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Background: Atrial fibrillation (AF) is an important cause of stroke. Continuous electrocardiography (ECG) monitoring with software-based analysis algorithms has been suggested to enhance the AF detection rate. We investigated the ability of stroke risk analysis (SRA) in the detection of AF in acute stroke patients., Methods: Consecutive stroke patients numbering 1,153 were screened. Patients with cardioembolic stroke related to AF (n = 296, paroxysmal n = 63, persistent n = 233) and patients with cryptogenic stroke (n = 309) after standard diagnostic work-up (bedside ECG monitoring, ultrasound, transesophageal echocardiography, 24 h Holter ECG) received SRA during their stay at the Stroke Unit. Determination of AF risk by SRA in the patients with AF and in the patient group with cryptogenic stroke was assessed and compared., Results: Median SRA monitoring analysis time was 16 h (range 2-206 h, interquartile range 10-36). In AF patients, SRA also detected a possible or definitive AF in 98%. The overall sensitivity of SRA to detect possible or definitive AF in patients with proven AF by standard diagnostic work up and cryptogenic stroke was 98%, specificity 27%, positive predictive value 56%, and the negative predictive value (NPV) was 92%. Area under ROC curve was 0.622., Conclusion: SRA was found to be highly sensitive to detect possible or definitive AF in clinical routine within a short monitoring time. However, low specificity and poor accuracy do not allow diagnosing AF by SRA alone, but with the high NPV compared to current diagnostic standard, it is a valid diagnostic tool to rule out AF. Thereby, SRA is a contribution to clarify stroke etiology., (© 2018 S. Karger AG, Basel.)

Background and Purpose: Computed tomography perfusion (CTP) has a high diagnostic value in the detection of acute ischemic stroke in the anterior circulation. However, the diagnostic value in suspected posterior circulation (PC) stroke is uncertain, and whole brain volume perfusion is not yet in widespread use. We therefore studied the additional value of whole brain volume perfusion to non-contrast CT (NCCT) and CT angiography source images (CTA-SI) for infarct detection in patients with suspected acute ischemic PC stroke., Methods: This is a retrospective review of patients with suspected stroke in the PC in a database of our stroke center (n = 3,011) who underwent NCCT, CTA and CTP within 9 h after stroke onset and CT or MRI on follow-up. Images were evaluated for signs and pc-ASPECTS locations of ischemia. Three imaging models - A (NCCT), B (NCCT + CTA-SI) and C (NCCT + CTA-SI + CTP) - were compared with regard to the misclassification rate relative to gold standard (infarction in follow-up imaging) using the McNemar's test., Results: Of 3,011 stroke patients, 267 patients had a suspected stroke in the PC and 188 patients (70.4%) evidenced a PC infarct on follow-up imaging. The sensitivity of Model C (76.6%) was higher compared with that of Model A (21.3%) and Model B (43.6%). CTP detected significantly more ischemic lesions, especially in the cerebellum, posterior cerebral artery territory and thalami., Conclusions: Our findings in a large cohort of consecutive patients show that CTP detects significantly more ischemic strokes in the PC than CTA and NCCT alone., (© 2016 S. Karger AG, Basel.)

Background and Purpose: Although sleep apnea (SA) is a risk factor for ischemic stroke and an important prognosticator in affected patients, the exact pathophysiological link between SA and stroke remains to be established. We investigated whether levels of C-reactive protein (CRP) and fibrinogen are increased in patients with acute stroke and SA compared with stroke patients without SA., Patients and Methods: 117 consecutive patients with ischemic stroke admitted to our stroke unit within 12 h after stroke onset were included in this study. On admission, CRP and fibrinogen levels were determined. All patients received cardiorespiratory polygraphy during the first 72 h of their hospital stay. In all patients, demographic data, National Institutes of Health Stroke Scale score and cerebrovascular risk factors were assessed., Results: SA defined by an apnea-hypopnea index (AHI) of > or =10/h was found in 64 (55%) patients. Elevated CRP and fibrinogen levels were seen twice as often in patients with SA than in patients without (CRP: 52 vs. 26%; fibrinogen: 72 vs. 37%). After multivariate logistic regression analysis, an AHI of > or =10/h was independently correlated with raised levels of both of these parameters., Conclusion: SA is independently associated with raised levels of CRP and fibrinogen in patients with acute ischemic stroke. We assume that both proteins are part of the pathophysiological pathway linking SA to stroke., ((c) 2007 S. Karger AG, Basel)

Background: Spontaneous cervical artery dissection (sCAD) is a common cause of stroke in patients below 55 years. Dermal connective tissue abnormalities have been observed in up to 60% of patients. A chromosomal locus for connective tissue abnormalities associated with sCAD has been mapped to chromosome 15q24 to a candidate region containing the lysyl oxidase-like 1 gene (LOXL1). LOXL1 an excellent candidate susceptibility gene for non-familial sCAD was investigated by mutation analysis and a genetic association study., Methods: We sequenced the whole coding region of the LOXL1 gene in 15 sCAD patients and performed a genetic association study in 157 sCAD patients using 12 single nucleotide polymorphisms (SNP)., Results: The SNP rs3825942 (Gly153Asp) showed marginal association with sCAD on an allele basis and in the dominant genetic model, and intronic SNP rs893817 under a recessive model only. None of the SNP haplotypes was associated with sCAD., Conclusions: Genetic variation in LOXL1 might play a role as a risk factor for sCAD.

Background: Of late, obstructive sleep apnea (OSA) has been suggested to be a risk factor for atherosclerotic artery disease. In the present study, we analyzed the prevalence of atherosclerosis in stroke patients with and without OSA., Patients and Methods: Two hundred and fourteen consecutive patients with ischemic stroke were included in this study. Patients were screened for classical cerebrovascular risk factors. All patients received a cardiorespiratory polygraphy to determine the apnea-hypopnea index. Duplex ultrasonography was used to evaluate the carotid bulb and the internal carotid artery for the presence of atherosclerotic lesions, which were graded in 'none', 'plaques with <50% stenosis', 'stenosis > or =50% to subtotal', and 'occlusion'., Results: Atherosclerotic lesions were identified in 42% of patients. These were significantly more prevalent in patients with OSA than in patients without. In multiple logistic regression analysis, this association was independent of other known vascular risk factors. Arterial hypertension, which was significantly related to atherosclerosis in univariate analysis, lost its statistical impact in multivariate analysis., Conclusion: This study confirms that OSA is an independent risk factor for atherosclerotic artery disease that may even outweigh the impact of arterial hypertension in selected patient collectives. To further elucidate this topic, treatment studies are needed that look for a possible improvement of markers and signs of atherosclerosis in patients with OSA.

Background and Purpose: Cervical artery dissection (CAD) is a common cause of ischemic stroke in younger aged subjects. Retrospective studies suggest cervical manipulative therapy (CMT) and preceding infections as extrinsic risk factors for CAD. In a case-control study, we assessed a questionnaire with 7 mild mechanical traumas as potential trigger factors for CAD, including CMT and recent infections., Patients and Methods: Forty-seven consecutive patients with CAD were compared with 47 consecutive patients of similar age with ischemic stroke due to etiologies other than CAD. Patients underwent a standardized face-to-face interview. We assessed head or neck pain and recent infection <7 days before symptom onset, as well as the following mechanical trigger factors <24 h and <7 days prior to symptom onset: (1) heavy lifting, (2) sexual intercourse, (3) mild direct or (4) indirect neck trauma, (5) jerky head movements, (6) sports activity, and (7) CMT., Results: We found no association between any single one of the above risk factors and CAD. CMT (CAD, n = 10; non-CAD, n = 5) and recent infections (CAD, n = 18; non-CAD, n = 10) were more frequent in the CAD group but failed to reach significance. However, the cumulative analysis of all mechanical trigger factors revealed a significant association of mechanical risk factors as a whole in CAD <24 h prior to symptom onset (p = 0.01)., Conclusion: Mild mechanical stress, including CMT, plays a role as possible trigger factor in the pathogenesis of CAD. CMT and recent infections alone failed to reach significance during the present investigation, presumably due to the relatively small sample size of the study cohort., ((c) 2007 S. Karger AG, Basel.)

Objectives: Proper assessment of the intracranial arteries by transcranial color-coded duplex sonography (TCCD) is occasionally made difficult by an insufficient temporal bone window, an unfavorable insonation angle, or low flow velocity or volume. In these cases, echocontrast could be helpful to increase the diagnostic confidence or to make the diagnosis at all., Material and Methods: We investigated 67 temporal windows of 47 patients with insufficient native transtemporal insonation conditions before and after the application of the second-generation (gas-filled) microbubble contrast agent Sonovue (in 20 patients out of these 47, both temporal windows were insufficient, in the remaining 27 only one side)., Results: As compared to the precontrast scans, echocontrast allowed for more segments to be evaluated by pulsed Doppler sonography (p < 0.0001) and for longer lumen segments to be displayed on color mode (p < 0.0001). With the help of contrast medium, flow velocity in the middle cerebral artery could be measured through 65 windows as compared to only 26 windows before contrast was applied (p < 0.0001)., Conclusions: In patients with poor precontrast visualization of intracranial arteries, echocontrast-enhanced TCCD is very helpful., (Copyright 2005 S. Karger AG, Basel.)

Background: Transesophageal echocardiography (TEE) and transcranial Doppler sonography (TCD) can identify right-to-left-shunts that predispose to paradoxical embolism. In a large cohort we compared the results of both techniques., Methods: 222 patients were investigated by both techniques using the contrast agent Echovist-300 and performing each test once without and once with the Valsalva maneuver (VM)., Results: TEE-proven right-to-left-shunts were detected by TCD with a high sensitivity of 94%. In addition, TCD revealed shunts not noted during TEE in about 20% of all patients studied. These shunts are in general smaller than those concordantly identified; however, 9% of the patients without a TEE-proven shunt presented with a shunt that allows a considerable amount of contrast medium to pass. There were 12% more microbubbles detected in the right middle cerebral artery than in the left middle cerebral artery during the TCD test performed with VM, but not during the TCD test performed without VM., Conclusions: Contrast-enhanced TEE and TCD are complementary methods in the assessment of stroke and stroke-prone patients. The side difference of microbubbles may indicate a selective streaming of cardiac emboli during VM., (Copyright 2004 S. Karger AG, Basel)

Background: Intracranial arterial stenosis is a rare cause of stroke in Caucasians. Detection of clinically silent circulating microemboli by transcranial Doppler sonography is now widely investigated in patients with carotid artery disease in the hope to identify patients at increased risk for stroke., Methods: In 33 patients with intracranial internal carotid (n = 12), middle cerebral (n = 18), posterior cerebral (n = 2), or basilar artery stenosis (n = 1), we performed a 1-hour microembolus detection downstream to the stenosis in the middle or in the posterior cerebral artery, respectively. The stenosis was assessed by transcranial Doppler and duplex ultrasound. 18 patients had been symptomatic in the dependent territory., Results: Five patients with ischaemic symptoms within the last 8 days and with a peak systolic flow velocity of > or =210 cm/s in the stenosis showed microembolic signals at a rate of 3-25 events/h, despite effective anticoagulation. All these 5 patients had a lesion pattern on cranial CT or MRI scan suggesting embolic origin. All the asymptomatic patients (n = 15) and all the patients with a peak systolic intrastenostic velocity of 160 to <210 cm/s (n = 13) did not show microembolic signals at all., Conclusion: Microembolic signals occur in recently symptomatic patients with high-grade intracranial arterial stenosis indicated by a sonographically measured stenotic peak flow velocity of > or =210 cm/s. Therapeutic anticoagulation was not sufficient to suppress microemboli formation., (Copyright 2002 S. Karger AG, Basel)

Background and Purpose: Cardiac right-to-left shunts (RLS) can be identified by transesophageal echocardiography (TEE) as well as by transcranial Doppler ultrasound (TCD) using contrast agents, such as Echovist-200 or Echovist-300 in conjunction with a Valsalva maneuver (VM) as provocation procedure. Both Echovist preparations are in use. Currently, the appropriate timing of the VM is still under debate., Methods: Sixty-four patients were investigated by both TEE and bilateral TCD of the middle cerebral arteries. The following protocol was applied in a randomized way: (1) no VM, (2) VM for 5 s starting with the beginning of Echovist-300 injection, (3) VM for 5 s starting 5 s after the beginning of Echovist-300 injection, (4) VM for 5 s starting 10 s after the beginning of Echovist-300 injection, and (5) VM for 5 s starting 5 s after the beginning of Echovist-200 injection., Results: In 27 patients, an RLS was demonstrated by both TEE and contrast TCD (shunt-positive). Twenty-two patients were negative in both investigations, no patient was positive on TEE but negative on TCD, 15 patients were only positive on at least one TCD investigation but negative on TEE. Tests 3 and 5 were the most appropriate ones; test 3 was slightly superior to test 5., Conclusions: TCD using Echovist-300 or Echovist-200 is a sensitive method to identify TEE-proven cardiac RLS. To achieve the best diagnostic accuracy, the VM should be performed for a duration of 5 s starting at 5 s following the beginning of contrast injection., (Copyright 2002 S. Karger AG, Basel)