Daniel P. Hsu

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.

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.

Magnetic resonance imaging results can affect therapy decisions in hyperacute stroke care

Background: Despite some limitations, a perfusion/diffusion mismatch can provide a working estimate of the ischemic penumbra in hyperacute stroke and has successfully been used to triage patients. Purpose: To evaluate whether the addition of magnetic resonance imaging (MRI) to clinical and non-contrast computed tomography (CT) data alters diagnosis and choice of therapy. Material and Methods: We retrospectively analyzed clinical records, and CT and MRI data fully available in 97 of 117 patients. Upon clinical examination and CT, a diagnosis and treatment path was scored and compared to treatment path after addition of MRI data. The MRI protocol included T2-weighted images, diffusion-weighted images (DWI), and perfusion-weighted images (PWI), and MR angiography (MRA). Results: MRI data were acquired in less than 15 min. In 20 of 97 patients (21%), the diagnosis changed after MRI. In 25 of 97 patients (26%), the presumptive treatment plan was changed after MRI evaluation. Thirteen patients had their treatment changed from thrombolytic to nonthrombolytic therapy. Three patients were changed from nonthrombolytic to intraarterial (IA) thrombolysis. In one patient, treatment was changed from intravenous (IV) to IA thrombolysis, and in five patients it was changed from IA to IV thrombolysis. In two patients, systemic heparin was added to antiplatelet therapy. Conclusion: The expansion of the acute stroke protocol to include MRI altered the therapy plan in 26% of our patients. The utility of MRI, shown here to improve patient stratification into best-treatment options, demonstrates the value of using MRI to optimize care in hyperacute stroke patients.

Prediction of adverse outcomes by blood glucose level after endovascular therapy for acute ischemic stroke

OBJECT The authors evaluated the prognostic significance of blood glucose level at admission (BGA) and change in blood glucose at 48 hours from the baseline value (CG48) in nondiabetic and diabetic patients before and after endovascular therapy for acute ischemic stroke (AIS). METHODS The BGA and CG48 data were analyzed in 614 patients with AIS who received endovascular therapy at 7 US centers between 2006 and 2009. Data reviewed included demographics, stroke risk factors, diabetic status, National Institutes of Health Stroke Scale (NIHSS) score at presentation, recanalization grade, intracranial hemorrhage (ICH) rate, and 90-day outcomes (mortality rate and modified Rankin Scale score of 3-6 [defined as poor outcome]). Variables with p values < 0.2 in univariate analysis were included in a binary logistic regression model for independent predictors of 90-day outcomes. RESULTS The mean patient age was 67.3 years, the median NIHSS score was 16, and 27% of patients had diabetes. In nondiabetic patients, BGA ≥ 116 mg/dl (≥ 6.4 mmol/L) and failure of glucose level to drop > 30 mg/dl (> 1.7 mmol/L) from the admission value were both significant predictors of 90-day poor outcome and death (p < 0.001). In patients with diabetes, BGA ≥ 116 mg/dl (≥ 6.4 mmol/L) was an independent predictor of poor outcome (p = 0.001). The CG48 was not a predictor of outcome in diabetic patients. A simplified 6-point scale including BGA, Thrombolysis in Myocardial Infarction (TIMI) Grade 2-3 Reperfusion, Age, presentation NIHSS score, CG48, and symptomatic ICH (BRANCH) corresponded with poor outcomes at 90 days; the area under the curve value was > 0.79. CONCLUSIONS Failure of blood glucose values to decrease in the first 48 hours after AIS intervention correlated with poor 90-day outcomes in nondiabetic patients. The BRANCH scale shows promise as a simple prognostication tool after endovascular therapy for AIS, and it merits prospective validation.

Evaluation of Image Quality of a 32-Channel versus a 12-Channel Head Coil at 1.5T for MR Imaging of the Brain

How much better is a 32-channel head coil at 1.5T when compared with a 12-channel coil? Does the higher spatial resolution and signal-to-noise ratio affect clinical interpretations? Here, 21 patients were consecutively imaged with both coils and the results in axial T2, T1, fluid-attenuated inversion recovery, and diffusion-weighted imaging sequences were assessed. Most of the improvement was seen in the FLAIR, DWI, and T2 sequences and to a lesser extent on T1 images. Artifacts were similar with both coils. Conclusion: Improvements in SNR and spatial resolution attributed to image acquisition with a 32-channel head coil are paralleled by perceived improvements in image quality. BACKGROUND AND PURPOSE: Multichannel phased-array head coils are undergoing exponential escalation of coil element numbers. While previous technical studies have found gains in SNR and spatial resolution with the addition of element coils, it remains to be determined how these gains affect clinical reading. The purpose of this clinical study was to determine if the SNR and spatial resolution characteristics of a 32-channel head coil result in improvements in perceived image quality and lesion evaluation. MATERIALS AND METHODS: Twenty-one patients underwent MR imaging of the brain at 1.5T sequentially with both a 12-channel and a 32-channel receive-only phased-array head coil. Axial T2WIs, T1WIs, FLAIR images, and DWIs were acquired. Anonymized images were compared side-by-side and by sequence for image quality, lesion evaluation, and artifacts by 3 neuroradiologists. Results of the comparison were analyzed for the preference for a specific head coil. RESULTS: FLAIR and DWI images acquired with the 32-channel coil showed significant improvement in image quality in several parameters. T2WIs also improved significantly with acquisition by the 32-channel coil, while T1WIs improved in a limited number of parameters. While lesion evaluation also improved with acquisition of images by the 32-channel coil, there was no apparent improvement in diagnostic quality. There was no difference in artifacts between the 2 coils. CONCLUSIONS: Improvements in SNR and spatial resolution attributed to image acquisition with a 32-channel head coil are paralleled by perceived improvements in image quality.

Standard of practice: endovascular treatment of intracranial atherosclerosis.

Background Symptomatic intracranial atherosclerotic disease (ICAD) worldwide represents one of the most prevalent causes of stroke. When severe, studies show that it has a very high risk for recurrent stroke, highlighting the need for effective preventative strategies. The mainstay of treatment has been medical therapy and is of critical importance in all patients with this disease. Endovascular therapy is also a possible therapeutic option but much remains to be defined in terms of best techniques and patient selection. This guideline will serve as recommendations for diagnosis and endovascular treatment of patients with ICAD. Methods A literature review was performed to extract published literature regarding ICAD, published from 2000 to 2011. Evidence was evaluated and classified according to American Heart Association (AHA)/American Stroke Association standard. Recommendations are made based on available evidence assessed by the Standards Committee of the Society of NeuroInterventional Surgery. The assessment was based on guidelines for evidence based medicine proposed by the American Academy of Neurology (AAN), the Stroke Council of the AHA and the University of Oxford, Centre for Evidence Based Medicine (CEBM). Results 59 publications were identified. The SAMMPRIS study is the only prospective, randomized, controlled trial available and is given an AHA level B designation, AAN class II and CEBM level 1b. The Stenting of Symptomatic Atherosclerotic Lesions in the Vertebral or Intracranial arteries (SSYLVIA) trial was a prospective, non-randomized study with the outcome assessment made by a non-operator study neurologist, allowing an AHA level B, AAN class III and CEBM level 2. The remaining studies were uncontrolled or did not have objective outcome measurement, and are thus classified as AHA level C, AAN class IV and CEBM level 4. Conclusion Medical management with combination aspirin and clopidogrel for 3 months and aggressive risk factor modification is the firstline therapy for patients with symptomatic ICAD. Endovascular angioplasty with or without stenting is a possible therapeutic option for selected patients with symptomatic ICAD. Further studies are necessary to define appropriate patient selection and the best therapeutic approach for various subsets of patients.

Comparison of brain MR images at 1.5T using BLADE and rectilinear techniques for patients who move during data acquisition

BACKGROUND AND PURPOSE: MR imaging of moving patients can be challenging and motion correction techniques have been proposed though some have associated new artifacts. The objective of this study was to semiquantitatively compare brain MR images of moving patients obtained at 1.5T by using partially radial and rectilinear acquisition techniques. MATERIALS AND METHODS: FLAIR, T2-, T1-, and contrast-enhanced T1-weighted image sets of 25 patients (14–94 years) obtained by using BLADE (like PROPELLER, a partially radial acquisition) and rectilinear techniques in the same imaging session were compared by 2 neuroradiologists in terms of extent of the motion artifact, image quality, and lesion visibility. ICC between opinions of the evaluators was calculated. RESULTS: Of the total of 70 image sets, the motion artifact was small in the partially radial images in 43 and in the rectilinear images in 13, and the opinions of the evaluators were discordant in the remaining 14 sets (ICC = 0.63, P < .05). The quality of partially radial images was higher for 36 sets versus 9 rectilinear sets, with disagreement between the 2 evaluators in the remaining 25 (ICC = 0.15, P < .05). Pathologic lesions were better characterized on 37 sets of partially radial images versus 13 sets of rectilinear images, and opinions of the evaluators differed in 20 sets (ICC = 0.90, P < .05). The neuroradiologists deemed 4 sets of rectilinear images nondiagnostic compared with only 1 set of radial images. CONCLUSIONS: The data demonstrate that our application of BLADE sequences reduces the extent of motion artifacts in brain images of moving patients, improving image quality and lesion characterization.

Standard of practice: embolization of spinal arteriovenous fistulae, spinal arteriovenous malformations, and tumors of the spinal axis

Spinal vascular malformations include a heterogeneous group of pathological/anatomical entities with congenital and acquired etiologies that induce spinal cord dysfunction, primarily through intradural extramedullary drainage and enlargement of the coronal venous plexus, resulting in venous hypertension and/or a direct mass effect. These lesions are rare, comprising approximately 5% of neurovascular disorders. Clinical manifestations are pain or venous congestive myelopathy, usually in the thoracolumbar spine. This may progress to hemorrhage from vascular thrombosis and necrotizing myelopathy (Foix–Alajouanine syndrome).1 Due to the differing hemodynamics, pathophysiology, and treatment considerations, a thorough knowledge of the various types of spinal dural arteriovenous fistulas (dAVFs) and arteriovenous malformations (AVMs) is essential. The first descriptions of the single coiled dural vessel form of spinal dAVF with intradural extramedullary venous drainage were published by Kendall and Logue in 1977.2 Type I spinal dAVFs (also known as angioma racemosum venosum) are the most common and comprise 56% of all spinal lesions in the spinal vascular malformation database at the University of Toronto.3 They occur nearly 3–4 times as frequently in men. These generally low flow lesions may be further divided into type I-A (single feeder dAVFs) and I-B (≥2 arterial feeders).4 Although they are typically supplied via radicular arteries, anterior spinal artery feeders have also been reported.5 Type II spinal AVMs (also known as angioma racemosum arteriovenosum) are characterized by a compact, glomus-type, totally intramedullary nidus. They have no gender predominance but are symptomatic in younger patients. Type III (juvenile or metameric) spinal AVMs are highly complex intramedullary lesions that frequently extend into the extramedullary, epidural, or even extraspinal compartments. Vascular …

Outcomes of intra-arterial thrombolytic treatment in acute ischemic stroke patients with a matched defect on diffusion and perfusion MR images

Background For acute ischemic stroke patients with matched defects on diffusion–perfusion imaging, the effects of reperfusion therapy remain poorly documented. The outcomes in a rare series of patients who had a matched defect and then underwent intra-arterial thrombolytic treatment (IAT) are reported. Methods Medical record and MR image review between 1 January 1998 and 15 October 2008 revealed only eight acute ischemic stroke patients satisfying the atypical combination of both matched defect and IAT. Successful recanalization (SR), favorable clinical response (FCR) and symptomatic intracranial hemorrhage (SICH) were defined respectively as thrombolysis in cerebral infarction score ≥2 after IAT, discharge National Institutes of Health Stroke Scale (NIHSS) 0–1/≥8 point decrease from baseline and intracranial hemorrhage in infarct zone with ≥4 point increase in NIHSS Score within 24 h of IAT. Results Median (range) baseline NIHSS score was 16.5 (6–22). Median (range) time delays from symptom onset to MRI and to IAT initiation were 200 (83–240) and 267.5 (160–360) min, respectively. Median (range) values of diffusion and perfusion lesion volumes were 119.5 (24–205) and 118 (18–207) ml. Out of eight patients, one (12.5%) achieved FCR, four (50%) had SICH and five (62.5%) died. Out of six patients with SR, one achieved FCR and four had SICH and died, and of two patients without SR, none had FCR or SICH and one died. Conclusion Our data on rare patients with matched defects who nevertheless had attempted rescue with IAT confirm a poor risk–benefit ratio generated by low favorable responses and high mortality rates, especially in large ischemic lesions.