Association of lipoprotein subfractions with endothelial function and arterial stiffness in acute ischemic stroke.

Hypercholesterolemia represents a risk factor for the development of atherosclerosis. Lipoprotein research has recently been focused on the phenomenon of atherogenic and non-atherogenic lipoproteins. The aim of this study was to explore the association of lipoprotein subfractions with a measure for endothelial function (represented by reactive hyperemia index [RHI]) and arterial stiffness (represented by augmentation index [AI]) in patients with acute ischemic stroke. We enrolled 51 patients with acute ischemic stroke. Blood samples were obtained within 24 h after the stroke onset in a fasting condition. Electrophoresis method on polyacrylamide gel was used for the analysis of plasma lipoproteins. RHI and AI was measured by peripheral arterial tonometry (EndoPAT2000 device). We failed to find any significant correlation between RHI and baseline characteristics of the population. Significant correlation was found between AI and age, hypertension, low density lipoprotein cholesterol (LDL) 1, LDL 3-7, score for anti-atherogenic risk and atherogenic profile. Age (beta = .362, p = .006) and LDL1 (beta = -0.283, p = .031) were the only independent variables significantly associated with AI in regression analysis. Significantly higher AI was found in an atherogenic lipoprotein profile compared to a non-atherogenic profile population (median 25% vs. median 11.5%, p = .043). In conclusion, our results suggest significant inverse correlation between levels of LDL 1 subfraction and measures of AI in patients with acute ischemic stroke. Significantly higher values of AI were observed in the population with an atherogenic lipoprotein profile.

Causes of Excessive Daytime Sleepiness in Patients with Acute Stroke--A Polysomnographic Study.

BACKGROUND: Sleep disorders are common in stroke patients. Sleep-disordered breathing (SDB), which is present in up to 72% of stroke patients, is the most frequent cause of excessive daytime sleepiness (EDS) in common population. The aim of this study was to assess the frequency of EDS in stroke patients and to analyze the impact of SDB, stroke severity, and location of stroke on EDS in the acute phase of stroke. METHODS: We enrolled 102 patients with the clinical diagnosis of acute stroke. Baseline clinical characteristics were recorded on admission. An Epworth sleepiness scale score higher than 9 was considered as EDS. To detect SDB, we performed standard overnight polysomnography within 4 ± 2 days after the stroke onset. RESULTS: EDS was present in 21 patients (20.6%). In a population with EDS, we found a significantly higher number of obstructive apneic pauses, central apneic pauses, as well as significantly higher values of respiratory disturbance index (RDI), RDI during nonrapid eye movement sleep, desaturation index, and significant decrease of REM sleep duration. RDI (odds ratio [OR], 1.031; 95% confidence interval [CI], 1.007-1.056; P = .01) and duration of REM sleep (OR, .922; 95% CI, .853-.997; P = .042) were the only independent variables significantly associated with EDS in a binary multivariate regression model. CONCLUSION: SDB is a common, significant, and treatable cause of EDS in acute stroke patients. We suppose that examination in sleep laboratories is reasonable in all stroke patients with EDS, although the impact of SDB therapy on EDS and overall outcome in acute stroke remains unknown.

Association of Sleep Disordered Breathing with Wake-Up Acute Ischemic Stroke: A Full Polysomnographic Study.

STUDY OBJECTIVES: Sleep disordered breathing (SDB) is a frequent comorbidity in stroke patients. SDB is one of the independent risk factors for ischemic stroke. Conversely, stroke may contribute to SDB onset or aggravate premorbid SDB. Multiple mechanisms underlying SDB might be responsible for the development of stroke. The aim of this study was to compare polysomnographic, clinical, and laboratory characteristics of wake-up (WUS) and non-wake-up acute ischemic strokes (NWUS). METHODS: We prospectively enrolled 88 patients with acute ischemic stroke. Clinical characteristics of the population were recorded on admission, and blood samples were obtained in the fasting condition following morning. SDB was assessed using standard overnight polysomnography in the acute phase of the stroke. RESULTS: WUS were present in 16 patients (18.2%), and NWUS in 72 patients (81.8%). In WUS compared to NWUS, we observed significantly higher values of apnea-hypopnea index (24.8 vs. 7.6, p = 0.007), desaturation index ([DI] 26.9 vs. 8.8, p = 0.005), arousal index (22.6 vs. 13.1, p = 0.035), diastolic blood pressure (91.6 mm Hg vs. 85.2 mm Hg, p = 0.039), triglyceride levels ([TG] 1.9 mmol/L vs. 1.2 mmol/L, p = 0.049), and significantly lower levels of D-dimer (0.4 µg/L vs. 0.7 µg/L, p = 0.035). DI (CI: 1.003-1.054, p = 0.031) and TG (CI: 1.002-1.877, p = 0.049) were the only independent variables significantly associated with WUS in binary logistic regression model. CONCLUSIONS: Although the design of our study does not prove the causal relationship between SDB and WUS, higher severity of SDB parameters in WUS supports this hypothesis. COMMENTARY: A commentary on this article appears in this issue on page 467.

Characteristics of Sleep-Disordered Breathing in Etiologic Subtypes of Minor-to-Moderate Acute Ischemic Stroke.

BACKGROUND: Sleep-disordered breathing (SDB) is frequent in stroke patients. A strong association has been suggested between SDB and atrial fibrillation (AF). In this study, we evaluated the characteristics of SDB in etiologic subtypes of acute ischemic stroke. We also investigated the relationship between SDB and AF in acute ischemic stroke. METHODS: We prospectively enrolled 72 patients with minor-to-moderate acute ischemic stroke. Clinical and laboratory characteristics of population were recorded on admission. SDB was assessed using standard polysomnography within 7 days after stroke onset. RESULTS: Apnea-hypopnea index (AHI) in small-vessel strokes was significantly lower than that in large-artery atherosclerosis strokes (P = .031), cardioembolic strokes (P = .011), and strokes of other or unknown etiology (.008). Desaturation index (DI) in small-vessel strokes was significantly lower than that in cardioembolic strokes and in large-artery strokes (P = .008, P = .035). Arousal index (AI) in large-artery strokes was significantly higher than that in small-vessel strokes (P = .013), cardioembolic strokes (P = .007), and strokes of other or unknown etiology (.027). In a multivariate regression model were age (odds ratio [OR], 1.083; 95% confidence interval [CI], 1.022-1.148; P = .007) and DI (OR, 1.037; 95% CI, 1.004-1.071; P = .026) the only significant variables independently associated with AF. CONCLUSIONS: We observed higher AHI, DI, and AI in large-artery strokes that may relate to more severe neurologic deficit in this subgroup. Age and DI were the only independent variables significantly associated with AF in acute ischemic stroke. Higher AHI and DI in cardioembolic strokes may thus mirror more frequent premorbid presence of SDB in patients with AF.

Sleep disorders in patients with multiple sclerosis.

OBJECTIVE: Poor sleep is a frequent symptom in patients with multiple sclerosis (MS). The objective of the study was to assess the relationship between nocturnal polysomnographic (PSG) findings and quality of sleep, fatigue, and increased daytime sleepiness among patients with MS. METHODS: Clinical characteristics were collected. Pittsburgh Sleep Quality Index (PSQI), Fatigue Severity Scale (FSS), Epworth Sleepiness Scale (ESS), and International Restless Legs Syndrome Rating Scale were used to assess quality of sleep, fatigue, excessive daytime sleepiness, and the presence of restless legs syndrome (RLS). All patients underwent nocturnal diagnostic PSG examination. RESULTS: Fifty patients with MS were enrolled into the study. Age was the only independent variable significantly determining apnea-hypopnea index and desaturation index (DI) (beta = 0.369, p = 0.010, beta 0.301, p = 0.040). PSQI and ESS score were significantly higher in a population with RLS (p = 0.004, p = 0.011). FSS significantly correlated with DI (r = 0.400, p = 0.048). Presence of RLS was the only independent variable significantly determining PSQI and ESS (p = 0.005, p = 0.025). DI and presence of RLS were independent variables determining FSS (p = 0.015, p = 0.024). CONCLUSION: Presence of RLS seems to be the main factor determining poor sleep, fatigue, and daytime somnolence. Sleep disordered breathing and its severity influences only fatigue in patients with MS.

Is nocturnal epilepsy cause of disturbed quality of sleep and elevated daytime sleepiness?

OBJECTIVES: Authors evaluated quality of sleep and daytime vigilance in patients with nocturnal epilepsy and compared it to those with daytime epilepsy. BACKGROUND: Nocturnal seizures are an important type of epilepsy. They can result in morbidity due to disruption of sleep architecture. Daytime sleepiness, as a serious consequence of nocturnal seizures, has negative influence on quality of life in patients with epilepsy. METHODS: Authors examined 100 patients with epilepsy. The occurrence of epileptic seizures in circadian rhythm, type of epilepsy and epileptic seizures, as well as aetiology of epilepsy were evaluated. Patients were divided in two groups, 17 patients with nocturnal epilepsy and 83 patients with epileptic seizures not related to sleep. All of them underwent overnight video-EEG-polysomnography and they filled in the Epworth Sleepiness Scale questionnaire (ESS) as well as The Pittsburgh Sleep Quality Index questionnaire (PSQI). RESULTS: Overnight video-EEG-polysomnography detected significant changes in the sleep architecture in patients with nocturnal epilepsy. Significant decrease of N3 stage of NREM sleep (14.31%±8.07 in the group of nocturnal epilepsy vs. 20.12%±9.24 in the group of daytime epilepsy, p=0.01). Concurrently, significantly poorer sleep quality according to PSQI (18.52±7.51 in the group of nocturnal epilepsy vs. 6.21±3.62 in the group of daytime epilepsy, p=0.01) and tendency to increased daytime sleepiness according to ESS was revealed in these patients. CONCLUSION: Remarkable changes in sleep architecture associated with poor quality of sleep and increased daytime sleepiness were detected in patients with nocturnal epilepsy. In conclusion, we emphasize the importance of sleep history taking in patients with epilepsy and their further evaluation in sleep laboratory.

Predictors of impaired endothelial function in obstructive sleep apnea syndrome.

OBJECTIVES: Obstructive sleep apnea syndrome (OSA) is associated with increased cardiovascular morbidity and mortality. Endothelial dysfunction (ED), accelerated atherosclerosis and autonomic dysfunction might be the key players responsible for development of vascular diseases in patients with OSA. In a population with suspected OSA and low burden of cardiovascular risk factors, we therefore aimed to investigate the association between potential cardiovascular risk factors including OSA-specific indices, ED and autonomic activity. METHODS: ED was investigated using reperfusion hyperaemia index (RHI). OSA was assessed using standard polysomnography, autonomic activity was assessed using baroreflex sensitivity (BRS). RESULTS: We enrolled 31 patients (42.1±11.7 years) with OSA. Significant inverse correlation was found between RHI and apnea-hypopnea index (AHI) (r=-0.550, p=0.001) and between RHI desaturation index (r=-0.533, p=0.002). Positive correlation was found between RHI and minimal nocturnal oxygen saturation (r=0.394, p=0.028). In a multiple regression model AHI was the only significant variable to predict RHI (ß=-0.522, p=0.003). We found no correlation between RHI and BRS. RHI in the population with severe OSA (AHI above 30) was significantly lower than RHI in the rest of the population (p=0.012). CONCLUSION: AHI was the only significant independent predictor of impaired endothelial function as expressed by RHI. RHI showed no association with BRS in patients with OSA.