Showing papers on "Cerebral infarction published in 1999"
TL;DR: Intracerebral hemorrhage (ICH) is more than twice as common as subarachnoid hemorrhages (SAH) and is much more likely to result in death or major disability than cerebral infarction or SAH.
Abstract: Intracerebral hemorrhage (ICH) is more than twice as common as subarachnoid hemorrhage (SAH) and is much more likely to result in death or major disability than cerebral infarction or SAH.1 Although >315 randomized clinical therapeutic trials for acute ischemic stroke and 78 trials for SAH were complete or ongoing (oral communication, Cochrane Collaboration, May 16, 1995) as of 1995, only the results of 4 small randomized surgical trials (353 total patients)2 3 4 5 and 4 small medical trials (513 total patients)6 7 8 9 of ICH had been published. In these small randomized studies, neither surgical nor medical treatment has been shown conclusively to benefit patients with ICH.
Advancing age and hypertension are the most important risk factors for ICH.10 11 12 13 14 15 ICH occurs slightly more frequently among men than women and is significantly more common among young and middle-aged blacks than whites of similar ages.10 16 Reported incidence rates of ICH among Asian populations are also higher than those reported for whites in the United States and Europe. Pathophysiological change in small arteries and arterioles due to sustained hypertension is generally regarded as the most important cause of ICH.11 12 14 17 18 Cerebral amyloid angiopathy is increasingly recognized as a cause of lobar ICH in the elderly.19 20 21 22 23 Other causes of ICH include vascular malformations, ruptured aneurysms, coagulation disorders, use of anticoagulants and thrombolytic agents, hemorrhage into a cerebral infarct, bleeding into brain tumors, and drug abuse.10
Of the estimated 37 000 Americans who experienced an ICH in 1997, 35% to 52% were dead at 1 month; half of the deaths occurred within the first 2 days.1 17 24 Only 10% of patients were living independently at 1 month; 20% were independent …
872 citations
TL;DR: The age-adjusted incidence rate of stroke due to stenosis of the large cervicocephalic vessels is nearly 4 times higher for men than for women, and there is no association between preceding transient ischemic attack and stroke mechanism.
Abstract: Background and Purpose—There is scant population-based information on functional outcome, survival, and recurrence for ischemic stroke subtypes. Methods—We identified all residents of Rochester, Minnesota, with a first ischemic stroke from 1985 through 1989 using the resources of the Rochester Epidemiology Project medical records linkage system. After reviewing medical records and imaging studies, we assigned patients to 4 major ischemic stroke categories based on National Institute of Neurological Diseases and Stroke Data Bank criteria: large-vessel cervical or intracranial atherosclerosis with stenosis (ATH, n=74), cardioembolic (CE, n=132), lacunar (LAC, n=72), and infarct of uncertain cause (IUC, n=164). We used the Rankin disability score to assess functional outcome and the Kaplan-Meier product-limit method and Cox proportional hazards regression analysis with bootstrap validation to estimate rates and identify predictors of survival and recurrent stroke among these patients. Results—Rankin disabili...
669 citations
TL;DR: In this article, the authors investigated the cohort of a randomized trial of thrombolysis to assess the early and late clinical course associated with different subtypes of hemorrhagic infarction (HI) and parenchymal hematoma (PH) detected within the first 36 hours of an ischemic stroke.
Abstract: Background and Purpose—The clinical correlates of the varying degrees of early hemorrhagic transformation of a cerebral infarct are unclear. We investigated the cohort of a randomized trial of thrombolysis to assess the early and late clinical course associated with different subtypes of hemorrhagic infarction (HI) and parenchymal hematoma (PH) detected within the first 36 hours of an ischemic stroke. Methods—We exploited the database of the European Cooperative Acute Stroke Study I (ECASS I), a randomized, placebo-controlled, phase III trial of intravenous recombinant tissue plasminogen activator in acute ischemic stroke. Findings on 24- to 36- hour CT were classified into 5 categories: no hemorrhagic transformation, HI types 1 and 2, and PH types 1 and 2. We assessed the risk of concomitant neurological deterioration and of 3-month death and disability associated with subtypes of hemorrhagic transformation, as opposed to no bleeding. Risks were adjusted for age and extent of ischemic damage on baseline ...
656 citations
TL;DR: Recovery of aphasia in adults can occur rapidly and is concomitant with an activation pattern that changes from left to a homologous right hemispheric pattern, even when the stroke evolves to completion.
Abstract: Background and Purpose—This study was undertaken to correlate functional recovery from aphasia after acute stroke with the temporal evolution of the anatomic, physiological, and functional changes as measured by MRI. Methods—Blood oxygenation level–dependent contrast and echo-planar MRI were used to map language comprehension in 6 normal adults and in 2 adult patients during recovery from acute stroke presenting with aphasia. Perfusion, diffusion, sodium, and conventional anatomic MRI were used to follow physiological and structural changes. Results—The normal activation pattern for language comprehension showed activation predominately in left-sided Wernicke’s and Broca’s areas, with laterality ratios of 0.8 and 0.3, respectively. Recovery of the patient confirmed as having a completed stroke affecting Broca’s area occurred rapidly with a shift of activation to the homologous region in the right hemisphere within 3 days, with continued rightward lateralization over 6 months. In the second patient, in who...
364 citations
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TL;DR: Although osmotherapy reduces brain water, and is used to treat ischemic edema, its efficacy remains to be proven, as the molecular events become clearer, novel treatments that block different stages of the injury cascade will be available for clinical testing.
279 citations
TL;DR: There is considerable lack of agreement, even among experienced clinicians, in recognizing and quantifying early CT changes, and improved methods of recognizing andquantifying early ischemic brain damage are needed.
Abstract: Background and Purpose—Ischemic changes identified on CT scans performed in the first few hours after stroke onset, which are thought to possibly represent early cytotoxic edema and development of irreversible injury, may have important implications for subsequent treatment. However, insecurity and conflicting data exist over the ability of clinicians to correctly recognize and interpret these changes. We performed a detailed review of selected baseline CT scans from the NINDS rt-PA Stroke Trial to test agreement among experienced stroke specialists and other physicians on the presence of early CT ischemic changes. Methods—Seventy baseline CT scans from the NINDS Stroke Trial were read and classified for the presence or absence of various early findings of ischemia by 16 individuals, including NINDS trial investigators, other neurologists, other emergency medicine physicians, and radiology or stroke fellows. CT scans included normal scans and scans from patients who later developed symptomatic intracrania...
278 citations
TL;DR: Early MRI and EEG can help to identify the infants with cerebral infarction who are likely to develop hemiplegia, and the concomitant involvement of hemisphere, internal capsule and basal ganglia was always associated with an abnormal outcome.
Abstract: Objective. The aim of this study was to identify prognostic factors in newborns with cerebral infarction. Design. Antenatal and perinatal factors and early clinical, electroencephalogram (EEG), and magnetic resonance imaging (MRI) findings were compared with neurodevelopmental outcome in 24 children with evidence of cerebral infarction on neonatal MRI. Results. Out of 24 infants, 19 had an infarction in the territory of a major cerebral vessel and 5 in the borderzone between cerebral arteries. Neuromotor outcome was normal in 17 and abnormal in 7 infants. Of these 7 infants, 5 infants showed a definite hemiplegia, whereas the other 2 showed some asymmetry of tone or function but no definite hemiplegia. None of the adverse antenatal or perinatal factors was significantly associated with abnormal outcome. Neonatal clinical examination was also not always predictive of the outcome. The extent of the lesion on MRI was a better predictor. In particular, it was the concomitant involvement of hemisphere, internal capsule and basal ganglia that was always associated with an abnormal outcome whereas the involvement of only one or two of the three tended to be associated with a normal outcome. EEG was also very helpful. Abnormal background activity either unilateral or bilateral was found in 6 infants and 5 out of 6 developed hemiplegia. In contrast, the presence of seizure activity in presence of a normal background was not related to abnormal outcome. Conclusions. Early MRI and EEG can help to identify the infants with cerebral infarction who are likely to develop hemiplegia.
270 citations
TL;DR: The risk factor profiles of stroke subtypes differ, reflecting different etiopathology, and reducing atherosclerotic diseases, including ischemic stroke, by lowering high serum cholesterol is one of the main targets in public health care.
Abstract: Background and Purpose—Blood pressure is an important risk factor for stroke, but the roles of serum total and HDL cholesterol, α-tocopherol, and β-carotene are poorly established. We studied these factors in relation to stroke subtypes. Methods—Male smokers (n=28 519) aged 50 to 69 years without a history of stroke participated in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study, a controlled trial to test the effect of α-tocopherol and β-carotene supplementation on cancer. From 1985 to 1993, a total of 1057 men suffered from primary stroke: 85 had subarachnoid hemorrhage; 112, intracerebral hemorrhage; 807, cerebral infarction; and 53, unspecified stroke. Results—Systolic blood pressure ≥160 mm Hg increased the risk of all stroke subtypes 2.5 to 4-fold. Serum total cholesterol was inversely associated with the risk of intracerebral hemorrhage, whereas the risk of cerebral infarction was raised at concentrations ≥7.0 mmol/L. The risks of subarachnoid hemorrhage and cerebral infarction w...
261 citations
TL;DR: Subacute CT infarct volume correlates moderately with 3-month clinical outcome as assessed by widely used neurological and functional assessment scales, and constrains the use of infarCT volume as a surrogate end point in ischemic stroke clinical trials.
Abstract: Background and Purpose —Reduction in infarct volume is the standard measure of therapeutic success in animal stroke models. Reduction in infarct volume has been advocated as a biological surrogate or auxiliary outcome measure for human stroke clinical trials to replace or supplement deficit, disability, and global clinical scales. However, few studies have investigated correlations between infarct volume and clinical end points in acute ischemic stroke patients.
Methods —CT scans at days 6 to 11 were acquired prospectively in 191 fully eligible patients enrolled in the Randomized Trial of Tirilazad Mesylate in Patients With Acute Stroke (RANTTAS). Patients were enrolled within 6 hours of onset of stroke in any vessel distribution. Infarct volume was measured by operator-assisted computerized planimetry.
Results —One hundred thirty-two patients had visible new supratentorial infarcts, with median infarct volume of 28.0 cm3 (interquartile range, 9.0 to 93.0 cm3). Fifty-nine patients had no visible new infarct. Correlations with standard 3-month outcome scales and mortality were as follows: Barthel Index, r =0.43; Glasgow Outcome Scale, r =0.53; National Institutes of Health Stroke Scale, r =0.54; mortality, r =0.31. For visible infarcts alone, correlations were as follows: BI, r =0.46; GOS, r =0.59; NIHSS, r =0.56; mortality, r =0.32.
Conclusions —Subacute CT infarct volume correlates moderately with 3-month clinical outcome as assessed by widely used neurological and functional assessment scales. The modesty of this linkage constrains the use of infarct volume as a surrogate end point in ischemic stroke clinical trials.
230 citations
TL;DR: The increased SI of subacute cerebral infarction on DW images reflects not only a shortening of ADC but a prolongation of T2 and spin-density values.
Abstract: PURPOSE: To quantify the relative contributions of spin density and T2 effects (“shine through”) on diffusion-weighted (DW) magnetic resonance (MR) images of acute and subacute cerebral infarction. MATERIALS AND METHODS: In 30 patients, 1.5-T imaging was performed within the first 7 days after onset of cerebral infarction. Estimates of T2, spin density, and apparent diffusion coefficient (ADC) in the region of stroke and contralateral normal brain were computed by means of standard regression techniques after quadruple-echo conventional MR imaging and single-shot echo-planar DW imaging with a maximum b value of 1,000 sec/mm2. Expected signal intensity (SI) enhancement ratios resulting from independent changes in T2, spin density, and ADC were then calculated for the DW sequence. RESULTS: The overall SI of cerebral infarction on DW images was significantly higher than that of normal brain throughout the 1st week after stroke (mean relative SI enhancement ratio, 2.29; P < .001). During the first 2 days afte...
228 citations
TL;DR: Surgical closure of PFO can be performed with minimal morbidity and mortality and may decrease the risk of recurrent stroke or TIA and may avoid lifelong anticoagulation in the young adult if there is no other indication.
Abstract: Background—The role of surgical closure of patent foramen ovale (PFO) for cerebral infarction (CI) or transient ischemic attack (TIA) resulting from paradoxical embolism is unclear, and its effect on recurrence is unknown. Our objective was to determine the outcome of surgical closure of PFO in patients with a prior ischemic neurological event, define the rate of CI or TIA recurrence after PFO closure, and identify risk factors for these recurrences. Methods and Results—We retrospectively analyzed 91 patients (58 men, 33 women) with ≥1 previous cerebrovascular ischemic events who underwent surgical PFO closure between April 1982 and March 1998. The presence of a PFO with a right-to-left shunt was confirmed with transesophageal echocardiography. Mean age was 44.2±12.2 years. The index event was a CI in 59 and a TIA in 32; a Valsalva-like episode preceded the event in 15 patients. Deep venous thrombosis was documented in 9 patients, and a hypercoagulable state was identified in 10. Surgical closure was perf...
TL;DR: Cerebral blood flow was measured in 20 patients with acute middle cerebral artery occlusion between 60 and 360 minutes after stroke onset andrete and confluent areas of CBF ≤20 cm3 · 100 g−1 · min−1 were identified in all patients.
Abstract: Background and Purpose—The ischemic core and penumbra have not been thoroughly characterized after acute cerebral thromboembolic occlusion in humans. Differentiation between areas of potentially viable and irreversibly injured ischemic tissue may facilitate assessment and treatment of stroke patients. Methods—Cerebral blood flow (CBF) was measured in 20 patients with acute middle cerebral artery (MCA) occlusion between 60 and 360 minutes after stroke onset, with the stable xenon computerized tomography (CT) technique. Threshold displays were generated at a single level, and the percentages of hemisphere with CBF ≤6, ≤10, 11 to 20, 21 to 30, and >30 cm3 · 100 g−1 · min−1 were measured. The corresponding images on 12 available follow-up CT scans were similarly assessed to determine the area of final infarct. Comparisons were analyzed with a paired Student’s t test and Pearson’s correlation coefficient. Results—Discrete and confluent areas of CBF ≤20 cm3 · 100 g−1 · min−1 were identified in all patients, ips...
TL;DR: Patients with recurrent stroke have, on average, poorer outcomes than those with first stroke, and clinical policy analyses should use different estimates of health and cost outcomes for first and recurrent stroke.
Abstract: Background and Purpose —Because recurrent strokes will tend to leave patients with greater disability than first strokes, patients with recurrent strokes should have poorer outcomes on average than those with first strokes. The extent of this difference has, however, not yet been estimated with precision.
Methods —Using a random 20% sample of Medicare patients aged 65 years and older admitted with a primary diagnosis of cerebral infarction during calendar year 1991, we used historical data from the previous 4 years to classify patients as having either first or recurrent stroke and followed survival and direct medical costs for 24 months after stroke. First and recurrent stroke groups were compared with the log-rank test (survival) and t test (cost) and also multivariate modeling.
Results —Survival from first stroke is consistently better than that for recurrent stroke: 24-month survival was 56.7% versus 48.3%, respectively. Costs were similar for the initial hospital stay and in months 1 to 3 after stroke. During months 4 to 24 after stroke, total costs were higher among those with recurrent stroke by approximately $375/mo across all patients, with this difference being greatest for younger patients and least for patients aged 80 years or older. Most of the difference in total monthly cost was attributable to nursing home utilization (averaging approximately $150/mo) and acute hospitalization (averaging approximately $120/mo).
Conclusions —Patients with recurrent stroke have, on average, poorer outcomes than those with first stroke. To be as accurate as possible, clinical policy analyses should use different estimates of health and cost outcomes for first and recurrent stroke.
TL;DR: For instance, this paper found that MRI infarcts, ventricular and sulcal widening, and white matter score were strongly associated with carotid intimal-medial thickness (IMT) and stenosis degree after adjustment for age and sex.
Abstract: Cerebral magnetic resonance imaging (MRI) has demonstrated a high prevalence of infarct-like lesions, white matter hyperintensities, and evidence of cerebral atrophy in older adults. While these findings are generally believed to be related to ischemia and atherosclerosis, their relationship to atherosclerosis in the carotid arteries remains to be explored. Study subjects were part of the multicenter Cardiovascular Health Study, a cross-sectional study of 3502 women and men >/=65 years of age undergoing cranial MRI and carotid ultrasonography. MRI infarcts were detected in 1068 participants (29.3%) and measurable carotid plaque in 2745 (75.3%). MRI infarcts, ventricular and sulcal widening, and white matter score were strongly associated with carotid intimal-medial thickness (IMT) and stenosis degree after adjustment for age and sex (all P<0. 01). Associations with plaque characteristics were less strong and less consistent; MRI infarcts were weakly associated only with surface irregularity, and ventricular size was weakly associated only with lesion density (both P<0.04). In contrast, sulcal widening was strongly related to plaque characteristics, with scores being higher in those with heterogeneous and irregular plaque (both P<0. 009). Adjustment for other risk factors, and for carotid IMT/stenosis, removed associations of MRI findings with plaque characteristics except for weak relationships remaining between MRI infarcts and surface irregularity and between sulcal score and heterogeneous plaque (both P<0.03). MRI abnormalities show strong and consistent relationships with increasing carotid IMT and stenosis degree but less strong associations with plaque characteristics, especially after adjusting for IMT and stenosis.
TL;DR: The anatomic and functional configuration of the CW reflects the degree of ICA obstruction, and patients with severe ICA stenosis did not show significantly increased CW vessel diameters.
Abstract: Background and Purpose—The circle of Willis (CW) is considered an important collateral pathway in maintaining adequate cerebral blood flow in patients with internal carotid artery (ICA) obstruction. We aimed to investigate the anatomic variation of the CW in patients with severe symptomatic carotid obstructive disease and to analyze diameter changes of its components in relation to varying grades of ICA obstruction and in relation to the presence or absence of (retrograde) collateral flow. Methods—Seventy-five patients with minor disabling neurological deficits and with ICA stenoses or occlusions were categorized into 4 groups according to the severity of ICA obstruction. This patient population reflected a relatively favorable subgroup of cerebral infarction (considering their minor neurological deficits). All subjects underwent magnetic resonance angiography, including magnetic resonance angiography sensitive to flow direction. CW morphology and the size of its components were determined and compared wi...
TL;DR: Observations provide evidence that iNOS is expressed in the human brain after ischemic infarction and support the hypothesis thatiNOS inhibitors may be useful in the treatment of isChemic stroke in humans.
Abstract: The inducible or “immunological” isoform of nitric oxide synthase (iNOS) is induced in many cell types by inflammatory stimuli and synthesizes toxic amounts of NO. In rodent models of focal cerebral ischemia, iNOS is expressed in neutrophils invading the injured brain and in local blood vessels. Studies with iNOS inhibitors and iNOS null mice indicate that NO produced by iNOS contributes to ischemic brain injury. In the present study, we sought to determine whether iNOS is also expressed in the human brain after ischemic stroke. Studies were conducted using immunohistochemistry on autopsy brains with neuropathological evidence of acute cerebral infarction. iNOS immunoreactivity was observed in neutrophils infiltrating the ischemic brain and in blood vessels within the ischemic territory. iNOS-positive cells also were immunoreactive for nitrotyrosine, reflecting protein nitration by NO-derived peroxynitrite and nitrites. iNOS or nitrotyrosine immunoreactivity was not detected outside the region of the infarct. These observations provide evidence that iNOS is expressed in the human brain after ischemic infarction and support the hypothesis that iNOS inhibitors may be useful in the treatment of ischemic stroke in humans.
TL;DR: Almost 1 of every 6 patients presenting with a classic lacunar syndrome has multiple infarctions demonstrated on diffusion-weighted imaging (DWI), which usually indicates an identifiable cause of stroke and therefore may influence clinical decisions regarding the extent of etiologic investigations and treatment for secondary prevention.
Abstract: Background and Purpose —Small infarcts in the territory of penetrator arteries were described as causing a number of distinct clinical syndromes. The vascular pathophysiology underlying such infarcts is difficult to ascertain without careful pathological study. However, the occurrence of multiple, small infarcts, linked closely in time but dispersed widely in the brain, raises the possibility of an embolic mechanism. The current study determines the frequency and clinical characteristics of patients with well-defined lacunar syndromes and the diffusion-weighted imaging (DWI) evidence of multiple acute lesions.
Methods —Sixty-two consecutive patients who presented to the emergency room with a clinically well-defined lacunar syndrome were studied by DWI within the first 3 days of admission.
Results —DWI showed multiple regions of increased signal intensity in 10 patients (16%). A hemispheric or brain stem lesion in a penetrator territory that accounted for the clinical syndrome (“index lesion”) was found in all. DWI-hyperintense lesions other than the index lesion (“subsidiary infarctions”) were punctate and lay within leptomeningeal artery territories in the majority. As opposed to patients with a single lacunar infarction, patients with a subsidiary infarction more frequently ( P <0.05) harbored an identifiable cause of stroke.
Conclusions —Almost 1 of every 6 patients presenting with a classic lacunar syndrome has multiple infarctions demonstrated on DWI. This DWI finding usually indicates an identifiable cause of stroke and therefore may influence clinical decisions regarding the extent of etiologic investigations and treatment for secondary prevention.
TL;DR: Evidence is provided that progressive treadmill aerobic exercise training improves volitional torque and torque/time generation and reduces reflexive torque/ time production in the hemiparetic limb.
Abstract: Background and Purpose—Despite the belief that after cerebral infarction only limited functional gains are possible beyond the subacute period, we tested the hypothesis that a 12-week program of “t...
Journal Article•
TL;DR: VEGF, which is important in angiogenesis, may also influence long term neuronal survival, and possibly its modulation may prove to be of therapeutic value for patients with ischemic stroke.
TL;DR: LI and DWML are epiphenomena that may morphologically characterize cerebral microangiopathy but do not in themselves indicate cognitive impairment.
Abstract: Background and Purpose —Cerebral microangiopathy, indicated on MRI by lacunar infarctions (LI) and deep white matter lesions (DWML), is said to lead to vascular dementia.
Methods —Fifty-seven patients with proven cerebral microangiopathy were assessed for changes in regional cerebral blood flow (rCBF) and glucose metabolism (rMRGlu) and compared with 19 age-matched controls. The findings were correlated with results of extensive neuropsychological testing, as well as with MRI findings. A special head holder ensured reproducibility of positioning during rCBF (single-photon emission CT [SPECT]), rMRGlu (positron emission tomography [PET]), and MR imaging. White matter and cortex were quantified with regions of interest defined on MRI and superimposed to corresponding PET/SPECT slices. LI and DWML were graded by number and extent.
Results —Even with severe DWML and multiple LI, rCBF and rMRGlu values were not reduced. ANOVAs identified brain atrophy and neuropsychological deficits as the main determinants for reduced rCBF and rMRGlu values in both cortex and white matter. Neuropsychological deficits correlated well with decreased rCBF and rMRGlu, whereas MRI patterns such as LI and DWML did not. Factor analysis revealed no correlation of LI and DWML with rCBF, rMRGlu, atrophy, and neuropsychological deficits, showing instead positive correlations between rCBF, rMRGlu, and neuropsychological performance and negative correlations of the latter 3 with brain atrophy.
Conclusions —From these data, we conclude that LI and DWML are epiphenomena that may morphologically characterize cerebral microangiopathy but do not in themselves indicate cognitive impairment. Dementia or neuropsychological deficits, by contrast, are reflected exclusively by functional imaging parameters (rCBF, rMRGlu) and cerebral atrophy.
TL;DR: The results of this case‐control study show a significant statistical link between idiopathic arterial ischemic strokes in children and varicella‐zoster virus infection.
Abstract: The results of this case-control study show a significant statistical link between idiopathic arterial ischemic strokes in children and varicella-zoster virus infection.
TL;DR: The data indicate that iv administration of progesterone at a dose of 8 mg/kg significantly reduces the volume of cerebral infarction and significantly improves outcome on the array of functional measures employed.
TL;DR: Cardiovascular complications, especially stroke and proteinuria, were common in patients with primary aldosteronism, andproteinuria might be an indicator for stroke as target-organ damage.
TL;DR: The partial sparing of the inferior vestibular labyrinth may indicate a decreased vulnerability to ischemia because of its better collateral blood supply and a transient period of reduced perfusion of the internal auditory artery.
Abstract: Objective: To study the pathophysiology of labyrinthine infarction. Background: The syndrome of sudden onset vertigo or hearing loss is commonly attributed to inner ear vascular disease, yet histologic studies of isolated labyrinthine infarction in humans have been rare and have not included a complete examination of the vertebrobasilar vascular system. Methods: Temporal bones, brainstem, cerebellum, and the supplying blood vessels were subjected to gross and microscopic postmortem examinations in a 92-year-old woman who had a sudden onset of vertigo and hearing loss in the right ear 7 years before death. Results: There were prominent atherosclerotic changes at the vertebrobasilar junction, but the internal auditory artery and its branches were patent on both sides. Histologic studies showed degenerative changes in the cochlea and vestibular labyrinth on the right. The posterior canal ampulla and saccular macule were relatively preserved showing partial areas of intact sensory epithelium with underlying nerve fibers. The right vestibulocochlear nerve showed a fibrotic scar and multiple patchy areas of degeneration. These findings are most consistent with a transient period of reduced perfusion of the internal auditory artery. Conclusion: The partial sparing of the inferior vestibular labyrinth may indicate a decreased vulnerability to ischemia because of its better collateral blood supply.
TL;DR: It is suggested that iNOS activation contributes to tissue damage and that selective inhibitors of this isoform may be of interest for the treatment of stroke.
Abstract: 1. The aim of this study was to investigate the effect of N-(3-(aminomethyl)benzyl)acetamidine (1400W), a selective inhibitor of inducible calcium-independent nitric oxide synthase (iNOS), on the functional and histopathological outcomes of experimental transient focal cerebral ischaemia in rats. 2. Transient ischaemia was produced by the occlusion for 2 h of both the left middle cerebral artery and common carotid artery. Treatments with 1400W (20 mg kg(-1)) or vehicle were started 18 h after occlusion of the arteries and consisted in seven subcutaneous injections at 8 h interval. Ischaemic outcomes and NOS activities (constitutive and calcium-independent NOS) were evaluated 3 days after ischaemia. 3. 1400W significantly reduced ischaemic lesion volume by 31%, and attenuated weight loss and neurological dysfunction. 4. 1400W attenuated the calcium-independent NOS activity in the infarct by 36% without affecting the constitutive NOS activity. 5. These findings suggest that iNOS activation contributes to tissue damage and that selective inhibitors of this isoform may be of interest for the treatment of stroke.
TL;DR: The validity of stroke diagnosis was good in registers of hospital diagnoses and causes of death justifying their use for endpoint assessment in epidemiological studies.
Abstract: The validity of stroke diagnosis in the National Hospital Discharge Register and the Register of Causes of Death was examined among 546 middle-aged men in Finland. The subjects were cases of cerebrovascular diseases of the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and identified by record linkage to the registers. In all, 375 events with cerebrovascular disease as hospital discharge diagnosis and 218 events with cerebrovascular disease as the underlying cause of death were reviewed using specific criteria modified from the classifications of the National Survey of Stroke and the WHO MONICA Study. For hospital stroke diagnoses, there was agreement on diagnosis for all strokes in 90%, for subarachnoid hemorrhage in 79%, intracerebral hemorrhage in 82%, and cerebral infarction in 90%. The respective agreement rates for stroke as the underlying cause of death were 97%, 95%, 91%, and 92%. The data were insufficient for review in 1% and 3% of the stroke events, respectively. Age, observation year and trial supplementation with alphatocopherol or beta-carotene had no effect on validity. In conclusion, the validity of stroke diagnosis was good in registers of hospital diagnoses and causes of death justifying their use for endpoint assessment in epidemiological studies.
TL;DR: The major advantages of the improved intraluminal MCAo model reported here, incorporating sutures coated with poly-l-lysine, include a 100% incidence of infarction of predictable location and size in mice having an initial neurological deficit.
TL;DR: Pretreatment SPECT can provide useful parameters to increase the efficacy of thrombolysis by reducing hemorrhagic complications and improving neurologic outcome and CBF parameters were significant among the three patient groups and three types of ischemic lesions.
Abstract: This study investigates retrospectively, in selected patients, the ischemic outcome (reversible ischemia, infarction, and hemorrhage) and neurologic outcome of acute stroke treated with intra-arterial thrombolysis and the predictive value of pretreatment single-photon emission-computed tomography (SPECT). Thirty patients with complete recanalization within 12 hours were analyzed. The extent of ischemia was outlined on SPECT, and two CBF parameters were calculated: the ratio of ischemic regional activity to CBF in the cerebellum and the asymmetry index. Reversible ischemia, infarction, and hemorrhage were identified by comparing SPECT and follow-up computed tomography. Nine patients (30%) had no or small infarction, 14 (47%) had medium or large infarction, and seven (23%) had hemorrhage. Forty-two lesions were identified (22 reversible ischemia, 13 infarction, and 7 hemorrhage). Duration of ischemia, urokinase dose, disease type, and occlusion site were nonsignificant factors, whereas neurologic outcome and CBF parameters were significant among the three patient groups and three types of ischemic lesions. Ischemic tissue with CBF greater than 55% of cerebellar flow still may be salvageable, even with treatment initiated 6 hours after onset of symptoms. Ischemic tissue with CBF greater than 35% of cerebellar flow still may be salvageable with early treatment (less than 5 hours). Ischemic tissue with with CBF less than 35% of cerebellar flow may be at risk for hemorrhage within the critical time window. Pretreatment SPECT can provide useful parameters to increase the efficacy of thrombolysis by reducing hemorrhagic complications and improving neurologic outcome.
TL;DR: Results indicate that early critical flow disturbance leading to rapid cell damage is the predominant cause of infarction, while secondary and delayed pathobiochemical processes in borderline or initially sufficiently perfused regions contribute only little to the final infarct, Therefore, emerging therapeutic strategies should be targeted to the initially critically perfused tissue subcompartments.
Abstract: Background—The efficiency of various strategies of neuroprotection is well documented in animal experiments but is thus far disappointing in ischemic stroke, for which only early reperfusion induced by thrombolysis has improved clinical outcome. This discrepancy between expectation from experimental research and clinical reality may be related to differences in the pathogenetic factors contributing to infarction. Summary of Comment—Positron emission tomography cerebral blood flow studies within 3 hours of onset were used to identify the various compartments of the infarct outlined on MRI 2 to 3 weeks after a hemispheric stroke in 10 patients. Critical hypoperfusion below the viability threshold accounted for the largest proportion (mean, 70%) of the final infarct, whereas penumbral tissue (18%) and initially sufficiently perfused tissue (12%) were responsible for considerably smaller portions of the final infarct. Conclusions—These results indicate that early critical flow disturbance leading to rapid cel...
TL;DR: The clinical and pathological features of recent, symptomatic internal carotid artery occlusion are described to examine the pathogenetic role of plaque instability at both extracranial and intracranial sites.
Abstract: Background and Purpose—It is now widely accepted that thrombotic coronary artery occlusion usually follows rupture of an unstable atherosclerotic plaque. The significance of such instability in arteries supplying the brain is less well appreciated. We therefore describe the clinical and pathological features of recent, symptomatic internal carotid artery occlusion to examine the pathogenetic role of plaque instability at both extracranial and intracranial sites. Methods—Cases were selected from a consecutive series of 188 adult neuropathology autopsies. In 90 of these, the principal neuropathological abnormality was cerebral infarction, in 14 cases due to recent occlusion of 1 or more segments of the internal carotid artery. In each case, a full systemic, cardiovascular, and neuropathological autopsy was performed. Plaque instability was assessed by the presence or absence of a large, necrotic, lipid core; a thin, fibrous cap; and superficial inflammation. Results—Of the 14 cases, 3 showed extracranial (c...