Importance and management of chronic sleep apnoea in cardiology

Hypoxic Burden Based on Automatically Identified Desaturations Is Associated with Adverse Health Outcomes

Rationale: Recent studies have shown that sleep apnea-specific intermittent hypoxemia quantified by the hypoxic burden (HB) predicted cardiovascular disease (CVD)-related mortality in community-based and clinical cohorts. Calculation of HB is based on manual scoring of hypopneas and apneas, which is time-consuming and prone to interscorer variability. Objective: To validate a novel method to quantify the HB that is based on automatically scored desaturations. Methods: The sample included 5,655 middle-aged or older adults from the Sleep Heart Health Study (52.8% women; age, 63.2 ± 11.3 yr). The original HB method was based on a subject-specific search window obtained from an ensemble average of oxygen saturation signals (as measured by pulse oximetry) and synchronized with respect to the termination of scored respiratory events. In this study, however, the search window was obtained from ensemble average of oxygen saturation signals that synchronized with respect to the minimum of all automatically identified desaturations (⩾2% and other thresholds, including 3% and 4%, in sensitivity analyses). The time interval between the two maxima around the minimum saturation was defined as the search window. The oximetry-derived HB (HBOxi) was defined as the total area under all desaturation curves (restricted by the search window) divided by the total sleep time. Logistic and Cox regression models assessed the adjusted odds ratio (aOR)/hazard ratio of excessive daytime sleepiness (EDS), hypertension (HTN), and CVD mortality per 1-standard deviation increase in HBOxi after adjusting for several covariates and confounders. Results: The Spearman's rank correlation between HB (median [interquartile range], 34.4 [18.4-59.8] % min/h) and HBOxi (median [interquartile range], 34.5 [21.6-53.8] % min/h) was 0.81 (P < 0.001). Similar to HB, HBOxi was significantly associated with EDS (aOR [95% confidence interval (CI)], 1.17 [1.09-1.26] per standard deviation), HTN (aOR [95% CI], 1.13 [1.05-1.21]), and CVD mortality (adjusted hazard ratio [95% CI], 1.15 [1.01-1.30]) in fully adjusted models. Conclusions: The HBOxi was highly correlated with the HB based on manually scored apneas and hypopneas and was associated with EDS, HTN, and CVD mortality with similar effect sizes as previously reported. This method could be incorporated into wearable technology that accurately records oxygen saturation signals.

Mediation effect of hypoxia in the relationship between obstructive sleep apnea and cardiovascular death risk

PURPOSE

This study aimed to explore the role of hypoxia in the relationship between obstructive sleep apnea (OSA) and cardiovascular disease (CVD) death risk based on data from the Sleep Heart Health Study (SHHS).

METHODS

Multivariate logistic regression analysis was used to analyze the association between OSA, hypoxia, and CVD death risk. Causal mediation analysis was performed to assess the role of hypoxia. The severity of OSA was evaluated by the apnea-hypopnea index (AHI), and the hypoxia was quantified by the percentage of sleep time with less than 90% oxygen saturation (PCTST90).

RESULTS

Of these 5,145 participants, 989 had no OSA, 2,110 had mild OSA, and 2,046 had moderate-to-severe OSA. After adjusting all confounders, mild OSA [odds ratio (OR): 1.800; 95% confidence interval (CI), 1.192-2.802], moderate-to-severe OSA (OR: 1.745; 95%CI, 1.148-2.758), 0 < PCTST90 < 1 (OR: 1.668; 95%CI, 1.184-2.385), and PCTST90 ≥ 1 (OR: 1.649; 95%CI, 1.148-2.400) were associated with an increased death risk of CVD. Furthermore, participants with mild OSA (OR: 3.742; 95%CI, 3.183-4.398) and moderate-to-severe OSA (OR: 19.671; 95%CI, 16.303-23.734) had a higher risk of hypoxia than those without OSA. Causal mediation analysis indicated that the average direct effect (ADM) of moderate-to-severe OSA and average causal mediation effect (ACME) of hypoxia on CVD death risk were 0.024 (95%CI, 0.004-0.040) and 0.013 (95%CI, 0.005-0.020), respectively, and the average mediating effect ratio was 33.94%.

CONCLUSION

Hypoxia played a mediating role in the increased death risk of CVD caused by OSA, and the mediating effect of hypoxia did not account for a large proportion.

Risk of Severe COVID-19 in Non-Adherent OSA Patients

BACKGROUND

Patients with obstructive sleep apnoea (OSA) are at increased risk of severe course of COVID-19. Vaccination remains to be the most effective prevention of complicated courses of infection. The best contemporary conservative treatment of OSA is continuous positive airway pressure (CPAP) therapy.

PURPOSE

To compare vaccination acceptance and outcomes of COVID-19 infection between OSA patients adhering to the CPAP therapy and those who rejected CPAP and surgical therapy.

PATIENTS AND METHODS

Subjects were divided into two groups: group A (N = 167) were individuals with sufficient CPAP adherence (more than 4 hours per night on average) over the last 10 years. Group B (N = 106) were individuals who did not use the CPAP therapy at all and had no indications to surgical therapy.

RESULTS

Three patients in group B died, and one had a severe course of COVID-19. None of the patients in group A died or experienced a severe course of COVID-19. Group A had a significantly higher proportion of males (77.8% compared to 66% in group B) and all parameters of OSA severity. The vaccination status was similar among both groups, with a complete triple dose vaccination rate of 69.5% and 67.9% in groups A and B, respectively.

CONCLUSION

The results show that the patients with OSA adherent to CPAP therapy were less likely to experience a severe course of COVID-19 or death than the OSA patients non-compliant with therapy, despite the former group having more severe OSA. This result underlines the importance of adherence to CPAP therapy in OSA.

Prognostic Impact of Obstructive Sleep Apnea in Patients Presenting with Acute Symptomatic Pulmonary Embolism

BACKGROUND

 In patients with pulmonary embolism (PE), there is a lack of comprehensive data on the prevalence and prognostic significance of pre-existing obstructive sleep apnea (OSA).

METHODS

 In this study of patients with PE from the Registro Informatizado de la Enfermedad TromboEmbólica (RIETE) registry, we assessed the prevalence of OSA, and the association between pre-existing OSA and the outcomes of all-cause mortality, PE-related mortality, recurrences, and major bleeding over 30 days after initiation of PE treatment. Additionally, we also examined rates of outcomes within 90 days and 1 year following the diagnosis of PE.

RESULTS

 Of 4,153 patients diagnosed with PE, 241 (5.8%; 95% confidence interval [CI]: 5.1-6.6%) had pre-existing OSA. Overall, 166 (4.0%; 95% CI: 3.4-4.6%) died during the first 30 days of follow-up. In multivariable analysis, the OSA syndrome was not a significant predictor of death from any cause (odds ratio [OR]: 1.5; 95% CI: 0.8-2.9; p = 0.19). However, patients with pre-existing OSA had an increased PE-specific mortality (adjusted OR: 3.0; 95% CI: 1.3-6.8; p = 0.01) compared with those without OSA. OSA was not significantly associated with 30-day recurrent venous thromboembolism (adjusted OR: 0.6; 95% CI: 0.1-4.7; p = 0.65) or major bleeds (adjusted OR: 1.0; 95% CI: 0.4-2.2; p = 1.0). Findings were similar at 90-day and 1-year follow-ups.

CONCLUSION

 In patients presenting with PE, pre-existing OSA is relatively infrequent. Patients with OSA were at increased risk of PE-related mortality when compared with those without OSA.

Association Between Obstructive Sleep Apnea-Hypopnea Syndrome and Outcomes in Patients With Myocardial Infarction in the Absence of Obstructive Coronary Artery Disease

Background and Aims: Myocardial infarction in the absence of obstructive coronary artery disease (MINOCA) occurs in 5-10% of all patients with acute myocardial infarction. Obstructive sleep apnea-hypopnea syndrome (OSAHS) is linked to increased cardiovascular morbidity and mortality, but the relationship of OSAHS and outcomes in patients with MINOCA remains unknown. We aimed to evaluate the association between OSAHS and clinical outcomes in patients with MINOCA. Methods: Between January 2015 and December 2016, we carried out a consecutive cohort study of 583 patients with MINOCA and followed them up for 3 years. An apnea-hypopnea index of ≥ 15 events per hour recorded by polysomnography was defined as the diagnostic criterion for OSAHS. The primary end point was all-cause mortality, and the second end point was major adverse cardiovascular or cerebrovascular events (MACCE), a composite of cardiac death, non-fatal myocardial infarction, heart failure, cardiovascular-related rehospitalization, and stroke. Results: All-cause mortality happened in 69 patients and MACCE occurred in 113 patients during the 3-year follow-up. Kaplan-Meier survival curves indicated the significant relationship of OSAHS with all-cause mortality (log-rank P = 0.012) and MACCE (log-rank P = 0.002). Multivariate Cox regression analysis indicated OSAHS as an independent predictor of all-cause mortality and MACCE [adjusted hazard ratio: 1.706; 95% confidence interval (CI): 1.286-2.423; P = 0.008; and adjusted hazard ratio: 1.733; 95% CI: 1.201-2.389; P < 0.001; respectively], independent of age, sex, cardiovascular risk factors and discharge medications. Conclusions: OSAHS is independently associated with increased risk of all-cause mortality and MACCE in patients with MINOCA. Intervention and treatment should be considered to alleviate OSAHS-associated risk.

Obstructive sleep apnea versus central sleep apnea: prognosis in systolic heart failure

Background

In chronic heart failure (CHF), obstructive sleep apnea (OSA) and Cheyne-Stokes respiration (CSR) are associated with increased mortality. The present study aimed to evaluate the prognostic effect of CSR compared to OSA, in otherwise similar groups of CHF patients.

Methods

Screening for sleep-disordered breathing (SDB) was conducted among patients with CHF of New York Heart Association (NYHA) class II-IV, and left ventricular ejection fraction (LVEF) of ≤45%. The study included 43 patients (4 women) with >25% CSR during sleeping time, and 19 patients (2 women) with OSA and an apnea-hypopnea index (AHI) of ≥6. Patients were followed for a median of 1,371 days. The primary endpoint was mortality, and the secondary endpoint was combined mortality and hospital admissions.

Results

Baseline parameters did not significantly differ between groups, but CSR patients were older and had higher AHI values than OSA patients. Five OSA patients (26%) died, and 14 (74%) met the combined end-point of death or hospitalization. CSR patients had significantly higher risk for both end-points, with 23 (53%) deaths [log-rank P=0.040; HR, 2.70 (1.01-7.22); P=0.047] and 40 (93%) deaths or readmissions [log-rank P=0.029; HR, 1.96 (1.06-3.63); P=0.032]. After adjustment for confounding risk factors, the association between CSR and death remained significant [HR, 4.73 (1.10-20.28); P=0.037], hospital admission rates were not significantly different.

Conclusions

Among patients with CHF, CSR was associated with higher mortality than OSA independently of age and cardiac systolic function. CSR was also an age-independent predictor of unfavorable outcome, but hospital admission rates were not significantly different between the two groups after adjustment.

Is Cumulative Time of Oxygen Desaturation a Better Predictor of Cardiovascular Mortality than Apnoea Hypopnoea Index?

In this paper, we explored the link between sleep apnoea and cardiovascular disease (CVD) using a time-series statistical measure of sleep apnoea-related oxygen desaturation. We compared the performance of a hypoxic measure derived from the polysomnogram with the Apnoea Hypopnoea Index (AHI) in predicting CVD mortality in patients of the Sleep Heart Health Study.We estimated the relative cumulative time of SpO₂ below 90% (T_r90) using pulse oximetry signals from polysomnogram recordings as the hypoxic measure of desaturation patterns. Then, the survival curves for hypoxia quintiles were evaluated for the prediction of CVD mortality and were compared with the results using AHI for prediction. We also calculated the Cox hazard ratios for T_r90 and AHI. Our results show that the T_r90 was a better predictor of CVD mortality outcomes than AHI.

[Physiopathology of obstructive sleep apnea syndrome]

An excellent grasp of the physiopathology of obstructive sleep apnea syndrome (OSAS) is essential to understanding its diagnostic and therapeutic modalities. A systematic review of the literature was performed on data specific to humans. Two aspects are involved: on one hand, the mechanisms contributing to intermittent obstruction of the upper airways (UA) during sleep and, on the other hand, the impact of this obstruction, e.g. neurocognitive disorders, cardiovascular disease and metabolic dysregulation. UA obstruction can be explained by anatomical, mechanical and neuro-functional conditions, especially the proprioceptive and chemical feedback of UA neuromuscular activity. Our understanding of the impact of OSAS has benefited from the recently developed concepts of oxidative stress and low-grade systemic inflammation, the discovery of hypoxia-sensitive agents and of the role of cytokines. The onset of this chain of events is determined by chronic intermittent hypoxia.

Prevalence and Predictors of Ocular Complications in Obstructive Sleep Apnea Patients: A Cross-sectional Case-control Study

Purpose:

This study sought to identify the magnitude and the possible risk factors of ocular complications in patients with Obstructive Sleep Apnea (OSA).

Methods:

A hospital-based cross-sectional study with a nested case-control design was conducted. Qualifying study subjects were patients who had been diagnosed with moderate to severe OSA (AHI index of ≥ 5, n=80), and control subjects (n=20) who had an AHI index of ≤ 5 (“normal”). Study participants were recruited from Mansoura University Hospital’s Sleep Disorders Clinic in Mansoura, Egypt.Selected subjects were assessed for ocular complications at Mansoura Univerity Hospital Ophthalmic Center, (Mansoura), Egypt. An ophthalmic history was recorded, and opthalmic testing was carried out. The testing included unaided visual acuity measurement, refraction, best-corrected visual acuity measurement, slit lamp bio-microscopic evaluation of the anterior segment and anterior segment photography, dilated fundus examination, intraocular pressure measurement, fundus photo, and fluorescein angiography, and visual field assessment. Various tests of OSA symptoms were also monitored, including the AHI, lowest oxygen concentrations and desaturation index plus the overall severity index. .

Results:

It was found that OSA patients n=28 (35%), n=24 (30%), n=4 (5%) had senile cataract, normal tension glaucoma, and retinal ischemia, respectively, with an overall prevalence of 45%. Additionally, the OSA group had seven times greater risk (OR=7.36, 95%CI: 1.6-33.86) of vision-threatening disorders compared to the controls. OSA patients were observed to be at a greater risk of senile cataract 28 (35%), normal tension glaucoma 24 (30%), retinal ischemia 4 (5%) and conjunctival hyperemia and dry eye (OR=3.77, 95%CI: 1.02-13.95, OR=4.36, 95%CI: 1.26-17.08). Also, multivariate logistic regression analysis testing showed that the lowest oxygen saturation index was the only significant predictor negatively associated with vision-threatening disorders (OR=0.84, 95%CI: 0.75-0.93).

Conclusion:

The risk of vision-threatening and non-threatening ocular disorders is higher among OSA cases. The lowest oxygen saturation index was the only significant predictor of vision-threatening disorders. These findings support the recommendation that a full ophthalmic examination should be carried out on patients with confirmed OSA.

Is dynamic desaturation better than a static index to quantify the mortality risk in heart failure patients with Cheyne-Stokes respiration?

Cheyne-Stokes respiration (CSR) is a periodic, highly dynamic, respiratory pattern and a known comorbidity in congestive heart failure (CHF) patients. It is generally seen as an indicator for a negative prognosis, even if no distinction in degree is known or understood. This paper aims to improve on existing attempts by creating a quantification of the behavior of the dynamic desaturation process of oxygen in the blood. We performed this work on a cohort of 11 subjects with CHF, reduced left ventricular ejection fraction, and CSR. The dynamic desaturation process was evaluated according to changes to peripheral capillary oxygenation S p O 2 resulting from highly nonlinear relationships in the ventilatory system perturbed by periodic breathing. Hypoxaemic burden expressed as a static index T 90 was compared to a novel relative desaturation index R D I , developed in this paper. While T 90 represents a single value calculated using a static cut-off value of 90 % S p O 2 , the R D I is more sensitive to dynamic influences as it uses the specific maximum change in saturation for each CSR episode. The threshold of T 90 = 22 min per night as suggested by Oldenburg et al. could not be confirmed to predict survival, but all central apneas resulting in a relative desaturation of S p O 2 above a cut-off value of 8 % were a 100 % positive predictor of mortality. The R D I proved sufficiently stable in intraindividual measurements across CSR epochs. Across the cohort, it showed a bimodal distribution for the deceased group, indicative of a possible aetiological difference. Hence, it is our conclusion that a dynamic approach to analyse desaturation of oxygen during Cheyne-Stokes respiration is to be strongly favoured over a static approach to analysis.

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.

Management of Sleep Disordered Breathing in Patients with Heart Failure

PURPOSE OF REVIEW

This paper reviews treatment options for sleep disordered breathing (SDB) in patients with heart failure. We sought to identify therapies for SDB with the best evidence for long-term use in patients with heart failure and to minimize uncertainties in clinical practice by examining frequently discussed questions: what is the role of continuous positive airway pressure (CPAP) in patients with heart failure? Is adaptive servo-ventilation (ASV) safe in patients with heart failure? To what extent is SDB a modifiable risk factor?

RECENT FINDINGS

Consistent evidence has demonstrated that the development of SDB in patients with heart failure is a poor prognostic indicator and a risk factor for cardiovascular mortality. However, despite numerous available interventions for obstructive sleep apnea and central sleep apnea, it remains unclear what effect these therapies have on patients with heart failure. To date, all major randomized clinical trials have failed to demonstrate a survival benefit with SDB therapy and one major study investigating the use of adaptive servo-ventilation demonstrated harm. Significant questions persist regarding the management of SDB in patients with heart failure. Until appropriately powered trials identify a treatment modality that increases cardiovascular survival in patients with SDB and heart failure, a patient's heart failure management should remain the priority of medical care.

Obstructive sleep apnea increases systolic and diastolic blood pressure variability in hypertensive patients

OBJECTIVE

Obstructive sleep apnea (OSA) has been identified as the most common secondary contributing factor for the development and worsening of hypertension. However, the underlying relationships between blood pressure variability (BPV) and OSA are still not very clear. Therefore, we investigated the influences of OSA on BPV in hypertensive patients and explored the potential pathophysiologic mechanisms.

PARTICIPANTS AND METHODS

Ambulatory blood pressure (BP) monitoring was carried out and polysomnography was performed to detect sleep apnea. A total of 86 hypertensive individuals were divided into patients without OSA (n=43) and patients with severe OSA (n=43). Systolic and diastolic BPV were obtained by calculating the SD, coefficient of variation, and average real variability during day-time, night-time, and over 24 h. The relationship between OSA and BPV was assessed after adjustment for potential confounding variables (age, sex, BMI, neck circumference, heart rate, and snoring history).

RESULTS

Compared with participants without OSA, nocturnal systolic BPV and 24-h systolic BP average real variability from OSA participants were obviously increased (P<0.05), but there were no statistically significant differences in day-time and 24-h systolic BP SD and coefficient of variation (P>0.05). Compared with participants without OSA, 24-h diastolic BPV and day-time diastolic BP SD from OSA participants were markedly increased (P<0.05), but nocturnal indices showed no significant differences between the two groups.

CONCLUSION

OSA mainly increases night-time systolic and 24-h diastolic BPV in hypertensive patients. This may provide a plausible explanation for OSA remaining a major risk determinant for cardiovascular diseases.

Sleep apnoea in patients with nocturnal hypertension - a multicenter study in the Czech Republic

Sleep apnoea (SA) is common in patients with hypertension. Nowadays, limited data on the prevalence of SA in nocturnal hypertension (NH) exist. Therefore, we studied the occurrence of SA in Czech patients and its association with 24-h ambulatory blood pressure monitoring (ABPM), breathing disturbances in sleep, anthropometric data, Mallampati score and Epworth sleepiness scale (ESS) using the Apnea Link device. Undiagnosed SA was found in 72.9 % patients (29.3 % mild, 26.6 % moderate, 17.0 % severe) of 188 patients with NH measured by ABPM. The median of the apnoea-hypopnoea index (AHI) was 12.0 (25th-75th percentile 5.0-23.8). Moderate/severe SA (AHI>/=15) was associated with BMI, waist circumference, mean night saturation (SpO(2)), t90, oxygen desaturation index (ODI), ESS (daytime BP only) (p</=0.032), but not ABPM parameters and Mallampati score (p>0.09). A likelihood of moderate/severe SA was enhanced by ODI>14.5 events/h (odds ratio=57.49, 95 % CI=22.79-145.01), t90>6.5 % (8.07, 4.09-15.92), mean night SpO(2)<93.5 % (3.55, 1.92-6.59), BMI>29.05 kg/m(2) (6.22, 3.10-12.49), circum waist>105.5 cm (3.73, 1.57-8.83), but not by any ABPM parameter. In conclusion, a high incidence of SA (72.9 %) was observed in Czech patients with NH. SA severity was associated with body characteristics and oxygenation parameters, but not with ABMP parameters and Mallampati score.

Impact of obstructive sleep apnea on cardiovascular outcomes in patients with acute symptomatic pulmonary embolism: Rationale and methodology for the POPE study

In normotensive patients with acute symptomatic pulmonary embolism (PE), the effect of undiagnosed obstructive sleep apnea (OSA) on cardiovascular (CV) outcomes lacks clarity. The Prognostic Significance of Obstructive Sleep Apnea in Patients With Acute Symptomatic Pulmonary Embolism (POPE) study is a multicenter, observational study designed to prospectively assess the prognostic significance of concomitant OSA in hemodynamically stable outpatients with acute symptomatic PE. Adult patients with acute stable PE are eligible. Recruited patients undergo an overnight sleep study using a level III portable diagnostic device within 7 days (and preferably within 48 hours) of diagnosis of PE. The sleep tracings are analyzed by a certified sleep technologist and audited by a sleep physician, both of whom are blinded to other study data. The patients are divided into 2 groups based on apnea-hypopnea index (AHI): OSA (AHI ≥15) and non-OSA (AHI <15) groups. The study uses a composite of PE-related death, CV death, clinical deterioration requiring an escalation of treatment, or nonfatal CV events (recurrent venous thromboembolism, acute myocardial infarction, or stroke) within 30 days after the diagnosis of PE as the primary outcome. The projected sample size of 225 patients will provide 80% power to test the hypothesis that OSA will increase the primary outcome from 7% in the non-OSA group to 20% in the OSA group, with α ≤0.05. The trial results will be important to understand the burden and CV effects of OSA in PE patients.

Severe obstructive sleep apnea: first screening with an implanted pacemaker

Sleep apnea syndrome (SAS) is a chronic condition associated with cardiovascular disease. In some pacemakers, an advanced algorithm using transthoracic impedance may be used to identify SAS. This algorithm may be also a useful tool for a long-term monitoring helping physicians to optimize therapy, reducing risk factors, and improving therapeutic compliance.

Patients with Cheyne-Stokes respiration and heart failure: patient tolerance after three-month discontinuation of treatment with adaptive servo-ventilation

The recent SERVE HF study concluded that patients with chronic heart failure (CHF) and Cheyne-Stokes respiration (CSR) have increased mortality when treated with adaptive servo-ventilation (ASV). We, therefore, wanted to explore if these patients tolerated discontinuation of ASV treatment. The study was a prospective post-ASV treatment observational design with a 3-month follow-up period. 14 patients from our outpatient clinic, all male, were originally diagnosed with CHF and Cheyne-Stokes respiration, which is a clinical form of central sleep apnea. Left ventricular ejection fraction (LVEF) was ≤45% when ASV treatment was initiated. Median machine use was 68 (42-78) months when the patients were instructed to terminate ASV treatment. The patients were then followed during conventional CHF treatment for 3 months. Study baseline was set the last ASV treatment day. Sleep data were collected from the machine the last day of use. Apnea-hypopnea index (AHI), LVEF, 6-min walk test and 24-h ambulatory electrocardiogram recordings were performed at baseline and at study end. Life quality data were obtained using The Minnesota Living with Heart Failure Questionaire (MLHFQ). New York Heart Association Functional Classification (NYHA) was registered. An ambulatory sleep screening was performed at study end. AHI increased significantly after 3 months without ASV treatment [from 1.6 (0.8-3.2) to 39.2 (24.3-44.1, p = 0.001)]. Quality of life (QOL) decreased significantly: 30 (13-54) at discontinuation of ASV vs. 46 (24-67) (MLHFQ) at study end, p = 0.04. Though there was no significant change in NYHA functional class, patients especially reported increased shortness of breath, reduced concentration and reduced memory after discontinuation of ASV treatment. There were no significant differences in LVEF, heart rhythm data and physical capacity. Left ventricular function was preserved indicating that discontinuation of ASV in heart failure patients does not affect cardiac capacity. There was a significant decrement in QOL that must be considered in further treatment of these patients.

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.

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

INTRODUCTION

Although it has been recognised as a cardiovascular risk factor, data on sleep apnoea screening before coronary artery bypass grafting (CABG) are scarce. This study sought to determine the prevalence, predictors and effects of sleep apnoea on re-admission in patients undergoing CABG.

METHOD

We prospectively recruited 152 patients to undergo an overnight sleep study before CABG. Sleep apnoea was defined as an apnoea-hypopnoea index of ≥15 events per hour. Data on unscheduled re-admission due to cardiovascular events were collected.

RESULTS

Among the 138 patients who completed the sleep study, sleep apnoea was diagnosed in 69 (50%). The patients who had sleep apnoea had a lower left ventricular ejection fraction (p = 0.029), a larger left atrial diameter (p = 0.014) and a larger left ventricular end-systolic dimension (p = 0.019) than those who did not. Angiographic SYNTAX and Gensini scores were similar in patients with and without sleep apnoea. The generalised structural equation model revealed that hypertension, a high body mass index and chronic renal failure were independent predictors of sleep apnoea (p < 0.05). After an average follow-up of 6 ± 3 months, 12 patients with sleep apnoea (17.3%) and three patients without sleep apnoea (4.3%) were involved in unscheduled re-admission. Patients with sleep apnoea were almost five times more likely to have an unscheduled re-admission due to cardiovascular events (adjusted odds ratio: 4.63, 95% CI: 1.24-17.31, p = 0.023) than those without sleep apnoea.

CONCLUSIONS

Sleep apnoea was prevalent and predictive of unscheduled re-admissions in patients scheduled for CABG.

Sleep apnea is associated with new-onset atrial fibrillation after coronary artery bypass grafting

PURPOSE

New-onset atrial fibrillation (AF) after coronary artery bypass grafting (CABG) remains a prevalent problem. We investigated the relationship between sleep apnea and new-onset post-CABG AF during inhospital stay.

MATERIALS AND METHODS

We prospectively recruited 171 patients listed for an elective CABG for an overnight sleep study. Sleep apnea was defined as apnea-hypopnea index greater than or equal to 5.

RESULTS

Among the 160 patients who completed the study, those in the sleep apnea group (n=128; 80%) had larger left atrial diameter (40.4±5.4 vs 38.4±6.0 mm; P=.03) and left ventricular end-diastolic dimension (52.6±7.9 vs 49.2±6.8 mm; P=.03) than those in the non-sleep apnea group. The incidence of new-onset post-CABG AF was higher for the sleep apnea than non-sleep apnea groups (24.8% vs 9.7%; P=.07). There was 1 inhospital death and 2 patients with acute renal failure requiring dialysis after CABG in the sleep apnea group. None of the patients developed inhospital stroke. Multiple logistic regression analysis showed that sleep apnea was an independent predictor of post-CABG AF (odds ratio, 4.4; 95% confidence interval, 1.1-18.1; P=.04).

CONCLUSION

Sleep apnea is prevalent in patients undergoing CABG. It increases the susceptibility to new-onset AF after CABG, probably related to atrial and ventricular remodeling.

CPAP treatment supported by telemedicine does not improve blood pressure in high cardiovascular risk OSA patients: a randomized, controlled trial

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) has been associated with hypertension, which is one of the intermediary mechanisms leading to increased cardiovascular morbidity. This study aimed at evaluating the effects of a combination of continuous positive airway pressure (CPAP) and telemedicine support on blood pressure (BP) reduction in high cardiovascular risk OSA patients.

DESIGN

A multi-center randomized controlled trial that compared standard CPAP care and CPAP care and a telemedicine intervention.

SETTING

Sleep clinics in France.

PATIENTS OR PARTICIPANTS

107 adult (18-65 years old) OSA patients (AHI > 15 events/h) with a high cardiovascular risk (cardiovascular SCORE > 5% or secondary prevention).

INTERVENTIONS

Patients were randomized to either standard care CPAP (n = 53) or CPAP and telemedicine (n = 54). Patients assigned to telemedicine were equipped with a smartphone for uploading BP measurements, CPAP adherence, sleepiness, and quality of life data; in return, they received pictograms containing health-related messages.

MEASUREMENTS

The main outcome was home self-measured BP and secondary outcomes were cardiovascular risk evolution, objective physical activity, CPAP adherence, sleepiness and quality of life.

RESULTS

Self-measured BP did not improve in either group (telemedicine or standard care). Patients in primary prevention showed greater BP reduction with CPAP treatment than those in secondary prevention.

CONCLUSIONS

CPAP treatment supported by telemedicine alone did not improve blood pressure and cardiovascular risk in high cardiovascular risk OSA patients. This study emphasizes the need for diet and physical activity training programs in addition to CPAP when aiming at decreasing cardiometabolic risk factors in these patients.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov identifier: NCT01226641.

Very early screening for sleep-disordered breathing in acute coronary syndrome in patients without acute heart failure

BACKGROUND

Obstructive sleep apnea (OSA) is frequently associated with acute coronary syndrome (ACS). Screening of sleep-disordered breathing (SDB) has not been previously evaluated in ACS within 72 h in intensive care settings and its management could potentially enhance patients' prognosis. This pilot study assessed the feasibility of SDB screening at the early phase of ACS.

METHODS

All consecutive patients admitted to the coronary care unit (CCU) for ACS without acute heart failure underwent one overnight-attended polysomnography (PSG) within 72 h after admission. A telemonitoring (TM) system was set up to remotely monitor the signals and repair faulty sensors. The 27 recordings were analyzed as respiratory polygraphy (RP) and as PSG, and the results were compared.

RESULTS

The TM system allowed successful intervention in 48% of recordings, resulting in excellent quality PSG for 89% of cases. The prevalence of SDB [apnea-hypopnea index (AHI) ≥ 15/h] was 82% and mainly consisted of central SDB and periodic breathing, except three patients with OSA. Compared with PSG, RP underestimated AHI, probably due to the poor sleep efficiency, reduction of slow-wave sleep, and alteration of rapid eye movement sleep.

CONCLUSION

An early SDB screening by remote-attended PSG is feasible in ACS patients shortly after admission to CCU. The TM enhanced the quality of PSG. A high prevalence of central SDB was noticed, for which the etiology remains unknown. Further large-scale studies are needed to determine whether central SDB is an incidental finding in early ACS and whether the presence and severity of SDB have a prognostic impact.

Non-invasive ventilation in the treatment of sleep-related breathing disorders: A review and update

Non-invasive mechanical ventilation (NIV) was originally used in patients with acute respiratory compromises or exacerbations of chronic respiratory diseases as an alternative to intubation. Over the last thirty years NIV has been used during the night in patients with stable chronic lung diseases such as obstructive sleep apnea, the overlap syndrome (COPD and obstructive sleep apnea), neuromuscular disorders, obesity-hypoventilation syndrome and in other conditions such as sleep disorders associated with congestive heart failure. In this review we discuss the different types of NIV, the specific conditions in which they can be used as well as the indications, recommendations, and evidence supporting the efficacy of NIV.

Impact of obstructive sleep apnea on cardiovascular outcomes in patients treated with percutaneous coronary intervention: rationale and design of the sleep and stent study

Elucidating the effects of obstructive sleep apnea (OSA) on cardiovascular outcomes is crucial in risk assessments and therapeutic recommendations for affected individuals. The Sleep and Stent Study is a multicenter observational study investigating the relationships between OSA and cardiovascular outcomes in patients treated with percutaneous coronary intervention (PCI). Eight centers in 5 countries (Singapore, China and Hong Kong, India, Myanmar, and Brazil) are participating in the study, and the recruitment target is 1600 patients. Adult patients age 18 to 80 years who have undergone successful PCI are eligible. Recruited patients will undergo an overnight sleep study using a level-3 portable diagnostic device before hospital discharge. The sleep tracings will be analyzed by a certified sleep technologist and audited by a sleep physician, both of whom will be blinded to other study data. The patients will be divided into 2 groups based on apnea-hypopnea index (AHI): OSA (AHI ≥15) and non-OSA (AHI <15) groups. The primary study endpoint of cardiovascular death, myocardial infarction, stroke, and unplanned revascularization will be compared between the OSA and non-OSA groups at a median follow-up of 2 years. Secondary endpoints include all-cause mortality, target-vessel revascularization, stent thrombosis, and hospitalization for heart failure. As of December 31, 2013, a total of 1358 patients have been recruited. Based on the complete preliminary results of the first 785 recruited patients, the prevalence of OSA was 48.3%. We expect the follow-up for primary endpoint to be completed in late 2015; study results will be presented in 2016.

Prognostic implication of obstructive sleep apnea diagnosed by post-discharge sleep study in patients presenting with acute coronary syndrome

OBJECTIVE

We aimed to determine the prognostic implications of obstructive sleep apnea (OSA) diagnosed during the recovery phase of acute coronary syndrome (ACS).

METHODS

Patients presenting with ACS and treated with percutaneous coronary intervention were recruited prospectively for a home-based sleep study within 30 days of hospital discharge. Major adverse cardiac and cerebrovascular events (MACCEs) assessed included cardiac death, myocardial infarction, stroke, unplanned revascularization, and hospitalization for heart failure.

RESULTS

Of the 85 patients recruited, 68 successfully completed the study. The median time from percutaneous coronary intervention to sleep study was 14 days (interquartile range: 7.5-27 days). OSA was diagnosed in 24 patients (35.3%) (apnea-hypopnea index > or =15). A drug-eluting stent was implanted into the target lesion in 45 patients (66.2%). None of the study patients had received treatment for OSA. At 24-month follow-up, the MACCE incidence was 34.9% in the OSA group and 5.1% in the non-OSA group (P=0.008, log-rank test). After adjusting for the possible confounding effect of age, gender, coronary intervention indications, hypertension, smoking, and body mass index, OSA remained an independent predictor of MACCEs (adjusted hazard ratio, 6.95; 95% confidence interval, 1.17-41.4; P=0.033).

CONCLUSION

OSA diagnosed in patients treated with percutaneous coronary intervention for ACS by post-discharge sleep studies conducted 2 weeks after percutaneous coronary intervention was independently associated with MACCEs at 24-month follow-up.

Use of an evidence-based protocol to screen for sleep-disordered breathing in a heart failure disease management clinic

Undiagnosed and untreated sleep-disordered breathing can lead to negative health outcomes and increased utilization of health resources among patients with heart failure. The purpose of this evidence-based practice project was to implement and evaluate a new multifaceted sleep-disordered breathing screening protocol in a heart failure disease management clinic. The combined use of a symptoms questionnaire, the Epworth sleepiness scale, and overnight pulse oximetry was significantly more effective in identifying patients with a positive diagnosis of sleep-disordered breathing than using the Epworth sleepiness scale alone (P < .05).

Effects of auto-servo ventilation on patients with sleep-disordered breathing, stable systolic heart failure and concomitant diastolic dysfunction: subanalysis of a randomized controlled trial

BACKGROUND

Systolic heart failure (HF) is frequently accompanied by diastolic dysfunction and sleep-disordered breathing (SDB).

OBJECTIVES

The objective of this subset analysis was to determine effect sizes of auto-servo ventilation (ASV and biphasic positive airway pressure ASV) on echocardiographic measures of diastolic function in patients with systolic HF and SDB.

METHODS

Thirty-two patients with stable systolic HF, concomitant diastolic dysfunction [age 66 ± 9 years old, left ventricular (LV) ejection fraction: 30 ± 7% and New York Heart Association class II: 72%] and SDB (apnea-hypopnea index, AHI: 48 ± 19/h; 53% had predominantly obstructive sleep apnea) receiving either ASV (n = 19) or optimal medical treatment (control, n = 13) were analyzed in a randomized controlled clinical trial. Polysomnographic and echocardiographic measurements were obtained at baseline and after 12 weeks.

RESULTS

AHI significantly improved in the ASV group compared to the control group (-39 ± 18 vs. -0.2 ± 13.2/h, p < 0.001). At baseline, 24 (75%) patients had impaired LV relaxation, and 8 (25%) had a pseudo-normalized filling pattern. At the 12-week control visit, diastolic function assessed by the isovolumetric relaxation time (-10.3 ± 26.1 vs. 9.3 ± 49.1, p = 0.48) and deceleration time (-43.9 ± 88.8 vs. 12.4 ± 68.8, p = 0.40) tended to improve after ASV treatment, but did not reach statistical significance. Likewise, the proportion of patients whose diastolic dysfunction improved was nonsignificantly higher in the ASV than in the control group, respectively (37 vs. 15%, p = 0.25).

CONCLUSIONS

ASV treatment efficiently abolishes SDB in patients with stable systolic HF and concomitant diastolic dysfunction, and was associated with a statistically nonsignificant improvement in measures of diastolic dysfunction. Thus, these data provide estimates of effect size and justify the evaluation of the effects of ASV on diastolic function in larger randomized controlled trials.