Showing papers in "Stroke in 1988"

Interobserver agreement for the assessment of handicap in stroke patients.

Abstract: Interobserver agreement for the assessment of handicap in stroke patients was investigated in a group of 10 senior neurologists and 24 residents from two centers. One hundred patients were separately interviewed by two physicians in different combinations. The degree of handicap was recorded by each observer on the modified Rankin scale, which has six grades (0-5). The agreement rates were corrected for chance (kappa statistics). Both physicians agreed on the degree of handicap in 65 patients; they differed by one grade in 32 patients and by two grades in 3 patients. Kappa for all pairwise observations was 0.56; the value for weighted kappa (with quadratic disagreement weights) was 0.91. Our results confirm the value of the modified Rankin scale in the assessment of handicap in stroke patients; nevertheless, further improvements are possible.

The Lausanne Stroke Registry: analysis of 1,000 consecutive patients with first stroke.

Abstract: We present epidemiologic, etiologic, and clinical data for 1,000 consecutive patients with a first stroke (cerebral infarction or hemorrhage) admitted to the Centre Hospitalier Universitaire Vaudois since 1982. The patients were evaluated using a standard protocol of tests (computed tomography, Doppler ultrasonography, and electrocardiography in all patients, as well as angiography and specific cardiac investigations in selected patients). Each case was coded prospectively into a computerized registry. We believe that the Lausanne Stroke Registry is the first registry with complete computed tomography and Doppler ultrasonography data on all patients, which allows correlation between clinical findings, presumed etiology, and stroke location. Although the Lausanne Stroke Registry is not population-based, it gives a good estimate of the stroke-related problems in patients admitted to a primary-care center since our hospital is the sole acute-care facility for stroke in the Lausanne area.

Recovery of motor function after stroke.

Abstract: The natural history of recovery of motor function after stroke is described using data from a 1-year community-based study in Auckland, New Zealand. Of 680 patients, 88% presented with a hemiparesis; the proportion of survivors with a persisting deficit declined to 71% at 1 month and 62% at 6 months after the onset of the stroke. At onset, there were equal proportions of people with mild, moderate, and severe motor deficits, but the majority (76%) of those who survived 6 months had either no or only a mild deficit. Recovery of motor function was associated with the stroke severity but not with age or sex; patients with a mild motor deficit at onset were 10 times more likely to recover their motor function than those with a severe stroke. Our results confirm the reasonably optimistic outcome for survivors of stroke and further suggest that recovery of motor function is confined to patients whose motor deficit at onset is either mild or moderate.

The Stroke Data Bank: design, methods, and baseline characteristics.

Abstract: The National Institute of Neurological and Communicative Disorders and Stroke initiated the Stroke Data Bank, which is a multicenter project to prospectively collect data on the clinical course and sequelae of stroke. Additional objectives were to provide information that would enable a standard diagnostic clinical evaluation, to identify prognostic factors, and to provide planning data for future studies. A brief description of the structure and methods precede the baseline characterization of 1,805 patients enrolled in the Stroke Data Bank between July 1983 and June 1986. Two thirds of these patients were admitted within 24 hours after stroke onset. Medical history, neurologic history, and hospitalization summaries are presented separately for the following stroke subtypes: infarction, unknown cause; embolism from cardiac source; infarction due to atherosclerosis; lacune; parenchymatous or intracerebral hemorrhage; subarachnoid hemorrhage; and other. The utility and limitations of these data are discussed.

Intra-arterial thrombolytic therapy improves outcome in patients with acute vertebrobasilar occlusive disease.

Abstract: In this retrospective analysis we report our treatment experience in 65 consecutive patients with clinical signs of severe brainstem ischemia with angiographically demonstrated thrombotic vertebrobasilar artery occlusions who received either local intra-arterial thrombolytic therapy (urokinase or streptokinase) (43 patients) or conventional therapy (antiplatelet agents or anticoagulants) (22 patients). We analyzed the data with respect to cerebral artery occlusion patterns, posttreatment arterial recanalization, and the clinical categories of favorable/unfavorable outcome and survival/death. In subgroup analyses, recanalization in patients who received thrombolytic therapy correlated significantly with clinical outcome; in 19 of 43 patients, recanalization was demonstrated angiographically, while in 24 patients the occlusion persisted. All patients without recanalization died, but 14 of the 19 patients displaying recanalization survived (p = 0.000007), 10 with a favorable clinical outcome. Only three of the 22 patients who received conventional therapy survived, all with a moderate clinical deficit. When we compared the treatment groups, highly significant differences in both outcome quality (p = 0.017) and survival (p = 0.0005) were found to depend on establishing recanalization. Our data support the concept that technically successful thrombolysis of vertebrobasilar artery occlusions is associated with beneficial clinical outcome.

Noninvasive assessment of CO2-induced cerebral vasomotor response in normal individuals and patients with internal carotid artery occlusions.

Abstract: To evaluate the CO2-induced vasomotor reactivity of the cerebral vasculature, relative changes of blood flow velocity within the middle cerebral artery were measured by transcranial Doppler ultrasonography during normocapnia and various degrees of hypercapnia and hypocapnia. We studied 40 normal individuals and 40 patients with unilateral and 15 patients with bilateral internal carotid artery occlusions. When blood flow velocity changes as percent of normocapnic values were plotted against end-tidal CO2 volume percent, a biasymptotic curve (a tangent-hyperbolic function) gave the best fit of the scattergram. The distance between the upper and lower asymptotes was defined as cerebral vasomotor reactivity. In the normal individuals, mean +/- SD vasomotor reactivity was 85.63 +/- 15.96%. In patients with internal carotid artery occlusions, vasomotor reactivity was significantly lower than normal on both the occluded (mean 45.2%, median 50.4%; p less than 0.0001) and the nonoccluded (mean +/- SD 67.7 + 13.3%, p less than 0.01) sides in the unilateral group and on both sides (mean +/- SD 36.6 +/- 15.9% and 44.9 +/- 24.6%, p less than 0.0001) in the bilateral group. The difference between vasomotor reactivity for symptomatic and asymptomatic unilateral occlusions was also highly significant (mean 37.6% and 62.9%, p less than 0.006). Vasomotor reactivity was also significantly lower in patients with low-flow infarctions on computed tomography than in patients with normal scans (mean +/- SD 36.7 +/- 25% and 60.2 +/- 16.9%, p less than 0.008). A striking association of low-flow infarctions, ischemic ophthalmopathy, and hypostatic transient ischemic attacks was found with vasomotor reactivities of less than 34% or even paradoxical reactions.(ABSTRACT TRUNCATED AT 250 WORDS)

White matter signal abnormalities in normal individuals: correlation with carotid ultrasonography, cerebral blood flow measurements, and cerebrovascular risk factors.

Abstract: We studied 52 asymptomatic subjects using magnetic resonance imaging, and we compared age-matched groups (51-70 years old) with and without white matter lesions with respect to carotid ultrasonography, cerebral blood flow (xenon-133 injection), and cerebrovascular risk factors. In the group with white matter signal abnormalities, we noted a higher frequency of extracranial carotid artery disease, a lower mean gray matter blood flow (F1), and a significant reduction (p less than 0.05) in blood flow of the slow-flowing (F2) compartment. Hypertension, diabetes mellitus, and cardiac diseases (p less than 0.002) were found more often in this group. Our results indicate that a higher incidence of changes known to be associated with an increased risk for stroke exists in the presence of white matter lesions in normal elderly individuals.

Reversible cerebral segmental vasoconstriction.

Abstract: Vasoconstriction is not recognized as a cause of cerebrovascular disease except in the vasospasm seen following subarachnoid hemorrhage and possibly in migraine. However, we found four patients to have transient, fully reversible vasoconstriction and dilatation prominently involving arteries around the circle of Willis. All four patients were evaluated for severe headaches and fluctuating or recurring motor or sensory deficits. No cause for the clinical syndromes and angiographic abnormalities was found. Similar patients are reported in the literature under various nosologies. This newly recognized clinical-angiographic syndrome should be differentiated from other known causes of vessel constriction and dilatation; the precipitants of reversible vasoconstriction may then be better defined.

Strong attenuation of ischemic and postischemic brain edema in rats by a novel free radical scavenger.

Abstract: Regional changes in the amount of free fatty acids, polyphosphoinositides, and water content in the cerebral cortex were examined using a middle cerebral artery occlusion model of rats. The amount of various free fatty acids increased as polyphosphoinositides decreased during 3 and 6 hours of ischemia in the occluded middle cerebral artery territory. After 3 hours of reperfusion following 3 hours of ischemia, free fatty acids partially recovered while polyphosphoinositides did not. Water content increased significantly after 3 and 6 hours of ischemia, and a further increase was found after 3 hours of reperfusion following 3 hours of ischemia. The change of polyenoic fatty acids in this occluded middle cerebral artery territory was much smaller than that in the case of decapitation ischemia, although the amounts of polyphosphoinositides and monoenoic and saturated fatty acids showed almost identical changes in both cases, probably because polyenoic fatty acids may be washed out and/or peroxidatively consumed in the middle cerebral artery occlusion model due to its residual blood flow. Changes in the area surrounding the occluded middle cerebral artery territory were similar to the above results, although less dramatic. However, there was no change in free fatty acids, polyphosphoinositides, and water content in the contralateral cortex. A novel free radical scavenger (MCI-186), which prevents both nonenzymatic peroxidation and lipoxygenase activity in vitro, markedly attenuated the ischemic and postischemic brain swelling. These results suggest that free radical mechanisms may be involved in ischemic and postischemic brain edema.

Local intra-arterial fibrinolytic therapy in acute carotid territory stroke. A pilot study.

Abstract: The possibility that intra-arterial local infusion of fibrinolytic agents may achieve recanalization of previously occluded carotid territory arteries in acute stroke was tested in a prospective angiography-based open pilot study at two centers. Fifteen of 20 patients with acute symptoms (mean treatment-onset interval 7.6 hours) demonstrated complete recanalization; 10 of the 15 patients exhibited clinical improvement of varying degree by the time of hospital discharge. Four of the 20 patients suffered hemorrhagic transformation of the infarcted territory without clinical deterioration or demise. Because of the study format and the limited number of patients, dose responses for recanalization and risk relations were not established. We conclude that local intra-arterial fibrinolytic therapy may lead to cerebral arterial recanalization in acute carotid territory thrombotic stroke. The particular implications and limitations of this approach are discussed.

Intracarotid urokinase with thromboembolic occlusion of the middle cerebral artery.

Abstract: Intracarotid urokinase infusion therapy was performed on 22 patients with evolving cerebral infarction due to acute thromboembolic occlusion of the middle cerebral artery. Mean time from onset of symptoms to start of infusion and mean dosage of urokinase were 4.5 hours and 927,000 units, respectively. Immediate recanalization was achieved in 10 patients (45%) after urokinase therapy. In patients with successful recanalization, rapid amelioration of symptoms followed the restoration of blood flow. Thrombolytic recanalization was associated with reduction of neurologic deficits and of computed tomography-demonstrable infarction volume. The reduction of infarction volume and functional outcome correlated highly with the degree of reflow. Hemorrhagic transformation of infarction occurred in four patients and controllable extracranial bleeding in three patients. These results support the safety and efficacy of urokinase therapy for acute thromboembolic occlusion of the middle cerebral artery.

Quality of Life 4 Years After Stroke

Abstract: The quality of life for 46 stroke survivors under the age of 65 years in a stroke register was studied 4 years after their first stroke. A questionnaire covering four domains of life (working conditions, activities at home, family relationships, and leisure time activities) was used for investigation of the quality of life. The results showed that in spite of a good recovery in terms of discharge from the hospital, activities of daily living, and return to work, the quality of life of most patients (83%) had not been restored to the prestroke level. Deterioration among the several domains of life ranged from 39% to 80%, the lowest being in the domain of activities at home and the highest in the domain of leisure time activities. Hemispheral localization of the lesion, paresis, coordination disturbances, and especially subjective tendency to depression were highly correlated with a deterioration in the quality of life. Dependence in activities of daily living and an inability to return to work were also associated with the lack of restoration. Our results suggest that much more attention should be paid to the quality of life of stroke patients.

Prediction of delayed cerebral ischemia, rebleeding, and outcome after aneurysmal subarachnoid hemorrhage.

Abstract: Using logistic regression, we analyzed the predictive value of a number of entry variables with respect to the outcome variables delayed cerebral ischemia, rebleeding, and poor outcome (death or severe disability) in patients with aneurysmal subarachnoid hemorrhage. The entry variables were clinical condition on admission (grades on the Glasgow Coma Scale, Hunt and Hess system), the amount of subarachnoid and intraventricular blood and the presence of hydrocephalus on the admission computed tomogram, and antifibrinolytic treatment with tranexamic acid. We used data from a prospectively studied population of 176 patients admitted within 72 hours after subarachnoid hemorrhage. The risk of delayed cerebral ischemia was best predicted by the amount of subarachnoid blood, intraventricular blood, and antifibrinolytic treatment irrespective of clinical condition and hydrocephalus. The site of delayed cerebral ischemia was not related to the location of the subarachnoid hemorrhage. Antifibrinolytic treatment was the only entry variable (negatively) predicting the risk of rebleeding. Death or severe disability after 3 months was best predicted by the amount of subarachnoid blood and the initial clinical condition reflected by the grade on the Glasgow Coma Scale.

Stroke incidence and risk factors for stroke in Copenhagen, Denmark.

Abstract: Stroke incidence in Copenhagen, Denmark was recorded in a random population sample of 19,327 persons invited for two health examinations with 5 years' interval from 1976 to 1983. Stroke incidence increased exponentially with age. After adjustment to the age and sex distribution of the Danish population in 1980, the estimated incidence of first stroke was 1.41/1000 women and 2.48/1000 men; the total incidence was 1.94/1000 population. Risk factor analysis was based on the initial examination of 13,088 persons greater than 35 years old without previous stroke who responded to the first invitation, in whom 295 first strokes were subsequently observed. We used the regression model of Cox. However, our use of this model differs from the somewhat automatic procedures normally used to develop prognostic models. Evaluation of the causative effect of a particular risk factor requires that the direction of mutual influences between the factor in question and other risk factors is established/postulated. Among the 16 potential risk factors for stroke we examined, significant effects were found for age, sex, household income, smoking habits, systolic blood pressure, diabetes, plasma cholesterol concentration, ischemic heart disease, and atrial fibrillation. No significant effect could be demonstrated for a positive family history of stroke, years of school education, marital status, alcohol consumption, daily use of tranquilizers, body mass index, or postmenopausal hormone treatment.

Cerebral vasospasm and eclampsia.

Abstract: We describe a patient who experienced focal cerebral and brainstem ischemia in the setting of postpartum eclampsia. Cerebral angiography showed spasm of large- and medium-caliber arteries. This case provides rare documentation that vasospasm may account for cerebral ischemia in eclamptic women with focal signs. This observation suggests that in such patients cerebral angiography may be informative and useful.

Rehabilitation outcome following initial unilateral hemispheric stroke. Life table analysis approach.

Abstract: Life table analysis is a powerful statistical tool that has become the preferred technique for studying both the natural history of and the effect of treatment on disease outcome We have found only one report using life table analysis to study rehabilitation outcome after stroke We assessed the recovery of both independent ambulation and overall self-care function in 95 consecutive patients with unilateral hemispheric stroke using life table analysis Our results support the segregation of patients into the following prognostic subgroups at the time of entry into the rehabilitation program (mean +/- SD 5 +/- 3 weeks after stroke): 1) motor deficit only, 2) motor deficit plus somatic sensory deficit, and 3) motor deficit plus somatic sensory deficit plus homonymous visual deficit The probabilities of reaching independence in ambulation, being able to walk 150 feet with assistance, reaching independence in self-care function, and reaching a point of assisted self care (Barthel Index score of greater than or equal to 60) are highly significantly different among subgroups The interval after stroke required to reach the plateau phase of recovery is also significantly different among subgroups We propose that life table analysis can be used 1) to define patient outcome goals, 2) to define the time required to reach such goals, 3) to identify patients with medical or behavioral comorbidity who are functioning below their expected level, and 4) to assess the effect of alternative treatment regimens on both final outcome and time to reach that outcome

21-Aminosteroid lipid peroxidation inhibitor U74006F protects against cerebral ischemia in gerbils.

Abstract: U74006F (21-[4-(2,6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-piperazinyl]-16 alpha-methylpregna-1,4,9(11)-triene-3,20-dione, monomethane sulfonate) is a novel and potent inhibitor of central nervous system tissue lipid peroxidation that is devoid of classical steroid hormonal activities. Its possible efficacy in attenuating postischemic mortality and neuronal necrosis was examined in gerbils following 3-hour unilateral carotid artery occlusion. Male Mongolian gerbils received two intraperitoneal injections of either vehicle or U74006F (3 or 10 mg/kg), the first injection 10 minutes before and the second injection at the end of the 3-hour ischemic episode. In an initial series of experiments, vehicle-treated gerbils displayed 60.9% (14 of 23) survival 24 hours after ischemia, which decreased to 34.8% (8 of 23) at 48 hours. In contrast, the 10 mg/kg U74006F-treated group showed 86.7% (13 of 15) survival at 24 hours (p less than 0.15 vs. vehicle) and 80.0% (12 of 15) survival at 48 hours (p less than 0.02). In a second series, neurons in the hippocampal CA1 subfield and the medial and lateral cerebral cortex were counted in gerbils surviving 24 hours after unilateral carotid artery occlusion. Comparison of neuronal densities in the ischemic hemisphere with those in the contralateral nonischemic hemisphere revealed significant neuronal preservation in all three brain regions of 10 mg/kg i.p. x 2 U74006F-treated gerbils. Our results show that U74006F can improve survival and attenuate neuronal necrosis in a severe brain ischemia model.(ABSTRACT TRUNCATED AT 250 WORDS)

The four-vessel occlusion rat model: method for complete occlusion of vertebral arteries and control of collateral circulation.

Abstract: Four-vessel occlusion in rats was introduced approximately 10 years ago to provide a rodent model of reversible forebrain ischemia. The model presented several advantages, which included ease of preparation, a high rate of predictable ischemic neuronal damage, a low incidence of seizures, and the absence of anesthesia. However, two issues concerning the efficient use of the four-vessel occlusion rat model as originally described by us'require clarification. First, several groupshave reported difficulty assuring complete occlusion of the vertebral arteries by electrocauterization through the alar foramina of the first cervical vertebra. Because this difficulty may stem partly from our failure to have adequately described details of this method in our original article, the following is provided to facilitate more effective use of the model. It is important to position the anesthetized rat's head in stereotactic ear bars with the head tilted down at approximately 30° to the horizontal. The cervical spine is gently stretched by placing tension on the rat's tail with a rubber band anchored to the table. These steps stabilize and rotate the first cervical vertebra such that the alar wings are horizontal to the table; the full perimeters of the alar foramina can therefore be seen. The alar foramina (see Figure 1 in Reference 1) are easily approached via a midline dorsal neck incision. A pivoting, dissection microscope with through-the-lens or direct lighting is essential to carry out the following procedure. Once the alar foramina are visualized with the microscope, a small (<1 mm) electrocautery needle is inserted vertically through the alar foramina and down into the bony tunnel of the first vertebra, through which the vertebral arteries travel. Brief, intermittent application of current to the needle tip will cauterize the vertebral arteries and avert bleeding in the majority of rats. In those rats

Atrial fibrillation and stroke: new ideas, persisting dilemmas.

Abstract: The risk of systemic embolism associated with atrial fibrillation (AF) in patients with rheumatic mitral valve disease has long been appreciated. In only the past decade has it become clear that nonrheumatic (nonvalvulopathic) AF is a marker of increased risk for ischemic stroke.Several recent clinical and epidemiologic surveys have confirmed this association (Table 1) and suggest a fivefold increased risk of stroke. At least 15% of all ischemic strokes and more than a third of ischemic strokes in the elderly are associated with AF.\"About one in three people with AF will experience a stroke during their lifetime.'An estimated 75,000 strokes occur each year among the 1-1.5 million North Americans with AF. In addition to these clinical strokes, AF has been associated with an undue risk of subclinical, \"silent\" strokes.Silent infarcts detected by computed tomography (CT) have been found in 35-37% of nonrheumatic AF patients with no history of stroke.In a preliminary report including patients with rheumatic and nonrheumatic AF but without previous stroke, CT evidence of previous stroke was 2.9-4.5 times as frequent as in non-AF patients. Kempster and colleagues found CT evidence of remote infarct in 13% of patients with AF-related stroke compared with 4% of non-AF controls. While these CT-defined infarcts are labeled asymptomatic or \"silent,\" it is likely that they take a subtle, but cumulative, toll on cognition in elderly people. Considering the combined risk of clinical and subclinical stroke, AF becomes a substantial threat to the brain. While the importance of AF-associated stroke is not in doubt, preventive strategies and management have remained empiric and controversial. Despite vigorous ongoing work by several groups of investigators, major unanswered questions remain in three related areas: the mechanism(s) of AF-

Evolution and testing of the lacunar hypothesis.

Abstract: Since Fisher's detailed observations in the 1960s, the term lacunar infarction has become established in the cerebrovascular literature. To some extent, users of the term implicitly accept the bipartite hypothesis that, among patients with cerebral infarction of diverse cause, there exists, first, a small number of distinct clinical syndromes that are associated with small deep infarcts or lacunes and, second, that these are the result of occlusion of single perforating arteries by characteristic vascular lesions. Several studies have suggested that lacunar infarcts may constitute up to 20% of all cases of cerebral infarction'though less is known about the specificity of the underlying arteriopathy. Despite their relative frequency, there have not been any trials of specific treatments, and furthermore, few treatment trials of cerebral infarction in general have taken this important subgroup into account, perhaps resulting in the inappropriate discarding of therapeutic measures that might benefit other subgroups.To decide whether this is due to some basic flaw in the hypothesis, to inadequate testing, or to poor communication of its clinical implications to other physicians, two questions need to be answered: are the clinically recognizable lacunar syndromes usually caused by lacunes and, if they are, are these lacunes usually caused by a specific disorder of the small perforating arteries at the base of the brain, which differs qualitatively from the more widely studied atheroma of extracranial arteries.

Family intervention after stroke: does counseling or education help?

Abstract: Two interventions for improving stroke caregiver knowledge, stabilizing family function, promoting patient adjustment, and enlisting the use of social resources after stroke were compared with routine medical and nursing care of stroke patients (n = 61) at a 440-bed Veterans Administration Medical Center. The education intervention (n = 64) consisted of classroom instruction for caregivers about basic stroke care principles. The counseling condition (n = 63) consisted of education plus seven follow-up problem-solving sessions with a social worker (for the caregiver). Six months and 1 year after the stroke, both interventions significantly improved caregiver knowledge and stabilized some aspects of family function better than routine care. Counseling was consistently more effective than education alone and resulted in better patient adjustment at 1 year. Neither intervention influenced the use of social resources.

Nuclear magnetic resonance image white matter lesions and risk factors for stroke in normal individuals.

Abstract: The incidence, average number, and localization of lesions of the white matter detected by the T2-weighted nuclear magnetic resonance images among volunteers without cerebrovascular symptoms have been correlated with the number of risk factors for stroke. Accepted risk factors were arterial hypertension, diabetes mellitus, smoking, hypercholesterolemia, and cardiac disease. The 42 subjects examined were divided into Group A (0-1 risk factor, mean age 59.36 +/- 5.73 years), Group B (2 risk factors, mean age 61.54 +/- 8.33 years), and Group C (greater than or equal to 3 risk factors, mean age 62.57 +/- 9.83 years). Multiple risk factors among the age-matched groups was accompanied by a highly significant increase (p less than 0.001, Group A versus Group B; p less than 0.01, Group A versus Group C) of the incidence of white matter lesions. The average number of white matter lesions was increased (p less than 0.001) when Group A was compared with Groups B and C. Ninety-two percent of the white matter lesions were localized in watershed zones. Only 11 of the 155 abnormalities of the white matter detected by nuclear magnetic resonance imaging could be detected by computed tomography. White matter lesions in T2-weighted images appear to be an early stage of cerebrovascular disease.

Effects of aging and hypertension on endothelium-dependent vascular relaxation in rat carotid artery.

Abstract: We evaluated the effects of aging and hypertension on endothelium-dependent relaxation of rat common carotid arteries using 14-week-old (young) and 11-month-old (old) Wistar-Kyoto rats (WKY) and age-matched spontaneously hypertensive rats (SHR). Isometric tension of common carotid artery ring segments was measured. With a resting tension of 2.0 g determined from the baseline tension-contraction curves, precontraction was induced by 10(-5) M 5-hydroxytryptamine and endothelium-dependent relaxation was measured by application of either acetylcholine or adenosine 5'-triphosphate (ATP). Mean arterial blood pressure was 73.1 +/- 3.0 mm Hg in WKY and 110.0 +/- 3.1 mm Hg in SHR. These baseline values were significantly different. Acetylcholine-induced maximal relaxations were 70.1 +/- 2.6% of the 5-hydroxytryptamine-induced contraction in young WKY, 45.6 +/- 2.1% in old WKY, 35.1 +/- 1.8% in young SHR, and 21.4 +/- 2.5% in old SHR. On the other hand, ATP-induced relaxations were 52.0 +/- 3.2%, 35.7 +/- 3.8%, 21.7 +/- 3.5%, and 17.0 +/- 1.8% in the groups, respectively. Acetylcholine-induced relaxations were significantly different between WKY and SHR, young and old, independently. On the other hand, ATP-induced relaxations were also significantly different between young and old WKY, although no significant difference was observed between young and old SHR. The fact that endothelium-dependent relaxation of a cephalic artery is impaired in old rats and in hypertensive rats suggests that aging and hypertension are risk factors that may augment the disturbance of the cerebral circulation in pathologic conditions.

Postinfarction seizures. A clinical study

Abstract: We retrospectively studied 90 patients with postinfarction seizures to determine the clinical features (onset, number, type), prognosis, and electroencephalographic and computed tomographic findings; we included infarctions of all etiologies. Thirty-three percent of the 90 seizures appeared early (within 2 weeks after the infarction), and 90% of the 30 early seizures appeared within 24 hours after the infarction. Seventy-three percent of the 90 seizures occurred within the first year, and only 2% occurred greater than 2 years after the infarction. Fifty-six percent of the 90 seizures were single, and status epilepticus was seen in only 8%. Early-onset seizures were more likely to be partial (57% of 30); late-onset seizures were more likely to be generalized (65% of 60). Thirty-nine percent of the 90 initial seizures recurred, and there was no significant difference in recurrence rate between early- or late-onset initial seizures. Twenty-two percent of the 90 initial seizures became multiple recurrent seizures, and we could identify a precipitating factor in 86% of the 35 recurrent seizures. The most common electroencephalographic abnormality in the 61 patients so examined was focal slowing (61%), but recurrent seizures occurred in 100% of the four patients with periodic lateralized epileptiform discharges and in 75% of the eight patients with diffuse slowing. Computed tomography in 61 patients showed that large infarctions were associated with early (p less than 0.021) and multiple (p less than 0.05) seizures. Deep infarctions on computed tomograms (cortical infarctions extending to subcortical structures) tended to cause recurrent seizures (p less than 0.057). Seizures in 88% of the 90 patients could be managed with monotherapy.

Neurologic manifestations of atrial myxoma. A 12-year experience and review.

Abstract: We present the results of a 12-year retrospective analysis of 11 patients, eight women and three men, aged 16-76 years, with pathologically documented atrial myxomas. Nine of the 11 patients were found to have a left atrial myxoma; right atrial myxomas were identified in two. Five of the 11 patients (45%) had abnormalities on neurologic examination, and five of five had computed tomographic evidence of nonhemorrhagic cerebral infarction. Neurologic symptoms were the initial presentation in four patients. Six patients reported a history of cardiac disease; eight of the 11 had abnormalities on cardiac auscultation. Echocardiography in 10 patients was diagnostic in all but one. Gated magnetic resonance imaging of the heart in two patients demonstrated myxoma position and movement. Follow-up examinations (varying from 1 month to 7 years after tumor resection) in nine of 11 patients demonstrated no recurrent neurologic symptoms. Cerebral infarction is a common complication of atrial myxomas and may be the presenting feature. Recurrent cerebral emboli before surgery is not uncommon. Cardiac auscultation may be normal, and electrocardiographic changes are often nonspecific. Delayed neurologic events following surgery are rare.

Stroke in thyrotoxicosis with atrial fibrillation.

Abstract: Chronic atrial fibrillation is associated with an increased risk of stroke. In elderly patients with thyrotoxicosis, atrial fibrillation is frequently encountered, and the true risk of cerebrovascular events in these patients is controversial. We retrospectively studied 610 patients with initially untreated thyrotoxicosis, 91 (14.9%) of whom had atrial fibrillation, with the highest frequency in the elderly patients. The risk of cerebrovascular events, with special attention to the first year after the diagnosis of thyrotoxicosis, was calculated using logistic regression methods with age, sex, and atrial fibrillation as independent variables. Only age was an important risk factor (p less than 0.005), whereas sex and atrial fibrillation were not significant (p = 0.09 and p = 0.17, respectively) as independent risk factors. This is contrary to other studies of patients with thyrotoxic atrial fibrillation, and the need for further clarification of this issue is clear. From our study the indication for prophylactic treatment with anticoagulants for prevention of stroke in thyrotoxic atrial fibrillation seems doubtful, especially as no controlled studies of such treatment in patients with atrial fibrillation are currently available.

Hyperglycemia enlarges infarct size in cerebrovascular occlusion in cats.

Abstract: We investigated the influence of serum glucose concentration on infarct size following middle cerebral artery occlusion in cats. These animals were deprived of food for 48 hours and infused with 1) saline for 1 hour before and 8 hours after occlusion (n = 8), 2) 10% glucose solution for 1 hour before and 6 hours after occlusion and saline for 2 additional hours (n = 8), or 3) 10% glucose for 1 hour before and saline for 8 hours after occlusion (n = 5). Nineteen cats killed after 2 weeks' survival were subjected to morphometric infarct size determinations. Eight normoglycemic and 11 hyperglycemic cats exhibited infarcts affecting 10.2 +/- 3.4% and 29.5 +/- 6.5% (mean +/- SEM) of their middle cerebral artery territories, respectively (p less than 0.02). Cats of the two hyperglycemic groups showed similarly sized infarcts. However, two of eight (25%) of cats with preocclusion and postocclusion hyperglycemia died 8 and 24 hours after occlusion with infarction of the entire middle cerebral artery territory, marked hemispheral edema, and brainstem compression. Our results demonstrate that serum glucose concentration at the time of large cerebral vessel occlusion influences stroke outcome.

Transcranial Doppler measurements of the middle cerebral artery. Effect of hematocrit.

Abstract: We evaluated the effects of hematocrit on blood velocity in the middle cerebral artery measured by transcranial Doppler ultrasonography in 45 patients. Hematocrits ranged from 16% to 46%, and systolic blood velocities ranged from 70 to 190 (mean 40 to 140) cm/sec. Decreases in hematocrit correlated with increases in blood velocity in the middle cerebral artery. These results suggest that transcranial Doppler measurements made in the presence of anemia may need correction.

Stroke in blacks.

Abstract: In an attempt to answer unresolved questions and to suggest directions for future research concerning stroke in black populations, data from the National Center for Health Statistics were examined and published studies were reviewed. Stroke was the third leading cause of death among U.S. blacks in 1982, accounting for 18,698 deaths, 8.25% of the total. Black men aged 35-74 years were 2.5 times and black women 2.4 times as likely as whites to die of stroke. A long-term decline in stroke mortality rates continued through 1982, with the declines since 1968 probably due to improved hypertension control. Data on morbidity trends are lacking. About 7% of black men and 11% of black women in the U.S. noninstitutionalized population aged 65 and over reported having had a stroke in 1977, black women having the highest prevalence of any group. In several studies, black women had higher incidence rates of stroke than white women in each age group. Black men had higher incidence rates than whites up to age 75 years. Survivorship and outcome following stroke may have been poorer in blacks than in whites. Advanced age and elevated blood pressure were the only putative risk factors for stroke for which published data were adequate to firmly establish the association in blacks. Thus, data are needed to examine trends in stroke incidence and survivorship in blacks and to assess the relation of many variables to the risk of stroke.