Intracranial Embolism and Thrombosis

✓ The microsurgical anatomy of the distal anterior cerebral artery (ACA) has been defined in 50 cerebral hemispheres. The distal ACA, the portion beginning at the anterior communicating artery (ACoA), was divided into four segments (A2 through A5) according to Fischer. The distal ACA gave origin to central and cerebral branches. The central branches passed to the optic chiasm, suprachiasmatic area, and anterior forebrain below the corpus callosum. The cerebral branches were divided into cortical, subcortical, and callosal branches. The most frequent site of origin of the cortical branches was as follows: orbitofrontal and frontopolar arteries, A2; the anterior and middle internal frontal and callosomarginal arteries, A3; the paracentral artery, A4; and the superior and inferior parietal arteries, A5. The posterior internal frontal artery arose with approximately equal frequency from A3 and A4 and the callosomarginal artery. All the cortical branches arose more frequently from the pe...

The aim of this study was to analyze age specific incidence rates (IRs) of cerebral thromboembolic attacks (CTA) among women and men 15-44 years of age in Denmark from 1980 through 1993 and quantify possible influences from oral contraceptives (OC) on the incidence figures. The discharge diagnoses ICD 432-436 from all Danish neurological, neurosurgical and medical departments during the period 1980-1993 were identified in a central diagnosis register. The use of OC was achieved from complete sale statistics during the study period and cross-sectional studies assessing the type-specific use of OC at different ages. During the 14-year study period, 2100 female and 2552 male attacks were registered. Men had an exponentially increasing IR with increasing age. Compared with men in the period 1980-1986, women had more attacks in the 20-35-year age group and fewer attacks above the age of 35. After 1987 the sex differences below the age of 35 were not significant. From the first half (1980...

Background The neuroprotective property of clomethiazole has been demonstrated in several animal models of global and focal brain ischemia. In this study the authors investigated the effect of clomethiazole on cerebral outcome in patients undergoing coronary artery bypass surgery. Methods Two hundred forty-five patients scheduled for coronary artery bypass surgery were recruited at two centers and prospectively randomized to clomethiazole edisilate (0.8%), 225 ml (1.8 mg) loading dose followed by a maintenance dose of 100 ml/h (0.8 mg/h) during surgery, or 0.9% NaCl (placebo) in a double-blind trial. Coronary artery grafting was completed during moderate hypothermic (28-32 degrees C) cardiopulmonary bypass. Plasma clomethiazole was measured at several intervals during and up to 24 h after the end of infusion. A battery of eight neuropsychological tests was administered preoperatively and repeated 4-7 weeks after surgery. Analysis of the change in neuropsychological test scores from ...

Background and Purpose —High-intensity transient signals (HITS) during cardiac surgery are capable of causing encephalopathy and cognitive deficits. This study was undertaken to determine whether intraoperative HITS cause alterations of neuropsychological function (NPF) and/or cerebral glucose metabolism (CMRGlc), even in a low-risk patient group, and whether induced changes are interrelated. Methods —Eighteen patients without signs of cerebrovascular disease underwent elective coronary artery bypass grafting (CABG), and two of these additionally underwent valve replacement in normothermia. Intraoperatively, HITS were recorded by means of transcranial Doppler ultrasonography (TCD). Perioperatively, NPF and CMRGlc were assessed using a standardized complex test battery and positron emission tomography with 18 F-2-fluoro-2-deoxy- d -glucose (FDG-PET), respectively. Results —Intraoperatively, the number of HITS ranged from 90 to 1710 per patient and hemisphere, more on the right side t...

Continuous recording of changes in local pO2 during and after brain infarction in surviving animals which can be followed for months or years, may provide interesting information concerning pathophysiology and treatment of stroke and thrombosis. We performed such measurements before, during and till 4 weeks after photochemical induction of a cerebrocortical infarction in three rabbits. Rose bengal--a photosensitive dye which sticks to endothelial cells and gives rise to endothelial damage and thrombosis when illuminated--was injected intravenously. After injection, a circular area (diameter 3 mm) of the brain cortex was illuminated using an optic fiber conducting light from a halogen lamp, whether or not filtered by heat and colour filters. In order to enable pO2 measurement in and near the infarct zone, we constructed a transparent plastic frame in which pO2 electrodes were fixed beneath and 1 mm besides a shaft permitting mounting of the optic fiber. A black adhesive ring (inner diameter 3 mm) was attached to the bottom of the frame providing a perfectly demarcated illumination area. After fixation the electrodes were calibrated and the frame was implanted in the rabbit's skull. Ten days later an infarction was induced; pO2 was monitored continuously before, during and till 4 hours after this induction. Furthermore, pO2 was recorded 24 hours, 48 hours, 5 days, 14 days and 4 weeks after infarction. Parameters describing the time course of pO2 were determined. In the illuminated area pO2 decreased after a certain latency time to reach a very low level, probably zero level, where it remained for at least 24 hours. Gradually, recovery was observed during the following days, and four weeks after infarction both level and pattern of electrode current appeared to be normal again. In the border zone pO2 decreased but did not reach zero level. Recovery was observed earlier than in the illuminated area.

Background and Purpose —Cerebral injury after cardiac surgery is now recognized as a serious and costly healthcare problem mandating immediate attention. To effect solution, those subgroups of patients at greatest risk must be identified, thereby allowing efficient implementation of new clinical strategies. No such subgroup has been identified; however, patients undergoing intracardiac surgery are thought to be at high risk, but comprehensive data regarding specific risk, impact on cost, and discharge disposition are not available. Methods —We prospectively studied 273 patients enrolled from 24 diverse US medical centers, who were undergoing intracardiac and coronary artery surgery. Patient data were collected using standardized methods and included clinical, historical, specialized testing, neurological outcome and autopsy data, and measures of resource utilization. Adverse outcomes were defined a priori and determined after database closure by a blinded independent panel. Stepwise...

✓ Systemic fibrinolytic therapy for acute stroke is no longer recommended because of resulting systemic fibrinolysis and the risk of intracerebral hemorrhage. Human tissue-type plasminogen activator (TPA) is a native enzyme that converts plasminogen to plasmin with subsequent clot lysis. The affinity for plasminogen is increased several-fold when the substrate is bound to fibrin. At appropriate dosage, “clot-specific” throm-bolysis may be achieved at the surface of the thrombus without creating systemic fibrinolysis. The authors designed a study to evaluate the effect of intravenous TPA administered 2 hours after acute thromboembolic stroke in rats. This time course was chosen to simulate an analogous clinical situation. Middle cerebral artery embolic stroke was caused by intracarotid injection of 0.025 cc of human blood clot in 16 rats. Regional cerebral blood flow, measured by the hydfogen clearance technique, and electroencephalographic (EEG) recordings were obtained every 30 min...

PURPOSE To study MR patterns of venous sinus occlusive disease and to relate them to the underlying pathophysiology by comparing the appearance and pathophysiologic features of venous sinus occlusive disease with those of arterial ischemic disease. METHODS The clinical data and MR examinations of 26 patients with venous sinus occlusive disease were retrospectively reviewed with special attention to mass effect, hemorrhage, and T2-weighted image abnormalities as well as to abnormal parenchymal, venous, or arterial enhancement after intravenous gadopentetate dimeglumine administration. Follow-up studies when available were evaluated for atrophy, infarction, chronic mass effect, and hemorrhage. RESULTS Mass effect was present in 25 of 26 patients. Eleven of the 26 had mass effect without abnormal signal on T2-weighted images. Fifteen patients had abnormal signal on T2-weighted images, but this was much less extensive than the degree of brain swelling in all cases. No patient showed abn...

A retrospective case control study was carried out in order to assess the risk of developing cerebral thromboembolism by use of low dose oral contraceptives (OC). The subjects were all the 794 women in Denmark aged 15-44 who had suffered a cerebral thromboembolic attack (CTA) during the period 1985-1989, and an age-matched randomly selected control population of 1588 women. CTA included occlusion of precerebral arteria (ICD 432), cerebral thrombosis (ICD 433), cerebral embolism (ICD 434), transitory cerebral ischaemia (TCI; ICD 435) and the unspecified group apoplexia cerebri (ICD 436). Of 692/1584 case/control questionnaires sent out, 590/1396 (85.1/88.1%) were returned. Among the cases, 15 refused to participate, 69 had a revised or unreliable diagnosis, 40 had previously had thromboembolic disease, 13 were pregnant, and 152 had a disease predisposing them for CTA, leaving 323 without known predisposition, of whom 320 reported use/non-use of OC. Among 1396 controls, eight either r...

Background: The neuroprotective property of clomethiazole has been demonstrated in several animal models of global and focal brain ischemia. In this study the authors investigated the effect of clomethiazole on cerebral outcome in patients under-going coronary artery bypass ...

Suppression of platelet activation improves the efficacy of thrombolytic therapy for stroke. Thus, combination treatment with recombinant tissue plasminogen activator (r-tPA) and 7E3 F(ab′)2, a GPIIb/IIIa inhibitor that binds the platelet to fibrin, may improve the efficacy of thrombolytic therapy in embolic stroke. Magnetic resonance imaging (MRI) was used to monitor treatment response in rats subjected to embolic middle cerebral artery (MCA) occlusion (MCAo). Animals were randomized into treated ( n = 12) and control ( n = 10) groups and received intravenous combination therapy or saline, respectively, 4 hours after MCAo. Magnetic resonance imaging (MRI) measurements performed 1 hour after MCAo showed no difference between groups. However, an increased incidence (50%) of MCA recanalization was found in the treated group at 24 hours compared with 20% in the control group. The area of low cerebral blood flow at 24 and 48 hours was significantly smaller in the combination treatment g...

A 27-year-old patient with a prolactinoma represents the first reported case of an isolated unilateral internuclear ophthalmoplegia secondary to embolism, and also appears to be the second reported case of embolism via a persistent primitive trigeminal artery. It is also the first incidence of ...

It has recently been found that patients receiving cerebral irradiation can develop hemorrhagic dysangiogeneses simulating occult vascular malformations. To analyze this connection, we report on five patients with occult cerebrovascular malformations occurring after "standard" or focused irradiation performed for brain tumors in four patients and for a deep-seated cavernous angioma in one patient. All lesions were within the radiation ports. The time interval between irradiation and the detection of the occult vascular malformations varied from 3 to 9 years; the ratio of female to male patients was 4:1. Four patients were < 15 years old when first irradiated. Four patients presented with acute symptoms (headache, vomiting, focal signs) and one was asymptomatic when the lesions were first detected. Serial magnetic resonance imaging scans were available in four patients and a computed tomographic scan in the other patient. The initial appearance was that of a hypointense T1-T2 focus; magnetic resonance imaging then revealed focal or multifocal T1 hyperintensity and T2 mixed signal intensity followed by a late ring of decreased signal intensity. Four patients were operated on and one was under neuroradiological monitoring. Histological features of these lesions included clusters of closely packed vascular spaces resembling cavernous malformations sometimes associated with a thrombosed thick-walled vein with intense hemosiderin deposition and fibroblastic proliferation; telangiectasic changes were also seen in the adjacent brain. Increased awareness of occult cerebrovascular malformations is necessary, because their occurrence is not infrequent and they have hemorrhagic potential. Children receiving cerebral irradiation are at greater risk of this complication.

We present five cases of giant serpentine aneurysms (large, partially thrombosed aneurysms containing tortuous vascular channels with a separate entrance and outflow pathway) and review 28 cases reported in the literature. Giant serpentine aneurysms should be considered as a subgroup of giant aneurysms, distinct from saccular and fusiform varieties, given their unique clinical presentation and radiographic features.

We retrospectively analyzed the epidemiological features of 164 out-clinic patients with a first-onset stroke between 15 and 49 years old. Ischemic stroke occurred in 141 patients, hemorrhagic stroke in 16 patients, and venous thrombosis in 7 patients. Forty-eight percent of ischemic strokes were atherothrombotic, but no etiology was found in 32% of patients with ischemic stroke. Systemic arterial hypertension was the most frequent etiology in the hemorrhagic stroke group. The most frequent risk factors were systemic arterial hypertension, smoking, hypercholesterolemia, alcoholism and diabetes mellitus. Although stroke in young adults deserves some specific etiological investigation, we found that ordinary risk factors such as hypertension, tobacco use, hypercholesteremia and diabetes were prevalent in our population. It seems that prevention campaigns should be the target of our work.

Background and Purpose —Cerebral injury after cardiac surgery is now recognized as a serious and costly healthcare problem mandating immediate attention. To effect solution, those subgroups of patients at greatest risk must be identified, thereby allowing efficient implementation of new clinical strategies. No such subgroup has been identified; however, patients undergoing intracardiac surgery are thought to be at high risk, but comprehensive data regarding specific risk, impact on cost, and discharge disposition are not available. Methods —We prospectively studied 273 patients enrolled from 24 diverse US medical centers, who were undergoing intracardiac and coronary artery surgery. Patient data were collected using standardized methods and included clinical, historical, specialized testing, neurological outcome and autopsy data, and measures of resource utilization. Adverse outcomes were defined a priori and determined after database closure by a blinded independent panel. Stepwise...

In rat middle cerebral artery (MCA) occlusion models with an intraluminal nylon monofilament, lesion volume and its reproducibility vary among laboratories. These variations may be caused by differences in the properties of nylon monofilaments. We performed the present study to compare the effects of two different types of 4-0 nylon monofilament on neurological and morphological outcomes in this model. We randomly and blindly used two types of 4-0 nylon monofilament (Ethilon, n = 15, and Nitcho, n = 15) to permanently occlude the ostium of the right MCA intraluminally in rats. Neurological outcome and lesion size were compared 24 hours after MCA occlusion between the two groups. The diameter, tensile strength, and extensibility of each filament were measured. Neurological outcome was not different between the groups. The mortality within 24 hours was 13% (2/15) in the Ethilon group and 0% in the Nitcho group. Total lesion volume in the former was 295.9 +/- 97.2 mm3 (mean +/- SD), significantly larger and more reproducible than that in the latter (190.3 +/- 144.7 mm3, P = .026). The Ethilon filament had a significantly larger diameter (Ethilon, 0.193 +/- 0.001 mm; Nitcho, 0.180 +/- 0.001 mm; P < .0001), poorer tensile strength, and better extensibility than the other. Exact diameter and quality are not always the same among nylon monofilaments, even if they meet the standard for the designation 4-0. The present study indicates that slight differences of filament characteristics significantly affect lesion volume and its reproducibility. This result may explain some conflicting observations in this MCA occlusion model.