Artery M1 Research Articles

Abstract 3548: Neuroimaging Modalities Predict Robust Collaterals For Optimal Intraarterial Acute Stroke Therapy

BACKGROUND: Collaterals during intra-arterial (IA) therapy have been shown to impact outcome. We sought to identify pre-treatment predictors of robust collaterals to improve patient selection for this therapy. METHODS: With institutional review board approval, we retrospectively reviewed patients from a single center receiving IA therapy for internal carotid artery (ICA) and middle cerebral artery (MCA) M1 segment occlusions from January 2009 to June 2011. We collected the following clinical data: age, gender, stroke score, and risk factors. Radiologic parameters included the pre-treatment Alberta Stroke Program Early CT Score (ASPECTS) on non-contrast CT (NCCT) and CT Perfusion (CTP) cerebral blood volume maps and site of occlusion. All patients had complete diagnostic angiography prior to IA therapy. Collateral circulation of the symptomatic MCA territory was based on a previously published protocol in which any collateral filling of the MCA M1 segment was scored 1, any filling up to the M2 segments was scored 2, any filling up to the M3 segments was scored 3, any filling up to the M4 segments was scored 4. Absent collaterals were scored 5. The endpoint was robust collaterals defined as a score < 4. Associations between demographic, clinical, and radiologic parameters and robust collaterals were determined using chi-squared analysis. Receiver-operating characteristic (ROC) curves determined sensitivities and specificities for significant predictors. RESULTS: Fifty-three patients were identified (mean age of 66 %/- 11 years, median stroke score of 16.5). Occlusions occurred in the MCA M1 segment (37), ICA origin (2), intracranial ICA (9), and tandem ICA origin with intracranial ICA or M1 MCA (5). Robust collaterals were identified in 42 patients and predicted by 2 correlates on multivariate analysis: NCCT ASPECTS > 8 (p = .011), where 89.2% of patients with NCCT ASPECTS > 8 had robust collaterals, compared to 56.3% of patients with NCCT ASPCECTS ≤ 8; and CTP ASPECTS > 7 (p < 0.001), where 100% of patients with CTP ASPECTS > 7 had robust collaterals, compared to 45.5% of patients with CTP ASPCECTS ≤ 7. NCCT ASPECTS > 8 had a sensitivity of 79% and a specificity of 64% in predicting robust collateral circulation. CTP ASPECTS > 7 had a sensitivity of 83% and a specificity of 100%. CONCLUSIONS: Higher ASPECT scores on baseline CT and CTP reflects presence of robust collaterals and can aid in patient selection for IA therapy. In addition, a protocol using CTP may further increase the selection accuracy.

Abstract 1911: Recanalization of Proximal Arterial Occlusion in the SENTIS Trial

Background: Collateral circulation may enhance recanalization in acute ischemic stroke. Augmentation of collaterals with partial aortic occlusion may promote recanalization and thereby influence outcomes in the SENTIS randomized controlled trial of the NeuroFlo device. We conducted a post hoc analysis of angiography acquired in SENTIS to evaluate potential differences in recanalization rates between NeuroFlo-treated and non-treated arms, accounting for site of arterial occlusion. Methods: Blinded imaging expert review of baseline and 6-hour follow-up angiography (CTA, MRA, or DSA) from the core lab was conducted for evaluation of recanalization. Recanalization was defined as TIMI 2-3 in the arterial segment distal to baseline occlusion. Baseline demographics, stroke presentation characteristics, and medical history variables were analyzed with respect to recanalization in univariate and subsequent multivariable logistic regression models after adjusting by treatment arm. Results: Serial angiography was available in 109/515 SENTIS subjects, including 56 in the treatment arm and 53 in the non-treated arm. Baseline demographics, stroke presentation characteristics, and medical history variables did not differ statistically between arms. Across all sites of arterial occlusion, recanalization occurred in 25.7% of cases, with similar rates between device (25.0%) and medical therapy (26.4%) arms. Age and baseline stroke severity (NIHSS score) were significant predictors of recanalization in univariate analyses. Multivariable logistic regression analyses confirmed that baseline NIHSS score was the sole predictor of recanalization (OR 0.90, p=0.0458) per one unit increase, with decreased recanalization in more severe strokes. Device treatment was not associated with significant increases in recanalization rates (p=NS). Recanalization of terminal internal carotid artery (12.5%), proximal MCA or M1 (17.9%) and M2 (46.7%) occlusions was not different between arms (all p=NS). Recanalization of proximal arterial occlusion in acute ischemic stroke cases enrolled in SENTIS was more frequent in M2 occlusions. Conclusions: More severe strokes at baseline were less likely to recanalize and device therapy did not increase recanalization rates. Treatment with the NeuroFlo device may invoke mechanisms of collateral perfusion distinct from direct arterial recanalization.

Abstract 2832: Rate of Change of ASPECTS can predict of outcome in Acute Ischemic Stroke patients undergoing Endovascular Therapy

Objectives: We sought to assess how rate of infarction impacts outcome in acute ischemic stroke (AIS) patients undergoing endovascular therapy Methods: With institutional approval, we conducted a retrospective chart review on consecutive patients receiving endovascular treatment for anterior circulation AIS at our centers between January 2009 and June 2011. Beside patient’s demographics, we collected data on time from stroke onset to end of endovascular procedure, site of occlusion, and recanalization described as a Thrombolysis in Myocardial Infarction (TIMI) score ≥ 2. Neuro-imaging data included the immediate pre-treatment Alberta Stroke Program Early CT Score (ASPECTS). The ASPECTS score at onset was presumed to be 10. We calculated the rate of infarction as 10-ASPECTS/hour (ΔA). Our endpoint was good outcome defined as a modified Rankin Score ≤ 2 at 90 days. These parameters were entered into univariate and multivariate analyses to determine independent predictors of outcome. Results: Our cohort included 81 patients (45 females, mean age 67±12 years, median stroke score 17, median time from stroke onset to procedure completion 440 minutes). Occlusions were found in the middle cerebral artery (MCA) M2 (11), MCA M1 (46), intracranial internal carotid artery (ICA) (10), ICA origin (2), and tandem ICA origin with intracranial ICA or MCA occlusion (12). The mean baseline ASPECTS was 9 (75 patients had ASPECTS > 7). Recanalization was observed in 50%. The mean change in ASPECTS prior to endovascular therapy was 0.47 units/hour ± 0.72 units. Three parameters predicted a good outcome: recanalization (OR 10.1, 95% CI 2.7, 38.1, p < 0.001), recanalization in the setting of a pre-treatment ASPECTS score > 8 (OR 5.8, 95% CI 1.8, 19.3, p =0.002), recanalization in the setting of a ΔA < 1 unit/hour (OR 2.7, 95% CI 1.0-7.4, p =0.043). In a multivariate analysis controlling for stroke score, ΔA < 1 units/hour still impacted outcome (OR 3.1, 95% CI 1.1-8.9, p=0.039). Conclusions: While rate of infarction may impact the final outcome in patients receiving endovascular therapy for AIS, perhaps a better marker is recanalization in patients with a pre-treatment ASPECTS > 8. Rate of infarction may still be a valuable parameter when selecting patients for this endovascular therapy, in particular those being transferred to treatment sites.

Mechanical Thrombectomy Using a Solitaire Stent in Acute Ischemic Stroke; Initial Experience in 40 Patients

ObjectiveThis study was conducted in order to demonstrate the initial experience of the Solitaire AB stent in mechanical intracranial thrombectomy.MethodsWe conducted a retrospective review of 40 consecutive patients who underwent intra-arterial Solitaire AB stent thrombectomy for treatment of acute ischemic strokes between October 2010 and November 2011. Demographic, clinical, and radiological presentations and outcomes were studied.ResultsTwenty six men and 14 women with a mean initial National Institutes of Health Stroke Scale (NIHSS) score of 14.1 (range, 8-26) and a mean age of 65.4 (range, 32-89) years were included in this study. Occlusion sites were as follows: internal carotid artery (n = 11), middle cerebral artery M1 (n = 22), M2 (n = 5), and basilar artery (n = 2). Successful revascularization was achieved in 36 (90%) patients. The mean NIHSS score was 11.6 (range, 1-23) at 24 hours after the procedure, and 42.5% of patients showed a modified Rankin scale score of ≤ 2 at 90 days. New occlusion by migrated emboli was observed in one (2.5%) case. Post-procedural intracerebral hemorrhage occurred in only one case (2.5%), with an all-cause mortality of two (5%).ConclusionThe Solitaire AB device is a relatively safe and effective tool for use in performance of mechanical thrombectomy in patients with acute ischemic stroke.

CT Angiographic Source Images Predict Outcome and Final Infarct Volume Better Than Noncontrast CT in Proximal Vascular Occlusions

Alberta Stroke Programme Early CT Score (ASPECTS) is widely used for assessment of early ischemic changes in acute stroke. We hypothesized that CT angiography source image (CTA-SI) ASPECTS correlates better with baseline National Institutes of Health Stroke Scale score, final ASPECTS and neurological outcomes when compared with noncontrast CT ASPECTS. We studied patients presenting with acute ischemic stroke and identified proximal arterial occlusions (internal carotid artery, middle cerebral artery M1, and proximal middle cerebral artery M2) from the Calgary CT Angiography database. CT scans were independently read by 3 observers for baseline noncontrast CT ASPECTS, CT angiography source image ASPECTS, and follow-up ASPECTS. Details of demographics and risk factors were noted. A modified Rankin Scale score ≤2 at 3 months was considered a favorable outcome. We identified 261 patients with proximal occlusions for analysis. We found a better correlation between CT angiography source image ASPECTS and follow-up ASPECTS (Spearman correlation coefficient r=0.65; 95% CI, 0.58 to 0.72; P<0.001) than between noncontrast CT ASPECTS and follow-up CT ASPECTS (r=0.46; 95% CI, 0.36 to 0.55; P<0.001). CT angiography source image ASPECTS correlated better with baseline National Institutes of Health Stroke Scale and 24-hour National Institutes of Health Stroke Scale when compared with noncontrast CT ASPECTS (P<0.001). In an adjusted model including both CT angiography source image ASPECTS and noncontrast CT ASPECTS, CT angiography source image ASPECTS was associated with good outcome (OR, 2.30; 95%, CI, 1.16 to 4.53), whereas noncontrast CT ASPECTS was not (OR, 1.54; 95% CI, 0.84 to 2.82). Among imaging parameters, CT angiography source image ASPECTS was the only independent predictor of good outcome (OR, 2.29; 95% CI, 1.16 to 4.53). CT angiography source image ASPECTS correlates better with baseline stroke severity, is a better predictor of final infarct extension, and independently predicts neurological outcome than noncontrast CT ASPECTS.

Targeted Extracranial-Intracranial Bypass With Intra-Aneurysmal Administration of Indocyanine Green: Case Report

Early origin of the middle cerebral artery M2 segment is a normal variant. When such a vessel is occluded proximally, the parenchyma distal to the vessel may become ischemic. Targeted extracranial to intracranial bypass to such a specific branch may preserve perfusion to the end organ. We describe the use of intra-aneurysmal injection of indocyanine green to identify a target middle cerebral artery branch (MCA) for bypass, immediately followed by proximal parent vessel sacrifice via endovascular embolization. A 45-year-old woman presented to an outside hospital with headaches. Magnetic resonance imaging revealed a giant aneurysm of the right MCA. The aneurysm gave rise to an M2 branch that supplied the right anterior frontal operculum, as well as the anterolateral portion of the superior temporal gyri. Balloon test occlusion was nondiagnostic because of the territory involved, and the risk of sizable infarction after vessel sacrifice was thought to be high. Craniotomy and targeted extracranial to intracranial bypass to an M4 opercular branch was performed with intra-aneurysmal injection of indocyanine green. In our combined endovascular/open cerebrovascular suite, an opercular MCA branch that fluoresced during the first-pass arterial circulation of indocyanine green was identified, and a superficial temporal artery to MCA bypass was performed. Angiographic verification of bypass patency was confirmed, followed by embolic occlusion of the giant aneurysm with preservation of flow to the parenchyma at risk through the bypass. Targeted bypass to distal branches is feasible with intra-arterial and intra-aneurysmal injection of indocyanine green, allowing confident preservation of blood supply to areas distal to the sacrificed vessel.

Clipping and superficial temporal artery–M2 bypass for unruptured anterior communicating artery aneurysm associated with atherosclerotic internal carotid artery occlusion: report of 2 cases

Background The management of the unruptured AcomA aneurysm associated with atherosclerotic occlusion of the unilateral internal carotid artery (ICA) raises several strategic dilemmas. Methods Two such patients with unruptured aneurysm on the AcomA, which supply cross-flow toward the hemisphere with ICA occlusion, are presented. Results Both patients were treated with STA-M2 bypass followed by clipping of the unruptured AcomA aneurysm in 1 stage through the transsylvian route. Both patients were doing well without neurological deficit nor cognitive impairment at 1 year follow-up. Conclusions In the surgical treatment of unruptured AcomA aneurysm with atherosclerotic ICA occlusion, preceding bypass would be ideal in case of intraoperative rupture as well as to reduce perioperative ischemia if the bypass procedure itself could be performed with minimal risk. Enough and atraumatic exposure of the sylvian fissure contributed to reduce brain retraction during the clipping of AcomA aneurysm and, in addition, to ease the STA-M2 bypass.

Recanalization and Outcome After Intra-Arterial Thrombolysis in Middle Cerebral Artery and Internal Carotid Artery Occlusion

Recent studies have reported sex differences in recanalization and outcome after intravenous thrombolysis (IVT) in acute ischemic stroke. We analyzed sex differences in outcome in consecutive patients with middle cerebral artery (MCA) M1 or M2 and internal carotid artery (ICA) occlusion treated with intra-arterial thrombolysis (IAT). Recanalization immediately after thrombolysis and outcome after 3 months were assessed. Two hundred five patients (111 men) with MCA and 43 (22 men) with ICA occlusion were identified. Baseline variables did not differ between the sexes except for a higher prevalence of smokers among men in the MCA group (31% vs 12%; P=0.001). Partial or complete recanalization (TIMI flow 2 or 3) of the MCA was observed in 71 (75%) women and 80 (72%) men (P=0.488). In the ICA group, 14 (67%) women and 11 men (50%) showed TIMI 2 or 3 recanalization (P=0.425). Favorable outcome (modified Rankin Scale score 0 to 2) was seen in 57 women (61%) and 63 men (57%) with MCA occlusion (P=0.512) and in 6 women (28%) and 4 men (18%) with ICA occlusion (P=0.656). After multiple-regression analyses, there was still no association between sex and outcome (P=0.763 for MCA and P=0.813 for ICA occlusion) or recanalization (P=0.488 for MCA and P=0.104 for ICA occlusion). There was no association between sex and recanalization or outcome after IAT. These findings are in contrast to previous studies reporting better recanalization and outcome after IVT in women and might have implications in the selection of patients for IAT or IVT.

NIHSS Score and Arteriographic Findings in Acute Ischemic Stroke

To test the hypothesis that the National Institutes of Health Stroke Scale (NIHSS) score is associated with the findings of arteriography performed within the first hours after ischemic stroke. We analyzed NIHSS scores on hospital admission and clinical and arteriographic findings of 226 consecutive patients (94 women, 132 men; mean age 62+/-12 years) who underwent arteriography within 6 hours of symptom onset in carotid stroke and within 12 hours in vertebrobasilar stroke. From stroke onset to hospital admission, 155+/-97 minutes elapsed, and from stroke onset to arteriography 245+/-100 minutes elapsed. Median NIHSS was 14 (range 3 to 38), and scores differed depending on the arteriographic findings (P<0.001). NIHSS scores in basilar, internal carotid, and middle cerebral artery M1 and M2 segment occlusions (central occlusions) were higher than in more peripherally located, nonvisible, or absent occlusions. Patients with NIHSS scores > or =10 had positive predictive values (PPVs) to show arterial occlusions in 97% of carotid and 96% of vertebrobasilar strokes. With an NIHSS score of > or =12, PPV to find a central occlusion was 91%. In a multivariate analysis, NIHSS subitems such as "level of consciousness questions," "gaze," "motor leg," and "neglect" were predictors of central occlusions. There is a significant association of NIHSS scores and the presence and location of a vessel occlusion. With an NIHSS score > or =10, a vessel occlusion will likely be seen on arteriography, and with a score > or =12, its location will probably be central.

中大脳動脈りゅう（Ｍ１‐２分岐部）への最適接近法の選択

The surgical treatment of the middle cerebral artery (M1-2 bifurcation) aneurysm (MCA AN) employs the pterional approach and comprises much of aneurysm surgeries. But the surgical management of MCA AN remains a technically challenging problem especially for inexperienced neurosurgeons. This is largely caused by the difficulty of securing the M1 artery as the parent artery before exposing the whole aneurysm. In this study, we retrospectively analyzed the relationship between the approaches and operative difficulties in 90 MCA ANs in 86 of our patients operated on by the same neurosurgeon (K.U.). The variations of the MCA ANs were classified according to the following 3 points: the length of M1, M1 configuration on the angiogram (antero-posterior view), and the aneurysmal dome direction to M2. We subdivided the pterional approach into the following 4 groups: 1) the proximal approach (PA) to secure the proximal M1 after having controlled the internal carotid artery, 2) the distal approach (DA) to secure the distal M1 in the space between M2 arteries after having opened the distal sylvian fissure, 3) the superior approach (SA) to secure the distal M1 after having opened the distal sylvian fissure and followed the medial surface of M2 superior trunk, and 4) the inferior approach (IA) to secure the distal M1 after having opened the distal sylvian fissure and followed the lateral surface of M2 inferior trunk. The PA is effective in the cases of short M1 but in the cases of long M1 the DA is effective. The PA is safe for the cases in which the direction of the aneurysm is at the medial side of M2 arteries. On the other hand, in the cases in which the direction of the aneurysm is lateral to the M2 arteries, DA and SA are safe. In view of the results, we designed a scoring system to indicate the difficulties of securing M1 as the parent artery regarding the above-mentioned 3 points. Using these scores, we were able to decide the optimum approach preoperatively. To secure the parent artery is indispensable to safe aneurysm surgery. Comparing the points of each approach to the aneurysm with this scoring system, we were able to construct a better and safer micro-dissection plan with the goal of securing the parent M1 artery, and perform the operation by following the pre-operative plan. Surgical success or failure is determined by preoperative planning.

Blood flow velocities in middle cerebral artery branches after subarachnoid hemorrhage.

In a prospective study, 55 patients were examined by transcranial duplex sonography (TCCS) after subarachnoid hemorrhage (SAH) to determine whether additional transcranial duplex examination on the middle cerebral artery M2 segments would aid in the examination of the MCA stem segment. The mean blood flow velocities and pulsatility index were correlated to the occurrence of delayed ischemic neurologic deficits (DIND). Out of 47 patients included, 21 did not experience any delayed deficit (group I), 15 did (group II), and in 11 the extent to which vasospasm contributed to a neurologic deficit was unclear (group III). The highest blood flow velocity and the greatest increase of mean blood flow velocity on 1 day were significantly higher in groups II and III both in M1 and in M2. In 10 patients in group II, where the onset day of DIND was known exactly, Doppler data indicating ischemia before or at the time of DIND were observed in nine. In eight patients, Doppler of the MCA stem alone would have provided enough information to recognize the risk of symptomatic vasospasm; in one patient, only the M2 Doppler gave an indication of ischemic complication. Transcranial duplex sonography may provide additional information to TCD by accurate delineation of M1/M2 vasospasm and therefore may help plan cerebral angiography and neurointerventional treatment.