Christine Kremer

Mechanism of Ischemic Infarct in Spontaneous Carotid Dissection

Background and Purpose— It is unclear whether stroke in patients with spontaneous dissection of the cervical internal carotid artery (ICAD) is due to thromboembolism or impaired hemodynamics. This study investigated the mechanism of stroke in ICAD by examining brain imaging and cerebrovascular findings of such patients. Methods— We retrospectively evaluated the prospectively collected brain CT, MR, and ultrasound findings of 141 consecutive patients with 143 ICADs causing ischemic stroke. Eleven patients were not included because they had an inappropriate temporal bone window (n=6) or were treated with thrombolysis (n=5). Thus, the data of 130 patients (76 men, 54 women) with 131 ICADs were analyzed. Results— All patients had territorial infarcts; 6 patients (5%) also had border-zone infarct patterns. Territorial infarcts affected the middle cerebral artery (MCA) in 130 of 131 cases (99%) and the anterior cerebral artery (ACA) in 1 case (1%). Additional vascular territories were affected in 8 patients with MCA infarcts (ACA, n=5 [4%]; posterior cerebral artery, n=3 [2%]). The pattern (hemodynamic versus thromboembolic) and extent of infarction were not influenced by vascular findings (MCA stenosis or occlusion, ACA occlusion, degree of obstruction in the dissected ICA, pattern of cross-flow in 115 patients with >80% ICA stenosis or occlusion). Conclusions— This study suggests that thromboembolism, not hemodynamic infarction, is the essential stroke mechanism in ICAD.

Carotid dissection with permanent and transient occlusion or severe stenosis Long-term outcome

Objective: To compare the rate of ischemic events and intracranial hemorrhage in the long-term follow-up of patients with persistent and transient severe stenosis or occlusion of the internal carotid artery (ICA) due to spontaneous dissection (ICAD). Methods: One hundred and sixty-one consecutive patients with unilateral ICAD causing severe stenosis or occlusion were examined clinically and by ultrasound 1 year after symptom onset. Forty-six cases with persistent and 46 age- and latency-matched cases with transient (recanalization complete or less than 50% stenosis) severe stenosis or occlusion of the ICA were enrolled. Nine patients with surgical, endovascular, or fibrinolytic therapy for ICAD or associated stroke were excluded. Antithrombotic therapy was given at the discretion of the treating physician. Clinical follow-ups were done annually. Results: Antithrombotic therapy and follow-up were similar in patients with permanent (6.2 ± 3.4 years) and transient (7.2 ± 4.3 years) severe stenosis or occlusion of the ICA. Cases with permanent carotid stenosis or occlusion showed annual rates of 0.7% for ipsilateral carotid territory stroke and of 1.4% for any stroke. Cases with transient carotid stenosis or occlusion showed annual rates of 0.3% for ipsilateral carotid territory stroke and of 0.6% for any stroke. Conclusions: This study suggests that ICAD has a benign long-term prognosis with low rates of ipsilateral carotid territory and any stroke and that the stroke rate in ICAD is not related to the persistence of severe carotid stenosis or occlusion. These results question the rationale of surgical or catheter-based revascularization in patients with ICAD.

The VITATOPS (Vitamins to Prevent Stroke) Trial: Rationale and Design of an International, Large, Simple, Randomised Trial of Homocysteine-Lowering Multivitamin Therapy in Patients with Recent Transient Ischaemic Attack or Stroke

Background: Epidemiological studies suggest that raised plasma concentrations of total homocysteine (tHcy) may be a common, causal and treatable risk factor for atherothromboembolic ischaemic stroke. Although tHcy can be lowered effectively with small doses of folic acid, vitamin B12 and vitamin B6, it is not known whether lowering tHcy, by means of multivitamin therapy, can prevent stroke and other major atherothromboembolic vascular events. Purpose: To determine whether vitamin supplements (folic acid 2 mg, B6 25 mg, B12 500 µg) reduce the risk of stroke, and other serious vascular events, in patients with recent stroke or transient ischaemic attacks of the brain or eye (TIA). Methods: An international, multi-centre, randomised, double-blind, placebo-controlled clinical trial. Results: As of November 2001, more than 1,400 patients have been randomised from 10 countries in four continents. Conclusion: VITATOPS aims to recruit and follow up 8,000 patients between 2000 and 2004, and provide a reliable estimate of the safety and effectiveness of dietary supplementation with folic acid, vitamin B12, and vitamin B6 in reducing recurrent serious vascular events among a wide range of patients with TIA and stroke.

Hypoxia-Induced Acute Mountain Sickness is Associated with Intracellular Cerebral Edema: A 3 T Magnetic Resonance Imaging Study

Acute mountain sickness is common among not acclimatized persons ascending to high altitude; the underlying mechanism is unknown, but may be related to cerebral edema. Nine healthy male students were studied before and after 6-h exposure to isobaric hypoxia. Subjects inhaled room air enriched with N2 to obtain arterial O2 saturation values of 75 to 80%. Acute mountain sickness was assessed with the environmental symptom questionnaire, and cerebral edema with 3 T magnetic resonance imaging in 18 regions of interest in the cerebral white matter. The main outcome measures were development of intra- and extracellular cerebral white matter edema assessed by visual inspection and quantitative analysis of apparent diffusion coefficients derived from diffusion-weighted imaging, and B0 signal intensities derived from T2-weighted imaging. Seven of nine subjects developed acute mountain sickness. Mean apparent diffusion coefficient increased 2.12% (baseline, 0.80±0.09; 6 h hypoxia, 0.81 ± 0.09; P = 0.034), and mean B0 signal intensity increased 4.56% (baseline, 432.1 ±98.2; 6 h hypoxia, 450.7 ± 102.5; P < 0.001). Visual inspection of magnetic resonance images failed to reveal cerebral edema. Cerebral acute mountain sickness scores showed a negative correlation with relative changes of apparent diffusion coefficients (r = 0.83, P = 0.006); there was no correlation with relative changes of B0 signal intensities. In conclusion, isobaric hypoxia is associated with mild extracellular (vasogenic) cerebral edema irrespective of the presence of acute mountain sickness in most subjects, and severe acute mountain sickness with additional mild intracellular (cytotoxic) cerebral edema.

Aortic embolism in Claude's syndrome

Introduction In 1912, Claude [1] described a crossed midbrain syndrome with oculomotor palsy and controlateral hemiataxia [1]. Autopsy showed a unilateral infarct involving the fascicular part of the oculomotor nerve, the medial longitudinal fascicle, the crossing fibers of the superior peduncle and the medial half of the red nucleus [2]. The cause of Claude’s syndrome has been assumed to be occlusive small artery disease [3] or has remained unclear [4]. We report a patient who suffered from Claude’s syndrome and multiple asymptomatic cerebral emboli probably originating from aortic plaques.

Prognosis of asymptomatic stenosis of the middle cerebral artery

Background: The risk of ischaemic events in asymptomatic intracranial atherosclerosis is unknown. Objective: To follow up patients with asymptomatic atherosclerotic middle cerebral artery stenosis (MCAS) to evaluate the long term stroke risk in its territory. Methods: Consecutive white patients with asymptomatic atherosclerotic MCAS were enrolled. Patients with MCAS of possible or proven non-atherosclerotic origin were excluded. MCAS was assessed by transcranial colour duplex sonography according to published angiography validated criteria. Medical treatment was given at the discretion of the treating physician. Results: 50 patients were included and followed for (mean (SD)) 815 (351) days; three were lost to follow up. MCAS was <50% in 38 and ⩾50% in 12. No patient suffered an ischaemic event in the MCAS territory; one had a transient ischaemic attack in the contralateral hemisphere. Three patients died, one from a subdural haematoma in the contralateral hemisphere, and two from non-stroke-related causes. Medical treatment at baseline included antithrombotic drugs in 42 cases (antiplatelet agent, n = 39; warfarin, n = 3), and statins in 22; at the end of follow up 45 of the 47 survivors were on antithrombotic drugs (antiplatelet agent, n = 37; warfarin, n = 8), and 30 were on statins. Conclusions: Asymptomatic MCAS of atherosclerotic origin appears to have a benign long term prognosis with a low risk of ipsilateral stroke in medically treated white patients.

Comparison of operative and endovascular treatment of anterior circulation aneurysms in patients in poor grades.

Abstract We assessed the outcome of surgical and endovascular treatment in patients in poor (Hunt & Hess IV or V) grade following subarachnoid haemorrhage due to anterior circulation aneurysm (ACA). There were 41 patients, treated surgically (20), by the endovascular route (20) or both (1). The aneurysms were clipped in 20 patients, wrapped in one; 19 were treated with Guglielmi detachable coils (GDC), one by parent vessel occlusion using detachable balloons. One GDC treatment was interrupted and the aneurysm was surgically clipped instead. We treated five patients surgically to evacuate accompanying intracerebral clots. We treated 14 (66 %) patients by the endovascular route and 15 (71 %) surgically within 72 h of the haemorrhage. The frequency of delayed ischaemic neurological deficit and/or cerebral infarct due to vasospasm did not differ significantly between the endovascular and surgical groups. We had one surgical and three endovascular procedure-related complications with clinical manifestations. Outcome was evaluated after 6 months. After GDC treatment, angiographic follow-up was carried out between 8 and 26 months (mean 17 months). Good outcomes were achieved in six (29 %) of the surgically treated patients (40 % of the survivors) and six (30 %) of the endovascular treatment patients (60 % of the survivors). Outcome was similar after surgical and endovascular approaches. The decision as to which treatment to chosen is influenced mainly by clinical factors such as cerebral haematoma or age.

Prognosis of aphasia in stroke patients early after iv thrombolysis.

OBJECTIVE Stroke patients with aphasia have a high long-term morbidity. Intravenous rt-PA (iv) thrombolysis is given more deliberately to these patients. Early outcome data is lacking. Aim of this study was to determine early benefit from rt-PA in patients with aphasia. METHODS Data of stroke patients treated by iv thrombolysis was scrutinized for the presence of aphasia defined as ≥1 point for aphasia on the National Institute of Health Stroke Scale (NIHSS). Improvement was defined as a gain of ≥1 point within 24h. Cranial computed tomography (CT) scans were evaluated regarding early ischemic changes (EICs), infarct volume and localization. RESULTS Fifty patients with aphasia were included. 16 (32%) of patients improved (4 (36%) minor, 7 (41%) moderate, 5 (23%) major stroke patients), while 44 (62%) remained unchanged. Of 28 patients with EICs, 10 (36%) improved compared to 7 out of 22 (32%) patients without (p=0.773). Aphasia outcome was significantly associated with infarct volume at admission and at 24h (Kruskal-Wallis, p=0.033, p≤0.001, respectively). CONCLUSION EICs are not predictive of aphasia outcome and patients with improvement showed smaller infarct volumes. One third improved within 24h, while two thirds remained unchanged. This might justify a closer follow-up of aphasia in stroke patients at the acute stage.

Migraine and delayed ischaemic neurological deficit after subarachnoid haemorrhage in women: a case–control study

The aim of the present case–control study was to investigate the role of migraine as a potential risk factor for a delayed ischaemic neurological deficit (DIND) after subarachnoid haemorrhage (SAH). A telephone interview was performed in patients or their relatives to determine the prevalence of migraine. Thirty‐six women aged <60 years had SAH with Hunt & Hess grade I–III and DIND (group A). This group was compared with an age‐matched group of 36 female SAH patients, Hunt & Hess grade I–III without DIND (group B). The two populations were also characterized regarding hypertension, smoking, diabetes mellitus and alcohol use. A significant difference was only found for the prevalence of migraine with 47% in group A and 25% in group B (P < 0.05; odds ratio: 2.68, confidence interval: 0.99–7.29). Migraineurs revealed similar prevalences of risk factors independently of the presence of DINDs. This retrospective study suggests that women with migraine have a higher risk to develop a DIND than women without migraine.

Outcome of men and women after atrial fibrillation and stroke

Atrial fibrillation (AF) is a well‐known risk factor for ischaemic stroke. The aim was to examine long‐term outcome of men and women after stroke related to AF.