Follow-up of Patients With Stroke Based on Opt-out Choice: Potential Approach for Acute Care Quality Registries or Observational Studies.

BACKGROUND AND OBJECTIVES: Restricting follow-up assessment of both interventional and observational studies to patients who provide informed consent introduces relevant selection bias-particularly by underrepresenting patients with neurologic communication deficits and impaired capacity to consent. Many patients who are initially unable to give consent may be willing to do so after recovery. Informing patients on study purposes and procedures with offering them the option of nonparticipation but not requesting explicit consent is called "opt-out" approach. We investigated whether an opt-out strategy yields meaningful follow-up rates in an acute stroke registry with an embedded controlled study. METHODS: The citywide Berlin-SPecific Acute Treatment in Ischemic or hAemorrhagic Stroke With Long Term Follow-up (B-SPATIAL) registry was designed to provide reliable information on process indicators and outcomes of specific acute stroke treatments to inform health care providers about quality of care and best practice strategies including the effects of a mobile stroke unit implementation. Because this information was regarded of high public interest, Berlin data protection authorities permitted data sampling without prior informed consent, using instead follow-up assessment on an "opt-out" basis. Patients were included if they had neurologic symptoms at ambulance or hospital arrival within 6 hours of onset and had a final diagnosis of stroke or TIA. Information on data collection and outcome assessment was sent by letter to patients 1 month before follow-up. RESULTS: From February 1, 2017, to January 31, 2020, a total of 10,597 patients were assessed. Thirty-one (0.3%) patients declined any data use, whereas 578 (5.5%) opted out of follow-up assessment. Of those not opting out (n = 9,988), functional outcome (modified Rankin Scale) was collected in 8,330 patients (83.4%) and vital status in 9,741 patients (97.5%). We received no complaints regarding data collection procedures. DISCUSSION: Opt-out-based follow-up collection offers a way to achieve high follow-up rates along with respecting patients' preferences.

Off-label-dosing of non-vitamin K-dependent oral antagonists in AF patients before and after stroke: results of the prospective multicenter Berlin Atrial Fibrillation Registry.

AIMS: We aimed to analyze prevalence and predictors of NOAC off-label under-dosing in AF patients before and after the index stroke. METHODS: The post hoc analysis included 1080 patients of the investigator-initiated, multicenter prospective Berlin Atrial Fibrillation Registry, designed to analyze medical stroke prevention in AF patients after acute ischemic stroke. RESULTS: At stroke onset, an off-label daily dose was prescribed in 61 (25.5%) of 239 NOAC patients with known AF and CHA2DS2-VASc score ≥ 1, of which 52 (21.8%) patients were under-dosed. Under-dosing was associated with age ≥ 80 years in patients on rivaroxaban [OR 2.90, 95% CI 1.05-7.9, P = 0.04; n = 29] or apixaban [OR 3.24, 95% CI 1.04-10.1, P = 0.04; n = 22]. At hospital discharge after the index stroke, NOAC off-label dose on admission was continued in 30 (49.2%) of 61 patients. Overall, 79 (13.7%) of 708 patients prescribed a NOAC at hospital discharge received an off-label dose, of whom 75 (10.6%) patients were under-dosed. Rivaroxaban under-dosing at discharge was associated with age ≥ 80 years [OR 3.49, 95% CI 1.24-9.84, P = 0.02; n = 19]; apixaban under-dosing with body weight ≤ 60 kg [OR 0.06, 95% CI 0.01-0.47, P < 0.01; n = 56], CHA2DS2-VASc score [OR per point 1.47, 95% CI 1.08-2.00, P = 0.01], and HAS-BLED score [OR per point 1.91, 95% CI 1.28-2.84, P < 0.01]. CONCLUSION: At stroke onset, off-label dosing was present in one out of four, and under-dosing in one out of five NOAC patients. Under-dosing of rivaroxaban or apixaban was related to old age. In-hospital treatment after stroke reduced off-label NOAC dosing, but one out of ten NOAC patients was under-dosed at discharge. CLINICAL TRIAL REGISTRATION: NCT02306824.

Association Between Adherence to Quality Indicators and 7-Day In-Hospital Mortality After Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Quality indicators (QI) are an accepted tool to measure performance of hospitals in routine care. We investigated the association between quality of acute stroke care defined by overall adherence to evidence-based QI and early outcome in German acute care hospitals. METHODS: Patients with ischemic stroke admitted to one of the hospitals cooperating within the ADSR (German Stroke Register Study Group) were analyzed. The ADSR is a voluntary network of 9 regional stroke registers monitoring quality of acute stroke care across 736 hospitals in Germany. Quality of stroke care was defined by adherence to 11 evidence-based indicators of early processes of stroke care. The correlation between overall adherence to QI with outcome was investigated by assessing the association between 7-day in-hospital mortality with the proportion of QI fulfilled from the total number of QI the individual patient was eligible for. Generalized linear mixed model analysis was performed adjusted for the variables age, sex, National Institutes of Health Stroke Scale and living will and as random effect for the variable hospital. RESULTS: Between 2015 and 2016, 388 012 patients with ischemic stroke were reported (median age 76 years, 52.4% male). Adherence to distinct QI ranged between 41.0% (thrombolysis in eligible patients) and 95.2% (early physiotherapy). Seven-day in-hospital mortality was 3.4%. The overall proportion of QI fulfilled was median 90% (interquartile range, 75%-100%). In multivariable analysis, a linear association between overall adherence to QI and 7-day in-hospital-mortality was observed (odds ratio adherence <50% versus 100%, 12.7 [95% CI, 11.8-13.7]; P<0.001). CONCLUSIONS: Higher quality of care measured by adherence to a set of evidence-based process QI for the early phase of stroke treatment was associated with lower in-hospital mortality.

Oral anticoagulation in patients with atrial fibrillation and acute ischaemic stroke: design and baseline data of the prospective multicentre Berlin Atrial Fibrillation Registry.

AIMS: The Berlin Atrial Fibrillation Registry was designed to analyse oral anticoagulation (OAC) prescription in patients with atrial fibrillation (AF) and acute ischaemic stroke. METHODS AND RESULTS: This investigator-initiated prospective multicentre registry enrolled patients at all 16 stroke units located in Berlin, Germany. The ongoing telephone follow-up is conducted centrally and will cover 5 years per patient. Within 2014 and 2016, 1080 patients gave written informed consent and 1048 patients were available for analysis. Median age was 77 years [interquartile range (IQR) 72-83], 503 (48%) patients were female, and 254 (24%) had a transient ischaemic attack (TIA). Overall, 470 (62%) out of 757 patients with known AF and a (pre-stroke) CHA2DS2-VASc ≥ 1 were anticoagulated at the time of stroke. At hospital discharge, 847 (81.3%) of 1042 patients were anticoagulated. Thereof 710 (68.1%) received a non-vitamin K-dependent oral anticoagulant (NOAC) and 137 (13.1%) a vitamin K antagonist (VKA). Pre-stroke intake of a NOAC [odds ratio (OR) 15.6 (95% confidence interval, 95% CI 1.97-122)] or VKA [OR 0.04 (95% CI 0.02-0.09)], an index TIA [OR 0.56 (95% CI 0.34-0.94)] rather than stroke, heart failure [OR 0.49 (95% CI 0.26-0.93)], and endovascular thrombectomy at hospital admission [OR 12.9 (95% CI 1.59-104)] were associated with NOAC prescription at discharge. Patients' age or AF type had no impact on OAC or NOAC use, respectively. CONCLUSION: About 60% of all registry patients with known AF received OAC at the time of stroke or TIA. At hospital discharge, more than 80% of AF patients were anticoagulated and about 80% of those were prescribed a NOAC.

Cerebral venous thrombosis in adults.

Thromboses of cerebral veins and/or sinuses (CVT) encompass a clinically rather heterogenous, relatively rare entity, which is nonetheless an important cause of stroke in the young. While until the mid of the last century the prognosis of CVT was thought to be poor or even fatal in the majority of cases, the advance and wider use of modern imaging technology since the early 1980s, together with the results of registries and population-based studies, revealed that CVT is more frequent and less life-threatening than previously assumed. However, because headache is frequently the only symptom, many oligosymptomatic cases might be overlooked. Both, CT- and MR-venography are suitable methods to confirm or rule out CVT, while the sensitivity of laboratory tests (D-dimer) alone is too low to rely on. Despite low evidence anticoagulation remains the treatment of choice during the acute phase and for secondary prevention.

[Certification criteria for stroke units in Germany : Update 2018]. / Zertifizierungskriterien für Stroke-Units in Deutschland : Update 2018.

This article describes the revised criteria for certified stroke units (SU) in Germany that will apply from 1 October 2018. Due to the high level of quality only minor adjustments and specifications were necessary in many places and the majority of criteria remained unchanged. For the first time a uniform personnel quota of ≥1.75 full-time staff per monitor bed is defined, which is a better reflection of the treatment reality. The evidence-based process of acute vascular imaging using computed tomography angiography (CTA) and alternatively magnetic resonance angiography (MRA) is now defined as a minimum rate of≥20 % of all brain infarcts. In this way the timely identification of suitable candidates for endovascular thrombectomy (ET) should be accomplished. Ultrasound diagnostics of arteries supplying the brain remain an integral part of additional diagnostics after cerebral ischemia because this generates supplementary information. The extended detection of atrial fibrillation is newly included as a diagnostic minimum standard and necessitates measures that go beyond a single long-term electrocardiograph (ECG). In order to facilitate the certification of telemedically supplied SU (Tele-SU), the minimum standard of stroke patients was reduced to ≥200 per year. A Tele-SU in the immediate catchment area of a certified SU (<20 km) must provide proof of a regional treatment need in order for certification to be approved. Quality criteria in the audit reports have now a greater importance. They require a concrete plan of action, which must be tracked within the framework of the interim report and must be presented for the recertification. Furthermore, the SU are called upon not to limit the endeavors for quality only to the minimum requirements.

Stroke unit care in germany: the german stroke registers study group (ADSR).

BACKGROUND: Factors influencing access to stroke unit (SU) care and data on quality of SU care in Germany are scarce. We investigated characteristics of patients directly admitted to a SU as well as patient-related and structural factors influencing adherence to predefined indicators of quality of acute stroke care across hospitals providing SU care. METHODS: Data were derived from the German Stroke Registers Study Group (ADSR), a voluntary network of 9 regional registers for monitoring quality of acute stroke care in Germany. Multivariable logistic regression analyses were performed to investigate characteristics influencing direct admission to SU. Generalized Linear Mixed Models (GLMM) were used to estimate the influence of structural hospital characteristics (percentage of patients admitted to SU, year of SU-certification, and number of stroke and TIA patients treated per year) on adherence to predefined quality indicators. RESULTS: In 2012 180,887 patients were treated in 255 hospitals providing certified SU care participating within the ADSR were included in the analysis; of those 82.4% were directly admitted to a SU. Ischemic stroke patients without disturbances of consciousness (p < .0001), an interval onset to admission time ≤3 h (p < .0001), and weekend admission (p < .0001) were more likely to be directly admitted to a SU. A higher proportion of quality indicators within predefined target ranges were achieved in hospitals with a higher proportion of SU admission (p = 0.0002). Quality of stroke care could be maintained even if certification was several years ago. CONCLUSIONS: Differences in demographical and clinical characteristics regarding the probability of SU admission were observed. The influence of structural characteristics on adherence to evidence-based quality indicators was low.

Influence of acute complications on outcome 3 months after ischemic stroke.

BACKGROUND: Early medical complications are potentially modifiable factors influencing in-hospital outcome. We investigated the influence of acute complications on mortality and poor outcome 3 months after ischemic stroke. METHODS: Data were obtained from patients admitted to one of 13 stroke units of the Berlin Stroke Registry (BSR) who participated in a 3-months-follow up between June 2010 and September 2012. We examined the influence of the cumulative number of early in-hospital complications on mortality and poor outcome (death, disability or institutionalization) 3 months after stroke using multivariable logistic regression analyses and calculated attributable fractions to determine the impact of early complications on mortality and poor outcome. RESULTS: A total of 2349 ischemic stroke patients alive at discharge from acute care were included in the analysis. Older age, stroke severity, pre-stroke dependency and early complications were independent predictors of mortality 3 months after stroke. Poor outcome was independently associated with older age, stroke severity, pre-stroke dependency, previous stroke and early complications. More than 60% of deaths and poor outcomes were attributed to age, pre-stroke dependency and stroke severity and in-hospital complications contributed to 12.3% of deaths and 9.1% of poor outcomes 3 months after stroke. CONCLUSION: The majority of deaths and poor outcomes after stroke were attributed to non-modifiable factors. However, early in-hospital complications significantly affect outcome in patients who survived the acute phase after stroke, underlining the need to improve prevention and treatment of complications in hospital.

Association between socioeconomic status and functional impairment 3 months after ischemic stroke: the Berlin Stroke Register.

BACKGROUND AND PURPOSE: We aimed to analyze the association between patient socioeconomic status and functional impairment 3 months after ischemic stroke and to identify factors that influence this association. METHODS: Data were obtained from the Berlin Stroke Register, a network of 14 stroke units in Berlin. Ischemic stroke patients consecutively admitted to 1 of the hospitals in the Berlin Stroke Register between June 2010 and September 2011, were followed-up 3 months after the index event by postal or telephone interview. We used multivariable logistic regression to examine the association between highest education as marker of socioeconomic status and functional impairment after stroke defined by Barthel Index categories. We adjusted for age, sex, prestroke dependency, stroke severity, functional deficit after stroke onset, and comorbidities as possible confounding factors. RESULTS: A total of 1688 ischemic stroke patients who were alive at 3 months and completed the questionnaire were included in the analysis; 40% of the patients were female and 50% of the patients were 70 years or older. Age, prestroke dependency, stroke severity, and the absence of comorbidities were significantly associated with good functional outcome at 3 months. In multivariable analysis, a higher probability of good outcome was observed in patients with college or university degree (odds ratio, 2.18; 95% confidence interval, 1.39-3.42) compared with patients with no completed education. CONCLUSIONS: Patients with lower education have considerably lower rates of good functional outcome after stroke that cannot be fully explained by variations in the patients' clinical and demographic characteristics.

Development of a clinical score (A2DS2) to predict pneumonia in acute ischemic stroke.

BACKGROUND AND PURPOSE: Poststroke pneumonia is a potentially preventable complication after stroke associated with poor outcome. We developed and externally validated a prognostic score for predicting risk of pneumonia after ischemic stroke. METHODS: The prognostic score was developed based on clinical data routinely collected after admission from the Berlin Stroke Register, Germany. The association of demographics, comorbidities, and clinical characteristics with poststroke pneumonia was investigated using multivariable logistic regression analyses. Independent predictors of poststroke pneumonia were translated into a point scoring system based on the corresponding regression coefficients. The predictive properties of the developed prognostic score were externally validated using an independent data set from the Stroke Register Northwest-Germany. RESULTS: Between 2007 and 2009, 15 335 patients with ischemic stroke were registered within the Berlin Stroke Register. The observed rate of pneumonia in hospital was 7.2%. A 10-point score was derived for prediction of poststroke pneumonia (Age ≥ 75 years=1, Atrial fibrillation=1, Dysphagia=2, male Sex=1, stroke Severity, National Institutes of Health Stroke Scale 0-4=0, 5-15=3, ≥ 16=5; A(2)DS(2)). The proportion of pneumonia varied between 0.3% in patients with a score of 0 point to 39.4% in patients with a score of 10 points. The score demonstrated excellent discrimination (C-statistic 0.84; 95% CI, 0.83-0.85) and calibration (McFadden R(2)=0.21). Prediction, discrimination, and calibration properties were reproduced in the validation cohort consisting of 45 085 patients with ischemic stroke. CONCLUSIONS: The A(2)DS(2) score is a valid tool for predicting poststroke pneumonia based on routinely available data. A(2)DS(2) might be useful for guiding monitoring of high-risk patients or prophylactic pneumonia management in clinical routine.

Revascularization of carotid artery stenosis - a brief update on current evidence.

Major and long-awaited trials comparing carotid endarterectomy (CEA) with carotid stenting (CAS) were published in recent years. Both, ICSS and CREST, documented a higher rate of periprocedural stroke and death in CAS, in particular in elderly patients, thereby confirming the results of prior trials and meta-analyses. In CREST, the composite endpoint included myocardial infarction (MI), which led to statistical equipoise between the treatment arms due to a higher rate of MI with CEA. However, whether MI is a relevant endpoint in trials for stroke prevention remains debatable. The stroke preventive benefit seems equally sustained after CEA and CAS, although the significance of restenoses, whose frequency is twice as high after CAS compared to CEA, is unclear in the long range. Emergent CEA in patients with clinically unstable carotid stenosis is associated with a very high complication risk, but the optimal treatment strategy for these patients remains to be elucidated. Recent evidence indicates a very low stroke risk of asymptomatic stenoses with intensive medical treatment, rendering revascularization almost unnecessary. The detection of microembolic signals on transcranial Doppler and rapid stenosis progression by duplex sonography might help to identify patients with higher stroke risk in whom revascularization is warranted.

Clinical characterization of symptomatic microangiopathic brain lesions.

BACKGROUND: Microangiopathic brain lesions can be separated in diffuse lesions - leukoaraiosis - and focal lesions - lacunes. Leukoaraiosis and lacunes are caused by common cerebrovascular risk factors, but whether they represent a common entity is not sufficiently investigated. The present study aimed to determine the clinical profiles associated with the extent of leukoaraiosis and lacunes. METHODS: Sixty-four consecutive patients with acute microangiopathic stroke were studied. Leukoaraiosis and lacunes were stratified according to their MRI-based extent. Standardized clinical assessment included clinical syndromes, cerebrovascular risk factors, cognitive performance, retinal imaging, ultrasonography, blood, and urine parameters. RESULTS: Different clinical profiles for leukoaraiosis and lacunes were found. Regarding leukoaraiosis, the cognitive scores (SISCO, mini mental score examination, mental examination) and the presence of hyperlipidemia decreased as the severity of leukoaraiosis increased. Univariate and multivariate analysis revealed that these cognitive score values as well as the presence of hyperlipidemia correlated significantly with no or only mild leukoaraiosis. Regarding lacunes, the percentage of migraine, previous stroke events, hydrocephalus, left ventricular hypertrophy, and a higher National Institutes of Health Stroke Scale increased as the number of lacunar lesions increased. Statistical analysis revealed that these parameters correlated not significantly with the number of lacunes. CONCLUSIONS: The findings suggests that leukoaraiosis and lacunes are different microangiopathic entities potentially requiering different treatment concepts.

Factors influencing in-hospital mortality and morbidity in patients treated on a stroke unit.

OBJECTIVE: To determine the extent that demographics, clinical characteristics, comorbidities, and complications contribute to the risk of in-hospital mortality and morbidity in acute stroke. METHODS: Data of consecutive patients admitted to 14 stroke units cooperating within the Berlin Stroke Register were analyzed. The association of demographics, clinical characteristics, comorbidities, and complications with the risk of in-hospital death and poor outcome at discharge was assessed, and independent attributable risks were calculated, applying average sequential attributable fractions. RESULTS: In a 3-year period, 16,518 consecutive patients with ischemic or hemorrhagic stroke were documented. In-hospital mortality was 5.4%, and 45.7% had a poor outcome (modifed Rankin Scale score ≥3). In patients with length of stay (LOS) ≤7 days, 37.5% of in-hospital deaths were attributed to stroke severity, 23.1% to sociodemographics (age and prestroke disability), and 28.9% to increased intracranial pressure (iICP) and other complications. In those with LOS >7 days, age and stroke severity accounted for 44.1%, whereas pneumonia (12.2%), other complications (12.6%), and iICP (8.3%) contributed to one-third of in-hospital deaths. For poor outcome, attributable risks were similar for prestroke disability, stroke severity, pneumonia, and other complications regardless of the patient's LOS. CONCLUSIONS: Approximately two-thirds of early death and poor outcome in acute stroke is attributed to nonmodifiable predictors, whereas main modifiable factors are early complications such as iICP, pneumonia, or other complications, on which stroke unit treatment should focus to further improve the prognosis of acute stroke.

Clinical and genetic features in a family with CADASIL and high lipoprotein (a) values.

We present a family with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and elevated lipoprotein(a) [Lp(a)] levels. In addition to neurological examinations, ultrasound of extra- and intracranial arteries, laboratory tests, and cerebral magnetic resonance imaging (MRI), a whole genome screening with mutation analyses was performed. Rather untypical for CADASIL, stenoses of large intracranial arteries were detected in the index patient. All affected subjects lacked a history of migraine, mood disturbances, and cognitive decline despite extensive white matter lesions in two individuals. Furthermore, evidence of early cerebral microangiopathy was demonstrated in three children (age 9, 11 and 13). We were able to explain the mechanism of elevated Lp(a) on the basis of the kringle IV type 2 repetition size. A mutation S118C located in exon 4 of Notch3 was responsible for CADASIL. Elevated Lp(a) might have contributed to the cerebrovascular phenotype in this family.

Increased prevalence of microangiopathic brain lesions among siblings of patients with lacunar stroke. A prospective multicenter study.

BACKGROUND: Family and twin studies suggest predisposing genetic factors in stroke. Lacunar infarcts represent a homogeneous phenotype, which is a prerequisite for genetic analyses. Applying an affected sib -pair analysis, we prospectively assessed the prevalence of microangiopathic brain lesions (MBL) and associated risk factors among siblings of patients with lacunar stroke. METHODS: Index patients fulfilled clinical criteria of a lacunar stroke in combination with a corresponding MBL on CT or MRI. Siblings were characterized as affected if MBL demonstrated on MRI. The prevalence of MBL was compared with population prevalence data extracted from other studies. RESULTS: From 784 patients screened, 81 index patients with lacunar stroke and 97 siblings were recruited, of which 42% were identified as affected. Compared with data from unselected historical controls and stratified by age groups, prevalence was between 2 and 5 times higher. CONCLUSIONS: Our results indicate that genetic stroke studies are feasible even in subtypes of ischemic stroke. The high prevalence of MBL among siblings of patients with lacunar infarct might suggest a familial aggregation. However, due to the small sample size these results need to be interpreted with caution and require confirmation by planned genetic analyses.

Cerebral microbleeds on MRI: prevalence, associations, and potential clinical implications.

OBJECTIVE: To assess the potential role of cerebral microbleeds (CMB) in intracerebral hemorrhage (ICH), as indicators of cerebral small-vessel disease, and their possible implications for antithrombotic treatment. METHODS: The author reviewed literature published through July 2005 from electronic MEDLINE, PubMed, and hand searches. CMB prevalence analyses were performed for subjects without cerebrovascular disease, with ICH, and with ischemic cerebrovascular disease. RESULTS: Prevalence data from more than 5,200 subjects were analyzed. In elderly subjects without cerebrovascular disease, CMB prevalence is between 5% and 6%, associated with advanced age, while data are inconsistent with regard to CMB and chronic hypertension. CMB are prevalent in 68% of patients with spontaneous ICH and 40% of those with ischemic cerebrovascular disease. Cerebral microangiopathy (lacunes, leukoaraiosis) is associated with the highest prevalence (57%) of CMB among patients with ischemic stroke. In patients with suspected cerebral amyloid angiopathy (CAA) or Alzheimer disease, CMB are predominantly located in the cortical-subcortical area. Current data provide no evidence that CMB increase the risk of ICH among patients on antithrombotic treatment or those treated with thrombolysis for acute stroke. CONCLUSIONS: Cerebral microbleeds might indicate a higher risk of future intracerebral hemorrhage and may be a marker of cerebral small-vessel disease and cerebral amyloid angiopathy. However, more prospective data are required in order to confirm these assumptions. Recommendations to guide antithrombotic treatment based on the detection of cerebral microbleeds are presently not justified.

Dynamic spin labeling angiography in extracranial carotid artery stenosis.

BACKGROUND AND PURPOSE: Similar to digital subtraction angiography, dynamic spin labeling angiography (DSLA) provides time-resolved measurements of the influx of blood into the cerebral vascular tree. We determined whether DSLA may help in assessing the degree of stenosis and whether it provides information about intracerebral collateralization and allows us to monitor the hemodynamic effects of vascular interventions. METHODS: We developed a segmented DSLA sequence that allowed the formation of images representing inflow delays in 41-ms increments. Thirty patients with unilateral carotid artery stenosis and 10 control subjects underwent DSLA. Arrival times of the labeled arterial blood bolus were measured in the carotid siphon (CS) and the middle cerebral artery (MCA) on both sides, and the corresponding side-to-side arrival time differences (ATDs) were calculated. ATDs before and after carotid endarterectomy or percutaneous angioplasty were studied in 10 patients. RESULTS: The degree of stenosis was significantly correlated with ATD in the cerebral vessels. Receiver operating characteristic analysis yielded a cutoff CS ATD of 110 ms to separate stenoses <70% from those > or =70%, with a sensitivity of 90% and a specificity of 67%. In one third of patients, ATD was higher in the MCA than in the CS; this finding suggested an absence of collateralization. Most patients had reduced ATD in the MCA. The degree of ATD reduction was regarded as a quantitative measure of collateralization. Successful intervention resulted in normalized ATDs. CONCLUSION: DSLA is a promising method that allowed us to noninvasively quantify the hemodynamic effect of extracranial carotid stenosis and the resulting intracranial collateralization.