Tenecteplase, 0.4 mg/kg, in Moderate and Severe Acute Ischemic Stroke: A Pooled Analysis of NOR-TEST and NOR-TEST 2A.

Background The optimal dose of tenecteplase in acute ischemic stroke remains to be defined. We present a pooled analysis of the 2 NOR-TESTs (Norwegian Tenecteplase Stroke Trials) exploring the efficacy and safety of tenecteplase, 0.4 mg/kg. Methods and Results We retrospectively reviewed 2 PROBE (Prospective Randomized Open, Blinded End-point) trials, NOR-TEST and NOR-TEST 2A. Patients were randomized to either tenecteplase, 0.4 mg/kg, or alteplase, 0.9 mg/kg. The primary end point was favorable functional outcome at 3 months (modified Rankin Scale score, 0-1) or return to baseline if prestroke modified Rankin Scale score was 2. Secondary end points included favorable functional and clinical outcome and safety data. The pooled analysis includes patients with National Institutes of Health Stroke Scale score ≥6 from both trials and an additional post hoc analysis of patients with National Institutes of Health Stroke Scale score ≤5 from NOR-TEST. The per-protocol analysis contains 483 patients, of whom 235 were assigned to tenecteplase and 248 were assigned to alteplase. In per-protocol analysis, functional outcome was better in the alteplase arm with cutoff modified Rankin Scale score of 2 (odds ratio [OR], 0.52 [95% CI, 0.33-0.80]; P=0.003) and expressed by ordinal shift analysis (OR, 1.64 [95% CI, 1.17-2.28]; P=0.004). Mortality at 3 months was higher in the tenecteplase arm (OR, 2.48 [95% CI, 1.20-5.10]; P=0.01). Mortality and intracranial hemorrhage rates were higher in the severe stroke group randomized to tenecteplase, whereas these rates were similar for alteplase and tenecteplase in moderate and mild stroke. Conclusions Tenecteplase, 0.4 mg/kg, is unsafe in moderate and severe stroke, and the risk of death and intracranial hemorrhage probably increases with stroke severity. A lower tenecteplase dose should be tested in future trials. Registration URL: https://www.clinicaltrials.gov; Unique identifiers: NCT01949948, NCT03854500.

Clinical manifestation of acute cerebral infarcts in multiple arterial territories.

OBJECTIVES: We aimed to assess frequencies and radiological aspects of single- and multiterritory clinical manifestation among patients with acute cerebral infarcts in multiple arterial territories (MACI). MATERIALS & METHODS: We retrospectively reviewed admission records and diffusion-weighted magnetic resonance imaging of patients with MACI admitted to our stroke unit between 2006 and 2017. MACI was defined as acute cerebral ischemic lesions in at least two out of three arterial cerebral territories, that is, the left anterior, right anterior and the bilateral posterior territory. Patients with single- and multiterritory clinical manifestation were then compared for topographical distribution of the ischemic lesions, the number of ischemic lesions, and The Oxfordshire Community Stroke Project classification. RESULTS: Out of 311 patients with MACI, 222 (71.4%) presented with single-territory clinical manifestation. Involvement of the left hemisphere (OR = 0.37, 95% CI 0.16-0.82), less than five ischemic lesions (OR = 0.58, 95% CI 0.35-0.97), and partial anterior circulation infarct clinical stroke syndrome (OR = 0.57, 95% CI 0.34-0.97) were associated with single-territory clinical manifestation. Involvement of all three territories (OR = 2.58, 95% = 1.48-4.50), more than 10 ischemic lesions (OR = 2.30, 95% CI 1.32-4.01) and total anterior circulation infarct clinical stroke syndrome (OR = 3.31, 95% CI 1.39-7.86) were associated with multiterritory clinical manifestation. CONCLUSION: Most patients with MACI present with single-territory clinical manifestation on admission. Diffusion-weighted magnetic resonance imaging is therefore necessary for a definite diagnosis.

Sonothrombolysis in Patients With Acute Ischemic Stroke With Large Vessel Occlusion: An Individual Patient Data Meta-Analysis.

BACKGROUND AND PURPOSE: Evidence about the utility of ultrasound-enhanced thrombolysis (sonothrombolysis) in patients with acute ischemic stroke (AIS) is conflicting. We aimed to evaluate the safety and efficacy of sonothrombolysis in patients with AIS with large vessel occlusion, by analyzing individual patient data of available randomized-controlled clinical trials. METHODS: We included all available randomized-controlled clinical trials comparing sonothrombolysis with or without addition of microspheres (treatment group) to intravenous thrombolysis alone (control group) in patients with AIS with large vessel occlusion. The primary outcome measure was the rate of complete recanalization at 1 to 36 hours following intravenous thrombolysis initiation. We present crude odds ratios (ORs) and ORs adjusted for the predefined variables of age, sex, baseline stroke severity, systolic blood pressure, and onset-to-treatment time. RESULTS: We included 7 randomized controlled clinical trials that enrolled 1102 patients with AIS. A total of 138 and 134 confirmed large vessel occlusion patients were randomized to treatment and control groups respectively. Patients randomized to sonothrombolysis had increased odds of complete recanalization compared with patients receiving intravenous thrombolysis alone (40.3% versus 22.4%; OR, 2.17 [95% CI, 1.03-4.54]; adjusted OR, 2.33 [95% CI, 1.02-5.34]). The likelihood of symptomatic intracranial hemorrhage was not significantly different between the 2 groups (7.3% versus 3.7%; OR, 2.03 [95% CI, 0.68-6.11]; adjusted OR, 2.55 [95% CI, 0.76-8.52]). No differences in the likelihood of asymptomatic intracranial hemorrhage, 3-month favorable functional and 3-month functional independence were documented. CONCLUSIONS: Sonothrombolysis was associated with a nearly 2-fold increase in the odds of complete recanalization compared with intravenous thrombolysis alone in patients with AIS with large vessel occlusions. Further study of the safety and efficacy of sonothrombolysis is warranted.

Short-Term Outcome and In-Hospital Complications After Acute Cerebral Infarcts in Multiple Arterial Territories.

Background and Purpose- Patients with acute cerebral infarcts in multiple arterial territories (MACI) represent a substantial portion of the stroke population. There are no data on short-term outcome and in-hospital complications in patients with MACI. We compared patients with MACI with patients having acute cerebral infarct(s) in a single arterial territory. Methods- We analyzed 3343 patients with diffusion-weighted imaging-confirmed acute cerebral infarcts. MACI was defined as at least 2 acute cerebral ischemic lesions in at least 2 arterial cerebral territories. Patients with MACI were compared with patients with acute cerebral infarct(s) in a single arterial territory for relevant in-hospital complications and short-term outcome, namely National Institutes of Health Stroke Scale and modified Rankin Scale at day 7 after admission or at discharge when earlier. Results- A total of 311 patients (9.3%) met the definition of MACI. Both median National Institutes of Health Stroke Scale (2 [1-7] versus 1 [0-4]) and modified Rankin Scale (3 [1-4] versus 2 [1-3]) were higher in patients with MACI. MACI was independently associated with higher National Institutes of Health Stroke Scale and modified Rankin Scale. Deep venous thrombosis, myocardial infarction, and any complications were more frequent in patients with MACI. Conclusions- In-hospital complications were more frequent in patients with MACI, which may adversely affect short-term clinical and functional outcome. Closer follow-up of patients with MACI during hospitalization may prevent such events and negative progression.

Incidence and Etiologies of Stroke Mimics After Incident Stroke or Transient Ischemic Attack.

Background and Purpose- Stroke mimics (SM) pose a common clinical challenge, but the burden of SM in patients with previous ischemic stroke (IS) or transient ischemic attack is unknown. The objective of this study was to calculate the incidence of SM in IS survivors, compare it with the incidence of recurrent stroke in the same population, and explore the time-dependent patterns of SM etiologies. Methods- This prospective cohort study registered SM events and etiologies among 1872 IS and transient ischemic attack survivors diagnosed with index stroke at Haukeland University Hospital stroke unit from 2007 to 2013 by review of medical records. Cumulative incidences of SM were estimated with a competing risks Cox model and compared with incidence of recurrent stroke in the same population. Results- During 8172 person-years of follow-up, 339 patients had 480 SM events. The cumulative incidence rate of SM during follow-up was 58.7 per 1.000 person-years (95% CI, 53.7-64.2) compared with 34.0 per 1.000 person-years (95% CI, 30.2-38.2) for recurrent stroke in the same time period. The risks of SM and recurrent stroke were highest the first year after index IS or transient ischemic attack. The most frequent SM diagnoses were sequelae of cerebral infarction (19.8%), medical observation, and evaluation for suspected cerebrovascular disease (15.6%) and infections (14.0%). The 2 most frequent and unspecific diagnoses (sequelae of cerebral infarction and medical observation) were clustered in the first months after index stroke. Conclusions- SM after IS or transient ischemic attack are more frequent than recurrent stroke and the risk is especially high in the early period. SMs are multietiological and unspecific diagnoses are most frequent early after index stroke.

Atrial fibrillation in cryptogenic stroke and transient ischaemic attack - The Nordic Atrial Fibrillation and Stroke (NOR-FIB) Study: Rationale and design.

PURPOSE: Paroxysmal atrial fibrillation is often suspected as a probable cause of cryptogenic stroke. Continuous long-term ECG monitoring using insertable cardiac monitors is a clinically effective technique to screen for atrial fibrillation and superior to conventional follow-up in cryptogenic stroke. However, more studies are needed to identify factors which can help selecting patients with the highest possibility of detecting atrial fibrillation with prolonged rhythm monitoring. The clinical relevance of short-term atrial fibrillation, the need for medical intervention and the evaluation as to whether intervention results in improved clinical outcomes should be assessed. METHOD: The Nordic Atrial Fibrillation and Stroke Study is an international, multicentre, prospective, observational trial evaluating the occurrence of occult atrial fibrillation in cryptogenic stroke and transient ischaemic attack. Patients with cryptogenic stroke or transient ischaemic attack from the Nordic countries are included and will have the Reveal LINQ® Insertable cardiac monitor system implanted for 12 months for atrial fibrillation detection. Biomarkers which can be used as predictors for atrial fibrillation and may identify patients, who could derive the most clinical benefit from the detection of atrial fibrillation by prolonged monitoring, are being studied. CONCLUSION: The primary endpoint is atrial fibrillation burden within 12 months of continuous rhythm monitoring. Secondary endpoints are atrial fibrillation burden within six months, levels of biomarkers predicting atrial fibrillation, CHA2DS2-VASc score, incidence of recurrent stroke or transient ischaemic attack, use of anticoagulation and antiarrhythmic drugs, and quality of life measurements. The clinical follow-up period is 12 months. The study started in 2017 and the completion is expected at the end of 2020.

Five-year readmission and mortality differ by ischemic stroke subtype.

BACKGROUND: Ischemic stroke subtype may influence the risk of readmission and mortality after ischemic stroke (IS) and transient ischemic attack (TIA) due to differences in comorbidity, risk factors, and stroke severity. We aimed to study the five-year incidence and risk of all-cause readmission, cause-specific readmission and mortality after IS or TIA by stroke subtype. METHODS: The medical records of 1453 patients admitted with IS or TIA to the stroke unit at Haukeland University Hospital, Norway, between 2007 and 2012 were reviewed for identification of unplanned readmissions within five years after discharge. Stroke etiology was classified as large-artery atherosclerosis (LAA), cardioembolism (CE), small vessel occlusion (SVO), stroke of other determined etiology (SOE), multiple etiologies (ME), or cryptogenic stroke (CS). Kaplan-Meier estimates and Cox regression analyses were used to determine incidences and risk of readmission and death. RESULTS: The five-year incidence of all-cause readmission was 72.6% (74% LAA, 81% CE, 65% SVO, 55% SOE, 71% ME, and 67% CS), with infections, cardiac disease, stroke-related events and fractures as the most frequent causes. Compared to patients with other subtypes, SVO subtype had a 21% lower risk of all-cause readmission and a 48% lower risk of death, whereas CE had a 25% higher risk of all cause readmission and a 34% higher risk of death. CE subtype also had a 75% higher risk of readmission due to cardiac disease, whereas CS subtype had a 44% lower risk of readmission with cardiac disease. CONCLUSION: The five-year incidence of readmission and mortality varied among the stroke subtypes. The risk of readmission and death are especially high in patients with CE subtype, and lowest for patients with SVO subtype.

Recurrent ischemic stroke: Incidence, predictors, and impact on mortality.

BACKGROUND AND PURPOSE: Recurrent ischemic stroke (IS) or TIA is frequent with a considerable variation in incidence and mortality across populations. Current data on stroke recurrence and mortality are useful to examine trends, risk factors, and treatment effects. In this study, we calculated the incidence of recurrent IS or TIA in a hospital-based stroke population in Western Norway, investigated recurrence factors, and estimated the effect of recurrence on all-cause mortality. METHODS: This prospective cohort study registered recurrence and mortality among 1872 IS and TIA survivors admitted to the stroke unit at Haukeland University Hospital between July 2007 and December 2013. Recurrence and death until September 1, 2016, were identified by medical chart review. Cumulative incidences of recurrence were estimated with a competing risks Cox model. Multivariate Cox models were used to examine recurrence factors and mortality. RESULTS: During follow-up, 220 patients had 277 recurrent IS or TIAs. The cumulative recurrence rate was 5.4% at 1 year, 11.3% at 5 years, and 14.2% at the end of follow-up. Hypertension (HR = 1.65, 95% CI 1.21-2.25), prior symptomatic stroke (HR = 1.63, 95% CI 1.18-2.24), chronic infarcts on MRI (HR = 1.48, 95% CI 1.10-1.99), and age (HR 1.02/year, 95% CI 1.00-1.03) were independently associated with recurrence. A total of 668 (35.7%) patients died during follow-up. Recurrence significantly increased the all-cause mortality (HR = 2.55, 95% CI 2.04-3.18). CONCLUSIONS: The risk of recurrent IS stroke or TIA was modest in our population and was associated with previously established risk factors. Recurrence more than doubled the all-cause mortality.

One-year versus five-year hospital readmission after ischemic stroke and TIA.

BACKGROUND: The burden of hospital readmission after stroke is substantial, but little knowledge exists on factors associated with long-term readmission after stroke. In a cohort comprising patients with ischemic stroke and transient ischemic attack (TIA), we examined and compared factors associated with readmission within 1 year and first readmission during year 2-5. METHODS: Patients with ischemic stroke or TIA who were discharged alive between July 2007 and October 2012, were followed for 5 years by review of medical charts. The timing and primary cause of the first unplanned readmission were registered. Cox regression was used to identify independent risk factors for readmission within 1 year and first readmission during year 2-5 after discharge. RESULTS: The cohort included 1453 patients, of whom 568 (39.1%) were readmitted within 1 year. Of the 830 patients that were alive and without readmission 1 year after discharge, 439 (52.9%) were readmitted within 5 years. Patients readmitted within 1 year were older, had more severe strokes, poorer functional outcome, and a higher occurrence of complications during index admission than patients readmitted during year 2-5. Cardiovascular comorbidity and secondary preventive treatment did not differ between the two groups of readmitted patients. Higher age, poorer functional outcome, coronary artery disease and hypertension were independently associated with readmission within both 1 year and during year 2-5. Peripheral artery disease was independently associated with readmission within 1 year, and atrial fibrillation was associated with readmission during year 2-5. CONCLUSIONS: More than half of all patients who survived the first year after stroke without any readmissions were readmitted within 5 years. Patients readmitted within 1 year and between years 2-5 shared many risk factors for readmission, but they differed in age, functional outcome and occurrence of complications during the index admission.

Thirty-day recurrence after ischemic stroke or TIA.

BACKGROUND: Incidence of recurrent stroke is highest within 30 days after the initial ischemic stroke (IS) or TIA, but knowledge about early recurrence is lacking. We aimed to identify etiological groups with highest risk of early recurrence and assess how the TOAST classification identified index stroke etiology. METHODS: Medical records of 1874 IS and TIA patients in the Bergen NORSTROKE registry were retrospectively reviewed for identification of recurrent IS or TIA within 30 days after index IS or TIA. Stroke etiology was determined by review of electronical medical journals. Logistic regression was used to calculate odds ratios (OR) for 30-day recurrence. RESULTS: Thirty-three patients (1.8%) were readmitted with recurrent IS or TIA within 30 days after index stroke. By using TOAST, 12 patients were initially classified with stroke of unknown etiology (SUE). Etiologies behind recurrent IS or TIA were after the recurrent episode identified as extracranial large artery atherosclerosis (LAA) in 14 patients (42.4%), intracranial arterial pathology in seven patients (21.2%), active malignancy in six patients (18.2%), and cardio embolism in four patients (12.1%). Small vessel occlusion and SUE were the causes in one patient each. Logistic regression showed that patients with stroke of other determined etiology (SOE) and LAA had increased risk of 30-day recurrence (OR = 9.72, 95% CI 1.84-51.3, p < 0.01 and OR = 4.36, 95% CI 2.01-9.47, p < 0.01, respectively). CONCLUSION: Patients with LAA and SOE had increased risk of recurrent IS or TIA within 30 days. TOAST was inadequate at identifying exact etiologies behind recurrent stroke at index event.

Thirty-day readmission after spontaneous intracerebral hemorrhage.

Background: Intracerebral hemorrhage (ICH) is the most severe form of stroke, but data on readmission after ICH are sparse. We aimed to determine frequency, causes, and predictors of 30-day readmission after ICH. Materials and Methods: This retrospective cohort study includes all spontaneous ICH survivors admitted to the stroke unit at Haukeland University Hospital in Bergen in Norway from July 2007 to December 2013. Patients were followed by review of electronic medical charts, and the first unplanned readmission within 30 days after discharge was used as final outcome. Cox regression analysis was performed to identify predictors of 30-day readmission. Results: We identified 226 patients with spontaneous ICH, 70 (31.0%) of whom died before discharge or were discharged to palliative care. Of the remaining 156 ICH survivors, 28 (18.0%) were readmitted within 30 days. Median time to readmission was 12 days (IQR 4.5 - 18.5). Most patients were readmitted due to infections (N = 13). None of the patients were readmitted with recurrent stroke. Pneumonia and enteral feeding during the index hospitalization were associated with readmission for infections (both p < .01). Age was the only independent predictor of readmission (HR 1.06, 95% CI 1.02 - 1.11, p = .006). Conclusions: Almost one in five of our spontaneous ICH survivors was readmitted within 30 days, and most readmissions were caused by infections.

Clinical Importance of Temporal Bone Features for the Efficacy of Contrast-Enhanced Sonothrombolysis: a Retrospective Analysis of the NOR-SASS Trial.

Contrast-enhanced sonothrombolysis (CEST) seems to be a safe and promising treatment in acute ischemic stroke. It remains unknown if temporal bone features may influence the efficacy of CEST. We investigated the association between different temporal bone features on admission computed tomography (CT) scan and the outcome in acute ischemic stroke patients included in the randomized Norwegian Sonothrombolysis in Acute Stroke Study (NOR-SASS). Patients diagnosed as stroke mimics and those with infratentorial stroke or with incorrect insonation were excluded. We retrospectively assessed temporal bone heterogeneity (presence of diploë), diploë ratio, thickness, and density on admission CT scans. National institute of Health Stroke Scale (NIHSS) at 24 h and modified Rankin Scale (mRS) at 3 months were correlated with CT findings both in CEST and sham CEST patients. A total of 99 patients were included of which 52 were assigned to CEST and 47 to sham CEST. Approximately 20% patients had a heterogeneous temporal bone in both the CEST and sham CEST group. All temporal bone CT features studied were associated with female sex. In the CEST group, temporal bone heterogeneity (p = 0.006) and higher temporal bone diploë ratio (p = 0.002) were associated with higher NIHSS at 24 h. There was no association between temporal bone features and mRS at 3 months. Approximately 20% of acute ischemic stroke patients have heterogeneous temporal bone and may be resistant to standard 2-MHz transcranial Doppler ultrasound treatment. Sonothrombolysis resistance may easily be predicted by admission CT for better selection.

The Impact of Ischaemic Stroke Subtype on 30-day Hospital Readmissions.

BACKGROUND: Stroke aetiology may affect the risk and causes of readmission after ischaemic stroke (IS) and transient ischaemic attack (TIA) due to differences in risk factors, functional outcome, and treatment. We aimed to examine frequencies, causes, and risk of 30-day readmission by stroke subtype, determine predictors of 30-day readmission, and study the impact of 30-day readmissions on one-year mortality. METHODS: All surviving patients admitted with IS or TIA from July 2007 to December 2013 were followed by review of medical records for all unplanned readmissions within 30 days after discharge. Stroke subtype was classified as large-artery atherosclerosis (LAA), cardioembolism (CE), small vessel occlusion (SVO), stroke of other determined aetiology (SOE), or stroke of undetermined aetiology (SUE). Cox regression analyses were performed to assess the risk of 30-day readmission for the stroke subtypes and identify predictors of 30-day readmission, and its impact on one-year mortality. RESULTS: Of 1874 patients, 200 (10.7%) were readmitted within 30 days [LAA 42/244 (17.2%), CE 75/605 (12.4%), SVO 12/205 (5.9%), SOE 6/32 (18.8%), SUE 65/788 (8.3%)]. The most frequent causes of readmissions were stroke-related event, infection, recurrent stroke/ TIA, and cardiac disease. After adjusting for age, sex, functional outcome, length of stay, and the risk factor burden, patients with LAA and SOE subtype had significantly higher risks of readmission for any cause, recurrent stroke or TIA, and stroke-related events. Predictors of 30-day readmission were higher age, peripheral arterial disease, enteral feeding, and LAA subtype. Thirty-day readmission was an independent predictor of one-year mortality. CONCLUSIONS: Patients with LAA or SOE have a high risk of 30-day readmission, possibly caused by an increased risk of recurrent stroke and stroke-related events. Awareness of the risk of readmission for different causes and appropriate handling according to stroke subtype may be useful for preventing some readmissions after stroke.

Time patterns in multiple acute cerebral infarcts.

Background Multiple acute cerebral infarcts in different arterial territories may be caused by several emboli concurrently or successively. Aim and/or hypothesis We hypothesized that the time from stroke onset to magnetic resonance imaging may shed light on underlying mechanisms of multiple acute cerebral infarcts. Methods This is a prospective observational cohort study involving 2697 ischemic stroke patients conducted at Haukeland University Hospital between February 2006 and October 2013. Only patients with diffusion-weighted imaging lesions in more than one arterial territory (left or right anterior circulation or posterior circulation) were included. The time from stroke onset to magnetic resonance imaging was registered and correlated with the etiology of multiple acute cerebral infarcts in each patient. Results We reviewed 2697 consecutive patients and 2220 (82%) underwent magnetic resonance imaging. Among these 2125 (96%) had diffusion-weighted imaging lesions. We found 187 multiple acute cerebral infarct patients who were then included in the study. There was positive correlation (0.20; p < .001) between time to magnetic resonance imaging and frequency of multiple acute cerebral infarcts caused by internal carotid stenosis. There was no correlation (-.02) between time to magnetic resonance imaging and frequency of multiple acute cerebral infarcts caused by cardiogenic embolism. Conclusions Multiple acute cerebral infarcts associated with cardiogenic embolism seem to happen concurrently as a shower of emboli whereas multiple acute cerebral infarcts associated with internal carotid artery stenosis seem to occur successively separated by hours or days.

Is higher body temperature beneficial in ischemic stroke patients with normal admission CT angiography of the cerebral arteries?

BACKGROUND: Low body temperature is considered beneficial in ischemic stroke due to neuroprotective mechanisms, yet some studies suggest that higher temperatures may improve clot lysis and outcomes in stroke patients treated with tissue plasminogen activator (tPA). The effect of increased body temperature in stroke patients treated with tPA and with normal computed tomography angiography (CTA) on admission is unknown. We hypothesized a beneficial effect of higher body temperature in the absence of visible clots on CTA, possibly due to enhanced lysis of small, peripheral clots. METHODS: Patients with ischemic stroke admitted to our Stroke Unit between February 2006 and April 2013 were prospectively registered in a database (Bergen NORSTROKE Registry). Ischemic stroke patients treated with tPA with normal CTA of the cerebral arteries were included. Outcomes were assessed by the modified Rankin Scale (mRS) after 1 week. An excellent outcome was defined as mRS=0, and a favorable outcome as mRS=0-1. RESULTS: A total of 172 patients were included, of which 48 (27.9%) had an admission body temperature ≥37.0°C, and 124 (72.1%) had a body temperature <37.0°C. Body temperature ≥37.0°C was independently associated with excellent outcomes (odds ratio [OR]: 2.8; 95% confidence interval [CI]: 1.24-6.46; P=0.014) and favorable outcomes (OR: 2.8; 95% CI: 1.13-4.98; P=0.015) when adjusted for confounders. CONCLUSION: We found an association between higher admission body temperature and improved outcome in tPA-treated stroke patients with normal admission CTA of the cerebral arteries. This may suggest a beneficial effect of higher body temperature on clot lysis in the absence of visible clots on CTA.