Hypoxic burden to guide CPAP treatment allocation in patients with obstructive sleep apnoea: a post hoc study of the ISAACC trial.

BACKGROUND: Hypoxic burden (HB) has emerged as a strong predictor of cardiovascular risk in obstructive sleep apnoea (OSA). We aimed to assess the potential of HB to predict the cardiovascular benefit of treating OSA with continuous positive airway pressure (CPAP). METHODS: This was a post hoc analysis of the ISAACC trial (ClinicalTrials.gov: NCT01335087) including non-sleepy patients with acute coronary syndrome (ACS) diagnosed with OSA (apnoea-hypopnoea index ≥15 events·h-1) by respiratory polygraphy. Patients were randomised to CPAP or usual care and followed for a minimum of 1 year. HB was calculated as the total area under all automatically identified desaturations divided by total sleep time. Patients were categorised as having high or low baseline HB according to the median value (73.1%min·h-1). Multivariable Cox regression models were used to assess whether the effect of CPAP on the incidence of cardiovascular outcomes was dependent on the baseline HB level. RESULTS: The population (362 patients assigned to CPAP and 365 patients assigned to usual care) was middle-aged (mean age 59.7 years), overweight/obese and mostly male (84.5%). A significant interaction was found between the treatment arm and the HB categories. In the high HB group, CPAP treatment was associated with a significant reduction in the incidence of cardiovascular events (HR 0.57, 95% CI 0.34-0.96). In the low HB group, CPAP-treated patients exhibited a trend toward a higher risk of cardiovascular outcomes than those receiving usual care (HR 1.33, 95% CI 0.79-2.25). The differential effect of the treatment depending on the baseline HB level followed a dose-response relationship. CONCLUSION: In non-sleepy ACS patients with OSA, high HB levels were associated with a long-term protective effect of CPAP on cardiovascular prognosis.

Proteomic profiling for prediction of recurrent cardiovascular event in patients with acute coronary syndrome and obstructive sleep apnea: A post-hoc analysis from the ISAACC study.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with a recurrent cardiovascular event (CVE) risk in patients with a first acute coronary syndrome (ACS). However, the pathological pathways by which OSA promotes this deleterious role are unknown. We aim to explore the proteomic profile associated with OSA that promote the recurrent CVE risk in severe OSA patients with ACS without previous cardiovascular diseases. METHODS: This post-hoc analysis from the ISAACC study (NCT01335087) included 86 patients admitted for ACS. Patients underwent respiratory polygraphy for the first 24-72 h to OSA diagnosis. We analyzed of 276 cardiovascular and inflammatory related proteins in baseline fasting plasma samples using proximity expression assay technology (Olink®, Sweden). Protein levels were compared between severe OSA patients with/without recurrent CVEs during follow-up. Random forest was conducted to select relevant proteins and generate a predictive model of recurrent CVE. RESULTS: We included 86 patients (median age: 61 years, median BMI: 29.4 kg/m2 and 86 % males) admitted for ACS with severe OSA (56 without recurrent CVE/30 with recurrent CVE). The plasma levels of 38 proteins were differentially expressed between groups. Additionally, 12 proteins had a significant association with respiratory polygraphy parameters. Three proteins discriminate with an AUC of 0.81 (95 % CI of 0.71-0.9) between severe OSA patients with and without recurrent CVE. These proteins were implicated in cell proliferation, communication and apoptosis, and regulation/response to the inflammatory and immune systems. CONCLUSION: In ACS patients with severe OSA, a proteomic profile was associated with recurrent CVEs. This proteomic profile was correlated with specific OSA parameters from respiratory polygraphy. Proteomic profiling may provide an new direction for patient risk stratification and clinical management.

Respiratory Polygraphy Patterns and Risk of Recurrent Cardiovascular Events in Patients With Acute Coronary Syndrome.

Introduction: Obstructive sleep apnea (OSA) severity is based on the apnea-hypopnea index (AHI). The AHI is a simplistic measure that is inadequate for capturing disease severity and its consequences in cardiovascular diseases (CVDs). Deleterious effects of OSA have been suggested to influence the prognosis of specific endotypes of patients with acute coronary syndrome (ACS). We aim to identify respiratory polygraphy (RP) patterns that contribute to identifying the risk of recurrent cardiovascular events in patients with ACS. Methods: Post hoc analysis of the ISAACC study, including 723 patients admitted for a first ACS (NCT01335087) in which RP was performed. To identify specific RP patterns, a principal component analysis (PCA) was performed using six RP parameters: AHI, oxygen desaturation index, mean and minimum oxygen saturation (SaO2), average duration of events and percentage of time with SaO2 < 90%. An independent HypnoLaus population-based cohort was used to validate the RP components. Results: From the ISAACC study, PCA showed that two RP components accounted for 70% of the variance in the RP data. These components were validated in the HypnoLaus cohort, with two similar RP components that explained 71.3% of the variance in the RP data. The first component (component 1) was mainly characterized by low mean SaO2 and obstructive respiratory events with severe desaturation, and the second component (component 2) was characterized by high mean SaO2 and long-duration obstructive respiratory events without severe desaturation. In the ISAACC cohort, component 2 was associated with an increased risk of recurrent cardiovascular events in the third tertile with an adjusted hazard ratio (95% CI) of 2.44 (1.07 to 5.56; p-value = 0.03) compared to first tertile. For component 1, no significant association was found for the risk of recurrent cardiovascular events. Conclusion: A RP component, mainly characterized by intermittent hypoxemia, is associated with a high risk of recurrent cardiovascular events in patients without previous CVD who have suffered a first ACS.

Long-Term Effect of Obstructive Sleep Apnea and Continuous Positive Airway Pressure Treatment on Blood Pressure in Patients with Acute Coronary Syndrome: A Clinical Trial.

Rationale: Obstructive sleep apnea (OSA) is prevalent in patients with acute coronary syndrome (ACS) and is a cause of secondary hypertension. Objectives: To explore the long-term effects of OSA and continuous positive airway pressure (CPAP) treatment on blood pressure (BP) in patients with ACS. Methods: Post hoc analysis of the ISAACC study (Continuous Positive Airway Pressure in Patients with Acute Coronary Syndrome and Obstructive Sleep Apnea; NCT01335087) included 1,803 patients admitted for ACS. Patients with OSA (apnea-hypopnea index [AHI], ⩾15 events/h) were randomly assigned to receive either CPAP or usual care and were seen in follow-up for 1-5 years. Office BP was determined at each visit. Results: We included 596 patients without OSA, 978 patients in the usual care or poor CPAP adherence group, and 229 patients in the good CPAP adherence group. At baseline, 52% of the patients were diagnosed with hypertension. Median (25th to 75th percentile) age and body mass index were 59 (52.0 to 67.0) years and 28.2 (25.6 to 31.2) kg/m2, respectively. After a median (25th to 75th percentile) follow-up of 41.2 (18.3 to 59.6) months, BP changes were similar in the OSA and non-OSA groups. However, we observed an increase in BP in the third tertile of the AHI (AHI, >40 events/h), with a maximum difference in mean BP of +3.3 mm Hg at 30 months. Patients with OSA with good CPAP adherence (⩾4 h/night) reduced mean BP after 18 months compared with patients with usual care/poor CPAP adherence, with a maximum mean difference (95% confidence interval) of -4.7 (-6.7 to -2.7) mm Hg. In patients with severe OSA, we observed a maximum mean difference of -7.1 (-10.3 to -3.8) mm Hg. Conclusions: In patients with ACS, severe OSA is associated with a long-term increase in BP, which is reduced by good CPAP adherence. Clinical trial registered with www.clinicaltrials.gov (NCT01335087).

Impact of Obstructive Sleep Apnea on Gestational Diabetes Mellitus.

INTRODUCTION: Obstructive sleep apnea (OSA) increases the risk of type 2 diabetes, and hyperinsulinemia. Pregnancy increases the risk of OSA; however, the relationship between OSA and gestational diabetes mellitus (GDM) is unclear. We aimed (1) to evaluate OSA prevalence in GDM patients; (2) to assess the association between OSA and GDM; and (3) to determine the relationships between sleep parameters with insulin resistance (IR). METHODS: A total of 177 consecutive women (89 with GDM, 88 controls) in the third trimester of pregnancy underwent a hospital polysomnography. OSA was defined when the apnea-hypopnea index (AHI) was ≥5h-1. RESULTS: Patients with GDM had higher pregestational body mass index (BMI) and neck circumference than controls, but no differences in snoring or OSA-symptoms, or AHI (3.2±6.0 vs. 1.9±2.7h-1, p=.069). OSA prevalence was not significantly different in both groups. We did not identify OSA as a GDM risk factor in the crude analysis 1.65 (95%CI: 0.73-3.77; p=.232). Multiple regression showed that total sleep time (TST), TST spent with oxygen saturation<90% (T90), and maximum duration of respiratory events as independent factors related with homeostasis model assessment of IR, while T90 was the only independent determinant of quantitative insulin sensitivity check index. CONCLUSION: OSA prevalence during the third trimester of pregnancy was not significantly different in patients with GDM than without GDM, and no associations between OSA and GDM determinants were found. We identified T90 and obstructive respiratory events length positive-related to IR, while TST showed an inverse relationship with IR in pregnant women.

Vitamin D as a biomarker of health in snoring children: a familial aggregation study.

BACKGROUND: Hypovitaminosis D is a common health problem. The purpose of this study was to investigate the inter-relationship between serum 25(OH)D levels and paternal and maternal vitamin D status in a sample of snoring children. METHODS: We selected 137 participants for whom serum 25(OH)D had been measured and underwent overnight polysomnography evaluation. Serum glucose, lipids, liver enzymes, parathyroid hormone, insulin, and glycated hemoglobin were also measured. Glucose and insulin levels were used to estimate insulin resistance with the homeostasis model assessment (HOMA-IR). RESULTS: Vitamin D insufficiency (<30 ng/mL) and deficiency (<20 ng/mL) were found in 40.9 and 17.5% of children, respectively. After adjustments for age, BMI z-score and seasonality, the odds ratio for risk of vitamin D insufficiency according to the vitamin D status of parents were: OR (95% CI): paternal insufficiency 15.1 (2.7-35.7), p = 0.002; maternal insufficiency 7.2 (2.4-22), p = 0.001. When children with vitamin D deficiency were analyzed separately, serum 25(OH)D concentration was found to be associated with the apnea-hypopnea index (r = -0.647, p = 0.009) and respiratory arousal index (r = -0.669, p = 0.034). CONCLUSIONS: Family patterns of vitamin D could be helpful for the early identification of children at risk of metabolic and/or sleep disturbances and when considering strategies to improve vitamin D status. IMPACT: Family patterns of vitamin D could be helpful for the early identification of snoring children at risk of metabolic and/or sleep disturbances. Significant associations were found between serum 25-hydroxyvitamin D (25(OH)D) concentrations in children and their parents. An inverse association between 25(OH)D levels and OSA severity was detected in deficient vitamin D children. Children with insufficient and deficient vitamin D status tended to have a worse metabolic profile, so strategies are needed to improve vitamin D status.

Surfactant protein D concentration in a pediatric population with suspected sleep disorder.

Obstructive sleep apnea (OSA) affects between 2% and 4% in children and there is a search for new biomarkers that can be useful both in the diagnosis and in the evolution of the disease. The surfactant protein D (SP-D) is a collection that is part of the innate immune system exerting an anti-inflammatory and antimicrobial effect. Thus, the objective of this study was to evaluate the concentration of SP-D in the suspect OSA pediatric population. A total of 178 children were recruited in this prospective study. Blood samples, sleep parameters, feeding habits, anthropometric, sociodemographic, and family data were collected. Specific biochemical determinations were made, and the plasmatic concentrations of SP-D were measured by enzyme-linked immunosorbent assay. We found no statistical correlation between the SP-D concentration and the apnea-hypopnea index (AHI) from the data. Nevertheless, the changes in SP-D levels could be correlated to a large extent by the arousals that often go along with hypopneas (r = -0.258, p = 0.011 unadjusted; r = -0.258, p = 0.014 adjusted by age and body mass inded [BMI] Z-score). Intermittent hypoxia was correlated with C-reactive protein levels (r = 0.547, p < 0.001 unadjusted; r = 0.542, p < 0.001 adjusted by age and BMI Z-score). Although AHI and SP-D did not appear to correlate, a secondary analysis suggests that sleep fragmentation, which is produced by arousals, may do, and further research is needed to determine the mechanisms by which changes in SP-D occur in OSA.

Impact of Obstructive Sleep Apnea on Gestational Diabetes Mellitus.

INTRODUCTION: Obstructive sleep apnea (OSA) increases the risk of type 2 diabetes, and hyperinsulinemia. Pregnancy increases the risk of OSA; however, the relationship between OSA and gestational diabetes mellitus (GDM) is unclear. We aimed (1) to evaluate OSA prevalence in GDM patients; (2) to assess the association between OSA and GDM; and (3) to determine the relationships between sleep parameters with insulin resistance (IR). METHODS: A total of 177 consecutive women (89 with GDM, 88 controls) in the third trimester of pregnancy underwent a hospital polysomnography. OSA was defined when the apnea-hypopnea index (AHI) was ≥5h-1. RESULTS: Patients with GDM had higher pregestational body mass index (BMI) and neck circumference than controls, but no differences in snoring or OSA-symptoms, or AHI (3.2±6.0 vs. 1.9±2.7h-1, p=.069). OSA prevalence was not significantly different in both groups. We did not identify OSA as a GDM risk factor in the crude analysis 1.65 (95%CI: 0.73-3.77; p=.232). Multiple regression showed that total sleep time (TST), TST spent with oxygen saturation<90% (T90), and maximum duration of respiratory events as independent factors related with homeostasis model assessment of IR, while T90 was the only independent determinant of quantitative insulin sensitivity check index. CONCLUSION: OSA prevalence during the third trimester of pregnancy was not significantly different in patients with GDM than without GDM, and no associations between OSA and GDM determinants were found. We identified T90 and obstructive respiratory events length positive-related to IR, while TST showed an inverse relationship with IR in pregnant women.

Polysomnographic Characteristics of Snoring Children: A Familial Study of Obstructive Sleep Apnea Syndrome.

BACKGROUND AND OBJECTIVES: Available evidence suggests a familial basis for OSA. The aim of the present study was to assess the potential influences of parental OSA in predicting the diagnosis and severity of OSA in snoring children. METHODS: Observational study, we prospectively enrolled 84 children and their parents. A complete nocturnal polysomnography was performed. Children were categorized into 3 severity groups according to the apnea-hypopnea index (AHI<1h-1, AHI≥1h-1 to AHI<5h-1, and AHI≥5h-1). Adults were grouped according two criteria (AHI≥5h-1 and ≥10h-1). RESULTS: There were no significant differences in age, gender, BMI and BMI z-score among groups. Among the children, 54.7% had an AHI≥1h-1 and 21.4% had an AHI≥5h-1. Overall, we observed that 60.7% of fathers and 23.8% of mothers of our population had OSA (AHI≥5h-1). The prevalence of fathers with OSA increases with the children's severity (83% in the group of children with moderate-severe OSA, p=0.035). The odds of having moderate-severe pediatric OSA (AHI≥5h-1) were more than 4 times higher among children with a father with AHI≥5h-1 (OR: 4.92, 95% CI: 1.27-19.06; p=0.021). There was no evidence of any maternal influence on OSA severity among the children studied. CONCLUSIONS: Our findings suggest a high prevalence of OSA among the family members studied with an increased association of childhood OSA with paternal OSA. Prediction of OSA risk among children can be significantly improved by adding data on paternal OSA status.

Long-term Effect of CPAP Treatment on Cardiovascular Events in Patients With Resistant Hypertension and Sleep Apnea. Data From the HIPARCO-2 Study.

BACKGROUND: There is some controversy about the effect of continuous positive airway pressure (CPAP) on the incidence of cardiovascular events (CVE). However, the incidence of CVE among patients with both obstructive sleep apnea (OSA) ans resistant hypertension (HR) has not been evaluated. Our objective was to analyze the long-term effect of CPAP treatment in patients with RH and OSA on the incidence of CVE. METHODS: Multi-center, observational and prospective study of patients with moderate-severe OSA and RH. All the patients were followed up every 3-6 months and the CVE incidence was measured. Patients adherent to CPAP (at least 4h/day) were compared with those with not adherent or those who had not been prescribed CPAP. RESULTS: Valid data were obtained from 163 patients with 64 CVE incidents. Treatment with CPAP was offered to 82%. After 58 months of follow-up, 58.3% of patients were adherent to CPAP. Patients not adherent to CPAP presented a non-significant increase in the total CVE incidence (HR:1.6; 95%CI: 0.96-2.7; p=0.07). A sensitivity analysis showed that patients not adherent to CPAP had a significant increase in the incidence of cerebrovascular events (HR: 3.1; CI95%: 1.07-15.1; p=0.041) and hypertensive crises (HR: 5.1; CI95%: 2.2-11.6; p=0.006), but the trend went in the opposite direction with respect to coronary events (HR: 0.22; CI95%: 0.05-1.02; p=0.053). CONCLUSIONS: In patients with RH and moderate-severe OSA, an uneffective treatment with CPAP showed a trend toward an increase in the incidence of CVE (particularly neurovascular events and hypertensive crises) without any changes with respect to coronary events.

The HIPARCO-2 study: long-term effect of continuous positive airway pressure on blood pressure in patients with resistant hypertension: a multicenter prospective study.

INTRODUCTION: Short-term treatment with continuous positive airway pressure (CPAP) produces a clinically significant reduction in blood pressure (BP) in patients with obstructive sleep apnea (OSA) and resistant hypertension. However, it is unknown whether this effect continues over the long-term. Our objective was to assess the effect of long-term CPAP on BP in patients with OSA and resistant hypertension. METHODS: The study included 161 patients diagnosed with both OSA [apnea--hypopnea index (AHI) ≥15] and resistant hypertension diagnosed via 24-hour ambulatory BP measurement (24-h ABPM), in whom a second analysis via 24-h ABPM was performed at the end of the follow-up. RESULTS: Patients were followed up within 59 months [interquartile range (IQR): 44-70]. CPAP treatment was prescribed to 82% of the patients (70% with good adherence to CPAP defined as use of CPAP at least 4 h/night). A comparison between the adherent group and nonadherent group (including those with CPAP not prescribed) showed that CPAP adherents had a significant drop in the 24-h BP, both systolic [-3.9 mmHg; 95% confidence interval (CI): -8.1 to 0.3] and diastolic pressure (-3.5 mmHg [95% [CI]: -6.4-0.5]), with a higher magnitude during the night (-5.5 and -4.9 mmHg, respectively). The CPAP adherent group needed a mean of 1.1 less antihypertensive drugs (particularly spironolactone). Finally, there was a positive correlation between the drop in 24-h SBP and the hours of CPAP use (r = 0.24; P = 0.01). CONCLUSION: Good adherence to long-term CPAP treatment largely succeeded in significantly reducing BP in those patients with OSA and resistant hypertension, despite the use of a lower number of antihypertensive drugs.

The Effect of Sleep Apnea on Cardiovascular Events in Different Acute Coronary Syndrome Phenotypes.

Rationale: Obstructive sleep apnea (OSA) is associated with increased cardiovascular disease (CVD) risk. Conversely, OSA has not been shown to increase recurrent cardiovascular events in patients with acute coronary syndrome (ACS). This lack of homogeneity could suggest that the deleterious effect of OSA and its contribution to CVD could depend on specific patient profiles.Objectives: To evaluate the effect of OSA on cardiovascular risk for patients with different ACS phenotypes.Methods:Post hoc analysis of the ISAACC (Continuous Positive Airway Pressure in Patients with ACS and OSA) study, including 1,701 patients admitted for ACS (NCT01335087). To evaluate the presence of OSA (apnea-hypopnea index ≥ 15 events · h-1), all patients underwent polygraphy. Patients were followed up for a minimum period of 1 year. We performed nonsupervised clustering using latent class analysis to identify subgroups of patients on the basis of 12 clinical factors associated with cardiovascular risk. The effect of OSA on recurrent cardiovascular event risk was evaluated for each phenotype identified.Measurements and Main Results: Two phenotypes were identified: patients without previous heart disease and without previous ACS ("no-previous-CVD" phenotype; 81%) and patients with previous heart disease and previous ACS ("previous-CVD" phenotype; 19%). The median (interquartile range) at follow-up was 2.67 (3.8) years. For the no-previous-CVD phenotype, the effect of OSA showed an adjusted hazard ratio (95% confidence interval) of 1.54 (1.06-2.24; P value = 0.02), whereas for the previous-CVD phenotype, the effect of OSA showed an adjusted hazard ratio of 0.69 (0.46-1.04; P value = 0.08).Conclusions: For patients with ACS and a specific phenotype, OSA is associated with an increased risk of recurrent cardiovascular events. These patients are mainly characterized by no previous heart disease and admission for a first ACS occurrence.

Obstructive sleep apnea is associated with worse clinical-radiological risk scores of pulmonary embolism.

Obstructive sleep apnea is a risk factor for pulmonary embolism, although its association with pulmonary embolism severity is unknown. Our objective was to study if obstructive sleep apnea is associated with worse pulmonary embolism severity scores and greater extent of arterial obstruction. In consecutive pulmonary embolism patients, we performed respiratory polygraphy and recorded sleep characteristics, classical risk factors for pulmonary embolism and physical activity 6-12 months after the pulmonary embolism episode. Simplified Geneva Prognostic Score and Pulmonary Embolism Severity Index were calculated at the time of the pulmonary embolism diagnosis. The Pulmonary Artery Obstruction Index and the right ventricle to left ventricle diameter ratio were measured by computed tomography pulmonary angiography. We included 120 patients, of whom 45.8% had moderate-severe obstructive sleep apnea (apnea-hypopnea index > 15 hr-1 ). There was a larger proportion of moderate-severe obstructive sleep apnea patients in the third and fourth Pulmonary Artery Obstruction Index quartiles and in the III-V Pulmonary Embolism Severity Index levels compared with apnea-hypopnea index < 15 hr-1 group. However, no differences were found between the proportion of patients with or without moderate-severe obstructive sleep apnea in their stratification by simplified Geneva Prognostic Score. The mean adjusted values of the simplified Geneva Prognostic Score, Pulmonary Embolism Severity Index and Pulmonary Artery Obstruction Index scores were higher in the apnea-hypopnea index > 15 hr-1 group (p < .05). Multiple linear regression analysis identified apnea-hypopnea index as the only independent factor related to Pulmonary Artery Obstruction Index and Pulmonary Embolism Severity Index, whereas desaturation index was associated with simplified Geneva Prognostic Score. Patients with pulmonary embolism and moderate-severe obstructive sleep apnea had greater pulmonary artery obstruction as well as more pulmonary embolism severity, assessed by both the simplified Geneva Prognostic Score and the Pulmonary Embolism Severity Index, compared with patients with apnea-hypopnea index ≤ 15 hr-1 . Moreover, these prognostic indices were independently related to sleep parameters.

Effect of obstructive sleep apnoea and its treatment with continuous positive airway pressure on the prevalence of cardiovascular events in patients with acute coronary syndrome (ISAACC study): a randomised controlled trial.

BACKGROUND: Despite the improvement in the prognosis of acute coronary syndrome (ACS), substantial morbidity and mortality remain. We aimed to evaluate the effect of obstructive sleep apnoea (OSA) and its treatment with continuous positive airway pressure (CPAP) on the clinical evolution of patients with ACS. METHODS: We designed a multicentre, open-label, parallel-group, randomised controlled trial of patients with ACS at 15 hospitals in Spain. Eligible non-sleepy patients were men and women aged 18 years and older, admitted to hospital for documented symptoms of ACS. All patients underwent respiratory polygraphy during the first 24-72 h after admission. OSA patients were randomly assigned (1:1) to CPAP treatment plus usual care (CPAP group) or usual care alone (UC group) by a computerised system available 24 h a day. A group of patients with ACS but without OSA was also included as a reference group. Because of the nature of the intervention, the trial intervention could not be masked to either investigators or patients. Patients were monitored and followed for a minimum of 1 year. Patients were examined at the time of inclusion; after 1 month, 3 months, 6 months, 12 months, 18 months, 24 months, 30 months, and 36 months; and every 12 months thereafter, if applicable, during the follow-up period. The primary endpoint was the prevalence of a composite of cardiovascular events (cardiovascular death or non-fatal events [Acute myocardial infarction, non-fatal stroke, hospital admission for heart failure, and new hospitalisations for unstable angina or transient ischaemic attack]) in patients followed up for a minimum of 1 year. The primary analysis was done according to the intention-to-treat principle. This study is registered with Clinicaltrials.gov, NCT01335087 and is now closed. FINDINGS: Between April 25, 2011, and Feb 2, 2018, a total of 2834 patients with ACS had respiratory polygraphy, of whom 2551 (90·01%) were recruited. 1264 (49·55%) patients had OSA and were randomly assigned to the CPAP group (n=633) or the UC group (n=631). 1287 (50·45%) patients did not have OSA, of whom 603 (46·85%) were randomly assigned to the reference group. Patients were followed up for a median of 3·35 years (IQR 1·50-5·31). The prevalence of cardiovascular events was similar in the CPAP and UC groups (98 events [16%] vs 108 events [17%]; hazard ratio [HR] 0·89 [95% CI 0·68-1·17]; p=0·40) during follow-up. Mean time of adherence to CPAP treatment was 2·78 h/night (SD 2·73). The prevalence of cardiovascular events was similar between patients in the reference group (90 [15%] events) and those in the UC group (102 (17%) events) during follow-up (1·01 [0·76-1·35]; p=0·93). The prevalence of cardiovascular events seem not to be related to CPAP compliance or OSA severity. 464 (74%) of 629 patients in the CPAP group had 1538 serious adverse events and 406 (65%) of 626 patients in the UC group had 1764 serious adverse events. INTERPRETATION: Among non-sleepy patients with ACS, the presence of OSA was not associated with an increased prevalence of cardiovascular events and treatment with CPAP did not significantly reduce this prevalence. FUNDING: ResMed (Australia), Fondo de Investigación Sanitaria (Fondo Europeo de Desarrollo Regional), the Spanish Respiratory Society, the Catalonian Cardiology Society, Esteve-Teijin, Oxigen Salud, and ALLER.

Factors associated with the changes from a resistant to a refractory phenotype in hypertensive patients: a Pragmatic Longitudinal Study.

Refractory hypertension (RfH) is defined as a lack of blood pressure control despite the administration of at least 5 anti-hypertensive drugs. The factors associated with its natural history are unknown. This study aimed to evaluate both the incidence of RfH in an cohort of patients with resistant hypertension (RH) and the factors involved in that progression. This was an observational prospective multicenter study (24 centers) with 172 patients with confirmed RH (24-h ABPM) who underwent a further 24 h ABPM study at the end of the follow-up. Prospective information was obtained from all patients in their corresponding Hypertension Units via a standard clinical protocol, and they all underwent a sleep study. Thirty patients were diagnosed with RfH (17.4%) after a mean follow-up of 57 months, despite the prescription of a greater number of long-acting thiazide-like diuretics and mineralocorticoid receptor antagonists. The factors associated with progression to RfH were: a longer period since the diagnosis of RH (OR: 1.06, 95% CI: 1.01-1.1, p = 0.007); the HbA1c concentration (OR: 1.42, 95% CI: 1.42-1.8; p = 0.005); the initial heart rate (OR: 1.05, 95% CI: 1.01-1.09, p = 0.004); and poor adherence to continuous positive airway pressure (CPAP) in cases of obstructive sleep apnea (OR: 3.36, 95% CI: 1.47-7.7, p = 0.004). In conclusion, a considerable percentage of patients evolved from the RH to the RfH phenotype despite changes in their treatment. Some easily measurable variables, such as heart rate, the time since the diagnosis, the HbA1c level, and the presence of untreated obstructive sleep apnea (or poor adherence to CPAP) have been demonstrated to be prognostic factors in the progression to RfH.

Biomarker panel in sleep apnea patients after an acute coronary event.

BACKGROUND: Acute coronary syndrome (ACS) is a major cause of death and closely related with obstructive sleep apnea (OSA). Our hypothesis is that several cardiovascular-related biomarkers could have a differential prognostic value for ACS severity in patients with OSA, and could also help (individually or combined) in the detection of OSA in patients after a coronary event. METHODS: Up to 361 consecutive individuals admitted due to ACS were included in the study. All of them were evaluated for ACS severity (Killip score, number of diseased vessels, ejection fraction) and further classified as OSA or non-OSA. Medical records were registered and eleven blood biomarkers were measured, including heart-type fatty acid-binding globulin, N-terminal pro-brain natriuretic peptide, matrix metalloproteinase-9 (MMP9), placental growth factor (PlGF) and high-sensitivity C-reactive protein. Odds ratios of every biomarker for ACS severity-related parameters were calculated and adjusted for age, gender, body-mass index (BMI), hypertension, diabetes, smoking and drinking. The use of clinical measures and biomarkers for the diagnosis of OSA in ACS patients was evaluated both alone and combined using ROC curves. RESULTS: Several biomarkers showed a significant association with ACS severity, which remained after adjusting for OSA and other potentially confounding variables. The mathematical combination of age, BMI, PlGF and MMP9 showed an area under the ROC curve (AUC) for OSA identification of 0.741, which was greater than any individual parameter or combination assessed: AUC(BMI):0.687, AUC(age):0.576, AUC(PlGF):0.584, AUC(MMP9):0.555. CONCLUSIONS: The usefulness of biomarkers in the assessment of ACS severity was independent of OSA and the other variables evaluated. In patients admitted after a coronary event, the combination of clinical measures and biomarkers showed a significant discriminating power for the detection of OSA. CLINICAL TRIAL REGISTRATION: NCT01335087 (clinicaltrials.gov).

Effect of continuous positive airway pressure in patients with true refractory hypertension and sleep apnea: a post-hoc intention-to-treat analysis of the HIPARCO randomized clinical trial.

RATIONALE: Continuous positive airway pressure (CPAP) can significantly reduce blood pressure (BP) levels in patients with resistant hypertension and sleep apnea (OSA); however, the effect on patients with refractory hypertension (RfH) is not known. This study seeks to evaluate the effect of CPAP treatment on BP levels in patients with OSA and RfH, compared with those with OSA and resistant hypertension. METHODS: Post-hoc analysis of the HIPARCO randomized clinical trial on the effect of CPAP treatment on BP levels in patients with resistant hypertension. Those patients with uncontrolled 24-h ambulatory BP monitoring readings (>130 and/or >80 mmHg) in SBP or DBP were considered to have resistant hypertension (if they were taking three or four antihypertensive drugs) or RfH (if they were taking at least five drugs). OSA patients were randomized to receive CPAP or usual care for 3 months. They underwent a second 24-h ambulatory BP monitoring study to establish the effect of CPAP treatment on BP levels in both groups. RESULTS: A total of 98 patients were randomized to CPAP (19 RfH/79 resistant hypertension) and 96 to usual care (21 RfH/75 resistant hypertension). BP readings dropped more marked in patients with RfH than resistant hypertension, in both 24-h SBP (-9 vs. -1.6 mmHg, P = 0.021) and 24-h DBP (-7.3 vs. -2.3 mmHg, P = 0.074), especially at night (-11.3 vs. -3.8, P = 0.121 and -8.8 vs. -2.2, P = 0.054) respectively. Adjusted difference between groups was statistically significant in 24-h SBP levels (-7.4 mmHg, P = 0.021). CONCLUSION: CPAP lowers BP levels in both resistant hypertension and RfH patients although the degree of this reduction is higher in those with RfH especially during the night.

Good long-term adherence to continuous positive airway pressure therapy in patients with resistant hypertension and sleep apnea.

Although adequate adherence is paramount in achieving the beneficial effects of continuous positive airway pressure therapy in patients with obstructive sleep apnea, long-term adherence and the variables involved in continuous positive airway pressure compliance in patients with resistant hypertension and obstructive sleep apnea are yet unknown. We conducted a prospective, multicentre, observational study in 177 patients recruited from hypertensive units with resistant hypertension confirmed by means of 24-hr blood pressure monitoring (blood pressure ≥ 130 and/or ≥ 80 mmHg, despite taking at least three antihypertensive drugs or < 130/80 mmHg with > 3 drugs) and obstructive sleep apnea (apnea-hypopnea index ≥ 5 in a respiratory polygraph) who were prescribed continuous positive airway pressure treatment. Good adherence was defined as an average cumulative continuous positive airway pressure use of ≥ 4 hr per night at the end of the follow-up. A multivariate Cox regression analysis was performed to identify independent predictors of continuous positive airway pressure adherence. Patients were followed for a median of 57.6 (42-72) months after initiating continuous positive airway pressure therapy. At the end of the follow-up, the median continuous positive airway pressure use was 5.7 (inter-quartile range 3.9-6.6) hr per night, and 132 patients (74.5%) showed good continuous positive airway pressure adherence. The only baseline variable associated with poor adherence was the presence of previous stroke (hazard ratio 4.00, 95% confidence interval 1.92-8.31). Adequate adherence at 1 month also predicted good adherence at the end of the follow-up (hazard ratio 14.4, 95% confidence interval 4.94-56). Both variables also predicted adherence at a threshold of 6 hr per night. Our results show that good continuous positive airway pressure adherence is an achievable and feasible goal in patients with resistant hypertension and obstructive sleep apnea. Previous stroke and short-term adherence predicted long-term adherence.

Beyond Resistant Hypertension.

Obstructive sleep apnea (OSA) is an independent cause of resistant hypertension (RH) but its association with refractory hypertension (RfH), a recently described form of severe hypertension, has not yet been investigated. This study seeks to analyze the association between the presence and severity of OSA/OSA syndrome with RfH and to compare it with a group of patients with OSA/OSA syndrome and RH. We conducted a multicenter, cross-sectional study of consecutive patients diagnosed with RH by means of 24-hour ambulatory blood pressure monitoring. Those patients with blood pressure levels ≥130/80 mm Hg, despite taking at least 5 antihypertensive drugs, were considered to have true RfH. All patients underwent a sleep study and completed a detailed clinical history related to OSA, current medication, and cardiovascular diseases. Overall, 229 patients were included (mean age, 58.3 years; 63% male), of whom 42 (18.3%) satisfied the criteria for RfH. Compared with those with RH, patients with RfH had a higher cardiovascular risk profile, higher blood pressure measurements, and a 2-fold greater risk of having both severe OSA (odds ratio, 2.1, with a prevalence of apnea-hypopnea index ≥15, 95.2% and apnea-hypopnea index ≥30, 64.3%) and OSA syndrome (apnea-hypopnea index ≥5+Epworth Sleepiness Scale >10; odds ratio, 1.9; 52.4% versus 37.3%; P=0.023), as well as higher OSA severity (apnea-hypopnea index, 41.8 versus 33.8 events/h; P=0.026). Patients with RfH had an even greater prevalence and severity of OSA and OSA syndrome than RH patients, highlighting the need to identify these patients to refer them to sleep units on a preferential basis.

Circulating branched-chain amino acids in children with obstructive sleep apnea.

INTRODUCTION: The effects of obstructive sleep apnea (OSA) on the metabolic system are not well understood, especially in children. Recent studies have provided evidence of the modulation of insulin action by branched-chain amino acids (BCAAs) and suggested novel mechanistic relationships between glucose and amino acid metabolic pathways. We hypothesized that plasma BCAA levels may serve as biomarkers of insulin resistance and metabolic dysfunction in children with OSA. METHODS: A polysomnography was conducted for the diagnosis of OSA in 90 snoring children, in a tertiary hospital. Anthropometric and clinical data were measured and venous blood samples were collected for the measurement of plasma glucose, insulin, HbA1c, and amino acids. RESULTS: Children with OSA had significantly higher levels of BCAAs (leucine, isoleucine, and total BCAAs) compared with those without OSA (P = 0.024). A positive significant correlation was observed between insulin levels and both leucine and isoleucine (r = 0.232; P < 0.05). On multivariate regression analyses, the presence of OSA was significantly associated with leucine, isoleucine, and total BCAA concentrations (P = 0.028), whereas the arousal index was associated with leucine, valine, and total BCAA levels (P = 0.037). CONCLUSIONS: The presence of OSA and sleep fragmentation may induce changes in branched-chain amino acid metabolism in snoring children, independently of obesity. These data may suggest a new mechanism linking OSA and glucose homeostasis.