Esteban Cheng-Ching

Addition of Hyperacute MRI Aids in Patient Selection, Decreasing the Use of Endovascular Stroke Therapy

Background and Purpose— The failure of recent trials to show the effectiveness of acute endovascular stroke therapy (EST) may be because of inadequate patient selection. We implemented a protocol to perform pretreatment MRI on patients with large-vessel occlusion eligible for EST to aid in patient selection. Methods— We retrospectively identified patients with large-vessel occlusion considered for EST from January 2008 to August 2012. Patients before April 30, 2010, were selected based on computed tomography/computed tomography angiography (prehyperacute protocol), whereas patients on or after April 30, 2010, were selected based on computed tomography/computed tomography angiography and MRI (hyperacute MRI protocol). Demographic, clinical features, and outcomes were collected. Univariate and multivariate analyses were performed. Results— We identified 267 patients: 88 patients in prehyperacute MRI period and 179 in hyperacute MRI period. Fewer patients evaluated in the hyperacute MRI period received EST (85 of 88, 96.6% versus 92 of 179, 51.7%; P<0.05). The hyperacute-MRI group had a more favorable outcome of a modified Rankin scale 0 to 2 at 30 days as a group (6 of 66, 9.1% versus 33 of 140, 23.6%; P=0.01), and when taken for EST (6 of 63, 9.5% versus 17 of 71, 23.9%; P=0.03). On adjusted multivariate analysis, the EST in the hyperacute MRI period was associated with a more favorable outcome (odds ratio, 3.4; 95% confidence interval, 1.1–10.6; P=0.03) and reduced mortality rate (odds ratio, 0.16; 95% confidence interval, 0.03–0.37; P<0.001). Conclusions— Implementation of hyperacute MRI protocol decreases the number of endovascular stroke interventions by half. Further investigation of MRI use for patient selection is warranted.

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.

Multicenter analysis of stenting in symptomatic intracranial atherosclerosis.

BACKGROUND Stenting for symptomatic intracranial atherosclerotic disease is a therapeutic option in patients in whom medical therapy fails. OBJECTIVE To determine the periprocedural complication rates and mid-term restenosis rates in patients treated with balloon-expandable stents (BESs) compared with self-expanding stents (SESs). METHODS A retrospective review of consecutive patients treated with intracranial stents at 5 institutions was performed. Predictors of 30-day stroke and death as well as mid-term restenosis rates were analyzed. RESULTS A total of 670 lesions were treated in 637 patients with a mean age of 57 ± 13 years. A total of 454 lesions (68%) were treated with BESs and 216 lesions (32%) with SESs. The overall 30-day periprocedural complication rate was 6.1%, without any difference noted between the 2 groups. Patients treated within 24 hours of the index event were significantly more likely to have experienced a periprocedural complication (odds ratio [OR], 4.0; 95% confidence interval [CI]: 1.7-6.7; P < .007), whereas focal lesions were less likely to have a complication (OR, 0.31; 95% CI: 0.13-0.72; P < .001). Midterm restenosis was less likely in patients with a lower percentage of posttreatment stenosis (OR, 0.97; 95% CI: 0.95-0.99; P < .006), which was more common in BES-treated patients and focal concentric lesions (OR, 0.33; 95% CI: 0.23-0.55; P < .0001). CONCLUSION BESs have periprocedural complication rates similar to those of SESs. Less posttreatment stenosis was associated with lower rates of mid-term restenosis. Future randomized trials comparing BESs and SESs may help to identify the stent type that is safest and most durable.

Predictors of biochemical aspirin and clopidogrel resistance in patients with ischemic stroke

Variable platelet response to aspirin and clopidogrel is a well-established phenomenon in patients with coronary artery disease. We sought to determine the predictors of an impaired biochemical response to aspirin and clopidogrel in patients with ischemic stroke. Patients with established cerebrovascular disease who underwent an aspirin/clopidogrel response panel (ie, light transmittance aggregometry) between June 2003 and March 2007 were identified through an electronic database. The medical records of these patients were retrospectively reviewed, and demographic characteristics, medical history, and laboratory results were recorded. Univariate and multivariate logistic regression analyses were performed to assess for factors associated with antiplatelet resistance. Of the 465 patients included in this study, 120 (28%) were biochemical aspirin nonresponders and 83 (28%) were biochemical clopidogrel nonresponders. Of the 270 patients on dual antiplatelet therapy, 25 (9.3%) were dual biochemical nonresponders. In binary logistic regression modeling, patients with congestive heart failure (odds ratio [OR] = 4.54; 95% confidence interval [CI] = 1.33-15.5; P = .02) and those with higher hemoglobin A1c values (OR = 1.41; 95% CI = 1.12-1.79; P = .004) had a significantly greater likelihood of having a biochemical nonresponse to aspirin therapy. African-American patients (OR = 2.19; 95% CI = 1.23-3.91; P < .007) were significantly more likely to be nonresponders to clopidogrel. This preliminary study shows that aspirin and clopidogrel biochemical nonresponse frequently occurs in ischemic stroke patients. In addition, some associated variables may affect the biochemical response to antiplatelet therapy. Further study is needed to explore whether this nonresponse has an impact on clinical outcomes.

High-resolution MRI vessel wall imaging in varicella zoster virus vasculopathy

Contrast-enhanced vessel wall imaging high-resolution MRI (HRMR) has revealed vessel wall thickening and enhancement in multiple intracranial vasculopathies, including varicella zoster virus (VZV) vasculopathy. We retrospectively reviewed a database of patients with virologically-verified VZV vasculopathy, who underwent initial and follow-up HRMR between April 2011 and May 2014. Six patients were identified. Baseline demographic and clinical characteristics were collected, including stroke risk factors, history of VZV-related disorders, neurological presentation, course and antiviral treatment. Initial HRMR in patients with VZV vasculopathy demonstrated various patterns of stenosis, vessel wall thickening and enhancement, predominantly in terminal internal carotid artery segments and the M1 segment of the middle cerebral arteries. Follow-up HRMR showed improvement of stenosis, with reduced vessel wall thickening and enhancement at multiple times after treatment. HRMR has the potential to assist in diagnosis and treatment of VZV vasculopathy.

Update on pharmacology of antiplatelets, anticoagulants, and thrombolytics

Understanding of the pharmacology of thrombolytics, anticoagulants, and antiplatelets is critical to performing safe and effective endovascular therapy for acute ischemic therapy. This is a basic review of the clinical pharmacologic data on the anticoagulants, antiplatelets, and fibrinolytic agents most commonly used in the treatment of stroke and in the neurointerventional suite.

Endovascular treatment of carotid embolic occlusions has a higher recanalization rate compared with cardioembolic occlusions

Background and purpose Treatment of large artery cerebral occlusions is rapidly evolving. We hypothesized that patients with intracranial embolic occlusions secondary to an extracranial carotid artery stenosis or occlusion have a higher probability of successful endovascular recanalization compared with those with cardioembolic occlusions. Methods We retrospectively reviewed the databases of three institutions (University of Pittsburgh Medical Center (UPMC), Michigan State University (MSU) and Cleveland Clinic Foundation (CCF)) for acute anterior circulation ischemic strokes treated with endovascular therapies from January 2006 to July 2008. After collection of demographic, radiographic and angiographic variables, two groups were identified: artery to artery embolic occlusions and cardioembolic/cryptogenic intracranial occlusions. We defined recanalization as TIMI 2 or 3 flow. A binary logistic regression model was constructed to determine which characteristics were unique to patients with carotid embolic occlusions. Results A total of 207 patients were identified (UPMC=100, CCF=71, MSU=36) with a mean age of 69±11 years and mean NIHSS of 17±5. Of these, 157 (75%) were due to a cardiac or cryptogenic source and 50 (25%) were from a carotid embolic source. The use of multimodal therapy (OR 2.6 (1.2–5.6), p<0.009) and the presence of a carotid embolic intracranial occlusion (OR 3.6 (1.2–7.1), p<0.012) were associated with successful recanalization, while carotid terminus occlusions were associated with unsuccessful recanalization (OR 0.35 (0.18–0.68), p<0.002). Conclusions Patients with intracranial occlusions secondary to an extracranial carotid stenosis or total occlusion appear to have more successful recanalization rates when treated with endovascular therapy compared with those with cardioembolic occlusions.

The Location of Pretreatment Hyperdense Middle Cerebral Artery Sign Predicts the Outcome of Intraarterial Thrombectomy for Acute Stroke

Intraarterial (IA) mechanical thrombectomy has an excellent recanalization rate but does not always correlate with good clinical outcomes. We aimed to investigate whether hyperdense middle cerebral artery sign (HMCAS) on preintervention nonenhanced CT (NECT) predicts IA therapy outcome for acute stroke.

Collateral Flow and Brain Changes on Computed Tomography Angiography Predict Infarct Volume on Early Diffusion-weighted Imaging

BACKGROUND We investigated whether a computed tomography (CT)-based score could predict a large infarct (≥ 80 mL) on early diffusion-weighted magnetic resonance imaging (DWI). METHODS Acute stroke patients considered for endovascular therapy within 8 hours of the onset of symptoms were included. The Alberta Stroke Program Early Computed Tomography Score (ASPECTS) was determined on noncontrast CT and computed tomography angiography source images (CTA-SI). Limited collateral flow was defined as less than 50% collateral filling on CTA-SI. RESULTS Fifty-six patients were analyzed. National Institutes of Health Stroke Scale score was 20 (15-24) in the large infarct group and 16 (11-20) in the small infarct group (P = .049). ASPECTS on noncontrast CT and CTA-SI was 5 (3-8) and 3 (2-6) in the large infarct group and 9 (8-10) and 8 (7-9) in the small infarct group (both P < .001), respectively. Limited collateral flow was frequent in the large infarct group than in the small infarct group (92% vs. 11%, P < .001). Multivariate analysis found that CTA-SI ASPECTS less than or equal to 5 (odds ratio [OR], 40.55; 95% confidence interval [CI], 1.10-1493.44; P = .044) and limited collateral flow (OR, 114.64; 95% CI, 1.93-6812.79; P = .023) were associated with a large infarct. Absence of ASPECTS less than or equal to 5 and limited collateral flow on CTA-SI predicted absence of a large infarct with a sensitivity of .89, specificity of 1.00, positive predictive value of 1.00, and negative predictive value of .71. CONCLUSIONS Assessment of ASPECTS and collateral flow on CTA-SI may be able to exclude a patient with large infarct on early DWI.

Intracranial Atherosclerosis as a Risk Factor for Ischemic Stroke during Open Heart Surgery

BACKGROUND Embolic stroke is a feared complication after open heart surgery. Many patients undergo testing of the carotid arteries before surgery, but intracranial atherosclerosis is not commonly assessed as a mechanism. METHODS We reviewed a prospectively maintained database of all open heart surgeries at our institution from 2005 to 2007 for patients who developed a periprocedural ischemic stroke. These patients were assessed for the mechanism of stroke through radiographic imaging of the intracranial circulation to determine the frequency of intracranial atherosclerosis as a mechanism for perioperative stroke. RESULTS A total of 10,367 patients underwent open heart surgery from 2005 to 2007 and 180 (1.74%) patients were noted to have an ischemic stroke. Of the 180 patients, 98 (55%) underwent intracranial imaging and 29 (30%) were noted to have narrowing of an intracranial vessel. Seventeen (17.4%) patients were found to have infarct ipsilateral to the stenosis, but 8 (8.1%) of these patients were also noted to have infarcts in other vascular territories. Thus, 9 (9.1%) patients were thought to have a stroke solely related to the intracranial stenosis. CONCLUSIONS Intracranial atherosclerosis may be an underreported mechanism for perioperative stroke after open heart surgery. Further study is required to better understand the prevalence of the disease in this population and subsequent risk of stroke.