Showing papers in "Stroke in 1991"

Atrial fibrillation as an independent risk factor for stroke: the Framingham Study.

Abstract: The impact of nonrheumatic atrial fibrillation, hypertension, coronary heart disease, and cardiac failure on stroke incidence was examined in 5,070 participants in the Framingham Study after 34 years of follow-up. Compared with subjects free of these conditions, the age-adjusted incidence of stroke was more than doubled in the presence of coronary heart disease (p less than 0.001) and more than trebled in the presence of hypertension (p less than 0.001). There was a more than fourfold excess of stroke in subjects with cardiac failure (p less than 0.001) and a near fivefold excess when atrial fibrillation was present (p less than 0.001). In persons with coronary heart disease or cardiac failure, atrial fibrillation doubled the stroke risk in men and trebled the risk in women. With increasing age the effects of hypertension, coronary heart disease, and cardiac failure on the risk of stroke became progressively weaker (p less than 0.05). Advancing age, however, did not reduce the significant impact of atrial...

Probability of stroke: a risk profile from the Framingham Study.

Abstract: A health risk appraisal function has been developed for the prediction of stroke using the Framingham Study cohort. The stroke risk factors included in the profile are age, systolic blood pressure, the use of antihypertensive therapy, diabetes mellitus, cigarette smoking, prior cardiovascular disease (coronary heart disease, cardiac failure, or intermittent claudication), atrial fibrillation, and left ventricular hypertrophy by electrocardiogram. Based on 472 stroke events occurring during 10 years' follow-up from biennial examinations 9 and 14, stroke probabilities were computed using the Cox proportional hazards model for each sex based on a point system. On the basis of the risk factors in the profile, which can be readily determined on routine physical examination in a physician's office, stroke risk can be estimated. An individual's risk can be related to the average risk of stroke for persons of the same age and sex. The information that one's risk of stroke is several times higher than average may provide the impetus for risk factor modification. It may also help to identify persons at substantially increased stroke risk resulting from borderline levels of multiple risk factors such as those with mild or borderline hypertension and facilitate multifactorial risk factor modification.

North American Symptomatic Carotid Endarterectomy Trial. Methods, patient characteristics, and progress.

Abstract: Fifty North American centers have combined to evaluate the benefit of carotid endarterectomy in randomized patients who have experienced symptoms related to arteriosclerotic stenosis of the carotid artery and who have received either best medical therapy alone or best medical therapy plus carotid endarterectomy. The outcome events are nonfatal and fatal stroke or death. A three-tier system identifies and adjudicates the type, severity, and location of each stroke and the cause of any death. Data about patients submitted to carotid endarterectomy outside the trial are compiled at the Nonrandomized Data Center at the Mayo Clinic. Between December 27, 1987, and October 1, 1990, 1,212 patients were randomized, 596 to medical therapy, 616 to carotid endarterectomy. Cross-over from the medical to the surgical arm has been low (4.2%). Patients eligible for the trial, but not randomized totaled 1,044; their characteristics were similar to those randomized so that, for the type of symptomatic patient in this study, our conclusions about the benefit of carotid endarterectomy can be generalized. Patients excluded by medical criteria totaled 679. Another 1,591 had carotid endarterectomy, but either lacked the disease under study, were asymptomatic, or received inadequate investigation to meet entry criteria. We set sample size at 1,900 patients, with continuing enrollment. The Monitoring Committee reviews at intervals the confidential analyses performed on the groups with moderate (30-69%) and severe (70-99%) stenosis. Stopping rules will be invoked for one or both groups if unequivocal benefit or harm is identified.

Polymorphonuclear leukocytes occlude capillaries following middle cerebral artery occlusion and reperfusion in baboons.

Abstract: Microvascular perfusion defects may accompany sustained occlusion and subsequent reperfusion of the middle cerebral artery; however, the nature of such "no-reflow" defects remains unclear.In the absence of antithrombotic pretreatment, we documented lenticulostriatal microvascular flow integrity following 3-hour middle cerebral artery occlusion and 1-hour reperfusion in a baboon occlusion/reperfusion model by two methods identifying 1) microvascular occlusion and 2) microvascular patency.Microvascular "no-reflow" involved capillaries (vessels of 4.0-7.5 microns diameter) of the lenticulostriatal territory. Capillary reflow included 27-39% of all capaillaries in two subjects, indicating a significant reduction of perfusion from normal (2p = 0.045). In identical experimental preparations, single polymorphonuclear leukocytes completely occluded 4.7% of microvessels of capillary diameter in randomly selected fields, partially occluded 3.5% of postcapillary venules, and occluded 40% (four of 10) of capillaries ...

A review of hemoglobin and the pathogenesis of cerebral vasospasm.

Abstract: We believe that current experimental and clinical evidence can be most satisfactorily interpreted by assuming that oxyhemoglobin is the cause of cerebral vasospasm that follows subarachnoid hemorrhage. We review the pathogenetic mechanisms by which oxyhemoglobin affects cerebral arteries. The relative importance of each of these mechanisms in the genesis of vasospasm, the biochemical pathways of oxyhemoglobin-induced smooth muscle contraction, and the intracellular actions of oxyhemoglobin on smooth muscle and on other cells in arteries are still not definitely established.

Use of sonography to evaluate carotid atherosclerosis in the elderly. The Cardiovascular Health Study. CHS Collaborative Research Group.

Abstract: Carotid sonography is being performed on more than 5,000 participants in the Cardiovascular Health Study, a prospective, multicenter study of cardiovascular disease in men and women aged 65 years and older. The sonographic methods used to examine and measure the extracranial carotid arteries are described. Initial validation studies were performed on 61 subjects with a mean age of 68.6 years. Analysis of within- and between-sonographer differences and between-reader differences were performed for selected variables. In general, the mean absolute differences for within- and between-sonographer comparisons were small, with even less variability between readers. Variability was less for the common carotid artery than for the internal carotid artery. These data suggest that carotid sonography is a reliable and reproducible method for use in the study of carotid atherosclerosis in population studies.

Benefit of a stroke unit: a randomized controlled trial.

Abstract: In a randomized controlled trial we compared the clinical outcome of acute stroke patients, 110 of whom were allocated to treatment in a stroke unit and 110 to treatment in general medical wards. No significant difference existed between these groups with regard to sex, age, marital status, medical history, or functional impairment on admission. Outcome was measured at 6 and 52 weeks after the stroke by the proportion of patients at home, the proportion of patients in an institution, the mortality, and the functional state. After 6 weeks 56.4% of the patients randomized to the stroke unit and 32.7% of the patients randomized to the general medical wards were at home (p = 0.0004), and after 52 weeks 62.7% and 44.6%, respectively, were at home (p = 0.002). After 6 weeks 36.3% of the patients from the stroke unit and 50.0% from the general medical wards were in an institution (p = 0.02); after 52 weeks 12.7% and 22.7%, respectively, were institutionalized (p = 0.016). After 6 weeks mortality was 7.3% for the stroke unit group and 17.3% for the general medical wards group (p = 0.027). After 52 weeks mortality was 24.6% for the stroke unit group and 32.7% for the general medical wards group (difference not significant). Functional state was significantly better for patients treated in the stroke unit after both 6 and 52 weeks. We conclude that care of patients with acute stroke in a stroke unit improves clinical outcome compared with treatment in general medical wards.

Vascular risks of asymptomatic carotid stenosis.

Abstract: We sought to determine the risks of stroke, myocardial ischemia, and vascular death in patients with asymptomatic carotid stenosis.Six hundred ninety-six patients with asymptomatic carotid stenosis referred to the Doppler laboratory were followed prospectively for a mean time of 41 months. These patients were studied both clinically and by carotid Doppler ultrasound, including evaluation of the effect of stroke risk factors.Transient ischemic attacks occurred in 75 patients and stroke in 29, while 132 had ischemic cardiac events. Five patients died from stroke and 59 from cardiac causes. Annual stroke rate was 1.3% in patients with carotid stenosis less than or equal to 75% and 3.3% in those with stenosis greater than 75%. Ipsilateral stroke rate was 2.5% in patients with greater than 75% carotid stenosis. Annual cardiac event rate was 8.3% and death rate 6.5% in patients with severe carotid stenosis.With carotid stenosis less than or equal to 75%, the stroke rate is negligible (1.3% annually) whereas the...

Death and functional outcome after spontaneous intracerebral hemorrhage. A prospective study of 166 cases using multivariate analysis.

Abstract: Using death and functional status as end points, we prospectively analyzed the outcome 6 months after spontaneous intracerebral hemorrhage in 166 patients admitted to an acute-care stroke unit on the first day of their stroke. Seventy-one patients (43%) died, 69 (42%) had a satisfactory outcome, and 26 (16%) had a poor functional outcome. Early (30-day) survival was correlated with morphologic parameters on the initial computed tomogram (hemorrhage size, midline shift, and intraventricular spread of the hemorrhage), while later (6-month) survival was correlated with age. Using logistic regression, we found five independent predictors of satisfactory outcome at 6 months: age, hemorrhage size, intraventricular spread of the hemorrhage, limb paresis, and communication disorders. Of these, age was the most important predictor by far.

Assessment of scales of disability and handicap for stroke patients.

Abstract: The purpose of the study is to compare the reliability of the Barthel activities of daily living score, which assesses disability, with the Rankin scale, which assesses handicap, and to determine their mutual agreement.Fifty patients with stroke of varying severity were identified by a community-based stroke register and interviewed by two of three research nurses on two occasions that were 2-3 weeks apart.There was no evidence of a systematic difference between the first and second measurements. Repeatability was assessed using a kappa statistic with quadratic disagreement weights (kappa w) to take account of extreme differences. This measure was very good for both Barthel (kappa w = 0.98) and Rankin (kappa w = 0.95) scales. There was also excellent agreement between raters for the Barthel scale (kappa w greater than or equal to 0.88), but some indication of disagreement (kappa w = 0.75) between raters for the Rankin scale. Analysis of variance confirmed these findings. A conversion from the Barthel to t...

Carotid surgery versus medical therapy in asymptomatic carotid stenosis. The CASANOVA Study Group.

Abstract: The CASANOVA study (Carotid Artery Stenosis with Asymptomatic Narrowing: Operation Versus Aspirin) is a multicenter trial in 410 patients with asymptomatic stenosis (50-90%) of the internal carotid artery who were randomized after angiography. In group A, 206 patients with unilateral and bilateral stenosis had surgery unilaterally or bilaterally, respectively. In group B, 160 patients with unilateral stenosis had no initial surgery, whereas those with bilateral stenosis had surgery on the more affected side. Patients were operated on during the 3-year follow-up period if one of the following events occurred: development of a stenosis exceeding 90%; development of a bilateral internal carotid artery stenosis greater than 50% (operation on the more affected side); transient ischemic attack in the region supplied by the internal carotid artery, together with a stenosis of this artery greater than 50%; development of an internal carotid stenosis greater than 50% contralateral to the operated side or restenosis greater than 50% in group A. All patients were treated with 330 mg acetylsalicylic acid and 75 mg dipyridamole three times daily. The minimal follow-up was 3 years. End points were ischemic neurologic deficit exceeding 24 hours or death due to surgery or stroke. Altogether, 334 carotid endarterectomies were performed. Complications of angiography and operation (6.9%) were included. Statistical analysis found no significant difference in the number of neurologic deficits and deaths between the two groups. Carotid endarterectomy for asymptomatic patients with a stenosis of the internal carotid artery of less than 90% is not recommended at this time except as part of a controlled clinical trial. However, cases of higher grade stenosis (greater than 90%) were excluded from this study and were referred for operation. No conclusion can be rendered regarding the potential benefit of endarterectomy in these higher risk categories.

Clinical alert: benefit of carotid endarterectomy for patients with high-grade stenosis of the internal carotid artery. National Institute of Neurological Disorders and Stroke Stroke and Trauma Division. North American Symptomatic Carotid Endarterectomy Trial (NASCET) investigators.

Abstract: The investigators of the North American Symptomatic Carotid Endarterectomy Trial (NASCET) are reporting the results of an interim analysis of the findings of a randomized controlled clinical trial of carotid endarterectomy for patients with a recent hemispheric, transient ischemic attack (TIA) or a mild (nondisabling) stroke and ipsilateral narrowing of the internal carotid artery. Two groups in the trial received best medical care, including antiplatelet therapy; one of the two groups also had endarterectomy. For patients with high-grade stenosis (70-99% narrowing in the luminal diameter), surgery was highly beneficial. Consequently, patients with high-grade stenosis are no longer being entered into the trial. Because the question of surgical benefit for patients with moderate stenosis (30-69%) has not yet been answered, that part of the trial dealing with symptomatic patients with moderate stenosis will continue. Because it also is not yet known whether asymptomatic patients will benefit from carotid endarterectomy, other trials for those patients will also continue.

Temporal thresholds for neocortical infarction in rats subjected to reversible focal cerebral ischemia.

Abstract: We investigated the temporal threshold for focal cerebral infarction in the spontaneously hypertensive rat. The right middle cerebral artery and common carotid artery were occluded for 0, 1, 2, 3, 4, or 24 hours, and all the animals were sacrificed 24 hours after the onset of ischemia. Cortical infarct volumes and edema volumes were quantified in serial frozen sections of hematoxylin and eosin-stained tissue using image analysis. Upon occlusion, blood flow in the core of the ischemic zone, measured with laser-Doppler flowmetry, fell to a mean +/- standard deviation of 21 +/- 7% of the preocclusion baseline value (n = 26). During the first hour of ischemia, blood flow in the densely ischemic zone rose to 27 +/- 8% of baseline (n = 25). Release of the middle cerebral artery and common carotid artery occlusions rapidly restored cortical blood flow to 213 +/- 83% of baseline (n = 21). Focal ischemia of 1 hour's duration caused little or no infarction, while ischemic intervals of 2 and 3 hours produced successively larger volumes of infarcted cortex. Ischemic intervals of 3-4 hours' duration followed by approximately 20 hours of recirculation yielded infarct volumes that were not significantly different from those after 24 hours of permanent focal ischemia. The results indicate that 3-4 hours of focal cerebral ischemia in this rat model is sufficient to attain maximal infarction and suggest that recirculation or pharmacological interventions after this time will provide little benefit.

Stroke recurrence within 2 years after ischemic infarction.

Abstract: We prospectively studied stroke recurrence in 1,273 patients with ischemic stroke who were entered into the Stroke Data Bank. Median follow-up was 13 months. The 2-year cumulative recurrence rate among these patients was 14.1%. Age, sex, race, history of hypertension, atrial fibrillation, or transient ischemic attacks, and stroke location were not associated with a higher risk of stroke recurrence. Patients with an elevated blood pressure, an abnormal initial computed tomogram, or a history of diabetes mellitus were at a higher risk of stroke recurrence. In contrast, patients with an infarct of unknown cause were at a lower risk of stroke recurrence than patients with a defined stroke mechanism, such as lacune, embolism, or atherosclerosis. A multivariate model suggests that patients at the lowest risk for stroke recurrence have a low diastolic blood pressure, no history of stroke, no history of diabetes mellitus, and an infarct of unknown cause.

Assessment of cerebral autoregulation dynamics from simultaneous arterial and venous transcranial Doppler recordings in humans.

Abstract: We investigated the validity of transcranial Doppler recordings for the analysis of dynamic responses of cerebral autoregulation. We found no significant differences in percentage changes among maximal (centerline) blood flow velocity, cross-sectional mean blood flow velocity, and signal power-estimated blood flow during 24-mm Hg stepwise changes in arterial blood pressure. We investigated blood flow propagation delays in the cerebral circulation with simultaneous Doppler recordings from the middle cerebral artery and the straight sinus. The time for a stepwise decrease in blood flow to propagate through the cerebral circulation was only 200 msec. Brief (1.37-second) carotid artery compression tests also demonstrated that the volume compliance effects of the cerebral vascular bed were small, only about 2.2% of normal blood flow in 1 second. Furthermore, transients associated with inertial and volume compliance died out after 108 msec. We also investigated the hypothesis that autoregulatory responses are influenced by hyperventilation using the same brief carotid artery compressions. One second after release, the flow index increased by 17% during normocapnia and 36% during hypocapnia. After 5 seconds, the flow index demonstrated a clear oscillatory response during hypocapnia that was not seen during normocapnia. These results suggest that the intact human cerebral circulation in the absence of pharmacological influences does not function as predicted from pial vessel observations in animals.

Snoring and the risk of ischemic brain infarction.

Abstract: To determine if a history of snoring is a risk factor for brain infarction, I conducted a case-control study of risk factors for ischemic stroke using 177 consecutive male patients aged 16-60 (mean 49) years with acute brain infarction. For each patient I chose an age-matched (+/- 6 years) male control. Arterial hypertension, coronary heart disease, snoring (habitually or often), and heavy drinking (greater than 300 g/wk) were risk factors in the stepwise multiple logistic regression analysis. The odds ratio of snoring for brain infarction was 2.13. By McNemar's test this association increased strongly if a history of sleep apnea, excessive daytime sleepiness, and obesity were all present with snoring (odds ratio 8.00). My study indicates that snoring may be a risk factor for ischemic stroke, possibly because of the higher prevalence of an obstructive sleep apnea syndrome among snorers than nonsnorers.

Transhemispheric diaschisis. A review and comment.

Abstract: We review here the literature in both animal models and humans concerning electrical activity, blood flow, and metabolism in the hemisphere contralateral to unilateral cerebral ischemia. We analyze the data by periods based on the time from initial injury to emphasize the time course of transhemispheric diaschisis. Contralateral electrical activity, such as evoked potential amplitude, is increased in the late stages after unilateral infarction, with the data from the more acute periods being inconclusive. Contralateral blood flow changes probably depend on the magnitude of the ischemic injury, with a larger insult resulting in a decrease not seen with smaller insults. Some studies have shown a decrease in contralateral blood flow over the first week followed by a gradual return toward baseline. Most measures of contralateral metabolism show a time course similar to blood flow, that is, a decrease followed by gradual recovery. The effects of corpus callosum section on transhemispheric diaschisis are not yet established. We provide examples to show that under certain conditions, diaschisis may represent a loss of remote inhibition rather than a loss of remote facilitation, as von Monakow originally suggested. By following the contralateral changes over time, particularly during the first minutes and hours of ischemia, insight will be gained into the brain's responses remote from the focus of ischemic injury. These responses should bear a relation to the brain's defense mechanisms ipsilaterally to the region of ischemia.

Detection of arterial emboli using Doppler ultrasound in rabbits.

Abstract: The purpose of this study was to develop an animal model that could be used to test the ability of Doppler ultrasound to detect arterial emboli composed of materials that are often involved in cerebral emboli. Emboli introduced into the rabbit aorta via the left renal artery consisted of clotted whole blood, platelets, atheromatous material, fat, or air. The ultrasound examination was carried out continuously during the studies using a multifrequency transcranial Doppler apparatus with a 2-MHz probe, a sample volume of 15 mm, at a depth of 15 mm. The intensity of the Doppler spectrum was measured and displayed as a 15-shade color scale, each shade representing a 3-dB difference. The diameter of the aorta at the site of the ultrasound examination was similar to the diameter of the middle cerebral artery in humans. All 125 emboli introduced were clearly detected because they caused a Doppler signal at least 15 dB greater than that of the surrounding blood. These results show that the potential for emboli detection using Doppler ultrasound in the clinical situation is now considerable.

Regional cerebrovascular oxygen saturation measured by optical spectroscopy in humans.

Abstract: Regional cerebrovascular oxygen saturation, a quantitative measure of hemoglobin saturation in the combined arterial, venous, and microcirculatory compartments of the brain, can be measured noninvasively with near infrared spectroscopy. We assessed the sensitivity of this aggregate saturation to cerebral hypoxia during transient cerebral hypoxic hypoxia in seven human subjects. Regional cerebrovascular oxygen saturation measured over the middle frontal gyrus and analog electroencephalogram were recorded. We compared the time to achieve two end points: the earliest paroxysmal burst of theta-delta background slowing and a cerebrovascular oxygen saturation of less than 55%. Saturation fell below 55% prior to the electroencephalographic change (p less than 0.05). In a related effort, we also compared spectroscopically measured regional cerebrovascular oxygen saturation with an estimate of this value calculated from arterial and cerebral mixed venous saturation in nine patients. A positive linear relation (n = 68, R2 = 0.55, s = 4.2) was noted.

Enhanced detection of intracardiac sources of cerebral emboli by transesophageal echocardiography.

Abstract: We performed transesophageal echocardiography in 50 consecutive hospitalized patients with recent transient ischemic attack or stroke of embolic origin to determine whether transesophageal echocardiography is more sensitive than transthoracic echocardiography in detection of possible intracardiac sources of embolism. Twenty-six of 50 patients with a negative transthoracic echocardiogram for potential source of emboli had a transesophageal echocardiography study that demonstrated at least one intracardiac abnormality. Abnormalities noted by transesophageal echocardiography included five of 50 patients with either a left atrial or left atrial appendage clot, four patients with a patent foramen ovale, and nine patients with spontaneous echocardiographic contrast. In 11 of 50 patients with no other source of embolism, we found highly mobile filamentous strands on the mitral valve, which have not been described previously. These mitral valve echo strands may represent a fissured surface or fibrosis that can serve as a nidus for thrombus formation. We detected no unexpected left ventricular thrombus or left atrial myxoma. Factors significantly associated with a greater likelihood of a positive transesophageal echocardiography study included left atrial enlargement, atrial fibrillation, and a calcified or thickened mitral valve. Our study suggests that transesophageal echocardiography is a valuable addition to transthoracic echocardiography in investigating potential intracardiac sources of embolism.

Determination of S-100 and glial fibrillary acidic protein concentrations in cerebrospinal fluid after brain infarction.

Abstract: We initiated the present study to evaluate the clinical value of consecutive concentration determinations of S-100 and glial fibrillary acidic proteins in cerebrospinal fluid from patients with brain infarction.We took sequential samples of cerebrospinal fluid from 28 patients within 48 hours, at 7 days, and at 18-21 days after the ictus. We measured astroglial protein concentrations using an enzyme-linked immunosorbent assay and also determined size of the infarction (computed tomography), clinical state of the patient (simplified activities of daily living test), blood-brain barrier dysfunction (cerebrospinal fluid/serum albumin ratio), and a myelin marker (myelin basic protein).We found a transient increase of both proteins in the cerebrospinal fluid during the first week after the ischemic stroke (p less than 0.05). This increment was significantly correlated with the size of the infarction and the clinical state of the patients.Transient release of astroglial proteins into the cerebrospinal fluid pos...

Autosomal dominant syndrome with strokelike episodes and leukoencephalopathy.

Abstract: We conducted a prospective survey of a family presenting a new syndrome characterized mainly by recurrent strokelike episodes and neuroimaging evidence of leukoencephalopathy.Forty-five members of a single family were studied clinically and with magnetic resonance imaging. Nine had strokelike episodes, including transient ischemic attacks, and minor or major strokes starting between the fourth and sixth decades, with neuroimaging evidence of small, deep infarcts and a widespread white matter disorder. Other symptoms included migraine (three), dementia (two), epilepsy (one), and hearing loss (one). In some patients, we found various immunologic anomalies and muscular lipidosis without ragged-red fibers. Eight other family members were clinically normal, but had identical neuroimaging signs of leukoencephalopathy. No abnormality was detected in the 28 other members of the family examined. Extensive investigations failed to reveal any known cause of cerebral ischemia.There appears to be a new syndrome in thi...

Stress hormone and blood glucose response following acute stroke in the elderly.

Abstract: We studied the relation of reactive hyperglycemia, stress hormone response, and outcome in 23 consecutive elderly patients (median age 80 [range 75-92] years) following an acute first stroke The median delay from the onset of the stroke to the first blood sample (day 0) was 9 (range 4-22) hours Subsequent blood samples were taken, after fasting, for the determination of blood glucose, cortisol, catecholamine, insulin, C-peptide, glucagon, and lactate concentrations on days 1, 2, 3, 7, 14, 30, and 90 For all 23 patients, a significant relation was found between the blood glucose concentration and survival (p = 003) and the blood glucose concentration decreased with time (p less than 0001) There was also a significant relation between blood glucose concentration and outcome (p = 002) For the 15 patients with complete data, the major determinants of the blood glucose concentration were the cortisol, insulin, and glucagon concentrations (all p less than 0001), which accounted for 42% of the variance When all the indexes were analyzed together by logistic regression, only the cortisol concentration was related to outcome (p = 002) Hyperglycemia following a stroke probably reflects the intensity of the stress hormone response We have confirmed that hyperglycemia is a predictor of outcome in persons with stroke

Epidemiology of subarachnoid hemorrhage in Finland from 1983 to 1985.

Abstract: The age-standardized incidence of subarachnoid hemorrhage was 33/100,000/yr among Finnish men and 25/100,000/yr among Finnish women. Subarachnoid hemorrhage represented 11% of all strokes detected during 1983-1985 in the community-based stroke register in three areas of Finland. Age-standardized mortality from subarachnoid hemorrhage was 18/100,000/yr among men and 12/100,000/yr among women aged 25-74 years, representing in men 22% and in women 23% of all deaths from stroke in the register. The case-fatality rate of subarachnoid hemorrhage was high: 35% among men and 33% among women within 2 days after the onset of the stroke attack and 48% in men and 46% in women at 1 month. Our findings suggest that the incidence and mortality of subarachnoid hemorrhage in Finland are among the highest worldwide, although differences in criteria, study methods, and classification procedures reduce the comparability of studies from different countries. The occurrence of subarachnoid hemorrhage in our present study is also higher than that previously reported in this country. We believe that this is more likely due to changes in diagnostic classification and improvements in detection of the disease than to a real increase in the morbidity and mortality of subarachnoid hemorrhage.

Reduction of central nervous system ischemic injury in rabbits using leukocyte adhesion antibody treatment.

Abstract: Activated leukocytes appear to be directly involved in ischemic central nervous system injury. A surface glycoprotein (CD18) on the leukocyte is required for endothelial adherence and subsequent function and can be blocked with leukocyte adhesion antibody treatment. We used two animal models to determine the efficacy of anti-CD18 antibody treatment in preserving neurologic function after central nervous system ischemia. We gave a dose of 1 mg/kg anti-CD18 to treatment rabbits 30 minutes before inducing irreversible ischemia in the brain with intraarterial microspheres or in the spinal cord using reversible aortic occlusion. Treatment with anti-CD18 produced a significant reduction in neurologic deficits in the reversible spinal cord model, but not in the irreversible microsphere model. This protective effect supports the active role of leukocytes in central nervous system reperfusion ischemic injury and offers potential for future therapy.

Temporal evolution of ischemic damage in rat brain measured by proton nuclear magnetic resonance imaging.

Abstract: We studied the effect of focal cerebral ischemia on the "state" of brain water using proton nuclear magnetic resonance imaging. Focal cerebral ischemia was induced in five halothane-anesthetized rats via tandem occlusion of the left common carotid artery and the left middle cerebral artery. The proton transverse relaxation time, the proton density, and the water diffusion coefficient were measured at various times from the same region of brain tissue from 1.5 to 168 hours after occlusion. Early measurements indicated significant changes in the transverse relaxation time (p = 0.004) and water diffusion coefficient (p = 0.002) of ischemic brain tissue compared with a homologous region from the contralateral hemisphere. However, the transverse relaxation time, proton density, and water diffusion coefficient in ischemic brain tissue showed different temporal evolutions over the study period. Diffusion coefficient weighting was superior to relaxation time and proton density weighting for the visualization of early cerebral ischemia. Our data suggest that nuclear magnetic resonance imaging is sensitive in detecting changes in proton-associated parameters during early cerebral ischemia and confirm significant changes (p less than or equal to 0.01) in the temporal evolution of transverse relaxation times, proton densities, and diffusion coefficients following middle cerebral artery occlusion.

Transesophageal echocardiography in the detection of potential cardiac source of embolism in stroke patients.

Abstract: To compare the diagnostic yields of transesophageal and transthoracic echocardiography in the detection of potential cardiac sources of embolism, 63 patients (mean +/- SD age 63 +/- 15 [range 18-87] years) with transient ischemic attacks or stroke underwent both procedures. Transthoracic echocardiography revealed a potential cardiac source of embolism in 14% (nine) of the patients, all of whom had clinical evidence of heart disease. Transesophageal echocardiography revealed a potential cardiac source of embolism in 41% (26) of the patients; 27% (seven) of these patients had no clinical cardiovascular abnormalities. Abnormalities detected only by transesophageal echocardiography in the patients with unsuspected cardiac disease included atrial septal aneurysm in two, patent foramen ovale in two, left atrial appendage thrombus in one, and myxomatous mitral valve in two. The 26 patients with an identified cardiac source of embolism were older (67.5 versus 59.4 years, p = 0.04), more frequently in atrial fibri...

Evaluation of 2,3,5-triphenyltetrazolium chloride staining to delineate rat brain infarcts.

Abstract: Accurate and reproducible determination of the size and location of cerebral infarcts is critical for the evaluation of experimental focal cerebral ischemia. The purpose of this study was to compare intracardiac perfusion of 2,3,5-triphenyltetrazolium chloride with immersion of brain tissue in 2,3,5-triphenyltetrazolium chloride to delineate brain infarcts in rats.After 6, 24, or 48 hours of ischemia induced by permanent middle cerebral artery occlusion, some rats were perfused with 2,3,5-triphenyltetrazolium chloride; other rats were given an overdose of barbiturates, after which brain sections were immersed in 2,3,5-triphenyltetrazolium chloride. Coronal sections were taken 4, 6, and 8 mm from the frontal pole, and infarct areas in perfused and immersed sections were compared; subsequently, the same sections were stained with hematoxylin and eosin.In rats subjected to 24 or 48 hours of occlusion, areas of infarction were clearly defined with both 2,3,5-triphenyltetrazolium chloride staining techniques, ...

Medullary arteries in aging and dementia.

Abstract: We examined sclerotic changes of the medullary arteries in 110 nonneuropsychiatric patients ranging in age from the second to the ninth decades, in 20 patients with subcortical arteriosclerotic encephalopathy (Binswanger's disease), and in 20 patients with dementia of the Alzheimer type. The principal sclerotic change was fibrohyaline thickening of the wall, which began to appear during the late fourth decade, increased in incidence gradually with age, and was most severe in patients with subcortical arteriosclerotic encephalopathy. Morphometry showed that the sclerotic changes of the medullary arteries were most prominent in the frontal lobe, followed by the parietal, occipital, and temporal lobes, in both the nonneuropsychiatric and demented groups. The sclerotic rate in the frontal lobe of patients with dementia of the Alzheimer type was slightly higher than that in the nonneuropsychiatric patients (p less than 0.05) but far less than that in the patients with subcortical arteriosclerotic encephalopathy (p less than 0.001). The sclerotic rate correlated well with the degree of ischemic white matter changes as well as with blood pressure.