Ashis H. Tayal

Conscious Sedation Versus General Anesthesia During Endovascular Therapy for Acute Anterior Circulation Stroke: Preliminary Results From a Retrospective, Multicenter Study

Background and Purpose— Patients undergoing intra-arterial therapy (IAT) for acute ischemic stroke receive either general anesthesia (GA) or conscious sedation. GA may delay time to treatment, whereas conscious sedation may result in patient movement and compromise the safety of the procedure. We sought to determine whether there were differences in safety and outcomes in GA patients before initiation of IAT. Methods— A cohort of 980 patients at 12 stroke centers underwent IAT for acute stroke between 2005 and 2009. Only patients with anterior circulation strokes due to large-vessel occlusion were included in the study. A binary logistic-regression model was used to determine independent predictors of good outcome and death. Results— The mean age was 66±15 years and median National Institutes of Health Stroke Scale score was 17 (interquartile range, 13–20). The overall recanalization rate was 68% and the symptomatic hemorrhage rate was 9.2%. GA was used in 44% of patients with no differences in intracranial hemorrhage rates when compared with the conscious sedation group. The use of GA was associated with poorer neurologic outcome at 90 days (odds ratio=2.33; 95% CI, 1.63–3.44; P<0.0001) and higher mortality (odds ratio=1.68; 95% CI, 1.23–2.30; P<0.0001) compared with conscious sedation. Conclusions— Patients placed under GA during IAT for anterior circulation stroke appear to have a higher chance of poor neurologic outcome and mortality. There do not appear to be differences in hemorrhagic complications between the 2 groups. Future clinical trials with IAT can help elucidate the etiology of the differences in outcomes.

Emergent Stenting of Extracranial Internal Carotid Artery Occlusion in Acute Stroke Has a High Revascularization Rate

Background and Purpose— Acute ischemic stroke attributable to extracranial internal carotid artery (ICA) occlusion is frequently associated with severe disability or death. In selected cases, revascularization with carotid artery stenting has been reported, but the safety, recanalization rate, and clinical outcomes in consecutive case series are not known. Methods— We retrospectively reviewed all of the cases of ICA occlusions that underwent cerebral angiography with the intent to revascularize over a 38-month period. Two groups were identified: (1) patients who presented with an acute clinical presentation within 6 hours of symptom onset (n=15); and (2) patients who presented subacutely with neurologic fluctuations because of the ICA occlusion (n=10). Results— Twenty-five patients with a mean age of 62±11 years and median National Institutes of Health Stroke Scale (NIHSS) of 14 were identified. Twenty-three of the 25 patients (92%) were successfully revascularized with carotid artery stenting. Patients in group 1 were younger and more likely to have a tandem occlusion and higher baseline NIHSS when compared with group 2. Patients in group 2 were more likely to show early clinical improvement defined as a reduction of their NIHSS by ≥4 points and a modified Rankin Score of ≤2 at 30-day follow-up. Two clinically insignificant adverse events were noted: 1 asymptomatic hemorrhage and 1 nonflow-limiting dissection. Conclusions— Endovascular treatment of acute ICA occlusion appears to have a high-recanalization rate and be relatively safe in our cohort of patients with acute ICA occlusion. Future prospective studies are necessary to determine which patients are most likely to benefit from this form of therapy.

Multimodal Reperfusion Therapy for Acute Ischemic Stroke: Factors Predicting Vessel Recanalization

Background and Purpose— Endovascular therapies using mechanical and pharmacological modalities for large vessel occlusions in acute stroke are rapidly evolving. Our aim was to determine whether one modality is associated with higher recanalization rates. Methods— We retrospectively reviewed 168 consecutive patients treated with intra-arterial (IA) therapy for acute ischemic stroke between May 1999 and November 15, 2005. Demographic, clinical, radiographic, angiographic, and procedural notes were reviewed. Recanalization was defined as achieving thrombolysis in myocardial infarction 2 or 3 flow after intervention. A logistic regression model was constructed to determine independent predictors of successful recanalization. Results— A total of 168 patients were reviewed with a mean age of 64±13 years and mean National Institutes of Health Stroke Scale score of 17±4. Recanalization was achieved in 106 (63%) patients. Independent predictors of recanalization include: the combination of IA thrombolytics and glycoprotein IIb/IIIa inhibitors (odds ratio [OR], 2.9 [95% CI, 1.04 to 6.7]; P<0.048), intracranial stent placement with angioplasty (OR, 4.8 [95% CI, 1.8 to 10.0]; P<0.001), or extracranial stent placement with angioplasty (OR, 4.2 [95% CI, 1.4 to 9.8]; P<0.014). Lesions at the terminus of the internal carotid artery were recalcitrant to revascularization (OR, 0.34 [95% CI, 0.16 to 0.73]; P value 0.006). Conclusions— Intracranial or extracranial stenting or combination therapy with IA thrombolytics and glycoprotein IIb/IIIa inhibitors in the setting of multimodal therapy is associated with successful recanalization in patients treated with multimodal endovascular reperfusion therapy for acute ischemic stroke.

Higher volume endovascular stroke centers have faster times to treatment, higher reperfusion rates and higher rates of good clinical outcomes

Background and purpose Technological advances have helped to improve the efficiency of treating patients with large vessel occlusion in acute ischemic stroke. Unfortunately, the sequence of events prior to reperfusion may lead to significant treatment delays. This study sought to determine if high-volume (HV) centers were efficient at delivery of endovascular treatment approaches. Methods A retrospective review was performed of nine centers to assess a series of time points from obtaining a CT scan to the end of the endovascular procedure. Demographic, radiographic and angiographic variables were assessed by multivariate analysis to determine if HV centers were more efficient at delivery of care. Results A total of 442 consecutive patients of mean age 66±14 years and median NIH Stroke Scale score of 18 were studied. HV centers were more likely to treat patients after intravenous administration of tissue plasminogen activator and those transferred from outside hospitals. After adjusting for appropriate variables, HV centers had significantly lower times from CT acquisition to groin puncture (OR 0.991, 95% CI 0.989 to 0.997, p=0.001) and total procedure times (OR 0.991, 95% CI 0.986 to 0.996, p=0.001). Additionally, patients treated at HV centers were more likely to have a good clinical outcome (OR 1.86, 95% CI 1.11 to 3.10, p<0.018) and successful reperfusion (OR 1.82, 95% CI 1.16 to 2.86, p<0.008). Conclusions Significant delays occur in treating patients with endovascular therapy in acute ischemic stroke, offering opportunities for improvements in systems of care. Ongoing prospective clinical trials can help to assess if HV centers are achieving better clinical outcomes and higher reperfusion rates.

Advanced modality imaging evaluation in acute ischemic stroke may lead to delayed endovascular reperfusion therapy without improvement in clinical outcomes

Purpose Advanced neuroimaging techniques may improve patient selection for endovascular stroke treatment but may also delay time to reperfusion. We studied the effect of advanced modality imaging with CT perfusion (CTP) or MRI compared with non-contrast CT (NCT) in a multicenter cohort. Materials and methods This is a retrospective study of 10 stroke centers who select patients for endovascular treatment using institutional protocols. Approval was obtained from each institutions review board as only de-identified information was used. We collected demographic and radiographic data, selected time intervals, and outcome data. ANOVA was used to compare the groups (NCT vs CTP vs MRI). Binary logistic regression analysis was performed to determine factors associated with a good clinical outcome. Results 556 patients were analyzed. Mean age was 66±15 years and median National Institutes of Health Stroke Scale score was 18 (IQR 14–22). NCT was used in 286 (51%) patients, CTP in 190 (34%) patients, and MRI in 80 (14%) patients. NCT patients had significantly lower median times to groin puncture (61 min, IQR (40–117)) compared with CTP (114 min, IQR (81–152)) or MRI (124 min, IQR (87–165)). There were no differences in clinical outcomes, hemorrhage rates, or final infarct volumes among the groups. Conclusions The current retrospective study shows that multimodal imaging may be associated with delays in treatment without reducing hemorrhage rates or improving clinical outcomes. This exploratory analysis suggests that prospective randomised studies are warranted to support the hypothesis that advanced modality imaging is superior to NCT in improving clinical outcomes.

Factors Predicting Hemorrhagic Complications after Multimodal Reperfusion Therapy for Acute Ischemic Stroke

BACKGROUND AND PURPOSE: We sought to find predictors for hemorrhagic complications in patients with acute ischemic stroke treated with multimodal endovascular therapy. MATERIALS AND METHODS: We retrospectively reviewed patients with acute ischemic stroke treated with multimodal endovascular therapy from May 1999 to March 2006. We reviewed clinical and angiographic data, admission CT Alberta Stroke Programme Early CT Score (ASPECTS), and the therapeutic endovascular interventions used. Posttreatment CT scans were reviewed for the presence of a parenchymal hematoma or hemorrhagic infarction based on defined criteria. Predictors for these types of hemorrhages were determined by logistic regression analysis. RESULTS: We identified 185 patients with a mean age of 65 ± 13 years and mean National Institutes of Health Stroke Scale score of 17 ± 4. Sixty-nine patients (37%) developed postprocedural hemorrhages: 24 (13%) parenchymal hematomas and 45 (24%) hemorrhagic infarctions. Patients with tandem occlusions (odds ratio [OR] 4.6 [1.4–6.5], P < .016), hyperglycemia (OR 2.8 [1.1–7.7], P < .043), or treated concomitantly with intravenous (IV) tissue plasminogen activator (tPA) and intra-arterial (IA) urokinase (OR 5.1 [1.1–25.0], P < .041) were at a significant risk for a parenchymal hematoma. Hemorrhagic infarction occurred significantly more in patients presenting with an ASPECTS ≤7 (OR 1.9 [1.3–2.7], P < .01). CONCLUSIONS: Hemorrhagic infarctions are related to the extent of infarct based on presentation CT, whereas parenchymal hematomas are associated with the presence of tandem occlusions, hyperglycemia, and treatment with both IV tPA and IA urokinase in patients with acute stroke treated with multimodal endovascular therapy.

Intra-arterial thrombolysis or stent placement during endovascular treatment for acute ischemic stroke leads to the highest recanalization rate: results of a multicenter retrospective study.

BACKGROUND:Reperfusion therapy for acute ischemic stroke (AIS) is rapidly evolving, with the development of multiple endovascular modalities that can be used alone or in combination. OBJECTIVE:To determine which pharmacologic or mechanical modality may be associated with increased rates of recanalization. METHODS:A cohort of 1122 patients with AIS involving the anterior circulation treated at 13 stroke centers underwent intra-arterial (IA) therapy within 8 hours of symptom onset. Demographic information, admission National Institutes of Health Stroke Scale (NIHSS), mechanical and pharmacologic treatments used, recanalization grade, and hemorrhagic complications were recorded. RESULTS:The mean age was 67 ± 16 years and the median NIHSS was 17. The sites of arterial occlusion before treatment were M1 middle cerebral artery (MCA) in 561 (50%) patients, carotid terminus in 214 (19%) patients, M2 MCA in 171 (15%) patients, tandem occlusions in 141 (13%) patients, and isolated extracranial internal carotid artery occlusion in 35 (3%) patients. Therapeutic interventions included multimodal therapy in 584 (52%) patients, pharmacologic therapy only in 264 (24%) patients, and mechanical therapy only in 274 (24%) patients. Patients treated with multimodal therapy had a significantly higher Thrombolysis in Myocardial Infarction 2 or 3 recanalization rate (435 patients [74%]) compared with pharmacologic therapy only (160 patients, [61%]) or mechanical only therapy (173 patients [63%]), P < .001. In binary logistic regression modeling, independent predictors of Thrombolysis in Myocardial Infarction 2 or 3 recanalization were use of IA thrombolytic OR 1.58 (1.21-2.08), P < .001 and stent deployment 1.91 (1.23-2.96), P < .001. CONCLUSION:Multimodal therapy has significantly higher recanalization rates compared with pharmacologic or mechanical therapy. Among the individual treatment modalities, stent deployment or IA thrombolytics increase the chance of recanalization.

Predictors and clinical relevance of hemorrhagic transformation after endovascular therapy for anterior circulation large vessel occlusion strokes: a multicenter retrospective analysis of 1122 patients

Background and purpose Endovascular techniques are frequently employed to treat large artery occlusion in acute ischemic stroke (AIS). We sought to determine the predictors and clinical impact of intracranial hemorrhage (ICH) after endovascular therapy. Methods Retrospective analysis of consecutive patients presenting to 13 high volume stroke centers with AIS due to proximal occlusion in the anterior circulation who underwent endovascular treatment within 8 h from symptom onset. Logistic regression was performed to determine the variables associated with ICH, hemorrhagic infarction (HI), and parenchymal hematomas (PHs), as well as 90 day poor outcome (modified Rankin Scale score ≥3) and mortality. Results There were a total of 363 ICHs (overall rate 32.3%; HI=267, 24%; PH=96, 8.5%) among the 1122 study patients (mean age 67±15 years; median National Institutes of Health Stroke Scale score 17 (IQR 13–20)). Independent predictors for HI included diabetes mellitus (OR 2.27, 95% CI (1.58 to 3.26), p<0.0001), preprocedure IV tissue plasminogen activator (tPA) (1.43 (1.03 to 2.08), p<0.037), Merci thrombectomy (1.47 (1.02 to 2.12), p<0.032), and longer time to puncture (1.001 (1.00 to 1.002), p<0.026). Patients with atrial fibrillation (1.61 (1.01 to 2.55), p<0.045) had a higher risk of PH while the use of IA tPA (0.57 (0.35 to 0.90), p<0.008) was associated with lower chances of PH. Both the presence of HI (2.23 (1.53 to 3.25), p<0.0001) and PH (6.24 (3.06 to 12.75), p<0.0001) were associated with poor functional outcomes; however, only PH was associated with higher mortality (3.53 (2.19 to 5.68), p<0.0001). Conclusions Greater understanding about the predictors and consequences of ICH post endovascular stroke therapy is essential to improve risk assessment, patient selection/clinical outcomes, and early prognostication. Our data suggest that patients with atrial fibrillation are particularly prone to severe ICH and question the ‘benign’ nature of HI suggested by earlier studies.

Quantitative Perihematomal Blood Flow in Spontaneous Intracerebral Hemorrhage Predicts In-Hospital Functional Outcome

Background and Purpose— Few data on xenon computed tomography–based quantitative cerebral blood flow (CBF) in spontaneous intracerebral hemorrhage have been reported. We correlated perihematomal CBF in a retrospective series of 42 subacute spontaneous intracerebral hemorrhage patients undergoing xenon computed tomography with in-hospital discharge status and mortality. Methods— We calculated 3 area-weighted mean CBF values: (1) within the computed tomography–visible rim of perihematomal edema, (2) within a 1-cm marginal radius around the hematoma, and (3) all cortical regions of interest immediately adjacent to the hematoma. Primary outcomes were in-hospital mortality and discharge status (ordinally as 0=home, 1=acute rehabilitation, 2=nursing home, 3=death). Discharge status was used as a surrogate for in-hospital functional outcome. Results— Median hematoma volume was 14.4 cm3 (range, 2 to 70). Median perihematomal (low-attenuation rim) CBF was 21.9 cm3·100 g−1·min−1 (range, 6.1 to 81.1), and the median 1-cm marginal radius CBF was 26.8 cm3·100 g−1·min−1 (range, 10.8 to 72.8). The median regional cortical CBF was 26.7 cm3·100 g−1·min−1 (range, 6.9 to 72.6). Eight patients had 1-cm marginal radius or regional cortical CBF values <20 cm3·100 g−1·min−1. Hematoma volume (odds ratio [OR], 1.68 per 10-cm3 volume; P=0.036) and intraventricular hemorrhage (OR, 1.88 per grade of intraventricular hemorrhage; P=0.036) predicted mortality. Two CBF measures, hydrocephalus, and IVH predicted poor in-hospital functional outcome in bivariate analysis. Each CBF measure (OR, 0.34 to 0.43; P<0.001 to 0.003) and intraventricular hemorrhage (OR, 3.42; P<0.001) predicted in-hospital functional outcome in multivariable analyses. Conclusions— Most spontaneous intracerebral hemorrhage patients lack perihematomal penumbra. Perihematomal CBF independently predicts in-hospital discharge status but not in-hospital mortality. Further studies are warranted to determine whether perihematomal CBF predicts long-term functional outcomes.

Posttreatment Variables Improve Outcome Prediction after Intra-Arterial Therapy for Acute Ischemic Stroke

Background: There are multiple clinical and radiographic factors that influence outcomes after endovascular reperfusion therapy (ERT) in acute ischemic stroke (AIS). We sought to derive and validate an outcome prediction score for AIS patients undergoing ERT based on readily available pretreatment and posttreatment factors. Methods: The derivation cohort included 511 patients with anterior circulation AIS treated with ERT at 10 centers between September 2009 and July 2011. The prospective validation cohort included 223 patients with anterior circulation AIS treated in the North American Solitaire Acute Stroke registry. Multivariable logistic regression identified predictors of good outcome (modified Rankin score ≤2 at 3 months) in the derivation cohort; model β coefficients were used to assign points and calculate a risk score. Discrimination was tested using C statistics with 95% confidence intervals (CIs) in the derivation and validation cohorts. Calibration was assessed using the Hosmer-Lemeshow test and plots of observed to expected outcomes. We assessed the net reclassification improvement for the derived score compared to the Totaled Health Risks in Vascular Events (THRIVE) score. Subgroup analysis in patients with pretreatment Alberta Stroke Program Early CT Score (ASPECTS) and posttreatment final infarct volume measurements was also performed to identify whether these radiographic predictors improved the model compared to simpler models. Results: Good outcome was noted in 186 (36.4%) and 100 patients (44.8%) in the derivation and validation cohorts, respectively. Combining readily available pretreatment and posttreatment variables, we created a score (acronym: SNARL) based on the following parameters: symptomatic hemorrhage [2 points: none, hemorrhagic infarction (HI)1-2 or parenchymal hematoma (PH) type 1; 0 points: PH2], baseline National Institutes of Health Stroke Scale score (3 points: 0-10; 1 point: 11-20; 0 points: >20), age (2 points: <60 years; 1 point: 60-79 years; 0 points: >79 years), reperfusion (3 points: Thrombolysis In Cerebral Ischemia score 2b or 3) and location of clot (1 point: M2; 0 points: M1 or internal carotid artery). The SNARL score demonstrated good discrimination in the derivation (C statistic 0.79, 95% CI 0.75-0.83) and validation cohorts (C statistic 0.74, 95% CI 0.68-0.81) and was superior to the THRIVE score (derivation cohort: C statistic 0.65, 95% CI 0.60-0.70; validation cohort: C-statistic 0.59, 95% CI 0.52-0.67; p < 0.01 in both cohorts) but was inferior to a score that included age, ASPECTS, reperfusion status and final infarct volume (C statistic 0.86, 95% CI 0.82-0.91; p = 0.04). Compared with the THRIVE score, the SNARL score resulted in a net reclassification improvement of 34.8%. Conclusions: Among AIS patients treated with ERT, pretreatment scores such as the THRIVE score provide only fair prognostic information. Inclusion of posttreatment variables such as reperfusion and symptomatic hemorrhage greatly influences outcome and results in improved outcome prediction.