Middle Cerebral Artery Trunk Occlusion Research Articles

Interventional reperfusion for acute embolism of the middle cerebral artery trunk with contralateral internal carotid artery congenital absence.

Internal carotid artery congenital absence with acute embolism of the middle cerebral artery trunk is very rare. A 65-year-old female with a history of hypertension and atrial fibrillation was admitted to the neurology department of our hospital. Computed tomography of the head and neck showed no carotid canal of the petrous portion of the temporal bone; digital subtraction angiography (DSA) showed no left internal carotid artery and the right middle cerebral artery trunk occlusion. These results suggested acute embolism of the middle cerebral artery trunk with contralateral internal carotid artery congenital absence. Mechanical thrombectomy was performed, which had a good outcome. This case showed the vascular anatomy features of ICA congenital absence with contralateral large vessel acute occlusion, and it is essential to promptly identify the vascular variation during the interventional procedure.

Nalmefene improves prognosis in patients with a large cerebral infarction: study protocol and preliminary results of a randomized, controlled, prospective trial

Background and objectives: Middle cerebral artery trunk occlusion can cause large infarctions. Clinically, thrombolytic therapy, defibrillation, vasodilation, and surgery are often used to treat these large infarctions. However, the therapeutic efficacy of these therapeutic interventions in promoting prognosis remains controversial. Nalmefene, an opioid receptor antagonist, exhibits a neuroprotective effect. Few clinical studies have reported on the therapeutic efficacy of nalmefene in the treatment of large cerebral infarctions. In this study, we investigated the therapeutic efficacy of nalmefene in restoring the neurologic function of patients with middle cerebral artery trunk infarction while using conventional treatment as a control. Design: A randomized, controlled, prospective trial. Methods: Two hundred and thirty-six patients with middle cerebral artery trunk infarction who will receive treatment at the First Hospital of Jilin University in China will be randomly divided into a control group (n = 116) and a nalmefene group (n = 120). Patients in the control group will receive conventional treatment. Patients in the nalmefene group will receive 10 successive days of intravenous nalmefene hydrochloride injection based on conventional treatment. Outcome measures and preliminary results: The primary outcome of this study is the efficacy rate at 20 days (i.e., 10 days after treatment). The secondary outcomes of this study include (1) the National Institutes of Health Stroke Scale (NIHSS) score at 20 days, which is used to evaluate neurologic function deficits; (2) Glasgow Coma Scale scores at 0 days (before treatment) and 10 days; (3) serum level of matrix metalloproteinase-9 at 0, 5, and 10 days (i.e., before treatment and 5 and 10 days of treatment); and (4) magnetic resonance imaging perfusion images of the head at 0 and 10 days. The results of a preliminary experiment involving participants receiving the same treatment as in the present study revealed that compared with the control group, the NIHSS score was significantly decreased, the efficacy rate was increased, Glasgow Coma Scale score was significantly increased, serum level of matrix metalloproteinase-9 was significantly decreased, cerebral blood flow and cerebral blood volume on the lesion side were significantly increased, and the mean transit time of contrast agent on the lesion side was significantly shortened in the nalmefene group. Discussion: Findings from this study will provide clinical evidence for use of nalmefene in combination with conventional treatment for large cerebral infarctions and data to support this combined therapy, which can improve the prognosis in patients with large cerebral infarctions. Ethics and dissemination: This study was designed in December 2011. Clinical ethics approval was received in November 2017. This trial was registered in December 2017. Patient recruitment will begin in January 2018 and end in January 2019. Data analysis will be completed in December 2019. Results will be disseminated for publication in a peer-reviewed journal. Trial registration: This trial was registered with the Chinese Clinical Trial Registry (registration number: ChiCTR-IOR-17013871).

Anomalies of the Middle Cerebral Artery

There are several anomalies of the middle cerebral artery (MCA) in humans, such as accessory MCA, duplicated MCA, fenestration of MCA, and duplicated origin of MCA. Recently, unfused or twig-like MCA, which indicates MCA trunk occlusion with collateral plexiform arterial network, have been reported. During the embryonic stage, MCA is thought to generate from plexiform arterial twigs arising from the anterior cerebral artery, and these twigs form the definitive MCA by fusion and regression at the end of the development stage. Any interruption during the fusion of the arterial twigs may result in MCA anomalies, and the unfused or twig-like MCA, especially, is hypothesized to be the persistent primitive arterial twigs. Clinically, it is challenging to differentiate the unfused or twig-like MCA from unilateral moyamoya disease, in which stenotic change begins at the MCA. The knowledge of the anomalies of the MCA is important to perform a safe surgical or endovascular intervention.

Cerebral arterial calcification is an imaging prognostic marker for revascularization treatment of acute middle cerebral arterial occlusion.

Background and PurposeTo study the significance of intracranial artery calcification as a prognostic marker for acute ischemic stroke patients undergoing revascularization treatment after middle cerebral artery (MCA) trunk occlusion.MethodsPatients with acute MCA trunk occlusion, who underwent intravenous and/or intra-arterial revascularization treatment, were enrolled. Intracranial artery calcification scores were calculated by counting calcified intracranial arteries among major seven arteries on computed tomographic angiography. Patients were divided into high (HCB; score ≥3) or low calcification burden (LCB; score <3) groups. Demographic, imaging, and outcome data were compared, and whether HCB is a prognostic factor was evaluated. Grave prognosis was defined as modified Rankin Scale 5-6 for this study.ResultsOf 80 enrolled patients, the HCB group comprised 15 patients, who were older, and more commonly had diabetes than patients in the LCB group. Initial National Institutes of Health Stroke Scale (NIHSS) scores did not differ (HCB 13.3±2.7 vs. LCB 14.6±3.8) between groups. The final good reperfusion after revascularization treatment (thrombolysis in cerebral infarction score 2b-3, HCB 66.7% vs. LCB 69.2%) was similarly achieved in both groups. However, the HCB group had significantly higher NIHSS scores at discharge (16.0±12.3 vs. 7.9±8.3), and more frequent grave outcome at 3 months (57.1% vs. 22.0%) than the LCB group. HCB was proven as an independent predictor for grave outcome at 3 months when several confounding factors were adjusted (odds ratio 4.135, 95% confidence interval, 1.045-16.359, P=0.043).ConclusionsIntracranial HCB was associated with grave prognosis in patients who have undergone revascularization for acute MCA trunk occlusion.

DWI-ASPECTS as a Predictor of Dramatic Recovery After Intravenous Recombinant Tissue Plasminogen Activator Administration in Patients With Middle Cerebral Artery Occlusion

In patients with middle cerebral artery trunk occlusion we investigated whether the diffusion-weighted imaging- the Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS) predicts short-term neurological recovery after intravenous recombinant tissue plasminogen activator administration, and investigated how DWI-ASPECTS relates to clinical outcome. Dramatic recovery was defined as a ≥ 10-point reduction or a total National Institutes of Health Stroke Scale score of 0 to 1 at 24 hours and 7 days. Early recanalization was defined as recanalization within 1 hours after intravenous recombinant tissue plasminogen activator. Favorable outcome at 3 months was defined as a modified Rankin Scale score of 0 to 2. Sixty-six patients (median age [interquartile], 79 [70-85] years, male; 34 [52%]) were enrolled. DWI-ASPECTS was 6 (5-9). Dramatic recovery was seen in 16 (24%) and 26 (39%) patients at 24 hours and on day 7, respectively. Early recanalization occurred in 22 (33%) patients. DWI-ASPECTS ≥ 7 was an independent predictor of dramatic recovery at 24 hours (odds ratio, 100.85; 95% confidence interval, 4.29-2371.40; P=0.004) and 7 days (odds ratio, 14.15; 95% confidence interval, 2.21-90.48; P=0.005). Although the favorable outcome rate was not significantly different between patients with DWI-ASPECTS ≥ 7 with and without early recanalization (60% versus 31%; P=0.228), it was statistically more frequent in patients with DWI-ASPECTS <7 with early recanalization than those without early recanalization (38% versus 0%; P=0.017). DWI-ASPECTS predicted short-term recovery in patients with middle cerebral artery trunk occlusion receiving intravenous recombinant tissue plasminogen activator. In patients with lower DWI-ASPECTS, there may still be benefit from early recanalization.

Low DWI-ASPECTS is associated with atrial fibrillation in acute stroke with the middle cerebral artery trunk occlusion

Background and purposeFor optimal acute stroke management and secondary prevention, discrimination of stroke etiology is crucial. We hypothesized that a low Alberta Stroke Program Early CT Score (ASPECTS) on diffusion-weighted imaging (DWI) immediately after stroke onset was associated with the presence of atrial fibrillation (AF). MethodsConsecutive patients admitted within 24h from stroke onset with an occlusion at the horizontal segment of the middle cerebral artery (M1) on initial MRA were retrospectively enrolled. AF was diagnosed based on continuous electrocardiogram monitoring during acute hospitalization or its confirmed history. ResultsOf the 206 patients (95 women, median age 77 [IQR 69–85] years, NIHSS score 18 [13–23]) enrolled, AF was identified in 138 patients (AF group): chronic AF in 89, known paroxysmal AF (pAF) in 13, and masked pAF on admission in 36. The ASPECTS score on the initial DWI, performed a median of 2.5h after onset, was lower in the AF group than in the others (4 [2–6] vs. 7 [4–8], p<0.001). With the optimal cut-off value of ≤6 (sensitivity, 78%; specificity, 57%; area under the ROC curve, 0.682), DWI-ASPECTS was independently associated with the presence of any AF (OR 5.05, 95%CI 2.36 to 10.8), as well as the presence of any pAF (OR 8.64, 95%CI 3.00 to 24.9) and that of masked pAF on admission (OR 10.0, 95%CI 3.06 to 32.9). ConclusionExtensive early ischemic change assessed by DWI-ASPECTS predicts the presence of AF, even initially masked pAF, in acute stroke patients with M1 occlusion.

Dynamics of Regional Distribution of Ischemic Lesions in Middle Cerebral Artery Trunk Occlusion Relates to Collateral Circulation

We describe the regional distribution of acute perfusion, diffusion, and final infarct lesions in middle cerebral artery (MCA) trunk occlusion. A total of 31 patients with acute ischemic stroke and MCA trunk occlusion were studied by multiparametric magnetic resonance imaging. Probabilistic maps of lesion distribution were generated. The probability of initial and final infarcts was highest in the central MCA region with decreasing probability toward the periphery where the probability of the tissue at risk of infarction to be saved was highest. The probability of brain regions being involved in acute diffusion lesions and evolving into or escaping from the final infarct relates to the anatomy of arterial blood supply.

Probabilistic cortical surface map of the middle cerebral artery territory for single-photon emission computed tomography studies

The middle cerebral artery (MCA) is the intracranial vessel most frequently affected by cerebrovascular diseases. A more accurate knowledge of the topography of this vessel may have an impact on treatment strategies for ischemic cerebrovascular diseases. The aim of this study was to construct a topographic map of the MCA territory for single-photon emission computed tomography (SPECT) using statistical brain mapping. The margin of the perfusion deficit associated with infarction due to arterial occlusion, as seen on SPECT imaging, is presumed to approximate the borders of the territory of the artery. Basing the study on this hypothesis, SPECT images obtained in 12 patients with large MCA infarctions due to angiographically confirmed MCA trunk occlusion were selected, anatomically standardized, and compared with SPECT images obtained in healthy volunteers to construct probabilistic cortical surface maps of the MCA territory. Crossed cerebellar diaschisis was used as a primary cutoff marker for creation of the map. This MCA map (Method C) was compared with the conventional region of interest (ROI) method (Method A) and previously reported predefined cortical templates (Method B) for preliminary clinical application. The probabilistic cortical surface map of the MCA territory showed that regions with the highest ratio of MCA territory included the transverse temporal gyrus (100%), supramarginal gyrus (100%), and inferior parietal lobule (91-92%). For preliminarily clinical application, this map (Method C) was compared with the conventional ROI method (Method A) in predicting hyperperfusion after carotid endarterectomy by performing a receiver operating characteristic (ROC) analysis, which demonstrated the statistically significant superiority of the MCA map (area under the ROC curve [Az] = 0.91) to the ROI method (Az = 0.75; p = 0.025). The ROC analysis also demonstrated a diagnostic value of the MCA map (Az = 0.95) that equaled predefined cortical templates (Method B) (Az = 0.93). The probabilistic cortical surface map of the MCA territory used for SPECT, which was created using statistical brain mapping techniques, would be useful for an objective assessment of the cerebral perfusion status of patients with cerebrovascular diseases.

中大脳動脈Ｍ１閉塞症における局所線溶療法の治療成績―閉塞部位による検討―

We performed intraarterial thrombolysis in 36 patients with evolving acute cerebral infarction due to occlusion of the middle cerebral artery (MCA). Angiographic sites of arterial occlusion were divided into 3 types: 1) M1 proximal occlusion type, MCA trunk occlusion proximal to the lenticulostriate arteries (16 patients), 2) M1 middle portion occlusion type, MCA trunk occlusion with partial involvement of the lenticulostriate arteries (9 patients), and 3) M1 distal occlusion type, MCA trunk occlusion distal to the lenticulostriate arteries (11 patients). The modified Rankin Scale (mRS) was used to assess clinical outcome at discharge. The rate of partial or complete recanalization in the proximal occlusion group was 44%, that in the middle portion occlusion group was 67%, and that in the distal occlusion group was 73%. There were trends toward the better recanalization rate in distal occlusions. Excellent or good outcome (mRS score 0 to 2) was seen in 13% of patients in the proximal occlusion group, 45% of those in the middle portion occlusion group, and 73% of those in the distal occlusion group. There was a significantly higher incidence of functionally independent patients in the distal occlusion group (p<0.05). Symptomatic cerebral hemorrhage occurred in 5 patients (14%). Intraarterial thrombolysis for acute middle cerebral artery occlusion is a very effective treatment modality for the M1 distal occlusion patients. But in M1 proximal occlusion patients, the recanalization rate is low, and the outcome is significantly poor even in the patients who underwent recanalization. Therefore we should consider intraarterial thrombolysis for the patients with the involvement of the lenticulostriate arteries.

A Digital Map of Middle Cerebral Artery Infarcts Associated With Middle Cerebral Artery Trunk and Branch Occlusion

Knowledge of the topographic distribution of infarcts of the middle cerebral artery (MCA) may give insight into the limits of the arterial territory and infarct mechanism and may influence the decision to use thrombolytic therapy. We describe the creation of a digital atlas of MCA (DA-MCA) infarction associated with MCA branch and trunk occlusion using magnetic resonance (MR) techniques. Hemispheric infarcts, with evidence of MCA trunk or branch occlusion, were manually segmented into binary images, linearly registered into a common stereotaxic coordinate space, and averaged to yield the probability of involvement by infarction at each voxel. Comparisons were made with existing maps of the MCA territory. Twenty-eight patients with median age of 74 years (range, 26 to 87 years) were studied. On the DA-MCA, the highest frequency of infarction was within the striatocapsular region, centrum semiovale, and the insula. The mean and maximal MCA infarct volumes were 195.5 cm3 and 366.3 cm3, respectively. Comparison with published maps showed that the most common difference from the DA-MCA was in the superomedial extent of the MCA territory. Some maps showed the MCA territory reaching the interhemispheric fissure, whereas in the DA-MCA it did not. There was a lower variability in the anterior boundary of the MCA territory compared with its posterior counterpart. We have created a digital atlas of MCA infarction using MR imaging techniques. This approach may be useful to establish the distribution of the MCA and other arterial territories and the border zones between them with greater certainty.

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Reperfusion Therapy for Acute Middle Cerebral Artery Trunk Occlusion

The purpose of this study was to test the hypothesis that direct percutaneous transluminal angioplasty (PTA) might reduce the incidence of haemorrhagic complications and might improve recanalization rate and clinical outcome as compared with intra-arterial (IA) thrombolysis in patients with acute middle cerebral artery (MCA) trunk occlusion. A total of 70 patients with acute MCA trunk occlusion were treated with IA reperfusion therapy. Thirty-six patients were treated with IA thrombolysis alone. In the other 34 patients, direct PTA was selected as the first choice of the treatment and subsequent thrombolysis was added if necessary for distal embolization. The modified Rankin scale (mRS) was used to assess clinical outcome at 90 days. As compared with IA thrombolysis, direct PTA provided significant increase in the rates of partial or complete recanalization (63.9 vs 91.2%, p < 0.01) and decrease in the incidence of large parenchymal hematoma with neurological deterioration (19.4% vs 2.9%, p=0.03). Despite such favorable effects, direct PTA did not improve the rate of a favorable outcome (mRS score 0 or 1, 41.7% for the IA thrombolysis group vs 52.9% for the PTA group, p=0.48). However, outcome classified in terms of independence (mRS score </= 2) was significantly better in the PTA group (73.5%) than the IA thrombolysis group (50.0%, p=0.04). In patients with acute MCA trunk occlusion, as compared with IA thrombolysis, direct PTA improved recanalization rate and reduced serious haemorrhagic complications, resulting in a significant increase in independent patients.

Weight-Adjusted and Activated Clotting Time–Guided Heparinization Might Reduce the Postprocedural Hemorrhage in Percutaneous Transluminal Angioplasty for Acute Middle Cerebral Artery Occlusion

To the Editor: We were impressed by the novel approach to treat acute ischemic stroke due to middle cerebral artery (MCA) occlusion proposed by Dr Nakano and coworkers.1 Instead of intravenous thrombolytic therapy, they had treated such disease with intra-arterial reperfusion therapy in 70 consecutive patients, 34 of whom with direct percutaneous transluminal angioplasty (PTA) over the infarct-related artery (IRA) and the remaining 36 with thrombolytic therapy alone. They found that the PTA group had not only higher IRA patency rate (91.2% versus 63.9%, P 24 hours) contrast medium extravasation or minor bleeding after the procedure. Consequently, the authors proposed that the direct PTA is an effective alternative to intra-arterial thrombolysis for MCA trunk occlusion. To our surprise is the principle of anticoagulant dosage the authors used, which is quite different from that used in conventional percutaneous coronary intervention …

Mechanical Recanalization for Acute Ischemic Stroke

Thrombolysis has become accepted as an effective treatment for acute ischemic stroke. However, two major problems remain: failure of recanalization and hemorrhagic complications. The combined use of mechanical recanalization techniques with thrombolytic agents occasionally may be required to improve recanalization rates and to reduce hemorrhagic complications. Percutaneous transluminal angioplasty (PTA), clot extraction utilizing retrieval devices, and clot fragmentation using energy of ultrasonic or laser vibrations and suction-creating saline jets are possible effective mechanical recanalization strategies, but mainly as a rescue therapy for patients with failed thrombolysis. However, for large artery occlusions, thrombolysis alone often results in failure of recanalization. In such cases, to minimize the total dose of thrombolytic agents and to prevent hemorrhagic complications, mechanical recanalization may be alternatively selected as the first choice of treatment. The safety and effectiveness of PTA for acute middle cerebral artery trunk occlusion has been reported using additional thrombolysis with low doses of thrombolytic agents for distal embolism by crushed fragments. Reduction of total doses of thrombolytic agents may decrease serious hemorrhagic complications, resulting in better clinical outcome.

Ultrasonographic prediction of patients’ outcome in hyperacute ischemic stroke

Objective: We examined whether carotid ultrasonographic (US) findings in hyperacute ischemic stroke are useful to predict patients’ outcome. Methods: We studied 73 consecutive patients with carotid stroke using both computed tomography (CT) and duplex carotid ultrasonogarphy within 6 h of stroke onset. We evaluated early CT findings defined as obscuration of the lentiform nucleus, loss of the insular ribbon and/or cortical effacement, and US findings indicating internal carotid artery (ICA) or middle cerebral artery trunk occlusion. The National Institute of Health Stroke Scale (NIHSS) at admission and modified Rankin scale on day 30 were assessed. Results: According to multiple logistic regression analysis, positive US findings ( P=0.0045, odds ratio, 11.1) provided the best predictor of modified Rankin scale score ≥3 compared with a baseline NIHSS≥16 ( P=0.036, odds ratio, 7.9) and early CT findings ( P=0.18). Conclusion: US findings of hyperacute stroke may provide a better predictor of patients’ outcome.

Diagnosis and Monitoring of Middle Cerebral Artery Occlusion with Contrast-Enhanced Transcranial Color-Coded Real-Time Sonography in Patients with Inadequate Acoustic Bone Windows

Transcranial color-coded real-time sonography (TCCS) is an emerging diagnostic technique that allows noninvasive imaging of intracranial vessels within parenchymal structures. However, in some patients, transcranial ultrasound is particularly hindered by insufficient ultrasound penetration through the temporal bone. The present study evaluates whether or not application of an echo-contrast agent in ultrasound-refractory patients with middle cerebral artery (MCA) trunk occlusion enhances image acquisition enough to yield accurate diagnoses. Contrast-enhanced (CE) TCCS examinations, computed tomography scans and angiographic studies were performed in 20 patients with clinical symptoms suggestive of MCA occlusion within 12 h of the onset of symptoms. For comparison, 20 control persons without history or clinical signs for cerebrovascular diseases were examined using CE-TCCS. In none of the patients or control subjects did unenhanced TCCS investigations depict any color-coded vascular signal of an intracranial vessel. After application of 9 mL of 400 mg/mL galactose-based microbubbles, CE-TCCS was performed. In subjects with MCA occlusion, CE-TCCS examinations were repeated within 24 h, 48 h and 5 days after stroke. In stroke patients ( n = 20), CE-TCCS showed an occluded MCA main stem in 11 patients, and this vessel was clearly demonstrable on the unaffected side. On the affected side, the posterior cerebral artery (PCA) and anterior cerebral artery (ACA) could be visualized in 8 of 11 subjects; in 3 patients, at least 1 of these vessels was detectable. Angiographic studies confirmed the diagnosis of MCA trunk occlusion in all 11 individuals. In follow-up investigations, 3 stroke patients had angiographic and CE-TCCS examinations consistent with vessel reperfusion. Nine stroke patients had a patent MCA shown in angiographic and CE-TCCS examinations. In the control group, the MCA trunk could be visualized in all subjects by CE-TCCS. CE-TCCS is a sensitive and specific ultrasound method for the diagnosis of MCA trunk occlusion that overcomes the anatomical hindrance of inadequate acoustic bone window. This technique may help to identify patients suitable for thrombolytic therapies and monitor their response.

Prediction of hemorrhagic complications after thrombolytic therapy for middle cerebral artery occlusion: value of pre- and post-therapeutic computed tomographic findings and angiographic occlusive site.

To evaluate the usefulness of pre- and post-therapeutic computed tomographic (CT) findings in predicting hemorrhagic complications, we retrospectively examined 35 patients treated with intra-arterial thrombolytic therapy for middle cerebral artery (MCA) occlusion. The presence or absence of early CT findings (loss of the insular ribbon, obscuration of the lentiform nucleus, and cortical effacement) and the presence and location of extravasation of contrast medium were evaluated on pre- and post-therapeutic CT scans, respectively. According to the angiographic occlusive site, the patients were classified into the following three groups: Group 1 (n = 13), MCA trunk occlusion involved lenticulostriate arteries; Group 2 (n = 11), occlusion of the MCA trunk without involvement of the lenticulostriate arteries; Group 3 (n = 11), occlusion of a branch of the MCA. Hemorrhagic complications (hemorrhagic transformation and/or massive brain swelling) were evaluated by reviewing CT scans obtained 3 to 14 days after thrombolytic therapy. No patient without extravasation (n = 17) showed hemorrhagic complications, and extravasation is the most useful finding in predicting hemorrhagic complications. There was significant correlation between extravasation and hemorrhagic complications (P < 0.01). In Groups 1 and 2, there was also significant correlation between early CT findings and hemorrhagic complications (P < 0.01), indicating that early CT findings are also useful in predicting hemorrhagic complications. In Group 1, 10 of 13 (76.9%) patients had both early CT findings and extravasation, and 6 of these 10 patients had hemorrhagic complications with clinical deterioration, suggesting the difficulty of thrombolytic therapy in this group. On the contrary, in Group 2, 8 of 11 (72.7%) patients had neither early CT findings nor extravasation and none of these 8 patients had hemorrhagic complications. In Group 3, however, early CT findings and extravasation had no correlation. Because the affected area was small in this group, it was difficult to evaluate cortical effacement. Although negative early CT findings did not always mean absence of extravasation and hemorrhagic complications in this group, the patients with hemorrhagic complications did not clinically deteriorate because of the small affected area. Hemorrhagic complications could be predicted by evaluation of angiographic occlusive site and pre- and post-therapeutic CT findings.

Effects of Recanalization and Collateral Blood Supply on Infarct Extent and Brain Edema after Middle Cerebral Artery Occlusion

A series of 53 patients with angiographically proven middle cerebral artery (MCA) trunk occlusions treated with intravenous (in 46) or intra-arterial (in 7) recombinant tissue plasminogen activator (rt-PA) and heparin anticoagulation was studied with serial computed tomography to find out whether recanalization promotes ischemic brain edema and hemorrhagic transformation. Partial or complete recanalization of the MCA trunk was shown in 11 patients immediately after rt-PA treatment by a second angiogram and in altogether 18 patients 1 day later by transcranial Doppler ultrasound or a third angiogram. During follow-up the extent of hypodensity increased in 5 of 18 patients (28%) with reperfusion at 24 h after symptom onset and in 23 of 35 patients (66%) without reperfusion (p < 0.01). The ischemic edema caused a midline shift in 1 of 18 patients (6%) with reperfusion at 24 h after symptom onset, but in 14 of 35 patients (40%) without reperfusion (p < 0.05). Hemorrhagic transformation was associated with reperfusion at 24 h in 7 (39%) patients and occurred in 13 (37%) patients without reperfusion (p > 0.5). Our data suggest that recanalization of MCA trunk occlusion within 24 h after symptom onset does not promote edema or hemorrhagic transformation of ischemic brain tissue.

Regional cerebral blood flow, sensory evoked potentials, and intracranial pressure in dogs with MCA occlusion by embolization or trapping.

Regional cerebral blood flow (rCBF), sensory evoked potentials (SEP), and intracranial pressure (ICP) were investigated in dogs with focal cerebral ischemia produced by a silicone cylinder embolus in the middle cerebral artery (MCA) trunk as compared to that produced by trapping the same vessel. These variables were measured at intervals of 1 hour for a period of 6 hours after MCA occlusion. In the embolized animals, rCBF decreased most extensively at the basal ganglia, from a control level of 53.9 +/- 3.9 (mean +/- SE) to 21.5 +/- 2.7 ml/100 gm/min at the 6th hour. Sensory evoked potentials decreased progressively from the resting level of 100% to 53.0% +/- 7.2% at the 3rd hour. Intracranial pressure, measured by epidural pressure on the occluded side, increased rapidly during the first 3 hours, from 10.6 +/- 0.3 to about 30 cm H2O. In the animals with trapping, the decreases in rCBF and declines of SEP were significantly less than those in the embolized animals, and no evident brain swelling was observed. This study demonstrates that MCA trunk occlusion by silicone cylinder embolization produces a more marked decrease in deep CBF, with diminution of SEP and increase in ICP, than that produced by trapping.