Beyond the AHI-pulse wave analysis during sleep for recognition of cardiovascular risk in sleep apnea patients.

Recent evidence supports the use of pulse wave analysis during sleep for assessing functional aspects of the cardiovascular system. The current study compared the influence of pulse wave and sleep study-derived parameters on cardiovascular risk assessment. In a multi-centric study design, 358 sleep apnea patients (age 55 ± 13 years, 64% male, body mass index 30 ± 6 kg m-2 , apnea-hypopnea index 13 [5-26] events per hr) underwent a standard overnight sleep recording. A novel cardiac risk index was computed based on pulse wave signals derived from pulse oximetry, reflecting vascular stiffness, cardiac variability, vascular autonomic tone and nocturnal hypoxia. Cardiovascular risk was determined using the ESC/ESH cardiovascular risk matrix, and categorized to high/low added cardiovascular risk. Comparisons between cardiac risk index and sleep parameters were performed for cardiovascular risk prediction. Apnea-hypopnea index, oxygen desaturation index and cardiac risk index were associated with high cardiovascular risk after adjustment for confounders (p = .002, .001, < .001, respectively). In a nested reference model consisting of age, gender and body mass index, adding cardiac risk index but not apnea-hypopnea index or oxygen desaturation index significantly increased the area under the receiver operating characteristic curve (p = .012, .22 and .16, respectively). In a direct comparison of oxygen desaturation index and cardiac risk index, only the novel risk index had an independent effect on cardiovascular risk prediction (pCRI  < .001, pODI  = .71). These results emphasize the association between nocturnal pulse wave and overall cardiovascular risk determined by an established risk matrix. Thus, pulse wave analysis during sleep provides a powerful approach for cardiovascular risk assessment in addition to conventional sleep study parameters.

Definition, discrimination, diagnosis and treatment of central breathing disturbances during sleep.

The complexity of central breathing disturbances during sleep has become increasingly obvious. They present as central sleep apnoeas (CSAs) and hypopnoeas, periodic breathing with apnoeas, or irregular breathing in patients with cardiovascular, other internal or neurological disorders, and can emerge under positive airway pressure treatment or opioid use, or at high altitude. As yet, there is insufficient knowledge on the clinical features, pathophysiological background and consecutive algorithms for stepped-care treatment. Most recently, it has been discussed intensively if CSA in heart failure is a "marker" of disease severity or a "mediator" of disease progression, and if and which type of positive airway pressure therapy is indicated. In addition, disturbances of respiratory drive or the translation of central impulses may result in hypoventilation, associated with cerebral or neuromuscular diseases, or severe diseases of lung or thorax. These statements report the results of an European Respiratory Society Task Force addressing actual diagnostic and therapeutic standards. The statements are based on a systematic review of the literature and a systematic two-step decision process. Although the Task Force does not make recommendations, it describes its current practice of treatment of CSA in heart failure and hypoventilation.

REM Sleep Imposes a Vascular Load in COPD Patients Independent of Sleep Apnea.

Arterial stiffness, a marker for cardiovascular risk, is increased in patients with Chronic Obstructive Pulmonary Disease (COPD) and Obstructive Sleep Apnea (OSA). The specific influence of both on arterial stiffness during sleep is unknown. Nocturnal arterial stiffness (Pulse Propagation Time (PPT) of the finger pulse wave) was calculated in 142 individuals evaluated for sleep apnea: 27 COPD patients (64.7 ± 11y, 31.2 ± 8 kg/m2), 72 patients with cardiovascular disease (CVD group, 58.7 ± 13y, 33.6 ± 6 kg/m2) and 43 healthy controls (HC group 49.3 ± 12y, 27.6 ± 3 kg/m2). Sleep stage related PPT changes were assessed in a subsample of COPD patients and matched controls (n = 12/12). Arterial stiffness during sleep was increased in COPD patients (i.e. shortened PPT) compared to healthy controls (158.2 ± 31 vs. 173.2 ± 38 ms, p = 0.075) and to patients with CVD (161.4 ± 41 ms). Arterial stiffening was particular strong during REM sleep (145.9 ± 28 vs. 172.4 ± 43 ms, COPD vs. HC, p = 0.003). In COPD, time SaO2 < 90% was associated with reduced arterial stiffness (Beta +1.7 ms (1.1-2.3)/10 min, p < 0.001). Sleep apnea did not affect PPT. In COPD, but not in matched controls, arterial stiffness increased from wakefulness to REM-sleep (ΔPPT-8.9 ± 10% in COPD and 3.7 ± 12% in matched controls, p = 0.021). Moreover, REM-sleep related arterial stiffening was correlated with elevated daytime blood pressure (r = -0.92, p < 0.001) and increased myocardial oxygen consumption (r = -0.88, p < 0.01). Hypoxia and REM sleep modulate arterial stiffness. In contrast to healthy controls, REM sleep imposes a vascular load in COPD patients independent of sleep apnea indices, intermittent and sustained hypoxia. The link between REM-sleep, vascular stiffness and daytime cardiovascular function suggests that REM-sleep plays a role for increased cardiovascular morbidity of COPD patients.

[Guidelines in Practice: The New S3 Guideline "Sleeping Disorders - Sleep-Related Abnormal Breathing"]. / Leitlinien in der Praxis: Die neue S3-Leitlinie "Nicht erholsamer Schlaf/Schlafstörungen" ­ Kapitel "Schlafbezogene Atmungsstörungen".

Sleep related breathing disorders include central sleep apnea (CSA), obstructive sleep apnea (OSA), sleep-related hypoventilation, and sleep-related hypoxia. These disorders are frequent and growing in clinical relevance. The related chapter of the S3 guideline "Non-restorative sleep/Sleep disorders", published by the German Sleep Society (DGSM), has recently been updated in November 2016. Epidemiology, diagnostics, therapeutic procedures, and classification of sleep related disorders have been revised. Concerning epidemiology, a considerably higher mortality rate among pregnant women with OSA has been emphasized. With regards to diagnostics, the authors point out that respiratory polygraphy may be sufficient in diagnosing OSA, if a typical clinical condition is given. For CSA, recommendations were changed to diagnose CSA with low apnea rates present. Significant changes for treating CSA in patients with left ventricular dysfunction have been introduced. In addition, there is now to be differentiated between sleep-related hypoventilation and sleep-related hypoxaemia. Obesity hypoventilation syndrome is discussed in more detail. This article sums up and comments on the published changes.

Parameters of Overnight Pulse Wave under Treatment in Obstructive Sleep Apnea.

BACKGROUND: Sleep-related breathing disorders may promote cardiovascular (CV) diseases. A novel and differentiated approach to overnight photoplethysmographic pulse wave analysis, which includes risk assessment and measurement of various pulse wave characteristics, has been evaluated in obstructive sleep apnea (OSA). OBJECTIVES: The purpose of this study was to assess if and which of the differentiated pulse wave characteristics might be influenced by OSA treatment with positive airway pressure (PAP). METHODS: The study included two protocols. In the case-control study (group A), pulse wave-derived CV risk indices recorded during PAP therapy were compared with those obtained in age, body mass index, and CV risk class-matched patients with untreated OSA (n = 67/67). In the prospective PAP treatment study (group B), 17 unselected patients undergoing a full-night sleep test at baseline and after 23 ± 19 weeks of treatment were analyzed. RESULTS: In untreated OSA patients (group A), the overnight hypoxic load was increased (SpO2 index 38.7 ± 17.5 vs. 24.0 ± 11.1, p < 0.001) and the pulse wave attenuation index (PWA-I) was lower (29.4 ± 9.2 vs. 33.5 ± 11.8, p = 0.022) than in treated patients. In group B, PAP therapy reduced the hypoxic load and increased the PWA-I significantly. The composite CV risk index was slightly but not significantly reduced. CONCLUSIONS: PAP therapy modified the hypoxic load and pulse wave-derived markers. The PWA-I - associated with sympathetic vascular tone - was most prominently modified by PAP. This novel approach to markers of CV function should be further evaluated in prospective studies.

Nasal continuous positive airway pressure: influence on digital volume pulse in obstructive sleep apnoea patients.

Obstructive sleep apnoea (OSA) is linked to increased cardiovascular risk. This risk can be reduced by nasal continuous positive airway pressure (nCPAP) treatment. As OSA is associated with an increase of several vasoconstrictive factors, we investigated whether nCPAP influences the digital volume pulse wave. We performed digital photoplethysmography during sleep at night in 94 consecutive patients who underwent polysomnography and 29 patients treated with nCPAP. Digital volume pulse waves were obtained independently of an investigator and were quantified using an algorithm for continuous automated analysis. In patients with OSA and an apnoea/hypopnoea index (AHI) of >10 events · h(-1), a significant vasoconstriction was observed during the night (p<0.0001 by Friedman's test). A significant positive correlation existed between vasoconstriction and AHI (Spearman correlation, r = 0.27; p<0.01; n = 94) and the arousal index (Spearman correlation, r = 0.21; p < 0.05; n = 94). After 6 months of nCPAP treatment, the AHI was significantly reduced from 27 ± 3 events · h(-1) to 4 ± 2 events · h(-1) (each n = 29; p<0.001) and vasoconstriction during the night was significantly reduced from 10 ± 3% to 3 ± 1% (p<0.01). We show changes in the reflective index during the night consistent with vasoconstriction in patients with OSA, which are significantly reduced after 6 months of nCPAP treatment.

Detection of Atrial Fibrillation Using a Home Blood Pressure Monitor.

PURPOSE: Atrial fibrillation (AF) is the most common arrhythmia and is associated with an increased risk of complications. A screening test has the potential to prevent AF-related complications. This study investigated the diagnostic accuracy of an automated device for home blood pressure (BP) monitoring, which implements an algorithm for AF detection. PATIENTS AND METHODS: A modified, automated oscillometric device for home BP monitoring (Omron BP785N (HEM-7321-Z), Omron Healthcare) with an AF detector was used to measure the BP in patients. During each BP measurements, the electrocardiogram (ECG) was recorded simultaneously. Simultaneous BP measurements and ECG recordings were obtained from 99 subjects. RESULTS: Twenty out of 20 patients with atrial fibrillation were correctly recognized by the device and the device correctly identified 67 patients with sinus rhythm as "Not-AF". On the other hand, 12 patients with basic rhythm: sinus rhythm were incorrectly referred to as "atrial fibrillation". In summary, the device has a diagnostic accuracy of 87.88% with a sensitivity of 100% and a specificity of 84.8%. On the other hand, in 23 patients, the raw data of the device showed that a body movement occurred during the measurement of the blood pressure. If these subjects were excluded of the analysis, then the diagnostic accuracy of the device would be even better, namely 90.79%. The sensitivity would be 100% and the specificity 89.5%. CONCLUSION: These data suggest that an automated device for home blood pressure has an excellent diagnostic accuracy for detecting an AF and could be used as a reliable screening test for early diagnosis of atrial fibrillation. Body movements have an impact of the accuracy and specificity of a blood pressure monitor.

Defining Extreme Phenotypes of OSA Across International Sleep Centers.

BACKGROUND: Extreme phenotypes of OSA have not been systematically defined. RESEARCH QUESTION: This study developed objective definitions of extreme phenotypes of OSA by using a multivariate approach. The utility of these definitions for identifying characteristics that confer predisposition toward or protection against OSA is shown in a new prospective sample. STUDY DESIGN AND METHODS: In a large international sample, race-specific liability scores were calculated from a weighted logistic regression that included age, sex, and BMI. Extreme cases were defined as individuals with an apnea-hypopnea index (AHI) ≥ 30 events/hour but low likelihood of OSA based on age, sex, and BMI (liability scores > 90th percentile). Similarly, extreme controls were individuals with an AHI < 5 events/hour but high likelihood of OSA (liability scores < 10th percentile). Definitions were applied to a prospective sample from the Sleep Apnea Global Interdisciplinary Consortium, and differences in photography-based craniofacial and intraoral phenotypes were evaluated. RESULTS: This study included retrospective data from 81,338 individuals. A total of 4,168 extreme cases and 1,432 extreme controls were identified by using liability scores. Extreme cases were younger (43.1 ± 14.7 years), overweight (28.6 ± 6.8 kg/m2), and predominantly female (71.1%). Extreme controls were older (53.8 ± 14.1 years), obese (34.0 ± 8.1 kg/m2), and predominantly male (65.8%). These objective definitions identified 29 extreme cases and 87 extreme controls among 1,424 Sleep Apnea Global Interdisciplinary Consortium participants with photography-based phenotyping. Comparisons suggest that a greater cervicomental angle increases risk for OSA in the absence of clinical risk factors, and smaller facial widths are protective in the presence of clinical risk factors. INTERPRETATION: This objective definition can be applied in sleep centers throughout the world to consistently define OSA extreme phenotypes for future studies on genetic, anatomic, and physiologic pathways to OSA.

[Actual Standard of Blood Pressure Measurement - Statement of the German High Blood Pressure League]. / Aktueller Standard der Blutdruckmessung ­ Stellungnahme der Deutschen Hochdruckliga e. V. DHL® ­ Deutsche Gesellschaft für Hypertonie und Prävention.

Arterial hypertension is one of the most prevalent chronic diseases, and a major risk factor for cardiovascular diseases. It is essential to perform the blood pressure measurement under standardized conditions in the office/clinical setting, otherwise inaccuracy of blood pressure values may lead to poor blood pressure control or misdiagnosis. Compliance with these standards by a trained observer is of crucial importance for a reliable and accurate blood pressure measurement in clinical practice. Regardless of the standardized assessment, it has to be kept in mind that available devices on the market may not measure blood pressure accurate enough. Therefore, a validated (e. g. German Hypertension League Quality Seal) blood pressure monitor should be used. Out-of-office (home and ambulatory) blood pressure measurements provide important information beyond determining resting office/clinical BP.

Continuous positive airway pressure treatment of mild to moderate obstructive sleep apnea reduces cardiovascular risk.

RATIONALE: Obstructive sleep apnea (OSA) is linked to increased cardiovascular risk, but the impact of mild forms of OSA and their treatment on cardiovascular outcomes remains controversial. OBJECTIVES: To prospectively investigate cardiovascular outcomes in treated versus untreated patients with OSA. METHODS: Consecutive sleep laboratory patients with all degrees of OSA were included. Endpoints were nonfatal (myocardial infarction, stroke, and acute coronary syndrome requiring revascularization procedures) and fatal (death from myocardial infarction or stroke) cardiovascular events. MEASUREMENTS AND MAIN RESULTS: Comparison of event-free survival rates in treated versus untreated patients (Kaplan-Meier estimates, log-rank test). Of 449 patients enrolled (age, 56.0 +/- 10.5 years; body mass index, 30.8 +/- 5.4 kg/m(2)), 364 patients received OSA treatment, and 85 patients remained untreated. Median follow-up was 72.0 months (range, 1-156). Mean apnea-hypopnea index before treatment was 30.9 +/- 21.8/hour in treated and 15.3 +/- 13.0/hour in untreated patients, but there were no differences in cardiovascular comorbidities or risk factors. In patients with mild-moderate OSA (n = 288), events were more frequent in untreated patients (estimated event-free survival at 10 yr, 51.8 vs. 80.3% [P < 0.001]; absolute risk reduction, 28.5%; number needed to treat to prevent one event/10 yr, 3.5). After adjustment for age, gender, cardiovascular risk factors, and comorbidities at baseline, OSA treatment was an independent predictor for events (hazard ratio, 0.36; 95% confidence interval, 0.21-0.62; P < 0.001). CONCLUSIONS: OSA treatment was associated with a cardiovascular risk reduction of 64% independent from age and preexisting cardiovascular comorbidities. OSA treatment should be considered for primary and secondary cardiovascular prevention, even in milder OSA.

[Abstract - Update Arterial Hypertension 2018]. / Primäre und sekundäre arterielle Hypertonie ­Update 2018.

Inadequate blood pressure measurement is among the main reasons for poor blood pressure control and misclassification of patients with normal or increased blood pressure. 24-hour ambulatory blood pressure measurement has the best predictive value for cardiovascular mortality, and it could be shown that those with masked hypertension (normal office blood pressure values but hypertensive values with 24-hour measurement) are especially at risk. An increased blood pressure variability seems to be a risk factor for the development of dementia and also raises the cardiovascular risk after TIA and minor stroke. Several new guidelines recommend lower target blood pressure values for most of the patients.

Recognizable clinical subtypes of obstructive sleep apnea across international sleep centers: a cluster analysis.

Study Objectives: A recent study of patients with moderate-severe obstructive sleep apnea (OSA) in Iceland identified three clinical clusters based on symptoms and comorbidities. We sought to verify this finding in a new cohort in Iceland and examine the generalizability of OSA clusters in an international ethnically diverse cohort. Methods: Using data on 972 patients with moderate-severe OSA (apnea-hypopnea index [AHI] ≥ 15 events per hour) recruited from the Sleep Apnea Global Interdisciplinary Consortium (SAGIC), we performed a latent class analysis of 18 self-reported symptom variables, hypertension, cardiovascular disease, and diabetes. Results: The original OSA clusters of disturbed sleep, minimally symptomatic, and excessively sleepy replicated among 215 SAGIC patients from Iceland. These clusters also generalized to 757 patients from five other countries. The three clusters had similar average AHI values in both Iceland and the international samples, suggesting clusters are not driven by OSA severity; differences in age, gender, and body mass index were also generally small. Within the international sample, the three original clusters were expanded to five optimal clusters: three were similar to those in Iceland (labeled disturbed sleep, minimal symptoms, and upper airway symptoms with sleepiness) and two were new, less symptomatic clusters (labeled upper airway symptoms dominant and sleepiness dominant). The five clusters showed differences in demographics and AHI, although all were middle-aged (44.6-54.5 years), obese (30.6-35.9 kg/m2), and had severe OSA (42.0-51.4 events per hour) on average. Conclusions: Results confirm and extend previously identified clinical clusters in OSA. These clusters provide an opportunity for a more personalized approach to the management of OSA.

Risk factors and myocardial infarction in patients with obstructive sleep apnea: impact of beta2-adrenergic receptor polymorphisms.

BACKGROUND: The increased sympathetic nervous activity in patients with obstructive sleep apnea (OSA) is largely responsible for the high prevalence of arterial hypertension, and it is suggested to adversely affect triglyceride and high-density lipoprotein (HDL) cholesterol levels in these patients. The functionally relevant polymorphisms of the beta2-adrenergic receptor (Arg-47Cys/Arg16Gly and Gln27Glu) have been shown to exert modifying effects on these risk factors in previous studies, but results are inconsistent. METHODS: We investigated a group of 429 patients (55 +/- 10.7 years; 361 men, 68 women) with moderate to severe obstructive sleep apnea (apnea/hypopnea index (AHI) 29.1 +/- 23.1/h) and, on average, a high cardiovascular risk profile (body mass index 31.1 +/- 5.6, with hypertension in 60.1%, dyslipidemia in 49.2%, and diabetes in 17.2% of patients). We typed the beta2-adrenergic receptor polymorphisms and investigated the five most frequent haplotypes for their modifying effects on OSA-induced changes in blood pressure, heart rate, and lipid levels. The prevalence of cardiovascular risk factors and coronary heart disease (n = 55, 12.8%) and survived myocardial infarction (n = 27, 6.3%) were compared between the genotypes and haplotypes. RESULTS: Multivariate linear/logistic regressions revealed a significant and independent (from BMI, age, sex, presence of diabetes, use of antidiabetic, lipid-lowering, and antihypertensive medication) influence of AHI on daytime systolic and diastolic blood pressure, heart rate, prevalence of hypertension, and triglyceride and HDL levels. The beta2-adrenergic receptor genotypes and haplotypes showed no modifying effects on these relationships or on the prevalence of dyslipidemia, diabetes, and coronary heart disease, yet, for all three polymorphisms, heterozygous carriers had a significantly lower relative risk for myocardial infarction (Arg-47Cys: n = 195, odds ratio (OR) = 0.32, P = 0.012; Arg16Gly: n = 197, OR = 0.39, P = 0.031; Gln27Glu: OR = 0.37, P = 0.023). Carriers of the most frequent haplotype (n = 113) (haplotype 1; heterozygous for all three polymorphisms) showed a five-fold lower prevalence of survived myocardial infarction (OR = 0.21, P = 0.023). CONCLUSION: Our study showed no significant modifying effect of the functionally relevant beta2-adrenergic receptor polymorphisms on OSA-induced blood pressure, heart rate, or lipid changes. Nevertheless, heterozygosity of these polymorphisms is associated with a lower prevalence of survived myocardial infarction in this group with, on average, a high cardiovascular risk profile.

[Primary and secondary arterial hypertension - update 2016]. / Primäre und sekundäre arterielle Hypertonie - Update 2016.

In patients with hypertension without diabetes and with an increased risk of cardiovascular complications a blood pressure of below 130 mmHg should be targeted. Hypertensive patients with an age above 80 years should be treated in the same way as younger hypertensive patients if they are otherwise healthy and functionally independent. On the other hand frail elderly patients could have an increased morbidity and mortality with intensive blood pressure control. In patients with resistant hypertension spironolactone was the most effective drug when given in addition to their baseline drugs (ACE-inhibitor/angiotensin receptor antagonist, calcium channel blocker and thiazide diuretic).

Detection of cardiovascular risk from a photoplethysmographic signal using a matching pursuit algorithm.

Cardiovascular disease is the main cause of death in Europe, and early detection of increased cardiovascular risk (CR) is of clinical importance. Pulse wave analysis based on pulse oximetry has proven useful for the recognition of increased CR. The current study provides a detailed description of the pulse wave analysis technology and its clinical application. A novel matching pursuit-based feature extraction algorithm was applied for signal decomposition of the overnight photoplethysmographic pulse wave signals obtained by a single-pulse oximeter sensor. The algorithm computes nine parameters (pulse index, SpO2 index, pulse wave amplitude index, respiratory-related pulse oscillations, pulse propagation time, periodic and symmetric desaturations, time under 90 % SpO2, difference between pulse and SpO2 index, and arrhythmia). The technology was applied in 631 patients referred for a sleep study with suspected sleep apnea. The technical failure rate was 1.4 %. Anthropometric data like age and BMI correlated significantly with measures of vascular stiffness and pulse rate variability (PPT and age r = -0.54, p < 0.001, PR and age r = -0.36, p < 0.01). The composite biosignal risk score showed a dose-response relationship with the number of CR factors (p < 0.001) and was further elevated in patients with sleep apnea (AHI ≥ 15n/h; p < 0.001). The developed algorithm extracts meaningful parameters indicative of cardiorespiratory and autonomic nervous system function and dysfunction in patients suspected of SDB.

The German Hypertension League (Deutsche Hochdruckliga) Quality Seal Protocol for blood pressure-measuring devices: 15-year experience and results from 105 devices for home blood pressure control.

OBJECTIVE: The German Hypertension League (Deutsche Hochdruckliga) established a program to assess the accuracy and reliability of blood pressure (BP)-measuring devices in 1999 (Quality Seal Protocol). Here, we report on the results of a testing series of 105 devices designed for BP self-measurement. METHODS: The test protocol for the validation of upper-arm, wrist, and finger devices was developed to compare device to conventional Riva-Rocci measurements based on five criteria: mean systolic and mean diastolic differences, their standard deviations, and a point score representing the correlation of systolic and diastolic errors of individual comparisons. The results of this testing are summarized. RESULTS: From 1999 to 2014, a total of 105 BP devices for self-measurement were tested according to the Quality Seal Protocol. Of these, 47.6% fulfilled all five validation criteria, 55.7% of the upper-arm devices (39 of 71) and 32.4% (11 of 34) of the wrist devices. Finger devices were not offered for testing. Forty-four devices (41.9%) failed multiple test criteria of the validation procedure. A subanalysis with 51 devices tested showed that a stricter definition of the passing point score with a limit of at least 55% would slightly increase the consistency with the conventional criteria in comparison with a point score criterion of at least 50%. It was therefore introduced in 2007. CONCLUSION: The results indicate the importance of a rigorous testing of a BP-measuring device used for home BP measurement to prevent patients from making erroneous treatment decisions.

Vascular stiffness determined from a nocturnal digital pulse wave signal: association with sleep, sleep-disordered breathing, and hypertension.

OBJECTIVES: Reflection of the finger pulse wave form is a valid measure of arterial stiffness, which may be continuously assessed during sleep. We investigated the relationships between sleep, sleep-disordered breathing, hypertension, and pulse propagation time (PPT) in patients with suspected sleep apnea. METHODS: The digital photoplethysmographic signal derived from finger pulse oximetry was recorded during overnight sleep studies in 440 patients (64% men, age 55 ±â€Š12 years, BMI 30 ±â€Š6 kg/m, apnea-hypopnea index 19 ±â€Š19 n/h). PPT, defined as the time interval between the systolic and diastolic peak of the finger pulse wave, was calculated. The influence of sleep stages on PPT were assessed in patients undergoing polysomnography. Generalized linear models were used to study predictors of PPT and hypertension. RESULTS: Mean overnight PPT was independently associated with age (ß = -1.34, P < 0.001), height (ß = 0.47, P = 0.047), history of smoking (ß = -9.44, P = 0.005), and apnea-hypopnea index (ß = -0.18, P = 0.043). PPT was shorter in hypertensive patients compared with normotensive patients (160 ±â€Š33 vs. 177 ±â€Š47 ms, P < 0.001) and independently associated with a diagnosis of hypertension (P = 0.043). PPT was influenced by sleep stage (highest PPT during slow wave sleep compared with wake and all other sleep stages, all P < 0.001) and varied across sleep apnea severity groups in normotensive but not in hypertensive patients (P = 0.028 and 0.64, respectively). CONCLUSION: Overnight PPT by oximetry was strongly associated with factors known to determine daytime vascular stiffness. In addition, PTT provides information on functional and structural vascular properties during sleep. This novel technique offers new opportunities to noninvasively monitor vascular function during the sleeping period.

[Sleep disorders: principles, basic diagnostics and elementary measures and recommendations]. / Schlafstörungen--ein praktischer Leitfaden. Grundlagen, Basis-Diagnostik, einfache Maßnahmen und Empfehlungen.

Sleep disorders are frequent. Economic costs and impairment of quality of life can be substantial. Usually, patients suffer from insomnia or hypersomnia. Several effective therapeutic options are available. Sleep disorders appear independently or accompany a multitude of organic and psychiatric diseases. Fatigue has to be distinguished from sleep disorders clearly. For classification, the ICSD-3, published by the American Academy of Sleep Medicine, is used. Patients should be explicitly asked for their sleep quality, for many do not report actively. Patient's history and clinical examination usually narrow the diagnosis to a large extent. Clinical diagnostics should be carried out according to the diagnostic algorithm by the German Sleep Society (DGSM). An optimal sleep hygiene and if necessary weight reduction are crucial and can prevent chronification and health consequences. In addition, assistive technology, drug therapy, behaviour therapy, and in few cases surgery are available.