Abstract TMP65: What Changes Improve Door-to-Needle Times? Results From a Single Center Door-to-Needle Improvement Initiative

Background: The benefit of thrombolysis is highly time dependent. Strategies and system changes to reduce door-to-needle time (DNT) have been proposed but the effectiveness of such strategies has not been fully evaluated.

Hypothesis: Specific change strategies to the system of delivering thrombolysis significantly improve DNT. Stroke severity also affects DNT significantly.

Methods: The Hurry Acute Stroke Treatment and Evaluation (HASTE) project was implemented in 3 phases at a single academic medical center to reduce DNT using four strategies. In HASTE-I (Jun 6 2012 - Jun 5 2013), baseline performance was analyzed with no changes made to stroke treatment. In HASTE-II (Jun 6 2013 - Jan 24 2015), three changes were implemented: 1) a STAT! stroke protocol to pre-notify the stroke team of the severity of incoming stroke patients; 2) administering tPA in the CT scanner; and 3) registering the patient as unknown prior to exact identification, to allow immediate order entry in our electronic health system. In HASTE-III (Jan 25 2015 - Jun 29 2015), we implemented a process to bring the patient directly to CT on the EMS stretcher. Decrease in DNT was analyzed using Wilcoxon rank sum and Kruskal Wallis tests, and multivariable linear regression. Log transformed DNT was modeled using a backward selection approach.

Results: There were 350 patients treated with tPA during the project. The results of the univariable and multivariable analyses are shown in the table. In univariable analyses, the following strategies improved DNT: STAT! stroke, patient registered as unknown , and stretcher to CT. Additionally, DNT was lower if tPA was administered in the CT. The stroke severity also affected DNT. Multivariable regression showed the following factors to be significant: giving tPA in the CT, stretcher to CT, patient registered as unknown , and stroke severity.

Conclusions: Stretcher to CT, patient registered as unknown , and administering tPA in CT were most efficacious in reducing DNT.

Abstract 5: Analysis of Workflow Aad Determinants of Delays in the Escape Randomized Controlled Trial

Introduction: The ESCAPE trial used innovative imaging and aggressive target time metrics to demonstrate the benefit of additional endovascular treatment over standard care in patients with disabling acute ischemic stroke. We performed a detailed analysis of workflow and determine modifiable factors resulting in delays.

Methods: The trial enrolled 316 patients fulfilling eligibility criteria and presenting within 12 hours of stroke symptom onset from 22 sites across 3 continents between February 2013 and October 2014. We considered four specific interval times: onset-to-ED arrival, ED-arrival-to-qualifying CT scan, qualifying CT scan-to-groin puncture, groin puncture-to-reperfusion. Missing times were not imputed. When reperfusion was not achieved, the reperfusion time was considered missing and was not imputed. Interval times from stroke symptom onset to first reperfusion are reported using medians and inter-quartile range. To assess the relationship between patient, hospital and health system characteristics as predictors of longer interval times, a negative binomial regression provided the best fit to the data.

Results: Stroke symptom onset to arrival in emergency room of endovascular capable hospital time was 42% (34 mins) longer among patients who received intravenous alteplase at the referring hospital (drip and ship) vs. patients directly transferred to the endovascular capable hospital (direct to mother ship) (Figure). Qualifying CT to groin puncture time was 15% (8 mins) shorter among patients presenting during work hours vs. off hours. Time from qualifying CT to groin puncture was 41% (24 min) shorter in drip and ship patients than vs. when intravenous alteplase was administered after qualifying CT (mothership). General anesthesia prolonged this time by 43% (22 min). Balloon guide catheter during endovascular procedure shortened time from groin puncture to reperfusion by 21% (8 mins).

Conclusions: Inefficiencies in triaging systems, presentation during off hours, intravenous alteplase administration, GA utilization and endovascular techniques offer major opportunities for improvement.

Abstract 201: Time is Brain: Results From the Escape Randomized Controlled Trial

Introduction: The ESCAPE trial used innovative imaging and aggressive target time metrics to demonstrate the benefit of additional endovascular treatment over standard care in patients with disabling acute ischemic stroke. We analyze the impact of time from onset to reperfusion and from imaging to reperfusion on clinical outcome.

Methods: The trial enrolled 316 patients fulfilling eligibility criteria and presenting within 12 hours of stroke symptom onset from 22 sites across 3 continents between February 2013 and October 2014. Logistic regression models were used to estimate the probability of functionally independent outcome (modified Rankin Scale 0-2 at 90 days) based on time from stroke symptom onset to qualifying CT, stroke symptom onset to first reperfusion and qualifying CT to reperfusion after adjusting for age, sex, baseline NIHSS, occlusion site, baseline Alberta Stroke Program Early CT Score (ASPECTS), intravenous alteplase administration (and time from stroke symptom onset to qualifying CT when the predictor time variable was time from qualifying CT to reperfusion).

Results: A 30-minute increase in time from qualifying CT to reperfusion decreases the probability of functionally independent outcome (mRS 0-2 at 90 days) by an absolute reduction of 8.5% (p=0.006). Similar trends in relationship between outcome and time from qualifying CT to reperfusion were noted for mRS cut-points 0-1 vs. 2-6 (p=0.08) and 0-3 vs. 4-6 (p=0.04). There was no relationship between clinical outcome and stroke symptom onset to qualifying CT for any mRS cut-point. A modest relationship was noted between stroke symptom onset to reperfusion time and the probability of achieving functionally independent outcome (mRS 0-2 vs. 3-6) (p = 0.04).

Conclusions and Relevance: The ESCAPE trial data with imaging based selection reveals that imaging-to-reperfusion time is more important than onset-to-imaging time as a predictor of outcome.

Trial Registration at clinicaltrials.gov NCT01778335

Scientific Rationale for the Inclusion and Exclusion Criteria for Intravenous Alteplase in Acute Ischemic Stroke

Purpose—

To critically review and evaluate the science behind individual eligibility criteria (indication/inclusion and contraindications/exclusion criteria) for intravenous recombinant tissue-type plasminogen activator (alteplase) treatment in acute ischemic stroke. This will allow us to better inform stroke providers of quantitative and qualitative risks associated with alteplase administration under selected commonly and uncommonly encountered clinical circumstances and to identify future research priorities concerning these eligibility criteria, which could potentially expand the safe and judicious use of alteplase and improve outcomes after stroke.

Methods—

Writing group members were nominated by the committee chair on the basis of their previous work in relevant topic areas and were approved by the American Heart Association Stroke Council’s Scientific Statement Oversight Committee and the American Heart Association’s Manuscript Oversight Committee. The writers used systematic literature reviews, references to published clinical and epidemiology studies, morbidity and mortality reports, clinical and public health guidelines, authoritative statements, personal files, and expert opinion to summarize existing evidence and to indicate gaps in current knowledge and, when appropriate, formulated recommendations using standard American Heart Association criteria. All members of the writing group had the opportunity to comment on and approved the final version of this document. The document underwent extensive American Heart Association internal peer review, Stroke Council Leadership review, and Scientific Statements Oversight Committee review before consideration and approval by the American Heart Association Science Advisory and Coordinating Committee.

Results—

After a review of the current literature, it was clearly evident that the levels of evidence supporting individual exclusion criteria for intravenous alteplase vary widely. Several exclusionary criteria have already undergone extensive scientific study such as the clear benefit of alteplase treatment in elderly stroke patients, those with severe stroke, those with diabetes mellitus and hyperglycemia, and those with minor early ischemic changes evident on computed tomography. Some exclusions such as recent intracranial surgery are likely based on common sense and sound judgment and are unlikely to ever be subjected to a randomized, clinical trial to evaluate safety. Most other contraindications or warnings range somewhere in between. However, the differential impact of each exclusion criterion varies not only with the evidence base behind it but also with the frequency of the exclusion within the stroke population, the probability of coexistence of multiple exclusion factors in a single patient, and the variation in practice among treating clinicians.

Effect of endovascular reperfusion in relation to site of arterial occlusion

OBJECTIVE

To assess whether the association between reperfusion and improved clinical outcomes after stroke differs depending on the site of the arterial occlusive lesion (AOL).

METHODS

We pooled data from Solitaire With the Intention for Thrombectomy (SWIFT), Solitaire FR Thrombectomy for Acute Revascularisation (STAR), Diffusion and Perfusion Imaging Evaluation for Understanding Stroke Evolution Study 2 (DEFUSE 2), and Interventional Management of Stroke Trial (IMS III) to compare the strength of the associations between reperfusion and clinical outcomes in patients with internal carotid artery (ICA), proximal middle cerebral artery (MCA) (M1), and distal MCA (M2/3/4) occlusions.

RESULTS

Among 710 included patients, the site of the AOL was the ICA in 161, the proximal MCA in 389, and the distal MCA in 160 patients (M2 = 131, M3 = 23, and M4 = 6). Reperfusion was associated with an increase in the rate of good functional outcome (modified Rankin Scale [mRS] score 0-2) in patients with ICA (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.7-7.2) and proximal MCA occlusions (OR 6.2, 95% CI 3.8-10.2), but not in patients with distal MCA occlusions (OR 1.4, 95% CI 0.8-2.6). Among patients with M2 occlusions, a subset of the distal MCA cohort, reperfusion was associated with excellent functional outcome (mRS 0-1; OR 2.2, 95% CI 1.0-4.7).

CONCLUSIONS

The association between endovascular reperfusion and better clinical outcomes is more profound in patients with ICA and proximal MCA occlusions compared to patients with distal MCA occlusions. Because there are limited data from randomized controlled trials on the effect of endovascular therapy in patients with distal MCA occlusions, these results underscore the need for inclusion of this subgroup in future endovascular therapy trials.

Small intracerebral hemorrhages have a low spot sign prevalence and are less likely to expand

Background

Hematoma expansion is a major predictor of morbidity and mortality after intracerebral hemorrhage (ICH). Both baseline hematoma volume and the CT-angiogram (CTA) spot sign predict hematoma expansion. Because the CTA spot sign may represent foci of active hemorrhage, we hypothesized that patients with smaller baseline hematoma volumes are less likely to be spot sign positive, and therefore less likely to expand.

Aim

We sought to validate our prior finding that small hematomas are unlikely to expand, and to determine the relationship between baseline hematoma volume, spot sign status, and risk of hematoma expansion.

Methods

Data were from the prospective PREDICT ICH study. Patients presenting within 6 h of symptom onset with completed baseline CT, CTA, and follow-up CT were included. Baseline hematoma volume was categorized a priori (<3 mL, 3–10 mL, 10–20 mL, >20 mL). The primary outcome was significant hematoma expansion (≥6 mL, ≥12.5 mL or ≥33%) and secondary outcomes were early neurological worsening, good clinical outcome (modified Rankin Scale 0–3), and mortality at 90 days.

Results

Among 315 patients meeting the inclusion criteria, baseline hematoma volume category predicted absolute hematoma expansion ( p < 0.001), spot sign prevalence ( p < 0.001), early neurologic worsening ( p = 0.002), clinical outcome ( p < 0.001), and mortality ( p < 0.001). Very small hematomas (<3 mL) were unlikely to be spot positive (7.7%), unlikely to expand (2.6%), and were associated with a 73% chance of good clinical outcome. Spot sign appeared to be most predictive of expansion in the 3–10 mL baseline hematoma volume category.

Conclusion

Very small hematomas are unlikely to expand and have a low spot sign prevalence. Hemostatic therapy trials may be best targeted at hemorrhages >3 mL in volume.

The future of endovascular treatment: Insights from the ESCAPE investigators

The ESCAPE trial demonstrated strong morbidity benefit and mortality reduction for endovascular stroke treatment. Following the release of the main results, the ESCAPE trial investigators convened at a 2-day close-out meeting in March 2015 in Banff, Alberta, Canada. Meeting discussions focused on system implications, procedural characteristics, and future directions. We report the proceedings of the meeting, which provide insights from the trialists into the issues of generalizability, treatment limitations, as well as future directions and opportunities in stroke care optimization.

Does the use of IV tPA in the current era of rapid and predictable recanalization by mechanical embolectomy represent good value?

As healthcare delivery in the USA transforms into a model that at its core requires value-based considerations, ischemic stroke is confronted by intersecting forces. Modern techniques allow rapid revascularization in the majority of patients with large vessel occlusions. Dramatic advances in the evidentiary basis for mechanical embolectomy are increasing the number of patients treated with this therapy. A key part of the therapeutic arsenal in many patients treated with interventional techniques has been concurrent intravenous thrombolysis. We consider whether this paradigm warrants change.

Perihematomal Edema Is Greater in the Presence of a Spot Sign but Does Not Predict Intracerebral Hematoma Expansion

BACKGROUND AND PURPOSE

Perihematomal edema volume may be related to intracerebral hemorrhage (ICH) volume at baseline and, consequently, with hematoma expansion. However, the relationship between perihematomal edema and hematoma expansion has not been well established. We aimed to investigate the relationship among baseline perihematomal edema, the computed tomographic angiography spot sign, hematoma expansion, and clinical outcome in patients with acute ICH.

METHODS

Predicting Hematoma Growth and Outcome in Intracerebral Hemorrhage Using Contrast Bolus CT (PREDICT) was a prospective observational cohort study of ICH patients presenting within 6 hours from onset. Patients underwent computed tomography and computed tomographic angiography scans at baseline and 24-hour computed tomography scan. A post hoc analysis of absolute perihematomal edema and relative perihematomal edema (absolute perihematomal edema divided by ICH) volumes was performed on baseline computed tomography scans (n=353). Primary outcome was significant hematoma expansion (>6 mL or >33%). Secondary outcomes were early neurological deterioration, 90-day mortality, and poor outcome.

RESULTS

Absolute perihematomal edema volume was higher in spot sign patients (24.5 [11.5-41.8] versus 12.6 [6.9-22] mL; P<0.001), but it was strongly correlated with ICH volume (ρ=0.905; P<0.001). Patients who experienced significant hematoma expansion had higher absolute perihematomal edema volume (18.4 [10-34.6] versus 11.8 [6.5-22] mL; P<0.001) but similar relative perihematomal edema volume (1.09 [0.89-1.37] versus 1.12 [0.88-1.54]; P=0.400). Absolute perihematomal edema volume and poorer outcomes were higher by tertiles of ICH volume, and perihematomal edema volume did not independently predict significant hematoma expansion.

CONCLUSIONS

Perihematomal edema volume is greater at baseline in the presence of a spot sign. However, it is strongly correlated with ICH volume and does not independently predict hematoma expansion.

Association Between CT Angiogram Collaterals and CT Perfusion in the Interventional Management of Stroke III Trial

BACKGROUND AND PURPOSE

Collateral flow can determine ischemic core and tissue at risk. Using the Interventional Management of Stroke (IMS) III trial data, we explored the relationship between computed tomography angiogram (CTA) collateral status and CT perfusion (CTP) parameters.

METHODS

Baseline CTA collaterals were trichotomized as good, intermediate, and poor, and CTP studies were analyzed to quantify ischemic core, tissue at risk, and mismatch ratios. Kruskal-Wallis and Spearman tests were used to measure the strength of association and correlation between CTA collaterals and CTP parameters.

RESULTS

A total of 95 patients had diagnostic CTP studies in the IMS III trial. Of these, 53 patients had M1/M2 middle cerebral artery±intracranial internal carotid artery occlusion, where baseline CTA collateral grading was performed. CTA collaterals were associated with smaller CTP measured ischemic core volume (P=0.0078) and higher mismatch (P=0.0004). There was moderate negative correlation between collaterals and core (rs=-0.45; 95% confidence interval, -0.64 to -0.20) and moderate positive correlation between collaterals and mismatch (rs=0.53; 95% confidence interval, 0.29-0.71).

CONCLUSION

Better collaterals were associated with smaller ischemic core and higher mismatch in the IMS III trial. Collateral assessment and perfusion imaging identify the same biological construct about ischemic tissue sustenance.

Endovascular Therapy Is Effective and Safe for Patients With Severe Ischemic Stroke: Pooled Analysis of Interventional Management of Stroke III and Multicenter Randomized Clinical Trial of Endovascular Therapy for Acute Ischemic Stroke in the Netherlands Data

BACKGROUND AND PURPOSE

We assessed the effect of endovascular treatment in acute ischemic stroke patients with severe neurological deficit (National Institutes of Health Stroke Scale score, ≥20) after a prespecified analysis plan.

METHODS

The pooled analysis of the Interventional Management of Stroke III (IMS III) and Multicenter Randomized Clinical Trial of Endovascular Therapy for Acute Ischemic Stroke in the Netherlands (MR CLEAN) trials included participants with an National Institutes of Health Stroke Scale score of ≥20 before intravenous tissue-type plasminogen activator (tPA) treatment (IMS III) or randomization (MR CLEAN) who were treated with intravenous tPA ≤3 hours of stroke onset. Our hypothesis was that participants with severe stroke randomized to endovascular therapy after intravenous tPA would have improved 90-day outcome (distribution of modified Rankin Scale scores), when compared with those who received intravenous tPA alone.

RESULTS

Among 342 participants in the pooled analysis (194 from IMS III and 148 from MR CLEAN), an ordinal logistic regression model showed that the endovascular group had superior 90-day outcome compared with the intravenous tPA group (adjusted odds ratio, 1.78; 95% confidence interval, 1.20-2.66). In the logistic regression model of the dichotomous outcome (modified Rankin Scale score, 0-2, or functional independence), the endovascular group had superior outcomes (adjusted odds ratio, 1.97; 95% confidence interval, 1.09-3.56). Functional independence (modified Rankin Scale score, ≤2) at 90 days was 25% in the endovascular group when compared with 14% in the intravenous tPA group.

CONCLUSIONS

Endovascular therapy after intravenous tPA within 3 hours of symptom onset improves functional outcome at 90 days after severe ischemic stroke.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00359424 (IMS III) and ISRCTN10888758 (MR CLEAN).

Intracerebral Hematoma Morphologic Appearance on Noncontrast Computed Tomography Predicts Significant Hematoma Expansion

Background and Purpose—

Hematoma expansion in intracerebral hemorrhage is associated with higher morbidity and mortality. The computed tomography (CT) angiographic spot sign is highly predictive of expansion, but other morphological features of intracerebral hemorrhage such as fluid levels, density heterogeneity, and margin irregularity may also predict expansion, particularly in centres where CT angiography is not readily available.

Methods—

Baseline noncontrast CT scans from patients enrolled in the Predicting Hematoma Growth and Outcome in Intracerebral Hemorrhage Using Contrast Bolus CT (PREDICT) study were assessed for the presence of fluid levels and degree of density heterogeneity and margin irregularity using previously validated scales. Presence and grade of these metrics were correlated with the presence of hematoma expansion as defined by the PREDICT study on 24-hour follow-up scan.

Results—

Three hundred eleven patients were included in the analysis. The presence of fluid levels and increasing heterogeneity and irregularity were associated with 24-hour hematoma expansion ( P =0.021, 0.003 and 0.049, respectively) as well as increases in absolute hematoma size. Fluid levels had the highest positive predictive value (50%; 28%–71%), whereas margin irregularity had the highest negative predictive value (78%; 71%–85). Noncontrast metrics had comparable predictive values as spot sign for expansion when controlled for vitamin K, antiplatelet use, and baseline National Institutes of Health Stroke Scale, although in a combined area under the receiver-operating characteristic curve model, spot sign remained the most predictive.

Conclusions—

Fluid levels, density heterogeneity, and margin irregularity on noncontrast CT are associated with hematoma expansion at 24 hours. These markers may assist in prediction of outcomes in scenarios where CT angiography is not readily available and may be of future help in refining the predictive value of the CT angiography spot sign.

Validation of the 9-Point and 24-Point Hematoma Expansion Prediction Scores and Derivation of the PREDICT A/B Scores

Background and Purpose—

Nine- and 24-point prediction scores have recently been published to predict hematoma expansion (HE) in acute intracerebral hemorrhage. We sought to validate these scores and perform an independent analysis of HE predictors.

Methods—

We retrospectively studied 301 primary or anticoagulation-associated intracerebral hemorrhage patients presenting <6 hours post ictus prospectively enrolled in the Predicting Hematoma Growth and Outcome in Intracerebral Hemorrhage Using Contrast Bolus Computed Tomography (PREDICT) study. Patients underwent baseline computed tomography angiography and 24-hour noncontrast computed tomography follow-up for HE analysis. Discrimination and calibration of the 9- and 24-point scores was assessed. Independent predictors of HE were identified using multivariable regression and incorporated into the PREDICT A/B scores, which were then compared with existing scores.

Results—

The 9- and 24-point HE scores demonstrated acceptable discrimination for HE>6 mL or 33% and >6 mL, respectively (area under the curve of 0.706 and 0.755, respectively). The 24-point score demonstrated appropriate calibration in the PREDICT cohort (χ 2 statistic, 11.5; P =0.175), whereas the 9-point score demonstrated poor calibration (χ 2 statistic, 34.3; P <0.001). Independent HE predictors included spot sign number, time from onset, warfarin use or international normalized ratio >1.5, Glasgow Coma Scale, and National Institutes of Health Stroke Scale and were included in PREDICT A/B scores. PREDICT A showed improved discrimination compared with both existing scores, whereas performance of PREDICT B varied by definition of expansion.

Conclusions—

The 9- and 24-point expansion scores demonstrate acceptable discrimination in an independent multicenter cohort; however, calibration was suboptimal for the 9-point score. The PREDICT A score showed improved discrimination for HE prediction but requires independent validation.

Outcome Differences between Intra-Arterial Iso- and Low-Osmolality Iodinated Radiographic Contrast Media in the Interventional Management of Stroke III Trial

BACKGROUND AND PURPOSE

Intracarotid arterial infusion of nonionic, low-osmolal iohexol contrast medium has been associated with increased intracranial hemorrhage in a rat middle cerebral artery occlusion model compared with saline infusion. Iso-osmolal iodixanol (290 mOsm/kg H2O) infusion demonstrated smaller infarcts and less intracranial hemorrhage compared with low-osmolal iopamidol and saline. No studies comparing iodinated radiographic contrast media in human stroke have been performed, to our knowledge. We hypothesized that low-osmolal contrast media may be associated with worse outcomes compared with iodixanol in the Interventional Management of Stroke III Trial (IMS III).

MATERIALS AND METHODS

We reviewed prospective iodinated radiographic contrast media data for 133 M1 occlusions treated with endovascular therapy. We compared 5 prespecified efficacy and safety end points (mRS 0-2 outcome, modified TICI 2b-3 reperfusion, asymptomatic and symptomatic intracranial hemorrhage, and mortality) between those receiving iodixanol (n = 31) or low-osmolal contrast media (n = 102). Variables imbalanced between iodinated radiographic contrast media types or associated with outcome were considered potential covariates for the adjusted models. In addition to the iodinated radiographic contrast media type, final covariates were those selected by using the stepwise method in a logistic regression model. Adjusted relative risks were then estimated by using a log-link regression model.

RESULTS

Of baseline or endovascular therapy variables potentially linked to outcome, prior antiplatelet agent use was more common and microcatheter iodinated radiographic contrast media injections were fewer with iodixanol. Relative risk point estimates are in favor of iodixanol for the 5 prespecified end points with M1 occlusion. The percentage of risk differences are numerically greater for microcatheter injections with iodixanol.

CONCLUSIONS

While data favoring the use of iso-osmolal iodixanol for reperfusion of M1 occlusion following IV rtPA are inconclusive, potential pathophysiologic mechanisms suggesting clinical benefit warrant further investigation.

Cerebral Perfusion Pressure is Maintained in Acute Intracerebral Hemorrhage: A CT Perfusion Study

BACKGROUND AND PURPOSE

Although blood pressure reduction has been postulated to result in a fall in cerebral perfusion pressure in patients with intracerebral hemorrhage, the latter is rarely measured. We assessed regional cerebral perfusion pressure in patients with intracerebral hemorrhage by using CT perfusion source data.

MATERIALS AND METHODS

Patients with acute primary intracerebral hemorrhage were randomized to target systolic blood pressures of <150 mm Hg (n = 37) or <180 mm Hg (n = 36). Regional maps of cerebral blood flow, cerebral perfusion pressure, and cerebrovascular resistance were generated by using CT perfusion source data, obtained 2 hours after randomization.

RESULTS

Perihematoma cerebral blood flow (38.7 ± 11.9 mL/100 g/min) was reduced relative to contralateral regions (44.1 ± 11.1 mL/100 g/min, P = .001), but cerebral perfusion pressure was not (14.4 ± 4.6 minutes(-1) versus 14.3 ± 4.8 minutes(-1), P = .93). Perihematoma cerebrovascular resistance (0.34 ± 0.11 g/mL) was higher than that in the contralateral region (0.30 ± 0.10 g/mL, P < .001). Ipsilateral and contralateral cerebral perfusion pressure in the external (15.0 ± 4.6 versus 15.6 ± 5.3 minutes(-1), P = .15) and internal (15.0 ± 4.8 versus 15.0 ± 4.8 minutes(-1), P = .90) borderzone regions were all similar. Borderzone cerebral perfusion pressure was similar to mean global cerebral perfusion pressure (14.7 ± 4.7 minutes(-1), P ≥ .29). Perihematoma cerebral perfusion pressure did not differ between blood pressure treatment groups (13.9 ± 5.5 minutes(-1) versus 14.8 ± 3.4 minutes(-1), P = .38) or vary with mean arterial pressure (r = -0.08, [-0.10, 0.05]).

CONCLUSIONS

Perihematoma cerebral perfusion pressure is maintained despite increased cerebrovascular resistance and reduced cerebral blood flow. Aggressive antihypertensive therapy does not affect perihematoma or borderzone cerebral perfusion pressure. Maintenance of cerebral perfusion pressure provides physiologic support for the safety of blood pressure reduction in intracerebral hemorrhage.

Choosing a Hyperacute Stroke Imaging Protocol for Proper Patient Selection and Time Efficient Endovascular Treatment: Lessons from Recent Trials

Recently, several prospective randomized control trials regarding endovascular treatment for patients with intracranial large artery occlusions causing acute ischemic stroke have been successfully reported. Effort to minimize time delays to endovascular treatment, patient selection and the use of retrievable stent were important factors for the success of these trials. The inclusion and exclusion criteria for each of these trials did include differences in imaging protocols. In this review, we focus on the importance of baseline non-invasive angiography prior to deciding endovascular treatment. Then imaging protocols are described for each trial according to measurement of infarct volume and collateral grading.

Carotid Webs and Recurrent Ischemic Strokes in the Era of CT Angiography

BACKGROUND AND PURPOSE

Carotid webs may cause recurrent ischemic stroke. We describe the prevalence, demographics, clinical presentation, imaging features, histopathology, and stroke risk associated with this under-recognized lesion.

MATERIALS AND METHODS

A carotid web was defined on CTA as a thin intraluminal filling defect along the posterior wall of the carotid bulb just beyond the carotid bifurcation on oblique sagittal section CTA that was seen as a septum on axial CTA. Using a prospective case series from April 2013 to April 2014, we describe the demographics, spectrum of imaging features on CTA, and histopathology of these carotid webs. From a retrospective analysis of patients at our center from May 2012 to April 2013 who had a baseline head and neck CTA followed by a brain MR imaging within 1-2 days of the CTA, we determine the period prevalence of carotid webs and the prevalence of ipsilateral stroke on imaging.

RESULTS

In the prospective series, the mean age was 50 years (range, 41-55 years); 5/7 patients were women. Recurrent stroke was seen in 5/7 (71.4%) patients with the carotid web; time to recurrence ranged from 1 to 97 months. Histopathology suggested a high probability of fibromuscular dysplasia. In the retrospective series, carotid webs were seen in 7/576 patients for a hospital-based-period prevalence of 1.2% (95% CI, 0.4%-2.5%). Two of these 7 patients had acute stroke in the vascular territory of the carotid web.

CONCLUSIONS

A carotid web may contribute to recurrent ischemic stroke in patients with no other determined stroke mechanism. Intimal variant fibromuscular dysplasia is the pathologic diagnosis in most cases. The prevalence of carotid web is low, while the optimal management strategy remains unknown.

Perihematoma cerebral blood flow is unaffected by statin use in acute intracerebral hemorrhage patients

Statin therapy has been associated with improved cerebral blood flow (CBF) and decreased perihematoma edema in animal models of intracerebral hemorrhage (ICH). We aimed to assess the relationship between statin use and cerebral hemodynamics in ICH patients. A post hoc analysis of 73 ICH patients enrolled in the Intracerebral Hemorrhage Acutely Decreasing Arterial Pressure Trial (ICH ADAPT). Patients presenting <24 hours from ICH onset were randomized to a systolic blood pressure target <150 or <180 mm Hg with computed tomography perfusion imaging 2 hours after randomization. Cerebral blood flow maps were calculated. Hematoma and edema volumes were measured planimetrically. Regression models were used to assess the relationship between statin use, perihematoma edema and cerebral hemodynamics. Fourteen patients (19%) were taking statins at the time of ICH. Statin-treated patients had similar median (IQR Q25 to 75) hematoma volumes (21.1 (9.5 to 38.3) mL versus 14.5 (5.6 to 27.7) mL, P=0.25), but larger median (IQR Q25 to 75) perihematoma edema volumes (2.9 (1.7 to 9.0) mL versus 2.2 (0.8 to 3.5) mL, P=0.02) compared with nontreated patients. Perihematoma and ipsilateral hemispheric CBF were similar in both groups. A multivariate linear regression model revealed that statin use and hematoma volumes were independent predictors of acute edema volumes. Statin use does not affect CBF in ICH patients. Statin use, along with hematoma volume, are independently associated with increased perihematoma edema volume.

Stroke prevention

The short-term risk of stroke after transient ischemic attack (TIA) is about 10% to 20% in the first 3 months, with much of the risk front-loaded in the first week. Unfortunately, little is known about the best therapies for hyperacute stroke prevention after TIA. A recent trial referred to by the acronym MATCH (for Management of Atherothrombosis With Clopidogrel in High-risk Patients With Recent Transient Ischemic Attack or Ischemic Stroke) provides hypothesis-generating data to suggest that double antiplatelet therapy in the short term may be appropriate. Here, the authors discuss treatment considerations, outlining the current knowledge and stressing the need for formal randomized trials to definitively establish the effectiveness of preventive therapies after minor stroke or TIA.