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Altered clot microstructure detected in obstructive sleep apnoea hypopnoea syndrome.

ABSTRACT: Abnormal clot microstructure plays a pivotal role in the pathophysiology of thromboembolic diseases. Assessing the viscoelastic properties of clot microstructure using novel parameters, Time to Gel Point (T GP ), Fractal Dimension (d f ) and clot elasticity (G? GP ) could explain the increased cardiovascular and thromboembolic events in patients with Obstructive Sleep Apnoea Hypopnea Syndrome (OSAHS). We wanted to compare T GP , d f , and G? GP and their diurnal variation in OSAHS and symptomatic comparators. thirty six patients attending a sleep disturbed breathing clinic with symptoms of OSAHS were recruited. T GP , d f and G? GP were measured alongside standard coagulation screening, thrombin generation assays, and platelet aggregometry at 16:00 h and immediately after an in-patient sleep study at 07:30 h. OSAHS group had significantly lower afternoon d f than comparators (1.705±0.033 vs. 1.731±0.031, p<0.05). d f showed diurnal variation and only in the OSAHS group, being significantly lower in the afternoon than morning (p<0.05). Diurnal changes in d f correlated with 4% DR, even after controlling for BMI (r=0.37, p=0.02). The lower d f in the afternoon in OSAHS suggests a partial compensatory change that may make up for other pro-clotting abnormalities/hypertension during the night. The change to the thrombotic tendency in the afternoon is biggest in severe OSAHS. d f Shows promise as a new microstructural indicator for abnormal haemostasis in OSAHS.

SUBMITTER: D'Silva L

PROVIDER: S-EPMC4867923 | biostudies-literature | 2016 Jan-Mar

REPOSITORIES: biostudies-literature

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Altered clot microstructure detected in obstructive sleep apnoea hypopnoea syndrome.

D'Silva Lindsay L Wilczynska Maria M Lewis Keir K Lewis Keir K Lawrence Matthew M Hawkins Karl K Williams Rhodri R Stanford Sophia S Davidson Simon S Morris Keith K Evans Adrian A

Sleep science (Sao Paulo, Brazil) 20160101 1

Abnormal clot microstructure plays a pivotal role in the pathophysiology of thromboembolic diseases. Assessing the viscoelastic properties of clot microstructure using novel parameters, Time to Gel Point (T GP ), Fractal Dimension (d f ) and clot elasticity (G׳ GP ) could explain the increased cardiovascular and thromboembolic events in patients with Obstructive Sleep Apnoea Hypopnea Syndrome (OSAHS). We wanted to compare T GP , d f , and G׳ GP and their diurnal variation in OSAHS and symptomati ...[more]

PMID: 27226818

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Project description:Recent insights into sleep apnoea pathogenesis reveal that a low respiratory arousal threshold (awaken easily) is important for many patients. As most patients experience stable breathing periods mediated by upper-airway dilator muscle activation via accumulation of respiratory stimuli, premature awakening may prevent respiratory stimuli build up as well as the resulting stabilization of sleep and breathing. The aim of the present physiological study was to determine the effects of a non-benzodiazepine sedative, eszopiclone, on the arousal threshold and the AHI (apnoea/hypopnoea index) in obstructive sleep apnoea patients. We hypothesized that eszopiclone would increase the arousal threshold and lower the AHI in patients with a low arousal threshold (0 to -15 cm H(2)O). Following a baseline overnight polysomnogram with an epiglottic pressure catheter to quantify the arousal threshold, 17 obstructive sleep apnoea patients, without major hypoxaemia [nadir SaO(2) (arterial blood oxygen saturation) >70%], returned on two additional nights and received 3 mg of eszopiclone or placebo immediately prior to each study. Compared with placebo, eszopiclone significantly increased the arousal threshold [-14.0 (-19.9 to -10.9) compared with -18.0 (-22.2 to -15.1) cm H(2)O; P<0.01], and sleep duration, improved sleep quality and lowered the AHI without respiratory event prolongation or worsening hypoxaemia. Among the eight patients identified as having a low arousal threshold, reductions in the AHI occurred invariably and were most pronounced (25±6 compared with 14±4 events/h of sleep; P<0.01). In conclusion, eszopiclone increases the arousal threshold and lowers the AHI in obstructive sleep apnoea patients that do not have marked overnight hypoxaemia. The greatest reductions in the AHI occurred in those with a low arousal threshold. The results of this single night physiological study suggest that certain sedatives may be of therapeutic benefit for a definable subgroup of patients. However, additional treatment strategies are probably required to achieve elimination of apnoea.

Project description:Obstructive sleep apnoea syndrome (OSAS) is a common disorder of multifactorial pathogenesis and is associated with obesity, diabetes and cardiovascular disease. Vitamin D is a fat-soluble vitamin with an important function in calcium absorption and homeostasis, which is also implicated in several nonskeletal conditions. The prevalence of vitamin D deficiency is increasing worldwide and is associated with similar metabolic disturbances to OSAS. Moreover, recent data suggest that in OSAS patients serum levels of vitamin D are lower compared with non-apnoeic subjects. However, the mechanisms linking vitamin D deficiency and OSAS are not completely understood and several hypotheses have been advanced. To date, a limited number of studies have assessed the association between lower serum concentrations of vitamin D and OSAS, and have reported inconsistent results. Similarly, contradictory results have been produced by studies which evaluated the effect of continuous positive airway pressure treatment on serum vitamin D levels. The aim of this review is to summarise current knowledge on the association between OSAS and vitamin D levels.Vitamin D insufficiency prevalence is increasing worldwide and presents with similar comorbidities and risk factors to OSAS.The nonskeletal actions of vitamin D may contribute to the development of OSAS through immune system modulation, myopathy and inflammation.Studies evaluating serum vitamin D concentrations in OSAS patients and the effect of CPAP treatment report contradictory results, often influenced by confounding factors, such as obesity.There appears to be potential for use of vitamin D supplementation in OSAS patients as a means of reducing the incidence of cardiovascular disease, a comorbidity common in both conditions.To assess the potential association between OSAS and serum levels of vitamin D.To discuss the pathogenetic mechanisms linking OSAS and vitamin D insufficiency.To illustrate the effect of CPAP treatment on vitamin D concentration in OSAS patients.

Project description:BackgroundHypoglossal nerve stimulation (HNS) with Inspire is a novel treatment indicated for moderate or severe obstructive sleep apnoea/hypopnoea syndrome (OSAHS), intolerant to or unable to be treated with continuous positive airway pressure (CPAP).ObjectiveThe aim of this study was to assess the cost effectiveness of treating moderate or severe OSAHS, in patients intolerant to CPAP, with HNS, compared with standard care, from a National Health Service (NHS) perspective.MethodsA cohort state transition model was developed to compare HNS with Inspire with no treatment in UK adult patients with moderate or severe OSAHS who have previously tried and have not responded to CPAP therapy. Published literature was applied in the model to estimate incremental cost-effectiveness ratios (ICERs; 2019 Great British pounds per quality-adjusted life-year [QALY] gained), from an NHS and personal social services (PSS) perspective, over a cohort's lifetime.ResultsThe model base-case predicts that patients undergoing HNS will incur lifetime costs of £65,026 compared with £36,727 among untreated patients. The HNS cohort would gain 12.72 QALYs compared with 11.15 QALYs in the no-treatment arm. The ICER of treating severe OSAHS with HNS is therefore estimated to be £17,989 per QALYs gained. Probabilistic sensitivity analysis found that at a threshold of £30,000/QALY, HNS has a 69% probability of being cost effective. Limitations of the model include uncertainty around the utility data that were not sourced directly from HNS clinical trials. There is further uncertainty in the relationship between change in the Apnoea-Hypopnoea Index (AHI) and reduction in ischaemic heart disease and stroke because of difficulty capturing the reduction in risk over a long time horizon in studies.ConclusionsOver a patient's lifetime, HNS with Inspire is expected to be cost effective when compared with no treatment in patients with severe OSAHS who have tried and have not responded to CPAP, from an NHS perspective.

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Altered clot microstructure detected in obstructive sleep apnoea hypopnoea syndrome.

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Altered clot microstructure detected in obstructive sleep apnoea hypopnoea syndrome.

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