Andrew D. Barreto

Safety of tPA in stroke mimics and neuroimaging-negative cerebral ischemia

Background: Patients with acute neurologic symptoms may have other causes simulating ischemic stroke, called stroke mimics (SM), but they may also have averted strokes that do not appear as infarcts on neuroimaging, which we call neuroimaging-negative cerebral ischemia (NNCI). We determined the safety and outcome of IV thrombolysis within 3 hours of symptom onset in patients with SM and NNCI. Methods: Patients treated with IV tissue plasminogen activator (tPA) within 3 hours of symptom onset were identified from our stroke registry from June 2004 to October 2008. We collected admission NIH Stroke Scale (NIHSS) score, modified Rankin score (mRS), length of stay (LOS), symptomatic intracerebral hemorrhage (sICH), and discharge diagnosis. Results: Among 512 treated patients, 21% were found not to have an infarct on follow-up imaging. In the SM group (14%), average age was 55 years, median admission NIHSS was 7, median discharge NIHSS was 0, median LOS was 3 days, and there were no instances of sICH. The most common etiologies were seizure, complicated migraine, and conversion disorder. In the NNCI group (7%), average age was 61 years, median admission NIHSS was 7, median discharge NIHSS was 0, median LOS was 3 days, and there were no instances of sICH. Nearly all SM (87%) and NNCI (91%) patients were functionally independent on discharge (mRS 0–1). Conclusions: Our data support the safety of administering IV tissue plasminogen activator to patients with suspected acute cerebral ischemia within 3 hours of symptom onset, even when the diagnosis ultimately is found not to be stroke or imaging does not show an infarct.

Transcranial ultrasound in clinical sonothrombolysis (TUCSON) trial

Microspheres (μS) reach intracranial occlusions and transmit energy momentum from an ultrasound wave to residual flow to promote recanalization. We report a randomized multicenter phase II trial of μS dose escalation with systemic thrombolysis.

A Pilot Randomized Clinical Safety Study of Sonothrombolysis Augmentation With Ultrasound-Activated Perflutren-Lipid Microspheres for Acute Ischemic Stroke

Background and Purpose— Ultrasound transiently expands perflutren-lipid microspheres (&mgr;S), transmitting energy momentum to surrounding fluids. We report a pilot safety/feasibility study of ultrasound-activated &mgr;S with systemic tissue plasminogen activator (tPA). Methods— Stroke subjects treated within 3 hours had abnormal Thrombolysis in Brain Ischemia (TIBI) residual flow grades 0 to 3 before tPA on transcranial Doppler (TCD). Randomization included Controls (tPA+TCD) or Target (tPA+TCD+2.8 mL &mgr;S). The primary safety end point was symptomatic intracranial hemorrhage (sICH) with worsening by ≥4 NIHSS points within 72 hours. Results— Fifteen subjects were randomized 3:1 to Target, n=12 or Control, n=3. After treatment, asymptomatic ICH occurred in 3 Target and 1 Control, and sICH was not seen in any study subject. &mgr;S reached MCA occlusions in all Target subjects at velocities higher than surrounding residual red blood cell flow: 39.8±11.3 vs 28.8±13.8 cm/s, P<0.001. In 75% of subjects, &mgr;S permeated to areas with no pretreatment residual flow, and in 83% residual flow velocity improved at a median of 30 minutes from start of &mgr;S infusion (range 30 s to 120 minutes) by a median of 17 cm/s (118% above pretreatment values). To provide perspective, current study recanalization rates were compared with the tPA control arm of the CLOTBUST trial: complete recanalization 50% versus 18%, partial 33% versus 33%, none 17% versus 49%, P=0.028. At 2 hours, sustained complete recanalization was 42% versus 13%, P=0.003, and NIHSS scores 0 to 3 were reached by 17% versus 8%, P=0.456. Conclusions— Perflutren &mgr;S reached and permeated beyond intracranial occlusions with no increase in sICH after systemic thrombolysis suggesting feasibility of further &mgr;S dose-escalation studies and development of drug delivery to tissues with compromised perfusion.

Thrombolytic Therapy for Patients Who Wake-Up With Stroke

Background and Purpose— Approximately 25% of ischemic stroke patients awaken with their deficits. The last-seen-normal time is defined as the time the patient went to sleep, which places these patients outside the window for thrombolysis. The purpose of this study was to describe our center’s experience with off-label, compassionate thrombolysis for wake-up stroke (WUS) patients. Methods— A retrospective review of our database identified 3 groups of ischemic stroke patients: (1) WUS treated with thrombolysis; (2) nontreated WUS; and (3) 0- to 3-hour intravenous tissue plasminogen activator-treated patients. Safety and clinical outcome measures were symptomatic intracerebral hemorrhage, excellent outcome (discharge modified Rankin score, 0–1), favorable outcome (modified Rankin score, 0–2), and mortality. Outcome measures were controlled for baseline NIHSS using logistic regression. Results— Forty-six thrombolysed and 34 nonthrombolysed WUS patients were identified. Sixty-one percent (28/46) of the treated WUS patients underwent intravenous thrombolysis alone whereas 30% (14/46) were given only intra-arterial thrombolysis. Four patients received both intravenous and intra-arterial thrombolysis (9%). Two symptomatic intracerebral hemorrhages occurred in treated WUS (4.3%). Controlling for NIHSS imbalance, treated WUS had higher rates of excellent (14% vs 6%; P=0.06) and favorable outcome (28% vs 13%; P=0.006), but higher mortality (15% vs 0%) compared to nontreated WUS. A second comparison controlling for baseline NIHSS between treated WUS and 174 intravenous tissue plasminogen activator patients treated within 3 hours of symptoms showed no significant differences in safety and clinical outcomes. Conclusion— Thrombolysis may be safe in WUS patients. Our center’s experience supports considering a prospective, randomized trial to assess the safety and outcome of thrombolysis for this specific patient population.

Imaging-Based Endovascular Therapy for Acute Ischemic Stroke due to Proximal Intracranial Anterior Circulation Occlusion Treated Beyond 8 Hours From Time Last Seen Well Retrospective Multicenter Analysis of 237 Consecutive Patients

Background and Purpose— Current selection criteria for intra-arterial therapies in the anterior circulation use time windows of 8 hours. Modern neuroimaging techniques have identified individuals with salvageable penumbra who present beyond this timeframe. We sought to assess safety, procedural, and clinical outcomes of MRI or CT perfusion imaging-based endovascular therapy in patients with anterior circulation stroke treated beyond 8 hours from time last seen well. Methods— We conducted a multicenter retrospective review of consecutive patients meeting the following criteria: (1) acute proximal intracranial anterior circulation occlusion; (2) endovascular treatment initiated >8 hours from time last seen well; and (3) treatment selection based on MRI or CT perfusion imaging. Results— Two hundred thirty-seven patients were identified (mean age, 63.8±16 years; mean baseline National Institutes of Health Stroke Scale, 15±5.5; mean time last seen well to treatment, 15±11.2 hours; male gender, 46%). Successful revascularization was achieved in 175 of 237 (73.84%) patients. Parenchymal hematoma occurred in 21 of 237 (8.86%) patients. The 90-day mortality rate was 21.5% (51 of 237). The rate of good outcomes was 45% (100 of 223) in the 223 patients with available modified Rankin Scale data at 90 days or time of hospital discharge. In multivariate analyses, age (OR, 0.96; 95% CI, 0.94 to 0.98; P=0.002), admission National Institutes of Health Stroke Scale (OR, 0.93; 0.87 to 0.98; P=0.016), and successful revascularization (OR, 4.32; 1.99 to 9.39; P<0.0001) were identified as independent predictors of good outcomes. Conclusions— Endovascular therapy can be instituted with acceptable safety beyond 8 hours from time last seen well when selection is based on advanced neuroimaging. Successful revascularization is significantly associated with higher rates of good outcomes. The benefit of this approach compared with standard medical therapy should be assessed in a prospective randomized trial.

Intraventricular hemorrhage: Anatomic relationships and clinical implications

Background: Spontaneous intracerebral hemorrhage (ICH) is frequently associated with intraventricular hemorrhage (IVH), which is an independent predictor of poor outcome. The purpose of this study was to examine the relationship between ICH volume and anatomic location to IVH, and to determine if ICH decompression into the ventricle is truly beneficial. Methods: We retrospectively analyzed the CT scans and charts of all patients with ICH admitted to our stroke center over a 3-year period. Outcome data were collected using our prospective stroke registry. Results: We identified 406 patients with ICH. A total of 45% had IVH. Thalamic and caudate locations had the highest IVH frequency (69% and 100%). ICH volume and ICH location were predictors of IVH (p < 0.001). Within each location, decompression ranges (specific volume ranges where ventricular rupture tends to occur) were established. Patients with IVH were twice as likely to have a poor outcome (discharge modified Rankin scale of 4 to 6) (OR 2.25, p = 0.001) when compared to patients without IVH. Caudate location was associated with a good outcome despite 100% incidence of IVH. Spontaneous ventricular decompression was not associated with better outcome, regardless of parenchymal volume reduction (p = 0.72). Conclusions: Intraventricular hemorrhage (IVH) occurs in nearly half of patients with spontaneous intracerebral hemorrhage (ICH) and is related to ICH volume and location. IVH is likely to occur within the “decompression ranges” that take into account both ICH location and volume. Further, spontaneous ventricular decompression does not translate to better clinical outcome. This information may prove useful for future ICH trials, and to the clinician communicating with patients and families. GLOSSARY: ANOVA = analysis of variance; EVD = external ventricular drainage; HSD = honestly significant differences; ICC = interclass correlation coefficient; ICH = intracerebral hemorrhage; IVH = intraventricular hemorrhage; LOS = length of stay; mRS = modified Rankin Scale.

The Spot Sign in Intracerebral Hemorrhage: The Importance of Looking for Contrast Extravasation

Background: The ‘spot sign’ is a bright spot on computerized tomography angiography (CTA) source images predictive of hematoma growth. Contrast extravasation (CE) is seen on routine head CT following CTA as pooling of contrast within the hematoma. Our aim was to re-evaluate the predictive value of both the spot sign and CE and measure the reliability of scoring them. Methods: Consecutive cases of spontaneous intracerebral hemorrhage (ICH) presenting within 4 h. The presence of a ‘spot’ and CE, ICH and intraventricular hemorrhage volume at baseline and on follow-up scans were assessed. Clinical outcome was captured using the modified Rankin Scale on hospital discharge. Results: We identified 28 patients with a mean age of 56.8 years, median ICH volume of 19 ml, and median NIH Stroke Scale score on admission of 17.5. 11/27 (40.7%) had a positive spot and 13/22 (59.1%) had CE. Interrater reliability was 0.812 (95% CI 0.57–0.91, p < 0.001) for the spot sign and 0.952 (95% CI 0.89–0.98, p < 0.001) for CE. ICH volume increased in 16/28 (57.1%) patients. Both the spot sign and CE were associated with ICH growth (p < 0.001) and poor outcome (p < 0.001). Conclusions: In ICH patients, the presence of the spot sign or CE is highly correlated with early ICH growth. In our experience, CE is a more sensitive predictor of ICH growth with a better negative predictive value than the spot sign; CE is more consistently identified even by experienced clinicians. Postcontrast CT should be done routinely after CTA in patients presenting with ICH within 4 h. Patients who are CE-positive may be candidates for hemostatic therapies or early surgical intervention.

Identifying Patients at High Risk for Poor Outcome After Intra-Arterial Therapy for Acute Ischemic Stroke

BACKGROUND AND PURPOSE Intra-arterial recanalization therapy (IAT) is increasingly used for acute stroke. Despite high rates of recanalization, the outcome is variable. We attempted to identify predictors of outcome that will enable better patient selection for IAT. METHODS All patients who underwent IAT at the University of Texas Houston Stroke Center were reviewed. Poor outcome was defined as modified Rankin Scale score 4 to 6 on hospital discharge. Findings were validated in an independent data set of 175 patients from the University of California at Los Angeles Stroke Center. RESULTS One hundred ninety patients were identified. Mean age was 62 years and median baseline National Institutes of Health Stroke Scale score was 0.18. Recanalization rate was 75%, symptomatic hemorrhage rate was 6%, and poor outcome rate was 66%. Variables associated with poor outcome were: age, baseline National Institutes of Health Stroke Scale, admission glucose, diabetes, heart disease, previous stroke, and the absence of mismatch on the pretreatment MRI. Logistic regression identified 3 variables independently associated with poor outcome: age (P=0.049; OR, 1.028), National Institutes of Health Stroke Scale (P=0.013; OR, 1.084), and admission glucose (P=0.031; OR, 1.011). Using these data, we devised the Houston IAT score: 1 point for age >75 years; 1 for National Institutes of Health Stroke Scale score >18, and 1 point for glucose >150 mg/dL (range, 0 to 3 mg/dL). The percentage of poor outcome by Houston IAT score was: score of 0, 44%; 1, 67%; 2, 97%; and 3, 100%. Recanalization rates were similar across the scores (P=0.4). Applying Houston IAT to the external cohort showed comparable trends in outcome and nearly identical rates in the Houston IAT therapy 3 tier. CONCLUSIONS The Houston IAT score estimates the chances of poor outcome after IAT, even with recanalization. It may be useful in comparing cohorts of patients and when assessing the results of clinical trials.

The IVH Score: A novel tool for estimating intraventricular hemorrhage volume: Clinical and research implications

Objective:Intraventricular extension of intracerebral hemorrhage (IVH) is an independent predictor of poor outcome. IVH volume may be important in outcome prediction and management; however, it is difficult to measure routinely. Design and Patients:We reviewed the charts and computed tomographies of a cohort of consecutive patients with IVH. The cohort was divided into two groups: index and validation by random sampling. IVH and intracerebral hemorrhage (ICH) volume were measured manually in all patients. IVH was also graded using a simple classification system termed IVH score (IVHS). Clinical outcome was determined by the modified Rankin Scale (mRS) at discharge and in-hospital death. Poor outcome was defined as mRS 4–6. Main Results:One hundred seventy-five patients were analyzed, 92 in the index group and 83 in the validation group. Exponential regression yielded the following formula for estimating IVH volume (mL): eÎVHS/5 (R2 = .75, p < 0.001). The IVH estimation formula was then verified in the validation group (R2 = .8, p < 0.001). The following correlations with mRS were obtained: IVH volume R = .305; ICH volume R = .468; total volume {lsqb;TV{rsqb; R = .571 (p < 0.001 for all three correlations). Partial correlation of TV with mRS controlling for ICH volume yielded R = .3 for TV (p < 0.001). Logistic regression model comparing ICH and TV association with poor outcome yielded the following: ICH odds ratio = 5.2, 95% confidence interval 2.3–11.6, p < 0.001; TV odds ratio = 41.6, 95% confidence interval 9.6–180.6, p < 0.001. Substituting TV for ICH volume in the ICH score resulted in a significant increase in the specificity from 64% to 87% for predicting mortality. Conclusions:IVHS enables clinicians to rapidly estimate IVH volume. The addition of IVH to ICH volume increases its predictive power for poor outcome and mortality significantly. IVHS and TV may be used in clinical practice and clinical trials of patients with ICH.

Thrombus Burden Is Associated With Clinical Outcome After Intra-Arterial Therapy for Acute Ischemic Stroke

Background and Purpose— Studies have established a relation between recanalization and improved clinical outcome in acute ischemic stroke patients; however, intra-arterial clot size has not been routinely assessed. The aim of the study was to determine the impact of intra-arterial thrombus burden on intra-arterial treatment (IAT) and clinical outcome. Methods— A retrospective review of our IAT stroke database included procedure time, recanalization, symptomatic intracranial hemorrhage, poor outcome (modified Rankin Scale score ≥4 at discharge), and mortality. The modified Thrombolysis in Myocardial Infarction thrombus grade was dichotomized into grades 0 to 3 (no clot or moderate thrombus, <2 vessel diameters) versus grade 4 (large thrombus, >2 vessel diameters). Results— Data were collected on 135 patients with thrombus grading. The baseline median National Institutes of Health Stroke Scale score was higher in patients of grade 4 compared with grades 0 to 3 (19 vs 17, P=0.012). Grade 4 thrombi required longer (median, range) times for IAT (113, 37 to 415 minutes vs 74, 22 to 215 minutes, respectively; P<0.001) and higher rates of mechanical clot disruption (wire, angioplasty, snare, stent, or Merci retriever) compared with grades 0 to 3 (76% vs 53%, P=0.005). There were no differences in rates of symptomatic intracranial hemorrhage (6.6% vs 4.1%, P=0.701) or recanalization (50% vs 61%, P=0.216) in grade 4 versus grades 0 to 3. Multivariate analysis adjusted for age, baseline National Institutes of Health Stroke Scale score, and artery of involvement showed that grade 4 thrombi were independently associated with poor outcome (odds ratio=2.4; 95% CI, 1.06 to 5.57; P=0.036) and mortality (odds ratio=4.0; 95% CI, 1.2 to 13.2; P=0.023). Conclusions— High thrombus grade as measured by the modified Thrombolysis in Myocardial Infarction criteria may be a risk factor that contributes to poor clinical outcome.