Role of anticardiolipin antibodies in young persons with migraine and transient focal neurologic events: a prospective study

Anticardiolipin antibodies (aCL) are a risk factor for cerebral ischemia. In migraine, the association is controversial, with widely varying results in different small series. The controversy in part may be due to the inherent difficulty in distinguishing the transient focal neurologic events (TFNE) of migraine from TIA. To assess the frequency of aCL in migraine, we prospectively evaluated consecutive adults under 60 years of age with migraine without aura and with recent TFNE (<24-hour duration) clinically suggestive of either migraine with aura or TIA. We concomitantly enrolled persons with no CNS disease. Each person was interviewed and had blood drawn for solid-phase ELISA with IgG and IgM aCL isotyping. Neuroradiologic studies were reviewed. Patients with TFNE were followed every 6 months for the duration of the 3-year study. The frequency of aCL positivity (IgG >20, IgG >40, IgM >7.5) for the 645 patients with TFNE (8.8, 3.1, 4.2%), the 518 persons in the TFNE subgroup with migraine with aura (8.9, 3.3, 4.1%), the 497 persons with migraine without aura (7.0, 2.0, 3.6%), and the 366 control subjects (9.3, 3.6, 3.9%) did not differ significantly between groups. In TFNE patients with elevated aCL titer, the association was positive with diabetes mellitus, TFNE duration <15 minutes, and diplopia and was negative with hemiparesis, tinnitus, and family history of stroke. Findings on imaging consistent with cerebral ischemia were more frequent in aCL-positive persons. The short-term risk of stroke was uniformly low. In young persons, aCL is not associated with migraine or with TFNE, although diabetes mellitus, negative family history of stroke, and brief duration of symptoms (including diplopia) may predict immunoreactivity. Imaging studies suggest an ischemic etiology of TFNE in this cohort.

Preliminary clinical-radiological assessment of a MR tissue signature model in human stroke

We evaluated the ability of an MR signature model (SM) of cerebral ischemic injury to stage the evolution of cellular damage in human stroke. In 19 patients with ischemic stroke of presumed embolic or non-embolic cause we carried out diffusion-weighted and T2-weighted MR imaging within 48 h of onset, and obtained apparent diffusion coefficient of water (ADCw), and T2 weighted images. We used the signatures obtained from these ADCw/T2 maps to formulate two patterns of damage signifying accelerated or non-accelerated progression of cellular death after stroke onset. Those patients with the accelerated pattern corresponded to those with the neuroradiological (NRC) and clinical diagnosis (TOAST.1 and TOAST.2) of presumed embolic stroke, with clinical diagnosis performed blinded both to NRC and to SM. Agreement between the SM and NRC was substantial (kappa=0.62), moderate (0.60<kappa<0.40) between the SM or NRC and TOAST.2, and fair (0.40<kappa<0.20) among the SM or NRC and TOAST.1. We believe these results constitute a preliminary validation of the MR tissue signature modeling in clinical stroke assessment.

Cost-effectiveness of tissue plasminogen activator for acute ischemic stroke. NINDS rt-PA Stroke Study Group

Tissue plasminogen activator (tPA) has been shown to improve 3-month outcome in stroke patients treated within 3 hours of symptom onset. The costs associated with this new treatment will be a factor in determining the extent of its utilization. Data from the NINDS rt-PA Stroke Trial and the medical literature were used to estimate the health and economic outcomes associated with using tPA in acute stroke patients. A Markov model was developed to estimate the costs per 1,000 patients eligible for treatment with tPA compared with the costs per 1,000 untreated patients. One-way and multiway sensitivity analyses (using Monte Carlo simulation) were performed to estimate the overall uncertainty of the model results. In the NINDS rt-PA Stroke Trial, the average length of stay was significantly shorter in tPA-treated patients than in placebo-treated patients (10.9 versus 12.4 days; p = 0.02) and more tPA patients were discharged to home than to inpatient rehabilitation or a nursing home (48% versus 36%; p = 0.002). The Markov model estimated an increase in hospitalization costs of $1.7 million and a decrease in rehabilitation costs of $1.4 million and nursing home cost of $4.8 million per 1,000 eligible treated patients for a health care system that includes acute through long-term care facilities. Multiway sensitivity analysis revealed a greater than 90% probability of cost savings. The estimated impact on long-term health outcomes was 564 (3 to 850) quality-adjusted life-years saved over 30 years of the model per 1,000 patients. Treating acute ischemic stroke patients with tPA within 3 hours of symptom onset improves functional outcome at 3 months and is likely to result in a net cost savings to the health care system.

Pilot study of functional MRI to assess cerebral activation of motor function after poststroke hemiparesis

BACKGROUND AND PURPOSE

Studies of cerebral activation of motor function after ischemic stroke may enhance our understanding of the underlying mechanisms of motor functional recovery, including the role of the noninfarcted hemisphere.

METHODS

Eight right-handed recovering hemiparetic or hemiplegic patients were studied using functional MRI. Results were evaluated for each patient to consider individual variability in original functional organization, neuroanatomy, infarct size and extent, treatment, age, and sex. The results were also pooled as a group for comparison with a control group of eight right-handed normal subjects.

RESULTS

In six of eight stroke patients, extended activation in ipsilateral sensorimotor cortex was observed during paretic hand movements. Bilateral activation of the primary sensorimotor cortex was recorded in three of these six patients; ipsilateral activation alone was recorded in the remaining three patients. Only two patients had mild synkinesia. Furthermore, in two male patients, the paretic hand movements activated extended areas of ipsilateral premotor and dorsolateral prefrontal cortex, when compared with normal subjects. In two patients with left frontal infarction, profound activation in the right supramarginal gyrus and in the right premotor cortex was observed during the ipsilateral paretic hand movements.

CONCLUSIONS

Synkinesia alone cannot explain the extent of ipsilateral activation in primary sensorimotor cortex. The explanation offered for our findings is that preexisting uncrossed motor neural pathways may be accessed or recruited to compensate for damage to the crossed motor pathways after ischemic stroke.

Cerebral venous thrombosis and anticardiolipin antibodies

BACKGROUND AND PURPOSE

The association of cerebral venous thrombosis (CVT) with a variety of pathological states is well established. However, there are only rare isolated reports of CVT associated with anticardiolipin antibodies (aCL).

METHODS

To clarify the clinical and neuradiological features as well as outcome of patients with CVT associated with aCL, we reviewed the records of all patients with CVT evaluated at our institution between 1989 and 1996 (retrospective and prospective) and systematically reviewed the pertinent literature.

RESULTS

We identified 8 aCL+ and 7 aCL- patients with CVT. No patients with lupus anticoagulant (LA) were identified. The mean age was 23 +/- 11.01 (range, < 1 to 36) years in the aCL+ and 38 +/- 9.30 (range, 25 to 54) years in the aCL- patients (P = .016). Six of 8 aCL+ and 5 of 7 aCL- patients were women. The dural sinuses were involved in all aCL+ and in 6 of 7 aCL- patients, while deep venous system thrombosis occurred in 5 of 8 (63%) aCL+ and 1 of 7 (14%) aCL- patients. In the aCL+ patients CVT was associated with puerperium or oral contraceptive use (n = 6), and sickle cell trait (n = 1), and in the aCL- patients CVT was associated with systemic lupus erythromatosus (n = 1), myelodysplasti syndrome (n = 1), colonic cancer (n = 1), oral contraceptive use or puerperium (n = 3), and dehydration (n = 1). Seven aCL+ patients received either intrasinus urokinase or intravenous heparin sulfate, and 1 received aspirin. Four aCL+ patients developed new onset or worsening of preexisting migraine, 2 developed recurrent peripheral venous thrombosis, and 1 went on to have intracranial hypertension. Twenty additional patients with CVT associated with antiphospholipid antibodies (aPL) were found reported in the literature. The overall mean age was 36 +/- 11.6 (range, 21 to 62) years, and 14 (70%) were women. LA was present in 11 of 18 tested, aCL in 7 (35%), LA and aCL in 1, and the type of aPL was not reported in 3. The mean age for the aCL+ only group was 28 years and for the LA+ (with or without aCL+) was 34 years. Only 1 patient, whose aPL type was not specified, had thrombosis of the deep venous system in addition to involvement of the dural sinuses.

CONCLUSIONS

Our series and review suggest that aCL may be an important factor contributing to development of CVT even in the presence of other potential etiologies or risk factors. Onset of aCL+ CVT occurs at a relative young age and with relatively more extensive superficial and deep cerebral venous system involvement than aCL- CVT.

Total quality improvement method for reduction of delays between emergency department admission and treatment of acute ischemic stroke. The National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group

OBJECTIVE

To develop an approach for reducing time between emergency department (ED) admission and treatment in patients with acute ischemic stroke to meet the challenge of providing tissue plasminogen activator treatment within 180 minutes.

DESIGN

An observational study.

SETTING

Forty trial-affiliated hospitals, including 30 community hospitals.

PARTICIPANTS

A total of 17,324 consecutive patients admitted to trial-affiliated hospital EDs within 24 hours of possible stroke, from January 1991 through October 1994.

INTERVENTION

Appraisal of the process of triage, evaluation, diagnosis, and treatment by means of total quality improvement techniques in each hospital. Staff participating in the process identified sources of variation and modifications by flow charting the process.

MAIN OUTCOME MEASURE

Time between ED admission and treatment with study medication.

RESULTS

Total quality improvement methods identified hospital-specific process improvements. Many improvements were administrative, requiring no additional resources. More than 50% of screened patients arrived too late to be treated. Only 1268 patients were admitted between 0 and 125 minutes from stroke onset with no other trial exclusion criteria; 48% were treated. Of 243 patients admitted between 126 and 170 minutes from stroke onset with no exclusion criteria, 4% were treated. Mean time from ED admission to treatment was similar in teaching and community hospitals.

CONCLUSIONS

Total quality improvement methods identified ED-specific sources of process variability and reduced time between ED admission and treatment. Therefore, these methods should be considered in developing and monitoring emergent stroke treatment protocols.

Thrombolytic therapy for stroke: the new paradigm

Roughly 80% of patients with acute stroke have thromboocclusive disease and may benefit from clot lysis with recombinant tissue plasminogen activator. To be effective, however, such treatment must be administered within three hours of stroke onset in carefully selected patients. Hospital protocols that mobilize an acute stroke team to minimize delays are needed nationwide.

IgG anticardiolipin antibody titer > 40 GPL and the risk of subsequent thrombo-occlusive events and death. A prospective cohort study

BACKGROUND

Anticardiolipin antibodies (aCL) have been associated with an increased risk of stroke and thrombo-occlusive events. Little is known about the influence of aCL on recurrent thrombo-occlusive events.

METHODS

Consecutively identified patients (n = 132) with focal cerebral ischemia [stroke = 112, transient ischemic attack (TIA) = 20] harboring aCL of at least 10 GPL units at the time of their index event were prospectively followed to estimate the effect of aCL titer on time to and risk of subsequent thrombo-occlusive events (stroke, TIA, deep venous thrombosis, pulmonary embolism, myocardial infarction) and death. On the basis of prior literature, we divided patients into those with aCL < or = 40 GPL (n = 111; mean age, 63 +/- 14 years; mean follow-up, 1.95 years) and those with aCL > 40 GPL (n = 21; mean age, 54 +/- 20 years; mean follow-up, 1.50 years).

RESULTS

There was no difference between groups for prevalence of hypertension, diabetes mellitus, cigarette smoking, atrial fibrillation, prior TIA, or sex. The GPL > 40 group was younger (54 +/- 20 versus 63 +/- 14 years; P = .055), had more prior strokes [9/21 (48%) versus 27/111 (20%); P = .030], more frequent subsequent thrombo-occlusive events and death [15/21 (71%) versus 51/111 (48%); P = .030], and a shorter median time (years) to event (0.15 versus 0.61, log rank P = .005). The risk ratio for recurrent event and death with GPL > 40 obtained from Cox proportional hazards models, adjusted for prior strokes, prior TIAs, hypertension, diabetes mellitus, atrial fibrillation, and cigarette smoking was 1.9 (95% confidence interval, 1.0 to 3.5; P = .051).

CONCLUSIONS

Our data suggest that subsequent thrombo-occlusive events and death after focal cerebral ischemia associated with IgG aCL may occur sooner and more frequently with GPL > 40.

Treatment of neurologic complications of antiphospholipid antibody syndrome

Thrombosis associated with antiphospholipid antibodies (aPL) occurs in both venous and the arterial circulation. The most common arterial thrombo-occlusive event is cerebral infarction. We briefly review treatment strategies aimed at patients with cerebrovascular disease and aPL. Besides general treatment issues, we discuss primary prevention and secondary prevention. Most regimens include antithrombotics or immune modulation. Prospective studies (currently underway) are required to better estimate the rate of recurrent thrombo-occlusive events on standardized therapy before one therapy can be recommended over another with reasonable evidence.

Neurological aspects of antiphospholipid antibody syndrome

Antiphospholipid antibodies (aPL) have been associated with a variety of neurological disorders, mostly linked to focal neuroparenchymal ischemia or infarction. Cerebral ischemia associated with the antiphospholipid syndrome (APS) occurs at a younger age than typical atherothrombotic cerebrovascular disease, is often recurrent, and high positive GPL values are usually linked to the presence of a lupus anticoagulant. When other features of the syndrome are not present and cerebral ischemia occurs only associated with anticardiolipin immunoreactivity, there appears to be no discerning features of these patients unless GPL > 40 for which recurrent thrombo-occlusive events appear to occur more frequently. Other neurological manifestations associated with aPL include cerebral venous sinus thrombosis, ocular ischemia, dementia, including ischemic encephalopathy, and chorea. The role of aPL in migrainous events is controversial and may not play a role in recent, large case-controlled studies. Most seizures in patients harboring aPL are associated with focal brain infarction.

Cerebrovascular complications of Fabry's disease

Fabry's disease (FD) is a rare, sex-linked disorder resulting from alpha-galactosidase deficiency. Cerebrovascular complications have been reported in the literature but have not been systematically analyzed. We report 2 patients and review 51 previously reported cases (descriptive meta-analysis) to clarify the clinical, radiologic, and pathologic features. The average age at onset of cerebrovascular symptoms was 33.8 years for hemizygous individuals (n = 43) and 40.3 years of heterozygotes (n = 10). The most frequent symptoms and signs were as follows (in descending order of frequency): hemiparesis, vertigo/dizziness, diplopia, dysarthria, nystagmus, nausea/vomiting, head pain, hemiataxia, and ataxia of gait, in the hemizygote group; and memory loss, dizziness, ataxia, hemiparesis, loss of consciousness and hemisensory symptoms, in the heterozygote group. The vertebrobasilar circulation was symptomatic in 67% of the hemizygotes and 60% of the heterozygotes. Intracerebral hemorrhage was found in 4 patients (3 hemizygotes and 1 heterozygote). Elongated, ectatic, tortuous vertebral and basilar arteries were the most common angiographic and pathologic features. For the hemizygotes, the recurrence rate for cerebrovascular disease was 76% and the death rate was 55%; 86% of the heterozygotes had recurrent cerebrovascular event(s) and 40% died. The cerebrovascular manifestations of FD, in both hemizygotes and heterozygotes, are predominantly due to dilative arteriopathy of the vertebrobasilar circulation, frequently recur, and portend a poor prognosis.

Effects of ramipril and enalapril on cerebral blood flow in elderly patients with asymptomatic carotid artery occlusive disease

We wished to determine in asymptomatic hypertensive patients with > or = 70% stenosis of an internal carotid artery the change in regional cerebral blood flow (rCBF) produced by ramipril and enalapril and to evaluate the influence of age on drug-induced changes in rCBF. In a prospective, randomized, single-blind, placebo-controlled investigation, using the 133Xenon inhalation technique, we assessed baseline rCBF in 15 patients (9 men and 6 women aged 60-79 years) after a 24-h antihypertensive drug-free period. All patients then received a single 5-mg oral dose of ramipril, enalapril, or placebo. rCBF was reassessed 2 h postdose. There was no significant change in the median rCBF in any of the three treatment groups. Neither did we observe any lateralization of BF to any specific cerebral region in any of the three groups. There were no observed or patient-reported adverse events (AE). Single 5-mg oral doses of either ramipril or enalapril did not decrease CBF significantly in asymptomatic hypertensive patients with > or = 70% stenosis of an internal carotid artery and are probably safe starting doses in such patients. In addition, this effect was not modified by age.

Cocaine-associated intracranial hemorrhage: absence of vasculitis in 14 cases

Complications associated with the use of cocaine are varied, and include cerebral hemorrhage and ischemia, with vasculitis and vasospasm as possible etiologies. We reviewed selected brain samples from 14 autopsy cases of cocaine-related cerebrovascular disease. Intracerebral or subarachnoid hemorrhage was present in 12 cases. Intracranial arterioles were either normal or showed nonspecific changes. From these observations, we suggest that intracranial hemorrhages occur in the absence of readily detectable vascular abnormalities.

A model to predict the histopathology of human stroke using diffusion and T2-weighted magnetic resonance imaging

BACKGROUND AND PURPOSE

We sought to identify MRI measures that have high probability in a short acquisition time to predict, at early time points after onset of ischemia, the eventual development of cerebral infarction in clinical patients who suffer occlusion of a cerebral artery.

METHODS

We developed an MR tissue signature model based on experimentally derived relationships of the apparent diffusion coefficient of water (ADCw) and T2 to ischemic brain tissue histopathology. In eight stroke patients we measured ADCw and T2 intensity using diffusion-weighted echo-planar imaging (DW-EPI). Tissue signature regions were defined, and theme maps of the ischemic focus at subacute time points after stroke onset were generated.

RESULTS

Five MR signatures were identified in human stroke foci: two that may predict either cell recovery or progression to necrosis, one that may mark the transition to cell necrosis, and two that may be markers of established cell necrosis.

CONCLUSIONS

An MR tissue signature model of ischemic histopathology using ADCw and T2 can now be tested for its potential to predict reversible and identify irreversible cellular damage in human ischemic brain regions.

Age and carotid artery occlusive disease are important determinants of cerebral blood flow changes after antihypertensive therapy

STUDY OBJECTIVE

To determine the short-term effects of antihypertensive therapy on cerebral blood flow (CBF).

DESIGN

Prospective, observational study.

SETTING

A university-affiliated teaching hospital.

PATIENTS

Twenty-four patients (age range 53-85 yrs) with chronic hypertension, nine of whom had carotid artery occlusive disease (CAOD).

INTERVENTIONS

The CBF (xenon-133 inhalation technique) and blood pressure were measured before and at 60 minutes after administration of antihypertensive therapy.

MEASUREMENTS AND MAIN RESULTS

Age was inversely related to the change in CBF in patients with CAOD (p < 0.01). In all patients, the change in CBF after taking antihypertensive drugs was significantly inversely associated with baseline CBF (p < 0.01). Changes in regional CBF, measured by asymmetry scores, were significantly greater in patients with CAOD than in those without CAOD (p < 0.05).

CONCLUSIONS

Elderly patients with occlusive extracranial cerebrovascular disease are at risk of drug-induced changes in both mean and regional CBF, and may benefit from a CBF assessment before being prescribed antihypertensive therapy.

The Warfarin-Aspirin Symptomatic Intracranial Disease Study

We conducted a retrospective, multicenter study to compare the efficacy of warfarin with aspirin for the prevention of major vascular events (ischemic stroke, myocardial infarction, or sudden death) in patients with symptomatic stenosis of a major intracranial artery. Patients with 50 to 99% stenosis of an intracranial artery (carotid; anterior, middle, or posterior cerebral; vertebral; or basilar) were identified by reviewing the results of consecutive angiograms performed at participating centers between 1985 and 1991. Only patients with TIA or stroke in the territory of the stenotic artery qualified for inclusion in the study. Patients were prescribed warfarin or aspirin according to local physician preference and were followed by chart review and personal or telephone interview. Seven centers enrolled 151 patients; 88 were treated with warfarin and 63 were treated with aspirin. Median follow-up was 14.7 months (warfarin group) and 19.3 months (aspirin group). Vascular risk factors and mean percent stenosis of the symptomatic artery were similar in the two groups, yet the rates of major vascular events were 18.1 per 100 patient-years of follow-up in the aspirin group (stroke rate, 10.4/100 patient-years; myocardial infarction or sudden death rate, 7.7/100 patient-years) compared with 8.4 per 100 patient-years of follow-up in the warfarin group (stroke rate, 3.6/100 patient-years; myocardial infarction or sudden death rate, 4.8/100 patient-years). Kaplan-Meier analysis showed a significantly higher percentage of patients free of major vascular events among patients treated with warfarin (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Recurrent stroke and thrombo-occlusive events in the antiphospholipid syndrome

We prospectively studied 81 consecutively identified patients with antiphospholipid antibodies (aPLs) who developed focal cerebral ischemia over a 7-year period. The mean age of this cohort was approximately a decade younger than the average atherothromboembolic stroke victim and women were more commonly involved than men. The frequency of conventional stroke risk factors was lowest in the group of stroke patients with the highest levels of IgG cardiolipin immunoreactivity. Other serological abnormalities associated with aPL (false-positive Venereal Disease Research Laboratory test, thrombocytopenia, prolonged activated partial thromboplastin time [aPTT]) were more common in the group with over 100 GPL units (high positive). Patients with the highest IgG anticardiolipin titers had the shortest times to subsequent thrombo-occlusive events. The most common recurrent event was cerebral infarction, often occurring within the first year of follow-up during a mean prospective follow-up of 3 years. Over one-half of the cohort had at least one recurrent thrombo-occlusive event during follow-up. This distinct syndrome of cerebral ischemia should be recognized for its younger age at onset, predominance of women, high risk of recurrent thrombo-occlusive events, and the possible use of the IgG anticardiolipin antibody titer for prognosis.

Vasospasm and thrombus formation as possible mechanisms of stroke related to alkaloidal cocaine

BACKGROUND

"Crack" cocaine (alkaloidal cocaine) induces ischemic stroke. However, the mechanisms by which this occurs are not well documented in humans. We present pertinent information on three patients whose ischemic strokes involved the territory of the internal carotid artery and were associated with crack use.

CASE DESCRIPTIONS

These patients were investigated clinically, radiologically, intraoperatively, and/or histopathologically at the same institution, and the diagnostic evaluations did not reveal a definite cardiac or hematologic cause of stroke. Large filling defects were noted on conventional carotid angiography in two of these patients; in the third patient, the histopathological changes were compatible with vasospasm. To our knowledge, these changes have not been previously documented in human arteries.

CONCLUSIONS

We suggest that some brain infarcts among crack cocaine users may result from vasospasm of large arteries and secondary intravascular thrombosis.

Cerebrovascular disease with antiphospholipid antibodies: immune mechanisms, significance, and therapeutic options

There has been a recent, dramatic surge in interest in antiphospholipid antibodies and associated clinical disorders, especially focal ischemic cerebrovascular disease. Antiphospholipid antibodies are a heterogeneous group of antibodies with varying specificities. Coagulation assays will detect lupus anticoagulants while enzyme-linked immunosorbent assays detect anticardiolipin antibodies. There are numerous potential links between antiphospholipid antibodies and coagulation disorders, including interaction of antiphospholipid antibodies and a cofactor, beta 2-glycoprotein I, which itself is involved in coagulation mechanisms. While the specific mechanism of antiphospholipid antibody-related coagulopathy is unknown, it is clear that antiphospholipid antibodies are associated with an immune-mediated prothrombotic state. Patients with the highest titers of IgG antiphospholipid antibodies have a relatively high risk of recurrent thrombotic events, especially stroke, deep venous thrombosis, and spontaneous abortion. Because of limited controlled, prospective data, current therapy remains empiric and directed at coagulation mechanisms, immune mechanisms, or both.

Adhesive glycoproteins CD11a and CD18 are upregulated in the leukocytes from patients with ischemic stroke and transient ischemic attacks

Leukocytes may have an important role in the pathogenesis of brain injury after ischemia. Expression of adhesion molecules on leukocytes and/or endothelia is needed for leukocytes to adhere to endothelia and infiltrate into the injured brain. The purpose of the present pilot study is to delineate whether the expression of leukocyte adhesion molecules, CD11a and CD18, are upregulated in patients with ischemic stroke and transient ischemic attack. Ten patients with ischemic stroke, 6 with transient ischemic attack (TIA), and 11 age and risk factor matched controls were studied. Using immunofluorescence phenotyping and flow cytometry, leukocyte membrane expression of CD11a and CD18 were measured within 72 h after onset of ischemia. Follow-up measurements were performed at 5-7 days after ictus in 6 patients with stroke, and at 3-5 days after ictus in 3 patients with TIA. CD11a immunofluorescence (IF) was significantly increased within 72 h after onset of symptoms in patients with stroke as well as TIA compared with the control group (p < 0.017). IF of CD18 also increased in both patient groups, but significance was reached only in the TIA group (p < 0.05). No difference of CD11a and CD18 IF was detected between stroke and TIA groups. Follow-up measurement of CD11a and CD18 showed a trend of decrease, but CD11a IF remained significantly elevated compared with the control group (p < 0.017). Expression of leukocyte adhesion molecules CD11a, and CD18 are upregulated in patients with ischemic stroke and TIA. Although these data are preliminary, our data suggest that these molecules are associated with cerebrovascular disorders including ischemic stroke and TIA.

Cerebral blood flow in migraine accompaniments and vertebrobasilar ischemia

BACKGROUND AND PURPOSE

Transient neurological symptoms of brain stem or occipital lobe origin may be caused by transient ischemic attack in the vertebrobasilar territory (VB-TIA) or late-onset (or late-life) migraine accompaniment (LOMA). It is often clinically difficult to distinguish between VB-TIA and LOMA.

METHODS

Cerebral blood flow of 23 patients with VB-TIA, 24 with LOMA, and 28 age-matched control subjects was measured using the 133Xe inhalation regional cerebral blood flow (rCBF) technique.

RESULTS

After adjusting for differences in baseline variables such as blood pressure, hematocrit, and PCO2, patients with VB-TIA had (1) lower mean rCBF than control subjects (P < .003) as measured by the initial slope index method; (2) more frequent anterior rCBF asymmetries than control subjects and patients with LOMA (P < .03 for both comparisons); and (3) higher mean interhemispheric rCBF differences compared with patients with LOMA (P = .08) and control subjects (P < .02).

CONCLUSIONS

Regional CBF patterns in patients with VB-TIA and LOMA differ, with lower rCBF and more asymmetry of the anterior blood flows in patients with VB-TIA, probably reflecting the effects of stroke risk factors on the cerebral circulation. Patients with LOMA have rCBF patterns more closely resembling those of age-matched healthy subjects. rCBF measurements may assist in the clinical diagnosis of VB-TIA and late-onset migrainous events.

Digital rectal examination, serum prostate specific antigen, and prostatic ultrasound: how effective is this diagnostic triad?

Ninety-nine of 105 consecutive men who underwent transrectal prostatic ultrasound (TRUS) at Highland Park Hospital had the results correlated with digital rectal examination (DRE), serum prostate specific antigen (PSA), and biopsy results. Ninety-six cases had evaluable ultrasound studies. Thirty-two of the 99 who underwent biopsy had primary carcinoma of the prostate. Prostate volume, predicted PSA, a ratio of observed/predicted PSA, and Gleason score were examined. There was no correlation between age and prostate volume, volume and the presence of carcinoma, or PSA and Gleason score. Thirty-one point six percent of the abnormal DREs, 36.6% of the abnormal TRUSs, and 40.6% of the elevated PSAs occurred in men with prostatic carcinoma (PCa). If PSA was normal (less than or equal to 4.0 ng/ml) and either DRE or TRUS was abnormal, then the risk of carcinoma was 2.9%. If PSA was elevated, regardless of the other two tests, the risk of finding PCa was at least 38%. If all three tests were abnormal, the risk of carcinoma was 38% in our series and 68% in a meta-analysis. Many men with PSA values between 4 and 10 ng/ml have benign biopsies. However, close future follow-up with consideration of repeat biopsy should be strongly considered.

Large cerebral vessel occlusive disease in systemic lupus erythematosus

We systematically investigated clinical, laboratory, radiologic, and pathologic features, including treatment and prognosis, of stroke syndromes in 30 patients, six from our institution and 24 from the literature, with systemic lupus erythematosus (SLE) and symptomatic large cerebral vessel occlusive disease, documented by angiography or autopsy. The average age at stroke onset was 35 years, and the diagnosis of SLE was made on average 4.4 years prior to that. At least 86% had active SLE at the time of their stroke. Headache was common at onset. We found major intracranial or extracranial vessel occlusive process by (1) thrombus, (2) dissection, (3) fibromuscular dysplasia or vasculitis, and (4) atherosclerosis. The presumed mechanisms were coagulopathy, cardiogenic embolism, large cerebral vessel vasculitis or occlusive vasculopathy, cervical arterial dissection, and premature atherosclerosis. The short-term death rate was 40% and the recurrent stroke rate was 13%. We conclude that symptomatic large cerebral vessel occlusive disease in SLE generally occurs several years after the diagnosis of SLE, usually during the active phase of the disease, is related to heterogeneous mechanisms, and carries a relatively poor short-term outcome.

Factors associated with early presentation of acute stroke

BACKGROUND AND PURPOSE

Patients with stroke symptoms commonly delay many hours before seeking medical attention. We sought to explore the factors associated with early presentation of stroke patients to physicians.

METHODS

We prospectively studied 100 consecutive acute stroke patients presenting to three large, urban medical centers. Using a standardized, structured interview and chart review, we assessed patient education about stroke, risk factors, clinical features of the stroke, source of stroke recognition, and timing of presentation. We did not study the distance from the site of stroke onset to the site of physician contact.

RESULTS

Stroke onset time was known in 96 of the patients. Mean patient age was 71.3 years, 79% had at least one stroke risk factor, 26% had prior transient ischemic attack, 19% had prior stroke, 74% had some high school education, and 86% had regular physicians. Only 8% had been previously educated about stroke symptoms. Eighty one percent of strokes were ischemic. The mean time to physician contact was 13.4 +/- 2.3 hours (median, 4.0 hours) and to neurologist contact was 21.2 +/- 2.9 hours. A skewed distribution of presentation times accounts for the mean-median differences. A small number of patients presenting very late could have an effect on the correlations between presentation time and the variables studied. Early presentation time was associated with increased age, the sudden onset of a stable deficit, and recognition that the symptoms signified stroke. Only the sudden onset of a stable deficit correlated independently with early presentation time (P = .0048). There was no correlation between presentation time and prior transient ischemic attack or stroke, headache, vomiting, loss of consciousness or seizures at onset, or stroke subtype, but a type II error could not be excluded.

CONCLUSIONS

Despite their education level, regular health care, and risk factors, especially prior stroke and transient ischemic attack, these patients were not knowledgeable about stroke and delayed many hours before contacting physicians. The course of symptoms and recognition that they signified stroke were associated with earlier presentation. Patient education focused on groups at risk may hasten the presentation and treatment of acute stroke.

Stroke

Illicit drugs, appetite suppressants, decongestants, and anabolic steroids may cause stroke. Drug abuse is a common cause of stroke in young patients. Mechanisms are varied, but it is particularly important to seek out infective endocarditis and most importantly, cerebral aneurysms, vascular malformations, and cardiac disorders in cocaine abusers. Drug-induced vasoconstriction, hypertension, or vasculitis probably contributes significantly to most patients' strokes. Tobacco smoking and heavy chronic alcohol consumption are independent risk factors for stroke; moderate drinking seems to protect from stroke in white patients. Oral contraceptives may increase the risk of stroke in female patients over 35 years of age who also have other risk factors.

Acute elevation and recovery of intracellular [Mg2+] following human focal cerebral ischemia

We used 31P magnetic resonance spectroscopy (MRS) to investigate changes in brain intracellular [Mg2+] following human focal cerebral ischemia. Mean brain pMg (where pMg = -log[Mg2+]) was significantly lower in the ischemic focus of all stroke patients (pMg = 3.34 +/- 0.28, n = 45, p < 0.01) when compared with normal controls (pMg = 3.50 +/- 0.08, n = 25). Ischemic brain pMg was also significantly reduced when the pH of the stroke region was acidotic (pH < 6.90, pMg = 3.07 +/- 0.44, n = 11, p < 0.01) and when the phosphocreatine index (PCrI = PCr/[PCr+Pi (inorganic phosphate)]) was reduced (PCrI < 0.47, pMg = 3.12 +/- 0.42, n = 13, p < 0.01). Mean brain pMg was significantly reduced at days 0 to 1 (acute) poststroke (pMg = 3.32 +/- 0.28, n = 26, p < 0.01) and at days 2 to 3 (subacute) poststroke (pMg = 3.38 +/- 0.28, n = 21, p = 0.03). There was also a significant (p < 0.01) correlation between decreased pMg and increased relative signal intensity of Pi (normalized by total phosphate signal, Pi/TP) for all stroke groups studied. During the temporal evolution of stroke, pH returned to normal levels by days 2 to 3, and pMg returned to normal by days 4 to 10 (subacute). PCrI and Pi/TP returned toward normal levels after 10 days (chronic), at a time when ischemic brain pH had become significantly alkalotic (pH = 7.10 +/- 0.24, n = 15, p < 0.01). Elevation of ischemic brain [Mg2+] is temporally linked to the acidotic phase of human stroke as well as the breakdown of energy metabolism. These acute changes in [Mg2+] may contribute to, or be a marker for, cellular injury.

Factors that predict antiphospholipid immunoreactivity in young people with transient focal neurological events

OBJECTIVE

To determine if clinical or radiological features in young people with transient focal neurological events may be used to predict the presence of antiphospholipid antibodies (aPL).

DESIGN

A combined retrospective and prospective study of young people with transient focal neurological events. Likelihood ratios and confidence intervals were calculated for the proportions; logistic regression analysis was performed to determine features predictive of aPL immunoreactivity.

SETTING

A referral hospital and adjacent outpatient clinic.

PATIENTS

Sixty-eight patients with one or more transient focal neurological events were screened for aPL. Forty-seven patients were obtained retrospectively from medical record review of every outpatient personally seen by two of us (G.E.T. and S.R.L.) during a 4.5-year period. Twenty-one patients were prospectively added prior to retrospective analysis. Patients older than 50 years or those with multiple sclerosis or epilepsy were excluded. Five patients fulfilling study criteria were excluded because aPL assay results were unavailable.

MAIN OUTCOME MEASURES

Transient neurological symptoms, stroke risk factors, occurrence of cerebral or ocular infarct or death, headache history, and serological and radiological studies were systematically obtained.

RESULTS

There were 29 aPL-positive patients compared with 39 aPL-negative ones. Features that distinguished the aPL-positive group included more common monocular visual symptoms (38% vs 15%, P = .03), hemisensory symptoms (76% vs 41%, P = .004), and systemic lupus erythematosus (14% vs 0%, P = .03) and less common binocular visual symptoms (28% vs 51%, P = .05), accompanying headache (66% vs 87%, P = .03), and personal (48% vs 74%, P = .03) and family (29% vs 61%, P = .01) history of migraine. No differences were noted between the groups for age, gender, stroke risk factor profile, and radiological features. In a logistic regression analysis, the estimated odds ratio for aPL positivity in patients with monocular visual disturbance, hemisensory symptoms, and no family history of migraine were 5.3, 7.5, and 3.0, respectively, when controlling for the other variables.

CONCLUSIONS

Several clinical features of transient focal neurological events in aPL-positive patients distinguish these individuals from their aPL-negative cohort. Amaurosis fugax, unilateral paresthesias, and no family history of migraine may predict aPL positivity in young persons with transient focal neurological deficits.

Altered brain energy metabolism in demented patients with multiple subcortical ischemic lesions. Working hypotheses

We report the results of brain metabolic studies (using magnetic resonance spectroscopy) in three groups of individuals: (1) demented patients with multiple subcortical ischemic lesions (n = 18); (2) nondemented, age-matched controls (n = 21); and (3) demented patients with neurodegenerative disease, probably of the Alzheimer type (n = 19). Patients with dementia with subcortical vascular lesions, as demonstrated by appropriate imaging studies, had an increase of phosphate energy charge in areas of the cerebral cortex (especially prominent in the frontal regions) superficial to and excluded from the subcortical lesions. We hypothesize that this increased energy charge might be caused by reduced metabolic activity of disconnected brain tissue or by astrocytic hypertrophy and hyperplasia that accompanies subtle ischemic, cortical alterations.

Intramedullary spinal sarcoidosis: clinical and magnetic resonance imaging characteristics

We present a retrospective series of the clinical and MRI findings in 16 patients with intramedullary spinal sarcoidosis (ISS), including 12 patients studied with gadolinium-DTPA. The spectrum of MRI findings includes leptomeningeal enhancement, fusiform spinal cord enlargement, focal or diffuse intramedullary disease, and spinal cord atrophy. We present a classification of ISS correlating the clinical progression and the temporal sequence of MRI abnormalities. Improvement occurred in five of 12 patients (42%) treated with immunosuppressive therapy.

Possible association of ischemic stroke with phentermine

BACKGROUND AND PURPOSE

Some commonly used anorexiants, including methamphetamine and phenylpropanolamine, have been associated with stroke. Because phentermine is an anorexiant with a chemical structure similar to that of amphetamines, similar side effects might be expected.

CASE DESCRIPTIONS

Two patients using phentermine (one was also using phendimetrazine) developed ischemic cerebrovascular disease. One suffered a cerebral infarct with angiographic evidence of vasculopathy involving multiple vascular beds. The other patient developed headache and a hemisensory disturbance of 7 days' duration.

CONCLUSIONS

Phentermine, and possibly phendimetrazine, should be considered an anorexiant and sympathomimetic drug that can be associated with ischemic cerebrovascular disease.

Cerebellar infarction. Clinical and anatomic observations in 66 cases

BACKGROUND AND PURPOSE

Cerebellar infarction displays different clinical features, depending on the vascular territory involved. We studied patients with infarcts in the territories of the posterior inferior cerebellar artery or the superior cerebellar artery to compare their clinical presentation, course, and prognosis.

METHODS

We retrospectively analyzed the clinical features, laboratory data, and imaging studies of 66 patients with cerebellar infarction collected consecutively at five institutions. All the cerebellar infarcts were documented on computed tomographic scan or magnetic resonance imaging.

RESULTS

Two distinct profiles emerged, depending on the vascular territory involved. In 36 patients with posterior inferior cerebellar artery territory infarcts, a triad of vertigo, headache, and gait imbalance predominated at stroke onset. Computed tomography showed severe cerebellar mass effect in 11 cases (30%), with associated hydrocephalus in seven. In these seven patients (19%), postinfarct swelling led to brain stem compression that resulted in four deaths. In 30 patients with superior cerebellar artery infarcts, gait disturbance predominated at onset; vertigo and headache were significantly less common. The clinical course was usually benign. Computed tomography showed marked cerebellar mass effect, hydrocephalus, and brain stem compression in only two instances (7%). Presumed cerebral embolism was the predominant stroke mechanism in patients with superior cerebellar artery distribution infarcts, whereas in those with posterior inferior cerebellar artery distribution infarcts, the stroke mechanism was equally divided between cardiogenic embolism and posterior circulation arterial disease.

CONCLUSIONS

Cerebellar infarcts in the posterior inferior cerebellar artery and superior cerebellar artery distribution have distinct differences in clinical presentation, course, and prognosis. These differences should help in the selection of appropriate monitoring and treatment strategies.

Human focal cerebral ischemia: evaluation of brain pH and energy metabolism with P-31 NMR spectroscopy

The authors investigated early human focal ischemia with phosphorus-31 nuclear magnetic resonance spectroscopy at 1.89 T to characterize the temporal evolution and relationship of brain pH and phosphate energy metabolism. Data from 65 symptomatic patients were prospectively studied; none of the patients had had ischemic stroke in the internal carotid artery territory before. Twenty-eight neurologically normal individuals served as control subjects. Serial ischemic brain pH levels indicated a progression from early acidosis to subacute alkalosis. When acidosis was present there was a significant elevation in the relative signal intensity of inorganic phosphate (Pi) and significant reductions in signal intensities of alpha-adenosine triphosphate (ATP) and gamma-ATP compared with those of control subjects. Ischemic brain pH values directly correlated with the relative signal intensity of phosphocreatine (PCr) and the PCr index and inversely correlated with the signal intensity of Pi. There was a general lack of correlation between either ischemic brain pH or phosphate energy metabolism and the initial clinical stroke severity. The data suggest a link between high-energy phosphate metabolism and brain pH, especially during the period of ischemic brain acidosis, and the authors propose that effective acute stroke therapy should be instituted during this period.

Distribution of the 72-kd heat-shock protein as a function of transient focal cerebral ischemia in rats

BACKGROUND AND PURPOSE

The significance and physiological implications of the expression of the 72-kd heat-shock protein in ischemic tissue are unknown. To enhance our understanding of the relation between ischemic cell damage and 72-kd heat-shock protein expression, we evaluated the cellular expression and the anatomic distribution of 72-kd heat-shock protein in conjunction with the morphological analysis of rat brain, as a function of the duration of a single arterial occlusion.

METHODS

Adult Wistar rats were subjected to graded transient middle cerebral artery occlusion (for a duration of 10, 20, 30, 60, 90, and 120 minutes and sham; n = 4 per group). Forty-eight hours after reopening the artery, brain tissue sections were analyzed to determine the extent of neuronal damage (hematoxylin and eosin staining), the extent of astrocytic reactivity (immunohistochemistry, using anti-glial fibrillary acidic protein), and the distribution of 72-kd heat-shock protein (immunohistochemistry, using a monoclonal antibody to 72-kd heat-shock protein).

RESULTS

We found that 72-kd heat-shock protein was sequentially expressed in morphologically intact neurons, microglia, and endothelial cells with increasing duration of ischemia; 72-kd heat-shock protein immunoreactivity was not detected in astrocytes. The duration of ischemia required to evoke a 72-kd heat-shock protein response in neurons was dependent on the anatomic site and followed a pattern of increasing neuronal sensitivity to ischemic cell damage with duration of ischemia: 72-kd heat-shock protein and neuronal damage were sequentially detected in the caudate putamen, globus pallidus, cerebral cortex, amygdala, and hippocampus with increasing duration of ischemia. With ischemia of long duration (greater than or equal to 90 minutes), neurons expressing 72-kd heat-shock protein were localized to a zone peripheral to the severely damaged ischemic core.

CONCLUSIONS

These studies suggest that 1) the expression of 72-kd heat-shock protein in neurons precedes the development of ischemic cellular alterations detectable by conventional hematoxylin and eosin light microscopy methods; 2) there is a hierarchy of cell types and anatomic sites that express 72-kd heat-shock protein, and this hierarchy reflects cellular and anatomic vulnerability to ischemic cell damage; and 3) 72-kd heat-shock protein induction in neurons bordering a necrotic ischemic core may be the morphological equivalent of the ischemic penumbra.

Transient ischemic attacks in the elderly: diagnosis and treatment

Transient ischemic attacks (TIAs) are the most reliable warning sign of impending stroke and are highly indicative of significant coronary artery disease. The history and physical examination may suggest the pathologic mechanism, an important clue to diagnosis and prognosis. Diagnostic testing is individualized but often includes ECG and cerebral contrast angiography. Exercise testing, echocardiography, ultrasound, CT, and/or MRI are sometimes indicated. The patient with recent TIAs may be hospitalized for acute management. Long-term treatment includes stroke risk factor modification, use of antiplatelet agents, and sometimes anticoagulant therapy. Selected older patients may be candidates for carotid endarterectomy.

Risk of recurrent thromboembolic events in patients with focal cerebral ischemia and antiphospholipid antibodies. The Antiphospholipid Antibodies in Stroke Study Group

Antiphospholipid antibodies are a marker for an increased risk of thrombosis, including stroke and transient ischemic attacks. Prior studies suggest that patients with these antibodies and thrombosis may be at increased risk for recurrent thrombotic events. We prospectively evaluated 75 patients with antiphospholipid antibodies and cerebral or ocular ischemia for recurrence of thrombosis. Twenty-six patients (35%) experienced a recurrent stroke or transient ischemic attack, with a mean time to recurrence of 1.18 years. Hypertension significantly increased the risk of a recurrent transient ischemic attack. Patients with coronary artery disease were three times as likely as those without to have a recurrent stroke or transient ischemic attack. There was a trend for treatment with a combination of aspirin and dipyridamole to reduce the risk of recurrent thrombotic events after adjusting for sex and ethnicity.

Magnetic resonance spectroscopy in cerebral ischemia

Magnetic resonance spectroscopy (MRS) has been a fundamental and invaluable tool in the fields of chemistry and physics for over 40 years and has only been applied directly to the field of medicine in the last decade. MRS has contributed significant information on ischemic brain metabolism in the clinical patient. The potential of spectroscopy now extends to the diagnostic monitoring of metabolic change, in identifying markers of a therapeutic window, and establishing prognosis and outcome. This article presents a review of MRS studies of cerebral ischemia in clinical patients.

The role of antiphospholipid antibodies in stroke

Antiphospholipid antibodies may be found in about 10% of all subjects with acute stroke but probably are present in as many as 50% of young persons with stroke and perhaps even in high prevalence in persons who have coexisting rheumatologic diseases such as SLE. In these latter groups, the association may be as high as 50%. Probably the best related syndrome is Sneddon's syndrome, which has a high prediction to dementia. Furthermore, vascular dementia may be a prominent feature of the aPL syndrome in subjects under age 55. The cause and mechanism by which aPL are related to stroke remain unknown. Likewise, there is a dearth of information about prognosis, morbidity, and stroke recurrence in subjects who have these immunoglobulin markers. Thus therapy remains very problematic, but current strategies include the use of antiaggregate therapy, warfarin, and limited implementation with prednisone and plasmaphoresis. Data that demonstrate clear cut benefit of any of these therapies are lacking. Ultimately, unraveling these crucial problems concerning the aPL syndrome may provide great insight into certain stroke mechanisms.

Therapeutic considerations for stroke patients with antiphospholipid antibodies

A variety of therapeutic regimens including corticosteroids, immunosuppressants, antiplatelet agents, and anticoagulants have been prescribed to stroke patients with antiphospholipid antibodies. Although some of these medications may be useful in reducing the risk of recurrent thromboembolic events and deserve further investigation, studies published to date do not establish the effectiveness of any specific treatment. We conclude that a prospective study should be undertaken to assess the management of patients with antiphospholipid antibodies.

Distribution of 72-kDa heat-shock protein in rat brain after hyperthermia

The distribution of the 72-kDa heat-shock protein (hsp72) in rat brain, 24 h following in vivo transient hyperthermia (41.5 degrees C, 15 min), was studied using immunohistochemistry (n = 22). Tissue sections were also stained with hematoxylin and eosin, and with an anti-glial fibrillary acidic protein to evaluate neuronal and astrocytic response to transient hyperthermia, respectively. hsp72 was observed in glia and endothelial cells throughout brain. hsp72 was also found in neurons located in the: dentate gyrus, habenula, and hypothalamus, granular layer of the cerebellum and the olfactory area. Our data indicate, that hyperthermia causes neuronal expression of hsp72, particularly in cerebral neuronal populations which control the neuroendocrine stress response.

Hypothermia reduces 72-kDa heat-shock protein induction in rat brain after transient forebrain ischemia

BACKGROUND AND PURPOSE

We examined the influence of concurrent moderate hypothermia (30 degrees C) and transient forebrain ischemia on the induction of 72-kDa heat-shock protein and neuronal damage in male Wistar rats.

SUMMARY OF REPORT

Experimental groups included: normothermic with 8 minutes of transient forebrain ischemia (group 1, n = 7), hypothermic without ischemia (group 2, n = 9), and hypothermic (30 degrees C) with 8 minutes of transient forebrain ischemia (group 3, n = 5). Intense 72-kDa heat-shock protein immunoreactivity was demonstrated in rat forebrain 48 hours after induction of normothermic forebrain ischemia (group 1); it was not detected in the brain of animals subjected to hypothermia without ischemia (group 2), and hypothermia during ischemia (group 3) significantly inhibited its expression compared with that in normothermic ischemia animals (group 1).

CONCLUSIONS

These observations suggest that 72-kDa heat-shock protein induction is not the mechanism by which moderate hypothermia protects against ischemic cell damage.

Thrombolytic therapy in cerebrovascular disorders

The knowledge obtained from the ongoing investigational trials of tPA for acute ischemic stroke will not only help establish the appropriate dose range and complication rates but will also further develop the clearly mandatory rapid, aggressive team approach needed to truly treat acute ischemic strokes successfully. Experimental cerebral ischemia data have pointed to the need to treat acute clinical stroke within only a few hours or less to effectively reduce stroke morbidity and mortality. Specifically, with reversible MCA occlusion models of focal cerebral ischemia (dogs and cats), the animals uniformly survive without neurological deficit if the occlusion is for less than 2 to 3 hours. Similarly in primates, MCA occlusion for 3 hours or less will lead to clinical improvement and a decrease in infarct size, with complete recovery generally associated with less than 2 hours of MCA occlusion. Therefore, it appears unlikely that ischemic brain can be salvaged if vascular occlusion persists longer than 4 to 6 hours (similar to the pathophysiology of myocardial ischemia). Further, at least one third of ischemic stroke patients reperfuse spontaneously (and obviously too late) within 48 hours of stroke onset. Several factors believed to be related to successful outcome after thrombolytic therapy are summarized in Table 16. A schematic approach to determining the response to thrombolytic agents in acute ischemic stroke is outlined in Table 17. Zivin succinctly reviews thrombolysis for stroke, both experimental and clinical, and summarizes some of the difficulties of the early clinical stroke trials with thrombolytic agents and speculates about future prospects. He believes tPA may prove valuable in the treatment of some forms of thromboembolic stroke. Its usefulness may depend in part on how quickly the drug can be initiated and the risk of side effects; factors that will require further study. The currently used doses of tPA may be too low to lyse large cerebral arterial clots and, therefore, if current trials do not show a positive treatment response, further trials with higher doses may be indicated. The implications of a potentially effective treatment for truly acute stroke are enormous: stroke will need to be considered by all (lay public through to caregivers) as a true medical emergency, analogous to MI and trauma.(ABSTRACT TRUNCATED AT 400 WORDS)

Assessing the effects of antihypertensive medication on cerebral blood flow: demonstration in internal carotid artery occlusion

Dynamic cerebral blood flow (CBF) studies using acetazolamide or hypercapnia as a vasodilatory challenge have attempted to evaluate intracranial hemodynamics. We report two patients with asymptomatic internal carotid artery occlusion in whom the vasodilatory stimulus was a single oral dose of antihypertensive medication (prazosin hydrochloride or enalapril maleate). In both patients, changes in regional CBF occurred that were larger than those seen in nine normal controls. One patient experienced an improvement in regional CBF with a reduction in probe pair asymmetry. In the other patient, who had bilateral carotid artery disease, a decrease in regional CBF in all 16 probes (mean decrease 12 percent) and an accentuation of the predose asymmetry were observed. Both patients remained asymptomatic throughout the study. Assessing these effects on cerebral circulation may help identify patients at risk for iatrogenic focal cerebral ischemia and provide information regarding the functional status of the cerebral vasculature.