA. Novel parameters such as the hypoxic burden have the potential to better capture the main features of OSA by maximizing the information available from the polysomnogram. These emerging measures have described multidimensional qualities of sleep-disordered breathing events and breathing irregularity and will ultimately result in better management of OSA.

Sleep Study and Oximetry Parameters for Predicting Postoperative Complications in Patients With OSA

In the surgical setting, OSA is associated with an increased risk of postoperative complications. At present, risk stratification using OSA-associated parameters derived from polysomnography (PSG) or overnight oximetry to predict postoperative complications has not been established. The objective of this narrative review is to evaluate the literature to determine the association between parameters extracted from in-laboratory PSG, portable PSG, or overnight oximetry and postoperative adverse events. We obtained pertinent articles from Ovid MEDLINE, Ovid MEDLINE In-Process & Other Non-Indexed Citations, and Embase (2008 to December 2017). The search included studies with adult patients undergoing surgery who had OSA diagnosed with portable PSG, in-laboratory PSG, or overnight oximetry that reported on specific sleep parameters and at least one adverse outcome. The search was restricted to English-language articles. The search yielded 1,810 articles, of which 21 were included in the review. Preoperative apnea-hypopnea index (AHI) and measurements of nocturnal hypoxemia such as oxygen desaturation index (ODI), cumulative sleep time percentage with oxyhemoglobin saturation (Spo₂) < 90% (CT90), minimum Spo₂, mean Spo₂, and longest apnea duration were associated with postoperative complications. OSA is associated with postoperative complications in the population undergoing surgery. Clinically and statistically significant associations between AHI and postoperative adverse events exists. Complications may be more likely to occur in the category of moderate to severe OSA (AHI ≥ 15). Other parameters from PSG or overnight oximetry such as ODI, CT90, mean and minimal Spo₂, and longest apnea duration can be associated with postoperative complications and may provide additional value in risk stratification and minimization.

Positive association of plasma leptin with sleep quality in obese type 2 diabetes patients

AIMS/INTRODUCTION

Poor sleep quality is associated with obesity and diabetes. The adipocyte-derived hormone, leptin, was recently shown to underlie the link between abnormal sleep and obesity. We aimed to investigate the association between leptin and sleep quality in type 2 diabetes patients.

MATERIALS AND METHODS

In the present cross-sectional study, we studied 182 type 2 diabetes patients, among whom 113 were diagnosed with obesity (body mass index ≥25 kg/m2 ). Fasting plasma leptin levels were measured, and sleep architecture was assessed using single-channel electroencephalography.

RESULTS

Using unadjusted analyses, the obese type 2 diabetes patients, but not their non-obese counterparts, showed a positive correlation between plasma leptin levels and a parameter for deep sleep assessed by delta power during the first sleep cycle. Multivariate analysis showed that plasma leptin levels were positively associated with delta power, but not with the total sleep time, after adjusting for potential confounders including age, body mass index and the apnea-hypopnea index, in the obesity group. However, neither delta power nor total sleep time was associated with leptin in the non-obesity group.

CONCLUSIONS

Plasma leptin levels are independently associated with sleep quality in obese, but not in non-obese, type 2 diabetes patients. The present study indicates a favorable relationship between leptin and sleep quality in obese type 2 diabetes patients.

Postoperative complications after elective coronary artery bypass grafting surgery in patients with sleep-disordered breathing

BACKGROUND

Sleep-disordered breathing (SDB) may increase the risk of postoperative complications in patients after cardiac surgery. This study evaluated the length of hospital stay as well as postoperative cardiac, respiratory, and renal complications after elective coronary artery bypass grafting (CABG) in patients without SDB, with central sleep apnea (CSA), or with obstructive sleep apnea (OSA).

METHODS

The presence and type of SDB had been assessed with polygraphic recordings in 100 patients the night before elective CABG surgery. SDB was defined as an apnea-hypopnea index (AHI) of ≥ 15/h. Prolonged length of hospital stay (LOS) and postoperative hemodynamic instability due to any cause were retrospectively evaluated as primary endpoints and cardiac, respiratory, and renal complications as secondary endpoints.

RESULTS

37% of patients had SDB, 14% CSA, and 23% OSA. LOS differed significantly between patients without SDB and those with CSA and OSA [median (25;75. percentile): 8.0 days (7.5;11.0) vs. 9.5 days (7.0;12.5) vs. 12.0 days (9.0;17.0), Kruskal-Wallis test between three groups: p = 0.023; OSA vs. no SDB: p = 0.005]. AHI was significantly associated with prolonged LOS [> 9 days; odds ratio (OR) (95% confidence interval): 1.047 (1.001;1.095), p = 0.044]. Prolonged need of vasopressors (≥ 48 h) was observed in 36% of patients without SDB, in 64% with CSA, and in 62% with OSA (p = 0.037). AHI was significantly associated with prolonged (≥ 48 h) need of vasopressors [OR (95% CI): 1.052 (1.002;1.104), p = 0.040], independent of any confounders.

CONCLUSIONS

SDB, particularly OSA, is associated with prolonged LOS after CABG, independent of known confounders. Prolonged LOS in patients with SDB may be due to increased postoperative hemodynamic instability due to any cause.

Obstructive sleep apnea and its effects on cardiovascular diseases: a narrative review

Obstructive sleep apnea (OSA) occurs in 5%-14% of adults but is often undiagnosed. Apneas cause acute physiological changes, including alveolar hypoventilation and pulmonary artery vasoconstriction; they also promote chronic vascular disease secondary to increased platelet adhesiveness, endothelial dysfunction, and accelerated atherosclerosis. The Sleep Heart Health Study demonstrated that OSA is a risk factor for stroke and that an increase of 1 unit in the apnea-hypopnea index increases stroke risk by 6% in men. Patients with OSA frequently have atrial fibrillation (AF). Patients with OSA and AF have an increased incidence of stroke compared with patients with only OSA. The treatment of OSA with CPAP reduces the incidence of stroke and decreases the recurrence rate of AF in patients undergoing pulmonary vein ablation procedures. Undertreated OSA has the potential to complicate the postoperative course of patients undergoing cardiac surgery and increase the frequency of arrhythmias and ischemic events. However, one prospective study demonstrated that OSA did not increase complications during the first 30 days following surgery but increased complications during the long-term follow-up. OSA is associated with increased atherosclerotic coronary disease and the development of coronary events and congestive heart failure. In summary, patients with OSA have an increased frequency of stroke and AF The treatment of these patients with CPAP reduces the frequency of stroke and AF recurrence rate in patients with AF undergoing either medical management or invasive procedures. However, well-designed clinical trials are necessary to answer critical questions regarding the management of OSA in patients with cardiovascular diseases.

Association between poor glycemic control, impaired sleep quality, and increased arterial thickening in type 2 diabetic patients

Objective

Poor sleep quality is an independent predictor of cardiovascular events. However, little is known about the association between glycemic control and objective sleep architecture and its influence on arteriosclerosis in patients with type-2 diabetes mellitus (DM). The present study examined the association of objective sleep architecture with both glycemic control and arteriosclerosis in type-2 DM patients.

Design

Cross-sectional study in vascular laboratory.

Methods

The subjects were 63 type-2 DM inpatients (M/F, 32/31; age, 57.5±13.1) without taking any sleeping promoting drug and chronic kidney disease. We examined objective sleep architecture by single-channel electroencephalography and arteriosclerosis by carotid-artery intima-media thickness (CA-IMT).

Results

HbA1c was associated significantly in a negative manner with REM sleep latency (interval between sleep-onset and the first REM period) (β=-0.280, p=0.033), but not with other measurements of sleep quality. REM sleep latency associated significantly in a positive manner with log delta power (the marker of deep sleep) during that period (β=0.544, p=0.001). In the model including variables univariately correlated with CA-IMT (REM sleep latency, age, DM duration, systolic blood pressure, and HbA1c) as independent variables, REM sleep latency (β=-0.232, p=0.038), but not HbA1c were significantly associated with CA-IMT. When log delta power was included in place of REM sleep latency, log delta power (β=-0.257, p=0.023) emerged as a significant factor associated with CA-IMT.

Conclusions

In type-2 DM patients, poor glycemic control was independently associated with poor quality of sleep as represented by decrease of REM sleep latency which might be responsible for increased CA-IMT, a relevant marker for arterial wall thickening.

Association between obstructive sleep apnea and premature supraventricular contractions

OBJECTIVE

The exact association between obstructive sleep apnea (OSA) and premature supraventricular contractions (PSVCs) has not been established.

METHODS

We prospectively performed polysomnography together with 24-hour Holter electrocardiography in 431 patients who were clinically suspected of having OSA and examined the association between OSA severity and PSVCs during wakefulness and sleep. The patients were classified into 4 groups according to the apnea-hypopnea index (AHI) quartiles (Q1=patients with AHI<13.8, Q2=those with 13.8≤AHI<28.8, Q3=those with 28.8≤AHI<48.1, Q4=those with AHI≥48.1).

RESULTS

The number of PSVCs/hour during sleep differed significantly among the 4 groups, but the number of PSVCs/hour during wakefulness did not. The prevalence of PSVC≥5/hour during sleep was significantly higher in Q4 (21.0%) than the other 3 groups (Q1, 9.0%; Q2, 8.0%; Q3, 6.0%; all p<0.05 for Q4), but the prevalence of PSVC≥5/hour during wakefulness did not differ among the 4 groups. A multivariate logistic regression analysis showed that the highest AHI quartile was significantly associated with PSVC≥5/hour during sleep (odds ratio 3.04, 95% confidence interval 1.44-6.42, p=0.004).

CONCLUSIONS

Severe OSA can cause PSVCs during sleep, but its effect appears not to be strong. Further studies are needed to clarify the clinical significance of this small but significant increase in PSVCs during sleep in severe OSA patients.

Delirium after cardiac surgery: have we overlooked obstructive sleep apnea?

Obstructive sleep apnea is common in patients with cardiovascular disease. It is well known that cardiac surgery is a risk factor for delirium. Researchers have shown that obstructive sleep apnea is an independent risk factor for the occurrence of delirium. In this manuscript we speculate on how obstructive sleep apnea may increase the risk of delirium in patients with cardiac surgery. If this is found to be confirmed, we would have another target through which we can decrease the risk of delirium in this population.