bluuebunny/crossref_metadata_2025 huggingface dataset:
Cerebral venous thrombosis in systemic lupus erythematosus.
Authors: Vidailhet M , Piette J C , Wechsler B , Bousser M G , Brunet P
Published: June 2011

We describe six cases of cerebral venous thrombosis in patients with systemic lupus erythematosus. In one patient, cerebral venous thrombosis was the initial manifestation of lupus; in the five others, it occurred 1-33 years after the diagnosis of lupus. The main clinical features of cerebral venous thrombosis were persistent headache in all six patients, focal symptoms in four, and seizures in three; papilledema was present in only one patient. Cerebral venous thrombosis was diagnosed based on angiography or magnetic resonance imaging. Both the transverse (in five patients) and the superior sagittal (in three) sinuses were involved. Extracranial arterial and/or venous thrombosis were present in three patients, abortion in two, thrombocytopenia in four, and lupus anticoagulant in three. The neurologic symptoms resolved rapidly in five patients treated with steroids and heparin. Cerebral venous thrombosis should be suspected in patients with lupus who complain of persistent headache, especially in the presence of neurologic symptoms.
Hemodilution and hypertension effects on cerebral hemorrhage in cerebral ischemia in rats.
Authors: Cole D J , Drummond J C , Ruta T S , Peckham N H
Published: June 2011

We determined the effect of hemodilution and hypertension on cerebral hemorrhage and brain injury in 32 rats subjected to 180 minutes of middle cerebral artery occlusion and 120 minutes of reperfusion. We divided the rats into four groups. In the control group (n = 8) neither hematocrit nor blood pressure was manipulated during occlusion, in the hemodilution group (n = 8) 5% albumin was administered to maintain a hematocrit of 30% during occlusion, in the hypertension group (n = 8) mean arterial blood pressure was increased to 30 mm Hg above baseline during occlusion with phenylephrine, and in the hemodilution/hypertension group (n = 8) albumin and phenylephrine were employed simultaneously during occlusion. We assessed the amount of cerebral hemorrhage (as concentration of extravasated hemoglobin) spectrophotometrically and the extent of ischemic injury (as percentage of the hemisphere with deficient staining) histochemically using 2,3,5-triphenyltetrazolium chloride. Mean +/- SD hemoglobin concentration in the hemisphere ipsilateral to the occlusion in the hemodilution/hypertension group (71 +/- 14 micrograms/g brain tissue) was significantly (p less than 0.05) greater than that in the hemodilution and hypertension groups (25 +/- 5 and 29 +/- 7 micrograms/g, respectively), hemoglobin concentrations in these two groups were in turn significantly (p less than 0.05) greater than that in the control group (2 +/- 3 micrograms/g). Mean +/- SD percentage of the ipsilateral hemisphere with deficient staining was significantly (p less than 0.05) less in the hypertension and hemodilution hypertension groups (8 +/- 3% and 11 +/- 6%, respectively) than in the control and hemodilution groups (26 +/- 8% and 26 +/- 7%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
The Willis lecture: transient ischemic attacks, scientific method, and new realities.
Authors: Toole J F
Published: June 2011

First described by Thomas Willis in 1679 and defined in the 1950s, transient ischemic attack is universally agreed to be an episode of focal neurologic deficit in a vascular distribution, sudden in onset and resolving without residual deficit in less than or equal to 24 hours. Transient ischemic attack is diagnosed by characteristic history and absence of residua on neurologic examination. After these criteria had been accepted, regional cerebral blood flow and computed cranial tomography in the 1970s, later positron emission tomography, and even more recently, magnetic resonance imaging reveal prolonged pathophysiologic and metabolic disturbances even in persons with all the definitional characteristics of transient ischemic attack. These persistent abnormalities necessitate reexamination of the validity of the concept of transient ischemic attack. Furthermore, our group suspects that transient ischemic attack is probably only a marker, and not itself the risk factor, for the cerebral infarction which frequently follows transient ischemic attack. Additionally, the surprising frequency with which cerebral infarction, unrecognized by patient or physician, is revealed using neuroimaging techniques has created a need to redefine the categories heretofore used for diagnosis and assessment of therapy and prognosis for transient ischemic attack and cerebral infarction.
Tolerance of low cerebral intracellular pH in rats during hyperbaric hypercapnia.
Authors: Xu Y , Cohen Y , Litt L , Chang L H , James T L
Published: June 2011

Brain acidosis from cerebral ischemia is characterized by average intracellular pH levels of approximately 5.8-6.2, which appear in turn to worsen cellular injury. We report that the brain is not injured when hypercapnia is used to reduce intracellular pH to about 6.2 during adequate oxygenation. A hyperbaric chamber is needed to achieve intracellular pH values so low because inspired CO2 tensions must be increased to approximately 1 atm.

Using in vivo phosphorus-31 and proton nuclear magnetic resonance spectroscopy, we measured brain intracellular pH and lactate concentration of rats inside a nonmagnetic polycarbonate chamber at a barometric pressure of 1,500 mm Hg. Intubated rats were ventilated with a 50% O2/50% CO2 gas mixture for specific times. All six rats ventilated for 15 minutes with CO2 tensions of approximately 750 mm Hg woke up without neurological impairment, despite a decrease in intracellular pH to about 6.2. Higher CO2 tensions and longer exposures resulted in cardiovascular collapse and sudden death, followed by the postmortem appearance of brain lactate.

Brain intracellular pH values near 6.2 can be induced briefly in vivo in ventilated rats without injury under hyperbaric hypercapnic conditions. If attempts are made to lower brain pH in vivo even further by increasing PCO2 beyond 750 mm Hg, mean arterial blood pressure and cerebral blood flow decrease to values incompatible with life.
Selection process for surgeons in the Asymptomatic Carotid Atherosclerosis Study.
Authors: Moore W S , Vescera C L , Robertson J T , Baker W H , Howard V J , Toole J F
Published: June 2011

The Asymptomatic Carotid Atherosclerosis Study is a prospective, multicenter, randomized clinical trial of carotid endarterectomy for the treatment of asymptomatic hemodynamically significant stenosis. This report describes the selection process for participating surgeons in the trial.

The Surgical Management Committee established guidelines for minimal annual experience and maximum neurological morbidity and mortality for surgeons to qualify to participate in the study. For approval, a surgeon must perform at least 12 carotid endarterectomies per year. Based on a review of the surgeon's last 50 consecutive endarterectomies, the combined neurological morbidity and mortality rate must be no greater than 5% for all indications and no greater than 3% for endarterectomies performed on asymptomatic patients.

One hundred sixty-four surgeons from 48 centers applied for approval: 117 were approved, 17 were rejected, and 30 were not reviewed. The 117 approved surgeons submitted a total of 5,641 endarterectomies with a combined mortality and neurological morbidity rate of 2.3% for the variety of indications for operation.

This overall experience with carotid endarterectomy is one of the largest series reported to date. The data from approved surgeons are well within the range of acceptable neurological morbidity and mortality rates recommended by the Stroke Council of the American Heart Association, which attests to the overall quality of the surgeons participating in the study.
Cerebral vasculitis associated with cocaine abuse.
Authors: Fredericks R K , Lefkowitz D S , Challa V R , Troost B T
Published: June 2011

Earlier reports of cocaine-associated cerebral vasculitis have been based primarily on angiographic findings without pathological verification.

We present a case of acute encephalopathy following intravenous and intranasal administration of cocaine. Brain biopsy revealed vascular changes involving primarily small arteries. Findings included lymphocytic infiltration, endothelial thickening, and deposition of proteinaceous amorphous material within and around vessel walls.

These abnormalities are consistent with pathological features of arteritis previously reported in association with amphetamine and multiple-drug abuse. Vasospasm-induced changes are an alternative explanation for the vascular picture seen in this case. The patient made modest improvement with high-dose intravenous steroids.
Changes in middle cerebral artery blood velocity in uremic patients after hemodialysis.
Authors: Postiglione A , Faccenda F , Gallotta G , Rubba P , Federico S
Published: June 2011

Strokes are a frequent complication in uremic patients on dialysis. We wanted to evaluate the effect of this treatment on cerebral hemodynamic parameters, particularly those of patients with carotid stenosis, who are at higher risk for atherothrombotic ischemic events.

We used transcranial Doppler ultrasonography to evaluate blood velocity of the middle cerebral artery in 18 uremic patients before and after hemodialysis. Carotid stenosis was evaluated by echo-Doppler investigation. Six patients were also studied before and after recombinant human erythropoietin treatment.

Dialysis treatment decreased mean blood velocity in all patients (p less than 0.001). Eight of 18 patients (44%) with mild (16-50%), moderate (51-80%), or severe (greater than 80%) carotid stenosis had lower velocity than patients with normal carotid arteries (p less than 0.01), and they experienced a further decrease to even lower levels after hemodialysis (p less than 0.05). In patients treated with recombinant human erythropoietin, hematocrit increased from 28 +/- 8% to 37 +/- 5% (p less than 0.001), and blood velocity had a further decrease by 11%. All changes were associated with modifications toward normality of pH, PaCO2, and hematocrit.

Transcranial Doppler ultrasonography represents a useful method for monitoring cerebral circulation of uremic patients, especially of those at possible risk for ischemia.
Surgical risk of hemorrhage in cerebral amyloid angiopathy.
Authors: Matkovic Z , Davis S , Gonzales M , Kalnins R , Masters C L
Published: June 2011

Cerebral amyloid angiopathy is increasingly recognized as a cause of lobar cerebral hemorrhage in normotensive elderly individuals. Isolated reports have suggested that neurosurgical intervention entails a high risk of precipitated hemorrhage. We identified 16 pathologically confirmed cases of cerebral amyloid angiopathy. Fourteen of these patients presented with lobar cerebral hemorrhage. Fifteen neurosurgical procedures in eight patients included eight clot evacuations, three abscess drainage procedures, two ventriculoperitoneal shunts, one biopsy, and one lobectomy. Recurrent postoperative cerebral hemorrhage was seen in four patients at 2 days, 9 days, 6 weeks, and 10 months, but surgery was thought to have precipitated the cerebral hemorrhage in only one patient. Recurrent cerebral hemorrhage also was seen in two of the eight nonoperated cases. Recurrent cerebral hemorrhage is characteristic of cerebral amyloid angiopathy, but we conclude that neurosurgical intervention, particularly evacuation of hematomas, is not associated with major risk of precipitated hemorrhage.
Suprasellar and intraventricular blood predict elevated plasma atrial natriuretic factor in subarachnoid hemorrhage.
Authors: Diringer M N , Lim J S , Kirsch J R , Hanley D F
Published: June 2011

Following subarachnoid hemorrhage, the plasma concentration of atrial natriuretic factor is elevated and appears to be independent of atrial stretch. While the hypothalamus and circumventricular organs contribute to sodium and intravascular volume regulation, their influence on atrial natriuretic factor is not known. We tested the hypothesis that, following subarachnoid hemorrhage, suprasellar cisternal blood, intraventricular blood, or ventricular enlargement would be associated with elevated plasma levels of atrial natriuretic factor. Computed tomograms of 26 patients performed less than or equal to 3 days after hemorrhage were analyzed to determine the presence of suprasellar or intraventricular blood and enlargement of the third or lateral ventricle. These results were correlated with the plasma atrial natriuretic factor and serum sodium concentrations. The initial atrial natriuretic factor concentration was elevated and was higher in patients with suprasellar or intraventricular blood than in those without (suprasellar: 131 +/- 20 and 54 +/- 10 pg/ml, respectively; intraventricular: 137 +/- 25 and 84 +/- 31 pg/ml, respectively). The atrial natriuretic factor concentration remained higher over the week following hemorrhage in patients with suprasellar blood than in those without (127 +/- 16 and 68 +/- 12 pg/ml, respectively). The atrial natriuretic factor concentration was not correlated with hyponatremia (125-134 meq/l) or age-corrected ventricular size. Hyponatremia did not correlate with the presence of intraventricular or suprasellar blood. Our data suggest that suprasellar and intraventricular blood disturb hypothalamic function, resulting in an elevated plasma atrial natriuretic factor concentration. The presence of a direct relation between atrial natriuretic factor and hyponatremia remains unclear.
Detection of paradoxical cerebral echo contrast embolization by transcranial Doppler ultrasound.
Authors: Teague S M , Sharma M K
Published: June 2011

Contrast echocardiography has been shown to be a sensitive method for detecting patent foramen ovale in embolic stroke, implying paradoxical embolization. However, not all two-dimensional echocardiographic studies are of diagnostic quality, and direct evidence for paradoxical cerebral embolization remains lacking. We addressed these problems by simultaneously using transcranial Doppler ultrasound and contrast echocardiography to compare relative sensitivity and concordance in the detection of right-to-left vascular shunting. Forty-six patients with stroke, transient neurologic defect, or question of atrial septal defect underwent study at rest and during Valsalva strain. Two-dimensional echocardiography detected shunting in 26% at rest and 15% during Valsalva strain, whereas transcranial Doppler study returned rates of 41% and 41%, respectively. Concordance was 82% and 75%, respectively. Discordant studies almost always had evidence of paradoxical contrast embolization by transcranial Doppler and intermediate findings by two-dimensional echocardiography. Transcranial Doppler is a sensitive, unambiguous technique for the detection of anatomic substrates and target organ involvement in patients suspected to have paradoxical cerebral embolization.
Role of platelet function in symptomatic cerebral vasospasm following aneurysmal subarachnoid hemorrhage.
Authors: Ohkuma H , Suzuki S , Kimura M , Sobata E
Published: June 2011

To evaluate the role of platelet function in the pathogenesis of cerebral vasospasm, we compared sequential changes of platelet aggregability and beta-thromboglobulin and thromboxane B2 concentrations in blood samples from the internal jugular and peripheral vein of 13 patients with aneurysmal subarachnoid hemorrhage. Platelet function in blood from the internal jugular vein tended to be enhanced during days 0-1 but recovered to the normal range during days 2-4. After day 5, platelet function showed various patterns depending on the presence of symptomatic vasospasm. In patients without symptomatic vasospasm, sequential changes were relatively minor, with normal or slightly high values. Patients with symptomatic vasospasm already showed high platelet aggregability during the early stage of vasospasm. The concentration of beta-thromboglobulin increased several days after the onset of vasospasm, reaching 80 ng/ml or more in patients with a poor prognosis. Two of the five patients with symptomatic vasospasm showed markedly high concentrations of thromboxane B2 after day 8. These results suggest that vasospasm activates platelets and promotes aggregability and that the resulting increased tendency for thrombus formation may affect the patient's prognosis during the advanced stage.
Diagnosis of cerebral amyloid angiopathy by enzyme-linked immunosorbent assay of cystatin C in cerebrospinal fluid.
Authors: Shimode K , Fujihara S , Nakamura M , Kobayashi S , Tsunematsu T
Published: June 2011

An abnormally low level of cystatin C in the cerebrospinal fluid is a diagnostic marker for the hereditary form of brain hemorrhage associated with amyloidosis that was first identified in Iceland. We developed an assay for cystatin C to use in the diagnosis of patients with cerebral amyloid angiopathy and brain hemorrhage. This test consists of a sandwich enzyme-linked immunosorbent assay using monoclonal mouse anticystatin C and polyclonal rabbit anticystatin C antibodies. The cystatin C level was assayed in cerebrospinal fluid samples from 29 patients with brain hemorrhage and 45 control patients with other neurological diseases. Fifteen patients with brain hemorrhage showed low cystatin C levels (less than or equal to 70 ng/ml) in a clinical setting in which the positive and negative findings were compatible with a diagnosis of cerebral amyloid angiopathy. Immunohistological examination of brain tissue obtained by biopsy from two of the 15 patients confirmed the diagnosis of cerebral amyloid angiopathy and identified the deposition of cystatin C and beta-protein. This enzyme-linked immunosorbent assay is simple to perform and may be useful for investigating patients suspected of having cerebral amyloid angiopathy with brain hemorrhage and the deposition of cystatin C.
Impact of unruptured intracranial aneurysms on public health in the United States.
Authors: Wiebers D O , Torner J C , Meissner I
Published: June 2011

Unruptured intracranial aneurysms constitute a significant public health problem that has not been quantified. The purpose of this study is to document the magnitude of this problem in the United States.

National Hospital Discharge Survey data from 1979, 1984, and 1989 served as the basis for calculating patient numbers and frequency distributions. Cost estimates included the direct costs of hospitalization and surgery for those who had surgery, disability and lost income from morbidity, and lost income from mortality.

The estimated lifetime cost (including hospitalization, surgery, morbidity, and mortality) for annual cases of patients hospitalized with unruptured intracranial aneurysms in the United States is $522,500,000 compared with $1,755,600,000 for patients with aneurysmal subarachnoid hemorrhage.

These data underscore the need to better understand unruptured intracranial aneurysm as a risk factor for subarachnoid hemorrhage, to define other subarachnoid hemorrhage risk factors, and to optimize the management of patients with these conditions.
Effect of lidocaine on somatosensory evoked response and cerebral blood flow after canine cerebral air embolism.
Authors: Dutka A J , Mink R , McDermott J , Clark J B , Hallenbeck J M
Published: June 2011

Victims of air embolism often recover rapidly on hyperbaric treatment then deteriorate again, even if hyperbaric treatment is continued. In previous animal experiments, lidocaine has been shown to improve recovery of somatosensory evoked response amplitude after air embolism. However, animals in these experiments rarely deteriorated. We have shown that the induction of air embolism and transient hypertension in canines produces deterioration despite hyperbaric treatment, and we decided to test the effect of lidocaine on somatosensory evoked potential recovery and cerebral blood flow in this model.

Dogs were treated with repeated doses of lidocaine or equivalent volumes of saline during hyperbaric therapy after internal carotid air embolism and transient hypertension. The investigators were unaware of treatment group assignment during the experiments. The amplitude of the median nerve somatosensory evoked potential and cerebral blood flow measured with carbon-14-labeled iodoantipyrine autoradiography were used to assess effect of therapy.

Lidocaine-treated dogs recovered 60 +/- 10% (mean +/- 95% confidence limits) of the baseline somatosensory evoked potential amplitude 220 minutes after air embolism; saline-treated dogs recovered 32 +/- 10% (a significant difference at p less than 0.01). Lidocaine-treated dogs also had higher cerebral blood flow values than saline-treated dogs 220 minutes after air embolism.

Lidocaine ameliorated the delayed deterioration of evoked potential associated with air embolism and hypertension in this canine model. The improved cerebral blood flow may be a mechanism of action of lidocaine or an associated effect of improved neuronal survival.
Early time course of N-acetylaspartate, creatine and phosphocreatine, and compounds containing choline in the brain after acute stroke. A proton magnetic resonance spectroscopy study.
Authors: Gideon P , Henriksen O , Sperling B , Christiansen P , Olsen T S , Jørgensen H S , Arlien-Søborg P
Published: June 2011

The early time course after acute stroke of cerebral N-acetylaspartate, creatine and phosphocreatine, and compounds containing choline was studied in vivo by means of localized water-suppressed proton magnetic resonance spectroscopy.

Eight patients with acute stroke were studied serially in the acute phase, 1 week after, and 2-4 weeks after the onset of clinical symptoms. Ten healthy volunteers served as controls. A stimulated echo (STEAM) sequence was used for measurement of the brain metabolites in a volume of interest located within the infarcted area as visualized by magnetic resonance imaging. For quantification, the unsaturated water signal was used as the internal standard. Regional cerebral blood flow in the infarcted area was measured relative to a symmetrically located unaffected area by means of single-photon emission computed tomographic scanning, using 99mTc-labeled d,l-hexamethylenepropyleneamine oxime as the flow tracer.

Relative regional cerebral blood flow was considerably reduced in the infarcted area in the acute phase. After 1 week, hyperemia was seen in all but one patient. The N-acetylaspartate content was significantly reduced, with the loss appearing to occur between 6 and 24 hours after the stroke incident. The reduction in N-acetylaspartate content was greater in the central part than in the peripheral part of the infarcted area. Creatine and phosphocreatine were also reduced in the infarcted area, whereas no significant change was seen in the choline content.

Assuming that N-acetylaspartate content reflects neuronal survival or loss, our results may suggest that treatment procedures with restoration of blood flow to severely ischemic areas should be initiated within the first 6 hours after stroke onset.
Imaging of the intracranial vertebrobasilar system using color-coded ultrasound.
Authors: Kaps M , Seidel G , Bauer T , Behrmann B
Published: June 2011

Anatomic variety and difficult accessibility of the vertebrobasilar arteries pose considerable problems to conventional ultrasound. We evaluated the diagnostic potential of transcranial color-coded sonography in the distal part of this system.

We insonated the intracranial section of the vertebrobasilar arteries through the foramen magnum window in 24 healthy individuals using a Doppler color flow imaging system in connection with a 2.5-MHz sector transducer. Magnetic resonance images in special inclination planes were performed and compared with the color-coded duplex images in five cases.

The B-mode image of the craniocervical junction and the intracranial parenchymal structures in addition to the color-coded blood flow allowed an unambiguous identification of the vertebrobasilar arteries (vertebral artery, 96%; basilar artery, 79%; and posterior inferior cerebellar artery, 50%). Blood flow velocities were measured considering the insonation angles: vertebral arteries, 50/24 cm/sec (30 degrees); basilar artery, 59/28 cm/sec (4 degrees); and posterior inferior cerebellar artery, 56/30 cm/sec (20 degrees) [peak systolic/end diastolic blood flow velocity (mean angle correction)].

Transcranial color-coded sonography enables accurate identification and differentiation of the intracranial vertebrobasilar arteries and improves accuracy of Doppler measurements. It may prove useful for evaluation of tortuosity and for hemodynamic studies in this vascular territory.
Risks and benefits of shunting in carotid endarterectomy. The International Transcranial Doppler Collaborators.
Authors: Halsey J H
Published: June 2011

Controversy continues about the pathogenesis of perioperative stroke in carotid endarterectomy and the use of shunting. The purpose of this study was to determine, using transcranial Doppler ultrasonography, the severity of ischemia during clamping of the carotid artery as a basis for analysis of complications in patients operated on with and without shunting.

In a retrospective study, 11 centers contributed 1,495 carotid endarterectomies monitored with transcranial Doppler. The cases were divided into groups with severe, mild, and no ischemia, and each group was subdivided according to shunt use. The perioperative rate of severe stroke attributable to intraoperative ischemia, in addition to total perioperative stroke, was determined for each subgroup.

Severe ischemia occurred in 7.2% of our cases but cleared spontaneously in about half of these. In those with persisting ischemia the rate of severe stroke was very high, while shunting protected against stroke in such cases. If ischemia did not occur, the stroke rate was higher with shunting, although not so high as in unshunted cases with severe ischemia. Slightly more than one third of the severe strokes were due to postoperative cerebral hemorrhage or carotid thrombosis, unrelated to clamp-induced ischemia or shunting.

Carotid endarterectomy complications might be reduced by selectively shunting only for severe persisting ischemia. Monitoring of cerebral ischemia would be essential to selective shunting.
Experimental evidence of ischemic thresholds and functional recovery.
Authors: Heiss W D
Published: June 2011

Impaired blood flow below certain critical levels and an insufficient supply of energy-rich substrates cause failure of neuronal function, triggering biochemical disturbances that eventually lead to ischemic cell damage.

This article reviews experimental studies that attempted to define those ischemic thresholds using functional and histological markers and, more recently, chemical markers of ischemic damage.

The duration of ischemia causing irreversible cell damage still is ill defined. Reestablishment of sufficient perfusion must be induced very early after an ischemic attack to ameliorate the potentially harmful biochemical sequelae of transient ischemia.
Ticlopidine versus aspirin for the prevention of recurrent stroke. Analysis of patients with minor stroke from the Ticlopidine Aspirin Stroke Study.
Authors: Harbison J W
Published: June 2011

Ticlopidine has not been formally compared with aspirin in patients with a completed stroke. We therefore performed an analysis on a subgroup of patients from the Ticlopidine Aspirin Stroke Study (TASS) with a recent minor completed stroke as the qualifying ischemic event.

This was a multicenter, double-blind, randomized trial of patients with a recent history of cerebral ischemia. Eligible patients had a qualifying minor stroke within 3 months of study entry. All patients received either 650 mg aspirin twice daily or 250 mg ticlopidine twice daily for up to 5.8 years. The primary study end point was the first occurrence of nonfatal stroke or death from any cause. A secondary end point was the first occurrence of a fatal or nonfatal stroke.

Minor stroke was the qualifying ischemic event in 927 patients (463 received ticlopidine and 464 received aspirin). The cumulative event rate at 1 year for nonfatal stroke or death was 6.3% for patients receiving ticlopidine and 10.8% for patients receiving aspirin, a 42% risk reduction in favor of ticlopidine. For fatal or nonfatal stroke, the cumulative event rate at 1 year was 4.8% for patients receiving ticlopidine and 7.5% for those receiving aspirin, a risk reduction of 36% for ticlopidine relative to aspirin. The overall risk reductions were 22.1% for nonfatal stroke or death and 19.9% for fatal or nonfatal stroke. Adverse reactions were reported in 58% of the ticlopidine patients and 51% of the aspirin patients.

The results in this subgroup are consistent with the overall TASS results and show that ticlopidine is somewhat more effective than aspirin for reducing the risk of stroke in patients with a completed minor stroke.
Cerebral blood flow velocity after hyperventilation-induced vasoconstriction in hypertensive patients.
Authors: Malatino L S , Bellofiore S , Costa M P , Lo Manto G , Finocchiaro F , Di Maria G U
Published: June 2011

The aim of our study was to evaluate by transcranial Doppler ultrasonography the dynamics of blood flow velocity changes in the middle cerebral artery during and after hypocapnia-induced vasoconstriction in untreated essential hypertensive patients.

Sixteen hypertensive patients (10 men and six women, 29-62 years of age) and 10 healthy control subjects (six men and four women, 30-62 years of age) were studied. Patients with mild-to-moderate essential hypertension (mean +/- SE blood pressure, 171/106 +/- 3/2 mm Hg) belonged to stage I or II of the World Health Organization classification. Mean blood flow velocity in the middle cerebral artery, arterial blood pressure, and end-tidal CO2 partial pressure were recorded at baseline, during 2-minute hyperventilation, and every 30 seconds up to 5 minutes after hyperventilation.

End-tidal CO2 partial pressure values overlapped in the two groups throughout the study. Baseline values of mean blood flow velocity in hypertensive patients were similar to those in normotensive subjects (mean +/- SE values, 64.7 +/- 3.9 cm/sec versus 58.6 +/- 3.7 cm/sec). A similar fall in mean blood flow velocity was observed in hypertensive patients and normotensive subjects (43.2 +/- 2.8% versus 46.7 +/- 3.6%). Mean blood flow velocity reverted to baseline more quickly in hypertensive patients: 1.5 minutes after hyperventilation, mean blood flow velocity was 60.7 +/- 3.1% and 84.9 +/- 1.8% of control in normotensive subjects and hypertensive patients, respectively. No changes in arterial blood pressure were observed in either group throughout the study.

This study demonstrates that the recovery of blood flow velocity in the middle cerebral artery after hyperventilation is faster in hypertensive patients than in normal subjects, thus providing further evidence that chronic hypertension is associated with changes in the dynamics of cerebral blood vessel reactivity.
Distribution and correlates of sonographically detected carotid artery disease in the Cardiovascular Health Study. The CHS Collaborative Research Group.
Authors: O'Leary D H , Polak J F , Kronmal R A , Kittner S J , Bond M G , Wolfson S K , Bommer W , Price T R , Gardin J M , Savage P J
Published: June 2011

This article describes the prevalence of extracranial carotid atherosclerosis assessed by ultrasonography, its association with risk factors, and its relation to symptomatic coronary disease and stroke in men and women aged > or = 65 years.

Maximum percent stenosis, maximum common carotid artery wall thickness, and maximum internal carotid artery wall thickness were assessed using duplex ultrasound in 5,201 men and women aged > or = 65 years in the Cardiovascular Health Study, a study of the risk factors and natural history of cardiovascular disease in the elderly. Existing coronary disease and stroke were assessed by physical examination and participant history.

Detectable carotid stenosis was present in 75% of men and 62% of women, although the prevalence of > or = 50% stenosis was low, 7% in men and 5% in women. Maximum stenosis and maximum wall thickness measurements increased with age and were uniformly greater at all ages in men than in women (p < 0.00001). Established risk factors for atherosclerosis (hypertension, smoking, diabetes) and indications of vascular disease (left ventricular hypertrophy, major electrocardiographic abnormality, bruits, and history of heart disease or stroke) related to all three carotid artery measures in the elderly. Of the three ultrasound measures, the best correlate for a history of coronary disease was maximum internal carotid artery wall thickness. For stroke the best correlate was common carotid artery wall thickness. Multiple logistic regression models of prevalent coronary heart disease and stroke that included the ultrasound findings indicated, after adjustment for age and sex, that maximum internal wall thickness and maximum common carotid wall thickness were significant correlates of both. Maximum stenosis did not add significantly to the correlation.

In the elderly the incidence of carotid atherosclerosis was high, although the frequency of severe disease was low. The prevalence and severity of carotid atherosclerosis continued to increase with age even in the late decades of life, and more disease was found in men than in women at all ages. Known risk factors for atherosclerosis continued to relate to carotid abnormalities in the later decades of life, both in symptomatic and asymptomatic subjects.
Spontaneous cerebral hypothermia diminishes focal infarction in rat brain.
Authors: Moyer D J , Welsh F A , Zager E L
Published: June 2011

Brain temperature during ischemia is known to strongly influence the extent of cellular injury. The objectives of the present study were to determine the effect of severe focal ischemia on brain temperature and to assess the influence of those changes on focal infarction.

Severe focal ischemia was produced in rats using permanent occlusion of the distal middle cerebral artery combined with transient (60-minute) bilateral carotid artery occlusion. The temperature of the ischemic focus was measured with a small subdural probe. Three groups of rats were studied. In the first group, brain temperature was permitted to decline spontaneously to 32 degrees C after occlusion. In the second, brain temperature was maintained at 37.5 degrees C during occlusion. In the third group, the brain temperature was maintained at 37.5 degrees C for 40 minutes postocclusion before cooling. After recovery for 24 hours, the volume of infarction was measured in histological sections.

In the absence of cranial heating, the brain temperature fell to 33 degrees C by 10 minutes postocclusion, and infarct volume was 19 +/- 9 mm3 (mean +/- SEM; n = 6). Maintaining brain temperature at 37.5 degrees C increased the volume of infarction to 82 +/- 16 mm3 (n = 7; p < 0.001). Delayed cooling did not prevent the increase in infarct volume (75 +/- 16 mm3; n = 6).

These results demonstrate that in the present model of transient focal ischemia, spontaneous cooling of the brain during ischemia diminishes the extent of focal infarction, relative to that observed when cerebral hypothermia is prevented or delayed for 40 minutes.
Thrombolysis in acute ischemic stroke: does it work?
Authors: Wardlaw J M , Warlow C P
Published: June 2011

This article is presented to provoke further discussion regarding the use of thrombolytic drugs to treat acute ischemic stroke.

Overview analysis of the six randomized trials of thrombolysis in acute ischemic stroke available in the world literature shows a 20% increase in the odds of death and a 30% reduction in the odds of death or deterioration (both with wide confidence intervals, neither result significant) after thrombolytic treatment for acute ischemic stroke. Exclusion of the two trials conducted without the benefit of computed tomographic scanning shows a 37% reduction in the odds of death (95% confidence interval, 74% reduction to 40% excess) and a significant reduction of 56% in the odds of death or deterioration after thrombolytic treatment (95% confidence interval, 20-76% reduction; 2p = 0.007). Analysis of all published studies (randomized and nonrandomized) shows that there does not appear to be an excess risk of hemorrhagic transformation of the cerebral infarct or of severe edema formation.

We believe the present evidence is sufficiently encouraging to warrant proper testing of thrombolysis in sufficiently large and well-designed randomized clinical trials to influence clinical practice.
Custom-tailored hemodilution with albumin and crystalloids in acute ischemic stroke.
Authors: Goslinga H , Eijzenbach V , Heuvelmans J H , van der Laan de Vries E , Melis V M , Schmid-Schönbein H , Bezemer P D
Published: June 2011

Hemodilution in the acute phase of ischemic stroke is still controversial. Multicenter studies have failed to demonstrate any benefit. The present study focuses attention on analysis of circulation in stroke and on individual restabilization of circulation.

The Amsterdam Stroke Study is a prospective, single-center, randomized clinical trial (n = 300). Normovolemic hemodilution is accomplished in a customized procedure by administration of 20% albumin plus crystalloids under hemodynamic and rheological monitoring in the acute phase of stroke. All patients receive general intensive care treatment and monitoring with a pulmonary artery catheter. This custom-tailored fluid therapy is guided on the basis of a target pulmonary capillary wedge pressure (12 +/- 3 mm Hg) and hematocrit (0.32 +/- 0.02). The control group receives only customized rehydration by infusion of crystalloids.

We obtained significant (p less than 0.05) reduction in mortality at 3 months (from 27% to 16%) and an increase in independence at home (from 35% to 48%) after viscosity reduction by means of hemodilution with albumin in the subgroup with a hematocrit less than 0.45 (n = 201) (specific viscosity effect). We also obtained a significant (p less than 0.005) reduction in mortality at 3 months (from 27% to 8%) and an increase in independence (from 35% to 59%) after only rehydration with crystalloids in the subgroup with overt dehydration (hematocrit greater than or equal to 0.45; n = 51) as compared with the normal-hematocrit group without signs of dehydration (hematocrit less than 0.45; n = 103) (specific rehydration effect).

This study may provide an explanation for the failures in former hemodilution trials and may re-establish proper hemodilution and rehydration as a valuable therapy in the acute phase of stroke, thus reducing mortality and improving independence after 3 months.
Measurement variability in duplex scan assessment of carotid atherosclerosis.
Authors: Sutton-Tyrrell K , Wolfson S K , Thompson T , Kelsey S F
Published: June 2011

The reproducibility of duplex scan measures of carotid atherosclerosis was evaluated as part of a study assessing the prevalence of carotid disease in elderly adults.

Doppler measures of blood flow velocity were used to evaluate disease severity, and extent of carotid plaque was scored from the B-mode image. A reader assigned a grade from 0 to 3 to each of seven segments in the carotid system, based on the number and size of lesions present. Reproducibility data were obtained from 30 study participants who underwent a repeat scan by a second sonographer. Each scan was then scored by two readers.

Doppler measures of blood flow velocity were found to be highly reproducible, with intraclass correlation coefficients of 0.81 for the common carotid artery, 0.84 for the internal carotid artery, and 0.77 for the internal carotid artery velocity to common carotid artery velocity ratio. Reproducibility of plaque grade was evaluated using segment as the unit of analysis, and both sonographer and reader variation were analyzed. When readers differed perfect agreement was achieved in 84% of the segments (K = 0.67), and when sonographers differed perfect agreement was obtained in 78% of the segments (K = 0.56). When both sonographer and reader differed, perfect agreement was obtained in 77% of the segments (K = 0.53). The plaque index, created by summing plaque grades from selected segments, was highly reproducible, with an intraclass correlation coefficient of 0.86.

The duplex scan protocol described here provides reliable measures of both extent and severity of carotid disease that are appropriate for use in cross-sectional studies.
A study of twins and stroke.
Authors: Brass L M , Isaacsohn J L , Merikangas K R , Robinette C D
Published: June 2011

Although there are strong genetic contributions to coronary artery disease, only a few studies have considered heritable influences on stroke.

We investigated the role of genetic factors in stroke using the Twin Registry maintained by the National Academy of Sciences-National Research Council. The registry includes 15,948 male twin pairs born between 1917 and 1927. In 1985, 9,475 twins responded to a mailed questionnaire, which covered vascular risk factors, cardiac events, and stroke.

Analysis of twin pairs in which both responded to the questionnaire, and a question on stroke, indicated proband concordance rates of 17.7% for monozygotic pairs and 3.6% for dizygotic pairs (relative risk = 4.3; chi 2 = 4.94, df = 1; p less than 0.05).

This nearly fivefold increase in the prevalence of stroke among the monozygotic compared with the dizygotic twin pairs suggests that genetic factors are involved in the etiology of stroke. The twin study paradigm holds considerable promise for identifying both genetic and environmental influences on stroke.
Failure of GM1 ganglioside to influence outcome in experimental focal ischemia.
Authors: Mayer S A , Pulsinelli W A
Published: June 2011

Reports of improved short-term (less than 72 hours) outcome in experimental models of mechanical and ischemic central nervous system injury suggest that exogenous ganglioside administration may confer a protective effect on neural tissue. We studied the effect of the monosialoganglioside GM1 on cerebral infarction and edema in spontaneously hypertensive rats subjected to permanent focal cerebral ischemia.

GM1 or normal saline was injected intramuscularly once a day for 3 days before and 30 and 120 minutes after occlusion of the right middle and common carotid arteries. Following a 24-hour survival period, the volume of infarction was measured by computer-assisted image analysis, and the extent of edema was assessed by measurements of tissue water content and hemispheric volume.

Infarct volume was similar among the GM1-treated (n = 10) and saline-treated (n = 10) rats (212 +/- 10 versus 220 +/- 13 microliters, respectively). In a second series of experiments, the brain water content and edema volume of the ischemic right hemisphere in GM1-treated rats (n = 10) did not differ from saline-treated controls (n = 10).

GM1 ganglioside does not effectively reduce cerebral infarction caused by permanent focal ischemia.
Infarction after aneurysm rupture does not depend on distribution or clearance rate of blood.
Authors: Brouwers P J , Wijdicks E F , Van Gijn J
Published: June 2011

We sought to determine the contribution of the amount, distribution, and clearance rate of extravasated blood in relation to occurrence of infarction and outcome in patients with aneurysmal subarachnoid hemorrhage.

We prospectively studied 59 consecutive patients with aneurysmal subarachnoid hemorrhage admitted within 72 hours by means of serial computed tomographic scanning, close clinical observation, and assessment of outcome after 3 months.

Infarction occurred in 17 of the 59 patients. The arterial territories involved hardly reflected the distribution of subarachnoid blood in the basal cisterns on computed tomography, and even the side of the infarcts corresponded only weakly with the side on which most extravasated blood was seen. Infarction occurred twice as often in patients with large amounts of subarachnoid blood; this difference was not significant on its own but is in agreement with previous studies. A low clearance rate of cisternal blood was not related to the occurrence of infarction; a relation between clearance rate and poor outcome was largely explained by the amount of subarachnoid blood on the initial computed tomogram and by a low Glasgow Coma Scale score on admission.

The fact that infarction is related to the total amount but not to the distribution or clearance rate of extravasated blood argues against a direct role of extravasated blood and in favor of systemic factors, dependent on the severity of the initial hemorrhage.
Asymptomatic coronary artery disease in patients with stroke. Prevalence, prognosis, diagnosis, and treatment.
Authors: Chimowitz M I , Mancini G B
Published: June 2011

The frequency of angiographically defined asymptomatic CAD in patients with carotid disease is 40%. Although the prognosis of patients with asymptomatic 1-vessel or 2-vessel CAD is good (annual cardiac mortality rate less than 2%), the prognosis of asymptomatic 3-vessel disease or left main CAD is substantially less favorable (annual cardiac mortality 5-8%). Preliminary data from nonrandomized studies suggest that coronary artery bypass surgery significantly lowers cardiac mortality in patients with asymptomatic 3-vessel or left main CAD. Further studies are needed to determine 1) vascular risk factor profiles that are predictive of asymptomatic CAD in patients with cerebrovascular disease and 2) the prevalence of asymptomatic CAD, especially 3-vessel and left main CAD, in patients with a variety of subtypes of cerebrovascular disease (e.g., carotid disease, atherosclerotic vertebrobasilar disease, cardioembolism, penetrating artery disease, stroke of undetermined cause). If the prevalence of asymptomatic 3-vessel or left main CAD is high in a subset of patients with cerebrovascular disease, a randomized study comparing coronary artery bypass surgery with best medical therapy (anti-ischemic agents, lipid-lowering therapy, and aspirin) may be warranted.
Silent stroke and carotid stenosis.
Authors: Norris J W , Zhu C Z
Published: June 2011

Silent cerebral infarction is often found on computed tomographic scan in patients with asymptomatic carotid stenosis, but its relation to the arterial stenosis is uncertain.

We compared computed tomographic scans and carotid Doppler in 115 patients with asymptomatic carotid stenosis, 203 with carotid transient ischemic attacks and carotid stenosis, and 63 with transient ischemic attacks but without carotid stenosis. There was no group with normal carotid arteries for comparison.

Lesions seen on CT scan were most common in the transient ischemic attack with carotid stenosis group (47%) compared with the other groups (30%, 19%) (p less than 0.001). Cerebral infarcts ipsilateral to the carotid stenosis were found in 10% of patients with mild (35-50%) stenosis, 17% in moderate (50-75%) stenosis, and 30% with severe (greater than 75%) carotid stenosis (p less than 0.001). In patients with asymptomatic carotid stenosis, 68% of infarcts were ipsilateral to the stenosis; in those with transient ischemic attacks and carotid stenosis, 86% of infarcts were ipsilateral to the stenosis.

The more severe the carotid stenosis, the higher the incidence of cerebral infarction ipsilateral to the stenosis. This finding applied to central infarcts as well as to peripheral infarcts in both symptomatic and asymptomatic patients. Silent cerebral infarction may be an indication for carotid endarterectomy in asymptomatic patients.