Showing papers in "Stroke in 1986"
TL;DR: In this article, the authors examined the incidence and size of infarction after occlusion of different portions of the rat middle cerebral artery (MCA) in order to define the reliability and predictability of this model of brain ischemia.
Abstract: We have examined the incidence and size of infarction after occlusion of different portions of the rat middle cerebral artery (MCA) in order to define the reliability and predictability of this model of brain ischemia. We developed a neurologic examination and have correlated changes in neurologic status with the size and location of areas of infarction. The MCA was surgically occluded at different sites in six groups of normal rats. After 24 hr, rats were evaluated for the extent of neurologic deficits and graded as having severe, moderate, or no deficit using a new examination developed for this model. After rats were sacrificed the incidence of infarction was determined at histologic examination. In a subset of rats, the size of the area of infarction was measured as a percent of the area of a standard coronal section. Focal (1-2 mm) occlusion of the MCA at its origin, at the olfactory tract, or lateral to the inferior cerebral vein produced infarction in 13%, 67%, and 0% of rats, respectively (N = 38) and produced variable neurologic deficits. However, more extensive (3 or 6 mm) occlusion of the MCA beginning proximal to the olfactory tract--thus isolating lenticulostriate end-arteries from the proximal and distal supply--produced infarctions of uniform size, location, and with severe neurologic deficit (Grade 2) in 100% of rats (N = 17). Neurologic deficit correlated significantly with the size of the infarcted area (Grade 2, N = 17, 28 +/- 5% infarction; Grade 1, N = 5, 19 +/- 5%; Grade 0, N = 3, 10 +/- 2%; p less than 0.05). We have characterized precise anatomical sites of the MCA that when surgically occluded reliably produce uniform cerebral infarction in rats, and have developed a neurologic grading system that can be used to evaluate the effects of cerebral ischemia rapidly and accurately. The model will be useful for experimental assessment of new therapies for irreversible cerebral ischemia.
2,669 citations
TL;DR: Validates the technique by comparing it to cerebral blood flow measured using intravenous Xenon133 and extracranial clearance recording and finds changes in MCA velocity reliably correlate with changes in cerebralBlood flow but the absolute velocity cannot be used as an indicator of CBF.
Abstract: Measurement of intracranial arterial blood flow velocity is a new technique with potentially a number of very useful applications. This study validates the technique by comparing it to cerebral blood flow (CBF) measured using intravenous Xenon133 and extracranial clearance recording. We have measured the middle cerebral artery (MCA) blood flow velocity in 17 symptomatic patients with the EME TC 264 transcranial Doppler velocimeter and compared these measurements to the ipsilateral hemispheric cerebral blood flow measured with an intravenous Xenon133 technique (Novo Cerebrograph 10A). Measurements were made at rest and during hypercapnia. The absolute measurement of MCA velocity and hemispheric CBF showed a poor correlation (r = 0.424, p less than 0.01) due to wide between-patient variations at rest but the blood flow response to hypercapnia, expressed as a reactivity index, showed a good correlation (r = 0.849, p less than 0.001). Thus changes in MCA velocity reliably correlate with changes in cerebral blood flow but the absolute velocity cannot be used as an indicator of CBF.
860 citations
TL;DR: It is concluded that subcortical parenchymal lesions are frequent incidental findings on MRI in the elderly, and may represent an index of chronic cerebrovascular diseases in such patients.
Abstract: Patchy subcortical foci of increased signal intensity are frequently identified on magnetic resonance imaging (MRI) in the elderly. The incidence and clinical correlates of these lesions remain unknown. In this report, 240 consecutive MRI scans performed over a 6-month period were reviewed (excluding patients with recent brain trauma or known demyelinating disease). Subcortical incidental lesions (ILs) were identified, which could not be accounted for by the patient's current clinical diagnosis, neurological status, or CT scan. The ILs were graded according to size, multiplicity, and location. The incidence and severity of ILs increased with advancing age (p less than 0.0005). Among patients over 50 years of age, the incidence and severity of ILs were correlated with a previous history of history of ischemic cerebrovascular disease (p less than 0.05) and with hypertension (p less than 0.05). Multivariable regression analysis identified age, prior brain ischemia, and hypertension as the major predictors of ILs in the elderly. Diabetes, coronary artery diseases, and sex did not play a significant role. With the exception of cerebrovascular disease, there was no association between ILs and any particular clinical entity, including dementia. It is concluded that subcortical parenchymal lesions are frequent incidental findings on MRI in the elderly, and may represent an index of chronic cerebrovascular diseases in such patients.
668 citations
TL;DR: Using a laser-Doppler flowmeter, it was found that the relative surface blood flow in cerebral cortex decreased to 62, 48, and 18% of baseline respectively after successive ligation of the right middle cerebral artery, and the right and left common carotid arteries.
Abstract: In the search for a more reproducible focal ischemic stroke model in the rat, we systematically interrupted blood flow to the right middle cerebral artery territory by ligating the right middle cerebral artery, and the right and left common carotid arteries in succession. Using a laser-Doppler flowmeter, we found that the relative surface blood flow in cerebral cortex supplied by the right middle cerebral artery decreased to 62, 48, and 18% of baseline respectively after successive ligation of the right middle cerebral artery, and the right and left common carotid arteries. A focal infarct in the cerebral cortex supplied by the right middle cerebral artery was consistently noted after ligation of the right middle cerebral and the right common carotid arteries and temporary clip occlusion of the left common carotid artery for 60 min. The surface areas of infarction measured 100 +/- 6 mm2 and the maximal cross-sectional area of infarction was 10.4 +/- 1.1 mm2 (N = 10). The mortality rate was 7% (N = 70). The characteristic changes of ischemic necrosis were limited to the cortex with sparing of subcortical structures. No motor deficits occurred. Occlusion of the right middle cerebral artery alone or together with the right common carotid artery did not consistently cause gross infarction and the maximal cross-sectional area of infarction was smaller (the right middle cerebral artery, 1.7 +/- 0.8 mm2, N = 10; the right middle cerebral artery plus the right common carotid artery, 4.8 +/- 1.9 mm2, N = 10). Permanent ligation of the right middle cerebral artery and both common carotid arteries had a high mortality (60% in 3 days, N = 10).(ABSTRACT TRUNCATED AT 250 WORDS)
653 citations
TL;DR: Clinical and pathological correlations lend support to the uniform hypothesis that MRI provides a nonspecific index of brain parenchymal alterations caused by aging and chronic cerebrovascular disease.
Abstract: The pathological correlates of subcortical lesions noted on magnetic resonance imaging (MRI) in the elderly are not known. Postmortem in vitro proton MRI was performed on the brains of seven consecutive elderly patients dying of nonneurologic causes. Scans were done in the fresh and fixed states with the specimen immersed in saline and formaldehyde respectively. A 1.5 Tesla superconductive system was used with a multiple spin-echo protocol generating T2 weighted images. Subcortical MRI lesions were localized in three dimensions and identified at brain cutting. In addition, pathological correlations were obtained from an eighth patient who underwent MRI eleven days before death. Histological examinations were performed in a blinded fashion, including control areas from the same brains. Subcortical MRI lesions were found to be associated with arteriosclerosis, dilated perivascular spaces, and vascular ectasia (p less than 0.05). These histological changes were characteristic of "etat crible" which, like subcortical MRI lesions, is associated with age and hypertension. Shrinkage (or atrophy) of the brain parenchyma around ectatic blood vessels would result in an extensive network of tunnels filled with extracellular water. The proton MRI signal from such areas of the brain would be increased. Gliosis and small areas of infarction occasionally coexisted with "etat crible," but these were not present in all areas with MRI lesions and could not be distinguished by MRI signal alone. In conclusion, clinical and pathological correlations lend support to the uniform hypothesis that MRI provides a nonspecific index of brain parenchymal alterations caused by aging and chronic cerebrovascular disease.
625 citations
TL;DR: A review of 33 studies identifies the factors of prior stroke, older age, urinary and bowel incontinence, and visuo-spatial deficits as adverse prognostic indicators of function as well as the prognostic value of severity of paralysis and onset-admission delay are ambiguous.
Abstract: A review of 33 studies identifies the factors of prior stroke, older age, urinary and bowel incontinence, and visuo-spatial deficits as adverse prognostic indicators of function. No relationship is shown between sex, hemisphere of stroke, and functional outcome. Functional admission score is a strong predictor of discharge functional status, but its relationship with improvement in function is unclear. Findings regarding the prognostic value of severity of paralysis and onset-admission delay are ambiguous. Comparison among studies is hindered by differences in patient samples, timing of assessments, criteria by which outcome is measured and measuring instrument used. Future studies should measure function at set times post-stroke, use functional scales whose reliability and validity is well established, and be conducted in several treatment centres to ensure that the sample is representative of the population to which the predictor measure is to be applied.
565 citations
TL;DR: The results implicate granulocyte participation in the acute phase of ischemic brain injury and signal a convergence of hemostatic and inflammatory processes during the immediate postischemic period.
Abstract: In an anesthetized canine model in which ischemia was induced by incremental air embolism, 16 animals were exposed to 1 hr of ischemia and monitored for 10 min (n = 4), 60 min (n = 6), or 240 min (n = 6). Fourteen animals were observed for corresponding periods without being subjected to ischemia 70 min (n = 4), 120 min (n = 4), or 300 min (n = 6). Autologous granulocytes were labeled with 111In and reinfused just before ischemia. At the conclusion of each experiment, a 14C-iodoantipyrine autoradiographic blood flow study was performed. Granulocyte accumulation measured by gamma scintigraphy (cpm/gm) occurred in the injured hemisphere of ischemic animals at 60 min in anterior brain segments and at 240 min in anterior, middle, and posterior segments. By means of a double-label autoradiography technique, clustering of punctate granulocyte images was detected in regions of low flow or heterogeneous flow in half of the animals at both 60 min and 240 min postischemia. Granulocyte clustering did not occur in the autoradiograms of nonischemic animals. The results implicate granulocyte participation in the acute phase of ischemic brain injury and signal a convergence of hemostatic and inflammatory processes during the immediate postischemic period.
504 citations
TL;DR: A complementary scale to assess conscious and aphasic patients is proposed and preliminary validation has been carried out in acute stroke patients, who commonly suffer neurological deficits without loss of consciousness.
Abstract: Acute central nervous system dysfunction resulting in coma can be measured simply and reliably by the Glasgow scale. However, when the injury does not impair consciousness and the patient has aphasia, no comparable scale exists. A complementary scale to assess conscious and aphasic patients is proposed. Preliminary validation has been carried out in acute stroke patients, who commonly suffer neurological deficits without loss of consciousness. A simple standardized scale aids in the monitoring of neurological status, and may help in the assessment of prognosis and therapy.
372 citations
TL;DR: The prognosis for survival and recovery was found to be better in the group of patients whose syndrome was nonvascular in origin than those with a vascular etiology and a program of intensive rehabilitation should be considered early in both groups.
Abstract: Etiology, clinical manifestations and outcome were reviewed in 139 cases of "locked-in syndrome." Six cases were reported from our center and the remaining 133 cases were taken from a review of the literature. The results of this review emphasized the necessity for a comprehensive program of pulmonary management in this population. Furthermore, an effective system of communication for the patient is considered essential in the management of the "locked-in" state. Reported mortality in the cases reviewed was 60%. Overall, the prognosis for survival and recovery was found to be better in the group of patients whose syndrome was nonvascular in origin than those with a vascular etiology. Functional recovery was generally good in those patients with a vascular etiology who survived beyond 4 months while recovery occurred earlier and more completely in the nonvascular group. Thus, a program of intensive rehabilitation should be considered early in both groups in order to assist each patient in attaining the highest level of function possible as recovery progresses.
364 citations
TL;DR: Lp(a) is not only a risk factor for CAD but also for CVD, and the ratio of LDL-C/HDL-C did not show any significant difference between the control and cerebrovascular disease group.
Abstract: To evaluate the role of lipoprotein(a) (Lp(a] in patients with cerebrovascular disease (CVD), lipid parameters were compared with a control group (CO). Additionally, the Lp(a) serum levels were investigated in a coronary artery disease (CAD) group. The CO was made up of 37 healthy persons (age: 54.5 +/- 7.7, 26 males and 11 females), the CVD group included 46 patients with sustained transient ischemic attack (TIA) prolonged reversible ischemic neurologic deficits (PRIND) and cerebral infarction (CI) (age: 53.6 +/- 9.7, 32 males and 14 females), and the CAD group was made up of 28 survivors of myocardial infarctions (age: 52.5 +/- 8.1, 18 males and 10 females). The median values of Lp(a) in CVD were significantly higher than in the CO (p less than 0.01) and did not differ significantly from the CAD. Total TC, HDL-C, TG, LDL-C and the ratio of LDL-C/HDL-C did not show any significant difference between the control and cerebrovascular disease group. For quantification of the vascular lesions of the carotid system, a Duplex Doppler score system was used. The score correlated with Lp(a) in patients between 40 to 65 years of age (r = 0.34, p less than 0.01). Thus, we conclude that Lp(a) is not only a risk factor for CAD but also for CVD.
358 citations
Journal Article•
TL;DR: A review of 33 studies identified the factors of prior stroke, older age, urinary and bowel incontinence, and visuo-spatial deficits as adverse prognostic indicators of function.
Abstract: A review of 33 studies identifies the factors of prior stroke, older age, urinary and bowel incontinence, and visuo-spatial deficits as adverse prognostic indicators of function. No relationship is shown between sex, hemisphere of stroke, and functional outcome. Functional admission score is a strong predictor of discharge functional status, but its relationship with improvement in function is unclear. Findings regarding the prognostic value of severity of paralysis and onset-admission delay are ambiguous. Comparison among studies is hindered by differences in patient samples, timing of assessments, criteria by which outcome is measured and measuring instrument used. Future studies should measure function at set times post-stroke, use functional scales whose reliability and validity is well established, and be conducted in several treatment centres to ensure that the sample is representative of the population to which the predictor measure is to be applied.
TL;DR: An increase in the regional vasodilatory capacity was observed postoperatively in the majority of patients, while 9 patients showed a significant redistribution of flow in favor of the non-occluded side and two patients showed even a paradoxical decrease in focal CBF preoperatively, i.e., a "steal" effect.
Abstract: Cerebral blood flow (CBF) was measured by xenon-133 inhalation tomography in 18 patients with cerebrovascular disease before and 4 months after extracranial-intracranial bypass surgery. Only patients who showed a reduced CBF in areas that were intact on the CT scan and relevant to the clinical and angiographical findings were operated. The majority of the patients had suffered a minor stroke with or without subsequent transient ischemic attacks. They were studied at least 6 weeks following the stroke. All patients had an occlusion of the relevant internal carotid artery. To identify preoperatively the patients with a compromised collateral circulation and hence reduced CBF due to reduced perfusion pressure, a cerebral vasodilatory stress test was performed using acetazolamide (Diamox). In normal subjects, Diamox has been shown to increase tomographic CBF without change of the flow distribution. In the present series 9 patients showed a significant redistribution of flow in favor of the non-occluded side ("positive" Diamox test). Two of these 9 patients showed even a paradoxical decrease in focal CBF preoperatively, i.e., a "steal" effect. These 2 patients were the only patients who improved in focal CBF after shunting. The remaining 9 patients all showed uniform flow responses ("negative" Diamox test), and none of these increased in focal CBF postoperatively. The finding of an unchanged flow map postoperatively confirmed that the low flow areas were not due to restricted flow via collateral pathways. However, an increase in the regional vasodilatory capacity was observed postoperatively in the majority of patients.
TL;DR: It is suggested that patients with PAF may benefit from treatment with anti-arrhythmic agents in order to prevent the development of CAF and that anticoagulants for stroke prevention seems especially desirable in atrial fibrillation (AF) of recent onset.
Abstract: The incidence of embolic complications among 426 patients with initial paroxysmal atrial fibrillation (PAF) was analysed. A distinct clustering of emboli was seen at the time of onset of PAF. After transition to chronic atrial fibrillation (CAF), which developed in 141 patients (33.1%), the incidence of emboli was seen to rise to a new level several times higher than the incidence level for patients with PAF. Also in this group a distinct clustering of emboli was seen during the first year after transition to CAF. On this background it is suggested that patients with PAF may benefit from treatment with anti-arrhythmic agents in order to prevent the development of CAF and that anticoagulants for stroke prevention seems especially desirable in atrial fibrillation (AF) of recent onset.
Journal Article•
TL;DR: In this paper, the authors reviewed 139 cases of "locked-in syndrome" and found that the prognosis for survival and recovery was better in the group of patients whose syndrome was nonvascular in origin than those with a vascular etiology.
Abstract: Etiology, clinical manifestations and outcome were reviewed in 139 cases of "locked-in syndrome." Six cases were reported from our center and the remaining 133 cases were taken from a review of the literature. The results of this review emphasized the necessity for a comprehensive program of pulmonary management in this population. Furthermore, an effective system of communication for the patient is considered essential in the management of the "locked-in" state. Reported mortality in the cases reviewed was 60%. Overall, the prognosis for survival and recovery was found to be better in the group of patients whose syndrome was nonvascular in origin than those with a vascular etiology. Functional recovery was generally good in those patients with a vascular etiology who survived beyond 4 months while recovery occurred earlier and more completely in the nonvascular group. Thus, a program of intensive rehabilitation should be considered early in both groups in order to assist each patient in attaining the hig...
TL;DR: Presentation with stroke or isolated TIA was not influenced by sex, age, level of MCA obstruction, collateral circulation nor associated carotid disease, and small and limited to the lenticulocapsular area, confirming that so-called lacunar infarcts may be due to large vessel disease.
Abstract: Three hundred and fifty-two patients with atherosclerotic middle cerebral artery stenosis (MCAS, 53%) or occlusion (MCAO, 47%) have been systematically studied. The study involved all patients entered into the EC/IC Bypass Study with isolated MCA disease or a tandem lesion predominating in the MCA ipsilateral to the ischemic events (18 patients with a tandem lesion of greater magnitude in the internal carotid artery were not included). The Asian patients represented 58% of all Asians entered into the EC/IC Bypass Study, whereas the white patients represented 18% of all whites and the black patients 34% of all blacks. Isolated TIAs were less frequent in MCAO (12%) than in MCAS (34%). Warning TIAs before a stroke occurred in one third of the cases. Presentation with stroke or isolated TIA was not influenced by sex, age, level of MCA obstruction, collateral circulation nor associated carotid disease. In MCAS, no major difference in presentation was found between severe and moderate stenosis. Pure motor hemiparesis occurred in 15% and pure sensory stroke in 2% of the patients with stroke and 30% of the MCA territory infarcts were small and limited to the lenticulocapsular area, confirming that so-called lacunar infarcts may be due to large vessel disease. During follow-up (42 months) of 164 medically-treated patients, further cerebrovascular events (TIA and stroke) occurred in 11.7% of the patients per year. In MCAO the stroke rate was 10.1% per patient-year and the ipsilateral infarct rate was 7.1% per patient-year. In MCAS, the stroke rate was 9.5% per patient-year and the ipsilateral stroke rate was 7.8% per patient-year.(ABSTRACT TRUNCATED AT 250 WORDS)
TL;DR: The psychometric performance scores of those who did not develop clinical signs of cerebral dysfunction induced in operation showed a significant difference only years after operation, and the harmful effects of long perfusion time in operation were reflected in the long-term neuropsychological performance.
Abstract: A prospective 5 years' neuropsychological, neurological, cardiological and electroencephalographical follow-up study was carried out in 44 patients who had undergone open-heart surgery for valve replacement. A distinct interrelationship was found between the clinical outcome immediately after operation and the neuropsychological long-term course despite the rapid recovery of occasional clinical disorders related to operative procedures. In fact, the psychometric performance scores of those who did not develop clinical signs of cerebral dysfunction induced in operation showed a significant difference only years after operation. Similarly, the harmful effects of long perfusion time (extracorporeal circulation) in operation were reflected in the long-term neuropsychological performance. Some evidence seemed to suggest that the correction of the prolonged circulatory disorder might possibly afford real enhancement of higher cerebral functions. The long-term results not only emphasize the importance of a careful clinical evaluation but also emphasize the necessity of considering the subclinical level of events both before and after operation when assessing the overall outcome and cerebral safety of cardiac surgery patients.
Journal Article•
TL;DR: The median values of Lp(a) in CVD were significantly higher than in the CO (p less than 0.01) and did not differ significantly from the CAD, and the ratio of LDL-C/HDL-C did not show any significant difference between the control and cerebrovascular disease group.
Abstract: To evaluate the role of lipoprotein(a) (Lp(a] in patients with cerebrovascular disease (CVD), lipid parameters were compared with a control group (CO). Additionally, the Lp(a) serum levels were investigated in a coronary artery disease (CAD) group. The CO was made up of 37 healthy persons (age: 54.5 +/- 7.7, 26 males and 11 females), the CVD group included 46 patients with sustained transient ischemic attack (TIA) prolonged reversible ischemic neurologic deficits (PRIND) and cerebral infarction (CI) (age: 53.6 +/- 9.7, 32 males and 14 females), and the CAD group was made up of 28 survivors of myocardial infarctions (age: 52.5 +/- 8.1, 18 males and 10 females). The median values of Lp(a) in CVD were significantly higher than in the CO (p less than 0.01) and did not differ significantly from the CAD. Total TC, HDL-C, TG, LDL-C and the ratio of LDL-C/HDL-C did not show any significant difference between the control and cerebrovascular disease group. For quantification of the vascular lesions of the carotid s...
TL;DR: A multicenter retrospective audit of carotid endarterectomies performed during 1981 was completed with 46 institutions contributing 3,328 cases, finding the incidence of stroke or death postoperatively was significantly lower for patients who were operated on for amaurosis fugax or for unspecified reasons.
Abstract: A multicenter retrospective audit of carotid endarterectomies performed during 1981 was completed with 46 institutions contributing 3,328 cases. Overall, there was a 2.5% risk of transient neurological dysfunction following surgery and a 6% risk of stroke or death. The intra-institutional combined major morbidity and mortality varied from 21% to 0. Those institutions with greater than 700 beds had a statistically lower incidence of stroke or death than did other institutions. The incidence of stroke or death postoperatively was significantly lower for patients who were operated on for amaurosis fugax or for unspecified reasons. Those patients who were operated on for a progressing stroke had a higher incidence of stroke but this group was at greatest risk for stroke without surgery. The incidence of postoperative stroke or death was related to the type of arterial repair; vein patch grafting was statistically better than both fabric patch grafting and primary closure. When all patients who were not monitored during surgery were compared to all patients who had electroencephalographic (EEG) monitoring, there was found to be a significant statistical difference in favor of the EEG group. Endarterectomy combined with coronary artery bypass or simultaneous bilateral endarterectomies had a statistically significant higher incidence of stroke or death than did unilateral carotid endarterectomy.
TL;DR: The study of 3 personal cases and 5 published cases of unilateral infarct limited to the territory of the tuberothalamic artery suggests that this syndrome should be differentiated from the other thalamic syndromes.
Abstract: The study of 3 personal cases and 5 published cases of unilateral infarct limited to the territory of the tuberothalamic artery suggests that this syndrome should be differentiated from the other thalamic syndromes. The onset is usually sudden, with moderate contralateral weakness. Sensory changes may be present but remain mild. The patients are apathetic, show perseveration and may be disoriented. In left-sided infarcts, transcortical aphasia, verbal and visual memory impairment and sometimes acalculia are found. In right-sided infarcts, hemispatial neglect, visual memory impairment and disturbed visuospatial processing are common. A decreased level of consciousness, disturbed ocular movements, severe motor weakness and delayed abnormal movements do not occur. Involvement of the ventral lateral and dorsomedial nucleus with sparing of the intralaminar nuclei, posterolateral formation and upper midbrain may explain this picture. The fact that the tuberothalamic artery arises from the posterior communicating artery, which often receives its supply from the carotid system, further justifies considering unilateral tuberothalamic infarcts as a syndrome.
TL;DR: Extent of carotid atherosclerosis was significantly greater in older individuals (p less than 0.01) and differences in extent with age were exaggerated in patients with coronary disease compared to coronary disease free controls.
Abstract: We have developed a scoring system to quantify extent of extracranial carotid artery atherosclerosis using real-time ultrasound (B-mode). To evaluate repeatability of this scoring system we correlated repeat scores obtained within a short interval of one another (6 months) in 52 individuals. We compared repeatability of extent measurements with repeatability of a measure of severity (single most severe lesion). Correlations between first and second studies for severity were weak (r2 = 0.20) but significant (p less than 0.001). Extent scores correlated much better (r2 = 0.77, p less than 0.001). In another group of 22 patients we found that the extent of atherosclerosis decreased following endarterectomy. We used this method to determine changes in extent of carotid atherosclerosis with age in two sets of individuals. One consisted of a cohort of 22 patients who underwent repeat B-mode studies separated by 1 1/2-3 years. This cohort demonstrated an increase in carotid score with age (p less than 0.05). In a second group of volunteers undergoing cardiac catheterization and B-mode evaluation of the carotid system, carotid scores could be compared in individuals with age differences that averaged 15 years. Extent of carotid atherosclerosis was significantly greater in older individuals (p less than 0.01) and differences in extent with age were exaggerated in patients with coronary disease compared to coronary disease free controls.
TL;DR: The autoregulatory capability of regional areas of the brain and spinal cord was demonstrated in 18 rats anesthetized with a continuous infusion of intravenous pentothal and this data provides a coherent reference point in establishing autoreGulatory curves under barbiturate anesthesia.
Abstract: The autoregulatory capability of regional areas of the brain and spinal cord was demonstrated in 18 rats anesthetized with a continuous infusion of intravenous pentothal. Blood flow was measured by the injection of radioactive microspheres (Co57, Sn113, Ru103, Sc46). Blood flow measurements were made at varying levels of mean arterial pressure (MAP) which was altered by neosynephrine to raise MAP or trimethaphan to lower MAP. Autoregulation of the spinal cord mirrored that of the brain, with an autoregulatory range of 60 to 120 mm Hg for both tissues. Within this range, cerebral blood flow (CBF) was 59.2 +/- 3.2 ml/100 g/min (SEM) and spinal cord blood flow (SCBF) was 61.1 +/- 3.6. There was no significant difference in CBF and SCBF in the autoregulatory range. Autoregulation was also demonstrated regionally in the left cortex, right cortex, brainstem, thalamus, cerebellum, hippocampus and cervical, thoracic and lumbar cord. This data provides a coherent reference point in establishing autoregulatory curves under barbiturate anesthesia. Further investigation of the effects of other anesthetic agents on autoregulation of the spinal cord is needed. It is possible that intraspinal cord compliance, like intracranial compliance, might be adversely affected by the effects of anesthetics on autoregulation.
TL;DR: The notion that calcium antagonists, through vascular and/or metabolic mechanisms, are effective in treating acute stroke is supported by results obtained in a chronic, relevant model of stroke with a method directly applicable also to humans.
Abstract: The appearance and evolution of brain infarcts over 3 days following proximal occlusion of the left middle cerebral artery (MCA) in SHR rats were measured non-invasively by magnetic resonance imaging (MRI) Infarcts were clearly visible in coronal, T2 weighted brain sections, 24, 48 and 72 h after MCA occlusion in the left hemisphere, as areas of increased NMR signals The infarcts were quantified by pixel counting in each section, the sum of 4 sections representing an accurate estimate of the total infarct size The location and extent of infarction, determined by MRI, were found to be highly reproducible and correlated well with post-mortem histological and biochemical data A neurological score, made every 24 h, paralleled the evolution of the infarct size, which culminated after 48 h Pre- or post-treatment of MCA occluded rats with the dihydropyridine calcium antagonist PN 200-110 resulted in a substantial reduction of infarct size, determined by MRI 24, 48 and 72 h after infarction, compared to vehicle treated controls These findings were corroborated by corresponding improvements of the neurological scores as well as histological and biochemical data Post-treatment with nimodipine showed qualitatively similar effects These results support the notion that calcium antagonists, through vascular and/or metabolic mechanisms, are effective in treating acute stroke Since they were obtained in a chronic, relevant model of stroke with a method directly applicable also to humans, they should encourage further clinical studies with calcium antagonists
TL;DR: The results show that viscosity changes must result in compensatory readjustments of vessel diameter, but that these adjustments do not occur where autoregulation to pressure changes is known to be defective.
Abstract: There is still considerable controversy regarding the influence of blood viscosity upon CBF. We have measured CBF with microspheres in 23 cats. Autoregulation was disturbed in the left caudate nucleus by microsurgical occlusion of the left middle cerebral artery. Induced hypertension or hypotension was used and i.v. mannitol (1 g/kg) administered. In all cats blood viscosity decreased an average of 16% at 15 minutes and, in 16 cats, increased 10% at 75 minutes post-mannitol. CBF in the right caudate was 79 +/- 6 ml/100g/min, in the left 38 +/- 6 (p less than 0.001). Only minor changes of CBF occurred in areas with presumed normal autoregulation, including the right caudate, in conjunction with pressure or viscosity changes. In the left caudate CBF decreased 21% with hypotension and 18% with higher viscosity, more than on the right (p less than 0.01 and p less than 0.2, respectively). CBF increased in the left caudate 56% with hypertension and 47% with lower viscosity, again much more than on the right (p less than 0.001 and p less than 0.01, respectively). In the other area which is (nearly) exclusively supplied by the middle cerebral artery of the cat, i.e., the ectosylvian cortex, results were similar to those in the caudate nucleus. These results show that viscosity changes must result in compensatory readjustments of vessel diameter, but that these adjustments do not occur where autoregulation to pressure changes is known to be defective. The adjustments to viscosity changes might be called blood viscosity autoregulation of CBF. We hypothesize that pressure autoregulation and blood viscosity autoregulation share the same mechanism.
TL;DR: In comparing this data with a previous study of 93 patients with proximal VA occlusive disease, distal VB occlogenic disease appears to carry a higher risk for brainstem ischemia.
Abstract: Forty-four patients with greater than or equal to 50% stenosis of a distal vertebral artery (VA) and/or basilar artery (BA) were followed up for an average of 6.1 years. Angiography was performed for definite vertebrobasilar (VB) transient ischemic attacks (TIA) in 19 (43%), for VB infarcts in 13 (30%) and for non localizing symptoms in 12 (27%). Stenosis in the BA with or without VA involvement was present in 28 patients (64%), while 16 patients (36%) had occlusive disease in one or both distal VA sparing the BA. In follow up, 7 patients (16%) had definite VB TIA and 3 patients had possible VB TIA. Eight patients (18%) sustained a stroke, 5 of which were in the VB territory. The observed stroke rate was 17 times the expected rate for a matched normal population. Eight patients died during follow up, three patients due to stroke (2 brainstem infarctions, one intraventricular hemorrhage). The observed 5 year survival rate was 78% compared to 90% in a matched normal population. In comparing this data with our previous study of 93 patients with proximal VA occlusive disease, distal VB occlusive disease appears to carry a higher risk for brainstem ischemia.
TL;DR: It is concluded that MRI reveals focal parenchymal changes in the majority of patients with transient ischemic attacks and is more sensitive than late generation CT scans, however, specificity appears to be poor, and may limit clinical usefulness.
Abstract: Twenty-two patients with the clinical diagnosis of transient ischemic attacks were prospectively evaluated by computed tomography (CT) and proton magnetic resonance imaging (MRI). Nineteen patients also underwent cerebral angiography. The MRI studies were performed with a prototype super-conductive magnet using a 0.6 Tesla or a 1.5 Tesla magnetic field. Two pulse sequence techniques were used resulting in T1 and T2 weighted images. All studies were interpreted descriptively by a single neuroradiologist in a blinded fashion, with special attention to focal parenchymal abnormalities. Patients with previously documented clinical strokes or reversible ischemic neurologic deficits lasting more than 24 hours were excluded. The CT scans revealed focal areas of abnormalities in 7 of 22 patients (32%), while the MRI scans showed focal changes in 17 patients (77%). All the CT lesions were clearly visualized on MRI. The MRI changes were better seen on T2 weighted images as areas of increased signal intensity. There was a marked preponderance of deep hemispheric lesions on both CT and MRI studies. Focal parenchymal abnormalities were not limited to the symptomatic vascular territory. We conclude that MRI reveals focal parenchymal changes in the majority of patients with transient ischemic attacks and is more sensitive than late generation CT scans. However, specificity appears to be poor, and may limit clinical usefulness. While the significance of the MRI "lesions" remains speculative, they may represent markers of chronic cerebrovascular disease in these patients.
TL;DR: The results support the use of saphenous vein patch angioplasty reconstruction of carotid endarterectomy to protect against early restenosis and thrombosis-occlusion.
Abstract: The hypothesis that saphenous vein patch angioplasty protects against early postoperative restenosis and thrombosis-occlusion was tested by comparing the clinical outcome and carotid artery status of 100 carotid endarterectomies with and 100 without saphenous vein patch angioplasty performed by a single surgeon over a 30-month period. The patient population, selection, perioperative management, and the technical aspects of the operation, except for the vein patch, were essentially identical in both groups. Carotid artery status was assessed by direct continuous wave Doppler and Gee OPG at three to six months and again at one year postoperatively. There were two hospital deaths, both in the nonpatched group, one cardiac and the other neurologic due to internal carotid thrombosis. Two reversible neurological deficits due to thrombosis and one due to restenosis occurred in the non-patched group. Asymptomatic greater than 50% diameter restenosis occurred in four and asymptomatic occlusion in one non-patched carotids. There were no restenosis, no occlusions and no neurologic symptoms in the patched group. Morbidity, mortality, restenosis or thrombosis-occlusion occurred in 10/100 (10%) non-patched and 0/100 (0%) patched arteries (p less than 0.01 by Chi Square). Restenosis or thrombosis-occlusion occurred in 9/100 (9%) of non-patched and 0/100 (0%) patched arteries (p less than 0.01). These results support the use of saphenous vein patch angioplasty reconstruction of carotid endarterectomy to protect against early restenosis and thrombosis-occlusion.
TL;DR: Duplex scanning was found to be an easily performed noninvasive method to study morphological and hemodynamic characteristics of vertebral arteries from their origin to the C4-C3 level.
Abstract: Vertebral arteries were studied by Duplex scanning in 50 normal subjects. Pretransverse and C6-C5, C5-C4 intertransverse segments were visualized in all cases on both sides; segment C4-C3 was visualized in 100% of the cases on the right side and in 90% on the left; ostium was obtained in 94% of the cases on the right and in 60% on the left. The left vertebral artery was dominant in 48% of the cases while the right vertebral artery was dominant in 14%. Three vertebral arteries were hypoplasic. Duplex scanning was thus found to be an easily performed noninvasive method to study morphological and hemodynamic characteristics of vertebral arteries from their origin to the C4-C3 level.
TL;DR: Results obtained with this method of temporary regional ischemia indicate that restoration of flow after 1-8 hr, but not after 24 hr, of MCA occlusion resulted in less severe neurological deficit and smaller infarcts than did permanent occlusions.
Abstract: Forty-four unanesthetized cats underwent temporary middle cerebral artery (MCA) occlusion with an implanted, externally controlled balloon cuff occluder. The occlusion was reversed to allow reperfusion of the MCA after 2 min to 24 hr of ischemia. Fourteen cats had temporary occlusions lasting 2 min to 3 hr; their neurological deficits improved or resolved after reperfusion, and brain sections showed only scattered microscopic areas of necrosis. After a 4-hr occlusion, five of nine cats (55%) recovered completely within 24 hr; two had persistent deficit when sacrificed, 10 days later, and each had a circumscribed infarct. All 18 cats undergoing 5-, 6-, 8-, and 24-hr occlusions sustained permanent neurological deficits. Three 3-hr occlusions at 2-day intervals in three cats resulted in permanent deficits and infarcts that were 25% larger than those after single 8-hr occlusions. Ten cats underwent permanent MCA occlusion; three deteriorated neurologically and died, and the survivors showed no improvement. Infarcts after 5-, 6-, and 8-hr occlusions followed by reperfusion were 66% smaller (p less than 0.05) than those after permanent occlusion; reperfusion after 24 hr of occlusion did not reduce infarct size. Hemorrhagic infarction occurred after two permanent occlusions, but after only one 5-hr temporary occlusion. The results obtained with this method of temporary regional ischemia indicate that restoration of flow after 1-8 hr, but not after 24 hr, of MCA occlusion resulted in less severe neurological deficit and smaller infarcts than did permanent occlusion. The infarct size correlated with the duration of MCA occlusion (p less than 0.05) rather than with the degree of deficit during occlusion.
TL;DR: It is suggested that when compounded by anemia and abnormal red cells, a hypercirculatory state may make patients in this age-group particularly prone to ischemic infarction.
Abstract: Regional cerebral blood flow, blood volume, fractional oxygen extraction and oxygen consumption were measured by positron emission tomography in six patients with sickle cell disease to see how oxygen delivery to the brain is maintained in the presence of both anemia and a low oxygen affinity hemoglobin. Both regional cerebral blood flow and blood volume were found to be markedly increased compared to values obtained from 14 normal subjects in the same age range. The mean fractional oxygen extraction was not significantly different in the two groups. Mean oxygen consumption in the two groups was also not significantly different but low values in individual patients with sickle cell disease and the presence of atrophy on the CT-scans of three of them were suggestive of some neuronal loss in patients without any history of nervous system involvement. In view of the known high values of cerebral blood flow and metabolism in childhood, it is suggested that when compounded by anemia and abnormal red cells, a hypercirculatory state may make patients in this age-group particularly prone to ischemic infarction.
TL;DR: Three patients who had painless dissections of the aorta which resulted in neurologic syndromes at the time of presentation are described, one of which progression to paraplegia occurred.
Abstract: We describe three patients who had painless dissections of the aorta which resulted in neurologic syndromes at the time of presentation. Two patients had acute hemimotor and sensory findings. In one of these cases progression to paraplegia occurred. In a third patient, acute weakness and ischemia of a leg occurred at presentation. We review previously described painless aortic dissections. Such aortic dissections may be suspected in the setting of an acute neurologic event by abnormalities in the examination of the peripheral pulses and the heart and by attention to characteristic chest x-ray changes.