Cardiorespiratory Sleep Study Research Articles

Is there room for in-hospital cardiorespiratory polygraphy sleep studies in children? – A real life practice

Is there room for in-hospital cardiorespiratory polygraphy sleep studies in children? – A real life practice

Sleep-related breathing disorders in patients with heart failure with reduced and mildly reduced ejection fraction: main types and their dependence on heart failure etiology

Aim. To identify and study the nature of sleep-related breathing disorders (SBDs) in a cohort of hospitalized patients with heart failure (HF) with reduced and mildly reduced ejection fraction (EF), as well as to clarify the relationship between SBD type, etiology and severity of HF.Material and methods. The study included 117 patients with HF with reduced and mildly reduced ejection fraction hospitalized at the National Medical Research Center for Therapy and Preventive Medicine from 2019 to 2021. All patients underwent clinical and paraclinical examination, including cardiorespiratory sleep study. Patients were divided into three groups according to the type and severity of SBD: no or mild SBD, predominantly with obstructive sleep apnea (OSA) and predominantly with central sleep apnea (CSA). Severity of SBD and clinical data were compared between these groups.Results. A total of 5 patients (4,27%) did not have any SBDs, while 47 (40,17%) were diagnosed with CSA, and 65 (55,56%) — OSA of varying severity. The proportions of patients with moderate and severe CSA and OSA differed insignificantly and amounted to 35,9% (n=42) and 44,4% (n=52), respectively. There were following proportions of diseases related to HF: coronary artery disease (41,88%), nonischemic cardiomyopathy (26,5%), arrhythmogenic cardiomyopathy (15,38%) and other causes (16,24%) (hypertension, myocarditis, heart defects). We found that reduced EF <40%, end-diastolic volume >210 ml, and ventricular ectopy (>300 extrasystoles/day) were associated with CSA, and body mass index >30 kg/m2 was traditionally associated with OSA.Conclusion. More than half of HF patients with reduced and mildly reduced EF have SBDs. Decreased LVEF and ventricular ectopic activity are associated with CSA, while increased body mass index is associated with OSA. Consideration of SBD risk factors may improve patient phenotyping for individualized therapy.

The role of 3D speckle tracking echocardiography in the diagnosis of obstructive sleep apnea and its severity

There is a consistent relationship between obstructive sleep apnea (OSA) and cardiovascular diseases. It is already recognized that OSA may influence the geometry and function of the right ventricle (RV). This has encouraged the development of echocardiographic evaluation for screening of OSA and its severity. Three-dimensional speckle tracking echocardiography (3D STE) is in assumption better, compared with 2D STE, because it overcomes the standard 2D echo limitations. Thus, the purpose of our study is to evaluate whether 3D STE measurements, could predict the positive diagnosis and severity of OSA. We enrolled 69 patients with OSA and 37 healthy volunteers who underwent a cardiorespiratory sleep study. 2DE was performed in all patients. RVEF and 3D RVGLS were measured by 3DSTE. NT pro BNP plasma level was also assessed in all participants. 3D RV GLS (− 13.5% vs. − 22.3%, p < 0.001) and 3D RVEF (31.9% vs. 50%, p < 0.001) were reduced in patients with OSA, compared with normal individuals. 3D Strain parameters showed better correlation to standard 2D variables, than 3D RVEF. Except for NT pro BNP (p = 0.059), all parameters served to distinguish between severe and mild-moderate cases of OSA. 3D STE may be a reliable and accurate method for predicting OSA. Consequently, 3D RV GLS is a good tool of assessing the RV global function in OSA, because it correlates well with other established measurements of RV systolic function. Furthermore, 3D RV GLS was a precise parameter in identifying severe cases of OSA, while NT pro BNP showed no association.

Cardiopulmonary exercise testing in patients with moderate-severe obesity: a clinical evaluation tool for OSA?

PurposeObstructive sleep apnea (OSA) is a widespread comorbidity of obesity. Nasal continuous positive airway pressure (CPAP) has been demonstrated very effective in treating patients with OSA. The aims of this study were to investigate whether or not cardiopulmonary exercise testing (CPET) can characterize patients with OSA and to evaluate the effect of nasal CPAP therapy.MethodsAn observational study was conducted on patients with moderate to severe obesity and suspected OSA. All patients underwent cardiorespiratory sleep study, spirometry, and functional evaluation with ECG-monitored, incremental, maximal CPET.ResultsOf the 147 patients, 94 presented with an apnea–hypopnea index (AHI) ≥ 15 events/h and were thus considered to have OSA (52 receiving nasal CPAP treatment; 42 untreated) while 53 formed a control group (AHI < 15 events/h). Patients with untreated OSA showed significantly lower oxygen uptake (VO2), heart rate, minute ventilation (VE), and end tidal carbon dioxide (PETCO2) at peak exercise compared to controls. Patients receiving nasal CPAP showed higher VE and VO2 at peak exercise compared to untreated patients. A difference in PETCO2 between the maximum value reached during test and peak exercise (ΔPETCO2 max-peak) of 1.71 mmHg was identified as a predictor of OSA.ConclusionPatients with moderate to severe obesity and untreated OSA presented a distinctive CPET-pattern characterized by lower aerobic and exercise capacity, higher PETCO2 at peak exercise associated with a lower ventilatory response. Nasal CPAP treatment was shown to positively affect these cardiorespiratory adaptations during exercise. ΔPETCO2 max-peak may be used to suggest OSA in patients with obesity.

Psychometric Properties and Predictive Value of a Screening Questionnaire for Obstructive Sleep Apnea in Young Children With Down Syndrome.

Study ObjectivesObstructive sleep apnea (OSA) is common in children with Down syndrome (DS) and is associated with adverse health and cognitive outcomes. Daytime clinical assessment is poorly predictive of OSA, so regular screening with sleep studies is recommended. However, sleep studies are costly and not available to all children worldwide. We aimed to evaluate the psychometric properties and predictive value of a newly developed screening questionnaire for OSA in this population.Methods202 children aged 6 months to 6th birthday with DS were recruited, of whom 188 completed cardio-respiratory sleep studies to generate an obstructive apnea hypopnea index (OAHI). Parents completed the 14-item Down syndrome OSA screening questionnaire. Responses were screened, a factor analysis undertaken, internal consistency calculated and receiver operator characteristic (ROC) curves drawn to generate an area under the curve (AUC) to assess criterion related validity.ResultsOf 188 children who completed cardiorespiratory sleep studies; parents completed the screening questionnaire for 186. Of this study population 15.4% had moderate to severe OSA defined by an OAHI of ≥5/h. Sixty-three (33.9%) participants were excluded due to “unsure” responses or where questions were not answered. Using the remaining 123 questionnaires a four-factor solution was found, with the 1st factor representing breathing related symptoms, explaining a high proportion of the variance. Internal consistency was acceptable with a Cronbach alpha of 0.87. ROC curves for the total score generated an AUC statistic of 0.497 and for the breathing subscale an AUC of 0.603 for moderate to severe OSA.ConclusionA well designed questionnaire with good psychometric properties had limited predictive value to screen for moderate to severe OSA in young children with DS. The use of a screening questionnaire is not recommended. Screening for OSA in this population requires objective sleep study measures.

Effects of acute exposure to moderate altitude on blood pressure and sleep breathing patterns

BackgroundAcute exposure to high altitude (>2500 m) is known to induce a rise in blood pressure (BP) and the appearance of sleep related breathing alterations, in particular central sleep apneas and periodic breathing. Little information is available on whether this is the case in humans also for acute exposure to moderate altitude (between 1500 and 2500 m). Aim of this study was to evaluate the effects of acute exposure of healthy volunteers to moderate altitude on conventional and ambulatory BP as well as on the frequency and severity of breathing alterations during sleep. MethodsForty-four healthy lowlanders underwent 24-hour ambulatory BP monitoring and nocturnal cardio-respiratory sleep study at sea level and during acute (1–2 days after arrival) exposure to moderate altitude (2035 m, Sestriere, Italy). The key variables investigated included average systolic and diastolic BP and heart rate over daytime, night-time and 24 h, the frequency of obstructive and central apneas/hypopnoeas and the behaviour of oxygen saturation during sleep. ResultsCompared to sea level, during moderate altitude exposure mean systolic/diastolic BP increased significantly during daytime (respectively from 125.6 ± 10.9 to 130.6 ± 12.3, p = 0.0032 and from 78.8 ± 6.7 to 81.8 ± 7.7 mmHg, p = 0.0048) and during night-time (respectively from 102.4 ± 12.4 to 107.4 ± 12.7, p = 0.0028, and from 62.0 ± 8.2 to 65.8 ± 8.2 mmHg, p = 0.0014), with no change in nocturnal BP dipping. BP increase was more evident in participants aged over 40 years. Apnea-hypopnea index (AHI) increased from 1.60 (0.40–2.90) to 5.4 (2.90–10.60), p < 0.0001), mainly because of increasing frequency of hypopneas and central apneas, in particular in males aged over 40 years. No association was found between size of BP changes and AHI. ConclusionOur results indicate that in healthy subjects even exposure to moderate altitude may induce significant, although mild, changes in ambulatory BP and in respiratory patterns during sleep with gender and age-related differences. Further studies are needed to explore the clinical relevance of these findings.

RELATIONSHIP BETWEEN SLEEP BREATHING PATTERNS AND BLOOD PRESSURE CHANGES DURING ACUTE HIGH ALTITUDE EXPOSURE. DATA FROM HIGHCARE STUDIES

Objective: Acute exposure to high/moderate altitude (HMA) induces increase in ambulatory blood pressure (BP), which may be particularly pronounced during the night, leading to reduced nocturnal BP dipping. Occurrence of central sleep apneas (CSA) is also typical for HMA exposure. Aim of this study was to investigate the relationship between variables characterizing respiration during sleep with nocturnal BP in subjects acutely exposed to HMA. Design and method: Aggregate data from several studies performed in the framework of HIGHCARE projects were analysed (HIGHCARE-Himalaya – 5400 m, Alps - 4559 m, Sestriere 2035 m, all in healthy volunteers; Andes – 3260 m, hypertensive subjects). HMA exposure duration ranged between 1 and 15 days. Data of subjects with at least 1 ambulatory BP monitoring at sea level (SL) and HMA (validated oscillometric device) and at least 1 cardio-respiratory sleep study (CSS) were analysed. Study variables included: mean nocturnal systolic(S) and diastolic (D)BP; size of nocturnal BP fall (%), apnea-hypopnea index (AHI), central apnea index (cAI), mean and minimum nocturnal oxygen saturation (SpO2mean and SpO2 min). Mixed linear models adjusting for age, sex, BMI, study, treatment were used to assess the relationship between variables of interest. Results: After excluding participants with incomplete data, 178 subjects were included (52.8% male, age 45.6 ± 11.7, BMI 25.3 ± 4.3). During HMA exposure we observed an increase in nocturnal SBP/DBP by 10.8 ± 12.9 mmHg, a reduction in nocturnal SBP/DBP fall by 2.5 ± 7.9%. Median SpO2mean was 82.6%, SpO2 min 70%, AHI 22.5, cAI 1.1. 82% of participants had AHI > 5. After adjusting for covariates no association was found between changes in nocturnal BP/dipping and AHI or cAI. We observed a direct relationship between SpO2mean and the change in nocturnal SBP fall (β=0.21 [0.04–0.39], p = 0.017). In categorical analysis participants who at HMA became nondippers (SBP fall < 10%) had lower SpO2mean than those who maintained nocturnal dipping (77.9 vs. 84.2%, adjusted p = 0.044). Conclusions: Attenuation of physiological nocturnal BP fall at HMA is associated with the degree of nocturnal hypoxemia but not with the severity of sleep breathing disorders induced by HMA exposure. These results may be relevant in conditions associated with nocturnal hypoxia and/or CSA.

Cardiorespiratory sleep studies at home: experience in research and clinical cohorts

ObjectiveTo evaluate the success rates of home cardiorespiratory polygraphy in children under investigation for sleep-disordered breathing and parent perspectives on equipment use at home.DesignProspective observational study.SettingSheffield, Evelina London and Southampton...

Effect of a 1-week intense myofunctional training on obstructive sleep apnoea in children with Down syndrome

BackgroundObstructive sleep apnoea (OSA) is common in children with Down syndrome (DS), yet difficult to treat. As muscular hypotonia of the upper airway may cause OSA and is also common...

Liver Enlargement Predicts Obstructive Sleep Apnea-Hypopnea Syndrome in Morbidly Obese Women.

Obstructive sleep apnea–hypopnea syndrome (OSAHS) is frequently present in patients with severe obesity, but its prevalence especially in women is not well defined. OSAHS and non-alcoholic fatty liver disease are common conditions, frequently associated in patients with central obesity and metabolic syndrome and are both the result of the accumulation of ectopic fat mass. Identifying predictors of risk of OSAHS may be useful to select the subjects requiring instrumental sleep evaluation. In this cross-sectional study, we have investigated the potential role of hepatic left lobe volume (HLLV) in predicting the presence of OSAHS. OSAHS was quantified by the apnea/hypopnea index (AHI) and oxygen desaturation index in a cardiorespiratory inpatient sleep study of 97 obese women [age: 47 ± 11 years body mass index (BMI): 50 ± 8 kg/m2]. OSAHS was diagnosed when AHI was ≥5. HLLV, subcutaneous and intra-abdominal fat were measured by ultrasound. After adjustment for age and BMI, both HLLV and neck circumference (NC) were independent predictors of AHI. OSAHS was found in 72% of patients; HLLV ≥ 370 cm3 was a predictor of OSAHS with a sensitivity of 66%, a specificity of 70%, a positive and negative predictive values of 85 and 44%, respectively (AUC = 0.67, p < 0.005). A multivariate logistic model was used including age, BMI, NC, and HLLV (the only independent predictors of AHI in a multiple linear regression analyses), and a cut off value for the predicted probability of OSAHS equal to 0.7 provided the best diagnostic results (AUC = 0.79, p < 0.005) in terms of sensitivity (76%), specificity (89%), negative and positive predictive values (59 and 95%, respectively). All patients with severe OSAHS were identified by this prediction model. In conclusion, HLLV, an established index of visceral adiposity, represents an anthropometric parameter closely associated with OSAHS in severely obese women.

Rationale and Design for a Monocentric Prospective Study: Sleep Apnea Diagnosis Using a Novel Pacemaker Algorithm and Link With Aldosterone Plasma Level in Patients Presenting With Diastolic Dysfunction (SAPAAD Study).

Previous studies showed good agreement between pacemaker respiratory disturbance index (RDI) and polysomnography for diagnosis of severe sleep apnea (SA). The aim of this study is to investigate the diagnostic accuracy of RDI compared with apnea-hypopnea index (AHI) from a cardiorespiratory sleep study for the diagnosis of severe SA within patients requiring a pacemaker and meeting diastolic dysfunction criteria. Secondary objectives are as follows: correlation between plasma aldosterone level and SA severity, diagnostic accuracy of RDI for moderate SA, prevalence of SA among patients with diastolic dysfunction, occurrence of arrhythmias, and improvement of RDI with continuous positive airway pressure therapy. We designed a monocentric prospective nonrandomized study of prevalent cases to include 68 patients with a 6-month follow-up. Both RDI and AHI will be compared 2 months after implantation and after 1 month of continuous positive airway pressure treatment in patients with severe SA. This is the first study that examines diagnostic accuracy of pacemaker algorithm for the diagnosis of SA and correlation with plasma aldosterone levels in patients with diastolic dysfunction.Protocol version: V04. 04/04/2017 Trial registration: ClinicalTrials.gov NCT02751021

Comparison of cardiorespiratory sleep study versus polysomnography for the diagnosis and decision to treat of obstructive sleep apnea

Comparison of cardiorespiratory sleep study versus polysomnography for the diagnosis and decision to treat of obstructive sleep apnea

Dysphagia and Obstructive Sleep Apnea in Acute, First-Ever, Ischemic Stroke

Obstructive sleep apnea (OSA) and dysphagia are common in acute stroke and are both associated with increased risk of complications and worse prognosis. The aims of the present study were (1) to evaluate the prevalence of OSA and dysphagia in patients with acute, first-ever, ischemic stroke; (2) to investigate their clinical correlates; and (3) to verify if these conditions are associated in acute ischemic stroke. We enrolled a cohort of 140 consecutive patients with acute-onset (<48 hours), first-ever ischemic stroke. Computed tomography (CT) and magnetic resonance imaging scans confirmed the diagnosis. Neurological deficit was measured using the National Institutes of Health Stroke Scale (NIHSS) by examiners trained and certified in the use of this scale. Patients underwent a clinical evaluation of dysphagia (Gugging Swallowing Screen) and a cardiorespiratory sleep study to evaluate the presence of OSA. There are 72 patients (51.4%) with obstructive sleep apnea (OSA+), and there are 81 patients (57.8%) with dysphagia (Dys+). OSA+ patients were significantly older (P = .046) and had greater body mass index (BMI) (P = .002), neck circumference (P = .001), presence of diabetes (P = .013), and hypertension (P < .001). Dys+ patients had greater NIHSS (P < .001), lower Alberta Stroke Programme Early CT Score (P < .001), with greater BMI (P = .030). The association of OSA and dysphagia was greater than that expected based on the prevalence of each condition in acute stroke (P < .001). OSA and dysphagia are associated in first-ever, acute ischemic stroke.

Prevalence of sleep apnea at the acute phase of ischemic stroke with or without thrombolysis

ObjectiveThe aim of the study was to compare the prevalence, type, and severity of sleep apnea during the acute phase of ischemic stroke among patients either receiving or not receiving thrombolysis. MethodsWe recruited 246 consecutive adult ischemic stroke patients. Patients underwent cardiorespiratory sleep study with portable three-channel device during the first 48 h after the symptom onset of ischemic stroke. ResultsWe enrolled 110 (65.5% male) stroke patients in the thrombolysis group and 94 (59.6% male) in the nonthrombolysis group. In the thrombolysis group, the median National Institutes of Health Stroke Scale (NIHSS) score was higher (5.5) compared to the nonthrombolysis group (2.0) (p < 0.001). There was a lower incidence of lacunar (17.3% vs 36.2%, p = 0.002) and cerebellar (2.7% vs 16.0%, p < 0.001) strokes and a higher frequency of middle cerebral artery syndrome (60.9% vs 33.0%, p < 0.001) in the thrombolysis group compared to the nonthrombolysis group. Sleep apnea defined as an apnea–hypopnea index (AHI) ≥ 5/h was diagnosed in 186 (91.2%) patients, its prevalence being higher in the thrombolysis (96.4%) compared to the nonthrombolysis (85.1%) group (p = 0.007). The mean baseline AHI was 33.7/h in the thrombolysis group compared to 26.8/h in the nonthrombolysis group (p = 0.017). ConclusionSleep apnea was present in the vast majority of ischemic stroke patients. The stroke patients treated with thrombolysis were more likely to have sleep apnea, to have elevated NIHSS score at admission, and to be younger. Sleep apnea was more severe among those receiving thrombolysis as compared to those who were not. Clinical trial registrationURL: http://www.clinicaltrials.cov. Unique identifier: NCT01861275.

Treatment of infants with Syndromic Robin sequence with modified palatal plates: a minimally invasive treatment option

BackgroundInfants with Robin sequence (RS) suffer from upper airway obstruction (UAO) and feeding problems. We developed an oral appliance with a velar extension in combination with functional treatment and appropriate feeding techniques, which was proven effective in isolated RS. As the above problems are particularly challenging in syndromic RS, we set out to evaluate our treatment concept also in these patients.MethodsWe searched our electronic departmental database to identify all children admitted to our department between 01/01/2003 and 31/12/2009 because of syndromic RS. UAO was quantified by cardiorespiratory sleep studies performed before and during treatment with a modified palatal plate. This appliance consists of a palatal part, covering the hard palate as well as the alveolar ridges and the potential cleft, and a velar extension shifting the tongue in a more anterior position, thereby opening the pharyngeal airway. It is adjusted by fiberoptic nasopharyngoscopy and controlled by cardiorespiratory sleep studies. Obstructive sleep apnea was defined as a mixed obstructive sleep apnea index (MOAI) >3/h. Feeding modalities before and after treatment and weight gain, determined as standard deviation score, were also evaluated.ResultsOf 68 children meeting inclusion criteria, 56 completed treatment (46 of these being infants). Underlying diagnoses included craniofacial dysostosis (N = 13) and synostosis syndromes (N = 5), unspecified dysmorphic syndromes (N = 23) and miscellaneous rare conditions (N = 27).Median MOAI decreased from 8.5 (range 0.3–76.0) at admission to 1.1 (0.0–5.2) at discharge (p < 0.001). 51 children received only a TPP and 5 additionally continuous positive airway pressure (CPAP) or high-flow nasal cannula during sleep for mild residual OSA. Three children ultimately required tracheostomy. The number of exclusively gavage fed infants was reduced from 23 to 7. Conversely, the number of children fed exclusively by mouth increased from 18 to 30. Median SDS for weight decreased from −1.6 (−3.5–1.7) to −1.3 (−4.1-2.5). Twelve children had their treatment prematurely discontinued, e.g. due to laryngeal collapse/laryngomalacia. No patient died during treatment.ConclusionTreatment of UAO and feeding problems in these children with syndromic RS by a modified palatal plate with a velar extension was shown to be effective and safe. If confirmed in prospective studies, it may help to avoid more invasive interventions.

De rhoncho dormientium : Dedicated to Prof. Dr. Wolfgang Pirsig on his 80th birthday

Obstructive sleep apnea (OSA) is a wide spread affliction that affects 4% of men and 2% of women in industrialised countries. Patients complain about disruptive snoring, daytime sleepiness and loss of intellectual power. OSA is associated with increased mortality. OSA has to be distinguished from simple snoring which is socially annoying but physically harmless. History taking, clinical examination, recording of daytime sleepiness, and cardio-respiratory sleep studies are necessary to make a proper diagnosis. In some cases more sophisticated studies are requested. Simple snoring does not harm the physical health. This indicates that the treatment itself may not harm the patient either. Therefore adjuvants or minimally invasive surgical techniques are favoured. The patients bedpartners should be involved to find the proper treatment for simple snorers. In sleep apneics the treatment focuses on the removal of the sleep related breathing disturbances and their health related consequences. Gold standard treatment of OSA is nasally applied continuous positive airway pressure (nCPAP). Unfortunately the longterm compliance of nCPAP is below 70%. Therefore, alternative treatment modalities are used. As conservative approaches oral appliances and conditioning (to avoid supine sleeping position) show promising results. Nasal appliances and transcutaneously performed electrostimulation have shown to be less effective. There are no drugs that have shown to be helpful in patients with sleep related breathing disorders. Surgical treatment complies with the severity of the disease and with the anatomical findings. A variety of surgical approaches to the soft palate, the base of tongue, the tonsils, and the upper and lower jaws have been described. Surgical success rates seem to decrease with increasing body weight and with increasing severity of OSA. Nasal surgery is mainly used to facilitate a necessary nCPAP therapy. Isolated nasal procedures show low impact on the severity of OSA. Modern sleep medicine is an interdisciplinary field which requires co-operation with different specialists in order to cope with our patients complaints.

Erythrocyte deformability, plasma lipid peroxidation and plasma protein oxidation in a group of OSAS subjects.

Considering that obstructive sleep apnea syndrome (OSAS) is usually associated with endothelial dysfunction, atherosclerosis and cardiovascular disorders, our aim was to examine the erythrocyte deformability and the oxidative status in a group of OSAS subjects. We consecutively enrolled 48 subjects with OSAS defined after a 1-night cardiorespiratory sleep study, subsequently subdivided according to the apnea/hypopnea index (AHI) value in two subgroups: Low (L = 21 subjects with AHI<30) and High (H = 27 subjects with AHI>30). We evaluated the erythrocyte deformability, expressed as elongation index (EI) and the parameters of the oxidative status, such as lipid peroxidation (expressed as thiobarbituric acid-reactive substances - TBARS) and protein oxidation (measured as carbonyl groups - PC). In the entire group and in the two subgroups of OSAS subjects we found a decreased erytrocyte deformability at all shear stresses, not correlated with the plasmatic oxidative stress nor with the polysomnographic parameters. Lipid peroxidation was increased in the whole group and in the H subgroup of OSAS while protein oxidation showed a different trend. As in OSAS the osmotic fragility and the metabolism of the red cells seem to be not impaired, the oxidative damage to the red cell membrane proteins might be responsible for the reduced erythrocyte deformability. This rheological alteration, in addition to the increase in whole blood and plasma viscosity and to the erythrocyte hyperaggregation, could influence the microcircolatory profile in OSAS subjects.

Effect of Obstructive Sleep Apnea in Acute Coronary Syndrome

The effect of obstructive sleep apnea (OSA) on clinical outcomes after acute coronary syndrome (ACS) is incompletely defined. We sought to determine the prevalence of OSA in patients with ACS and evaluate prognostic impact of OSA and continuous positive airway pressure (CPAP) therapy in these patients. This was a prospective longitudinal cohort study of 73 patients admitted on cardiac intensive care unit for ACS. Cardiorespiratory sleep study and/or polysomnography were performed in all patients. CPAP was recommended if Apnea-Hypopnea Index ≥5. The main study outcome was a composite of death for any cause, myocardial infarction, and myocardial revascularization. OSA was diagnosed in 46 patients (63%). Age and cardiovascular risk factors were not significantly different between groups. OSA was classified as mild (m-OSA) in 14 patients (30%) and as moderate-to-severe (s-OSA) in 32 patients (70%). After a median follow-up of 75 months (interquartile range 71 to 79), patients with s-OSA had lower event-free survival rate. After adjustment for gender, patients with s-OSA showed a significantly higher incidence of the composite end point (hazard ratio 3.58, 95% CI 1.09 to 17.73, p = 0.035). Adherence to CPAP occurred in 19 patients (41%), but compliance to CPAP therapy did not reduce the risk of composite end point (hazard ratio 0.87, 95% CI 0.31 to 2.46, p = 0.798). In conclusion, OSA is an underdiagnosed disease with high prevalence in patients with ACS. It is urgent to establish screening protocols because those have high diagnostic yield and allow identifying a group of patients with manifestly unfavorable prognosis.

The Plasminogen System and Transforming Growth Factor-β in Subjects With Obstructive Sleep Apnea Syndrome: Effects of CPAP Treatment.

Obstructive sleep apnea syndrome (OSAS) has emerged as a risk factor for cardiovascular disease. A prothrombotic state may affect coagulation and participate in the atherosclerotic process in subjects with OSAS. These alterations in coagulation seem to involve the plasminogen activation system. We evaluated the imbalances of the plasminogen activation system related to OSAS, and we assessed the effects of CPAP on the plasminogen activation system. Thirty-nine subjects were submitted to a home-based cardiorespiratory sleep study, and 14 healthy subjects (apnea-hypopnea index < 5) were used as controls. Serum levels of urokinase-type plasminogen activator (uPA), tissue-type plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), and active transforming growth factor-β (TGF-β) were measured. These molecules were reassessed in only 17 of the subjects after 1 month of CPAP. PAI-1 and tPA were significantly higher in the subjects with OSAS compared with the controls, whereas TGF-β and uPA levels were lower. PAI-1 showed a significant positive correlation with the apnea-hypopnea index, percentage of time spent at O2 saturation < 90%, and oxygen desaturation index, whereas TGF-β was inversely related to all 3 of these parameters. After the CPAP therapy, PAI-1 significantly decreased, whereas TGF-β showed a significant increase, although the values did not reach those of the controls. uPA and tPA did not show significant differences after the treatment. Our results suggest an imbalance of fibrinolysis related to OSAS and an improvement of the prothrombotic state after the CPAP treatment.

Nitric oxide metabolites and erythrocyte deformability in a group of subjects with obstructive sleep apnea syndrome

Our aim was to evaluate nitric oxide metabolites (nitrite and nitrate), expressed as NOx, and erythrocyte deformability, expressed as elongation index, in a group of subjects with obstructive sleep apnea syndrome (OSAS). We enrolled 48 subjects (36 men and 12 women; mean age 50.3±14.68 yrs) with OSAS diagnosed after a 1-night cardiorespiratory sleep study. OSAS severity was assessed evaluating the apnea/hypopnea index (AHI) and subjects were subdivided in two subgroups: Low (L=AHI<30) and High (H=AHI>30). NOx was examined converting nitrate into nitrite with a nitrate reductase and then assessing nitrite with spectrophotometry after the addition of Griess reagent. The elongation index was obtained using the diffractometer Rheodyn SSD of Myrenne at shear stresses of 30 and 60 Pa and it was expressed as elongation index (EI). We found no difference in NOx among the entire group of OSAS subjects and normal controls, while we observed a NOx decrease in the H subgroup in comparison with L subgroup, but not in comparison with normal controls. We noted a significant decrease in EI at each shear stress in the entire group and also in the two subgroups in comparison with controls. The decrease in NO bioavailability and in erythrocyte deformability might contribute to explain the increased cardiovascular risk in OSAS subjects.