Christine A.C. Wijman

Risk Factors of Symptomatic Intracerebral Hemorrhage After tPA Therapy for Acute Stroke

Background— Studies evaluating predictors of tPA-associated symptomatic intracerebral hemorrhage (SICH) have typically focused on clinical and CT-based variables. MRI-based variables have generally not been included in predictive models, and little is known about the influence of reperfusion on SICH risk. Methods— Seventy-four patients were prospectively enrolled in an open-label study of intravenous tPA administered between 3 and 6 hours after symptom onset. An MRI was obtained before and 3 to 6 hours after tPA administration. The association between several clinical and MRI-based variables and tPA-associated SICH was determined using multivariate logistic regression analysis. SICH was defined as a ≥2 point change in National Institutes of Health Stroke Scale Score (NIHSSS) associated with any degree of hemorrhage on CT or MRI. Reperfusion was defined as a decrease in PWI lesion volume of at least 30% between baseline and the early follow-up MRI. Results— SICH occurred in 7 of 74 (9.5%) patients. In univariate analysis, NIHSSS, DWI lesion volume, PWI lesion volume, and reperfusion status were associated with an increased risk of SICH (P<0.05). In multivariate analysis, DWI lesion volume was the single independent baseline predictor of SICH (odds ratio 1.42; 95% CI 1.13 to 1.78 per 10 mL increase in DWI lesion volume). When early reperfusion status was included in the predictive model, the interaction between DWI lesion volume and reperfusion status was the only independent predictor of SICH (odds ratio 1.77; 95% CI 1.25 to 2.50 per 10 mL increase in DWI lesion volume). Conclusion— Patients with large baseline DWI lesion volumes who achieve early reperfusion appear to be at greatest risk of SICH after tPA therapy.

Cerebral Microembolism and Early Recurrent Cerebral or Retinal Ischemic Events

BACKGROUND AND PURPOSE We investigated whether cerebral microembolism as detected by transcranial Doppler ultrasonography (TCD) identifies patients at an increased risk for early, recurrent cerebral or retinal ischemic events. METHODS Records of consecutive patients examined during a 40-month period in the Neurovascular Laboratory were reviewed for the presence of cerebral microembolism. Of the original 302 patients, 229 with 310 arteries met inclusionary criteria. Follow-up information was obtained from the laboratorys database as well as the hospital records. Microembolus detection studies were performed on TC-2000 or TC-2020 instruments equipped with special software, and criteria established a priori were used for microembolus selection. TCD testing was performed a median interval of 9 days after the initial symptoms of cerebral ischemia. Severity of arterial stenosis was determined by cerebral angiography or noninvasive methods. RESULTS Microembolic signals were detected more frequently in symptomatic (40/140; 28.6%) than asymptomatic (21/170; 12.4%) arteries (P < .001). Ten recurrent ischemic events occurred during a median follow-up of 8 days after TCD examination, all in the territories of symptomatic arteries. Nine events occurred in the territories of microembolic signal positive arteries (9/61; 14.8%) and one in the territory of a microembolic signal-negative artery (1/249; 0.4%) (P < .00). No association was detected in the subgroup with known cardiac lesions. Microembolic signals were more frequent in arteries with lesions causing 70% or more stenosis or occlusion (26/99; 26.3%) than in those with a degree of stenosis less than 70% (17/126; 13.5%) (P = .016). CONCLUSIONS In this retrospective study, microembolic signals were more common in the territories of symptomatic arteries and particularly those with severely stenotic lesions. During a short follow-up, recurrent ischemic events were more common along the territories of arteries with TCD-detected microembolism and previous symptoms of cerebral or retinal ischemia.

Migrainous Visual Accompaniments Are Not Rare in Late Life The Framingham Study

BACKGROUND AND PURPOSE Questionnaires to elicit symptoms of transient ischemic attacks (TIAs) may detect late-life transient visual symptoms similar to the visual aura of migraine, often without headache. We determined the frequency, characteristics, and stroke outcome of these symptoms in the Framingham Study. METHODS During 1971-1989, at biennial examinations, 2110 subjects of the Framingham cohort were systematically queried about the occurrence of sudden visual symptoms. RESULTS Visual migrainous symptoms were reported by 1.23% (26/2110) of subjects (1.33% of women and 1.08% of men). In 65% of subjects the episodes were stereotyped, and they began after age 50 years in 77%. Mean +/- SD age at onset of the episodes was 56.2+/-18.7 years. In 58% of subjects the episodes were never accompanied by headaches, and 42% had no headache history. The number of episodes ranged from 1 to 500 and was 10 or more in 69% of subjects. The episodes lasted 15 to 60 minutes in 50% of subjects. Sixty-five percent of the subjects were examined by a study neurologist, and only 19% of them met the criteria of the International Headache Society. Twelve percent of subjects sustained a stroke after the onset of migrainous visual symptoms: a subarachnoid hemorrhage 1 year later, an atherothrombotic brain stem infarct 3 years later, and a cardioembolic stroke 27 years later. In contrast, of 87 subjects with TIAs in the same cohort, 33% developed a stroke (P = 0.030), two thirds within 6 months of TIA onset. CONCLUSIONS Late-life-onset transient visual phenomena similar to the visual aura of migraine are not rare and often occur in the absence of headache. These symptoms appear not to be associated with an increased risk of stroke, and invasive diagnostic procedures or therapeutic measures are generally not indicated.

Retinal Ischemia and Embolism

Objectives: To identify the most likely mechanisms of retinal ischemia and embolism in a hospital-referred population, and to determine the frequency of recurrent vascular events during the 3-month period following initial presentation. Methods: Consecutive patients presenting to 2 tertiary medical centers and their outpatient clinics were prospectively enrolled over a 22-month period. Eligible patients presented with histories of transient or permanent monocular visual loss, or had evidence of asymptomatic retinal embolism on routine ophthalmological examination. They underwent a rapid and standardized evaluation that included imaging studies as well as blood tests, and follow-up was obtained at 1 and 3 months. Results: Seventy-seven patients were enrolled. Enrollment diagnoses consisted of amaurosis fugax (n = 32), asymptomatic retinal embolism (n = 34), and central or branch retinal artery occlusion (n = 11). Eight different presumed etiologies of retinal artery distribution embolism or hypoperfusion were identified. Extracranial internal carotid artery occlusion or more than 50% stenosis was observed in 17/77 (22.1%) cases, making it the largest etiologic subgroup. Uncommon but treatable conditions were identified in 8/77 (10.4%) patients, and an etiologic diagnosis could not be made in 35/77 (45.5%) patients. Recurrent events occurred in, respectively, 14/77 (18.2%) and 6/73 (8.2%) patients at the 1- and 3-month follow-ups. They included 2 infarcts and 2 deaths; ischemic events of the retina were more common than those involving the brain. Conclusion: Severe stenosis of the extracranial internal carotid artery is the most common identified condition associated with retinal ischemia and embolism, but a variety of other, potentially treatable, conditions can be diagnosed if appropriate and specific evaluations are conducted. The frequency of recurrent vascular ischemic events is highest during the 1st month of follow-up and decreases during the 2nd and 3rd months. Recurrences range from relatively innocuous episodes of amaurosis fugax to vascular death.

Cerebral air embolism as a cause of stroke during cardiac catherization

Central nervous system complications occur in approximately 0.2% of patients undergoing cardiac catherization, and are thought to result from either embolism of particulate material to the brain or systemic hypotension.1 Often, the cause of CNS deficits during cardiac catheterization remains uncertain.2 Cerebral arterial air embolism has been recognized as a complication of cardiac catheterization, as well as other invasive diagnostic and therapeutic procedures.3,4 We diagnosed cerebral arterial air embolism based on the CT findings of a patient who developed sudden neurologic deficits while undergoing cardiac catheterization. Case report. A 65-year-old man with an acute anterior myocardial infarction was treated with IV tissue plasminogen activator, nitroglycerine, lopressor, aspirin, and heparin prior to transfer to our hospital. Two days later he underwent cardiac catheterization. The catheter was advanced into the ascending aorta over a 0.089-cm guide wire in standard fashion, attached to the manifold with a fluid-to-fluid connection, aspirated and flushed, and then advanced into the left ventricle, when the patient became unresponsive with his eyes deviated to …

Cerebral Microembolism in Patients With Retinal Ischemia

BACKGROUND AND PURPOSE We investigated the frequency of cerebral microembolism detected by transcranial Doppler ultrasonography in patients with clinical evidence of retinal ischemia, including transient monocular blindness, central and branch retinal artery infarction, and ischemic oculopathy, and assessed its correlation with carotid artery stenosis. METHODS Records of 331 consecutive patients examined during a 47-month period at the Neurovascular Laboratory were reviewed. Of the original 453 intracranial arteries, 186 middle cerebral arteries (MCAs) satisfied qualifying criteria that excluded patients with cardiac embolic sources. Forty-five MCAs ipsilateral to the symptomatic eye constituted the study group. The control group consisted of 141 asymptomatic MCAs. Microembolus detection studies were performed on transcranial Doppler instruments equipped with special software, and the degree of carotid artery stenosis was measured by cerebral or MR angiography or by color duplex studies. RESULTS Microembolism was detected in 40.0% of study MCAs and 9.2% of controls (P < 0.001). In the study group, microembolic signals were detected in 61.9% of MCAs tested within a week of symptom onset and 20.8% of those tested afterward (P < 0.001). Severe (> or = 70%) carotid stenosis or occlusion was more frequent in the study group (P < 0.001). Microembolic signals were detected in 25.3% and 11.2%, respectively, of MCAs distal to carotid arteries with 70% to 100% and 0% to 69% stenosis (P = 0.013). CONCLUSIONS In patients without cardiac embolic sources, cerebral microembolism is frequently present on the side of retinal ischemia, particularly during the week after onset of symptoms. It is often associated with severe stenosis or occlusion of the ipsilateral carotid artery.

Extent of hypoattenuation on CT angiography source images in basilar artery occlusion: prognostic value in the Basilar Artery International Cooperation Study.

Background and Purpose— The posterior circulation Acute Stroke Prognosis Early CT Score (pc-ASPECTS) quantifies the extent of early ischemic changes in the posterior circulation with a 10-point grading system. We hypothesized that pc-ASPECTS applied to CT angiography source images predicts functional outcome of patients in the Basilar Artery International Cooperation Study (BASICS). Methods— BASICS was a prospective, observational registry of consecutive patients with acute symptomatic basilar artery occlusion. Functional outcome was assessed at 1 month. We applied pc-ASPECTS to CT angiography source images of patients with CT angiography for confirmation of basilar artery occlusion. We calculated unadjusted and adjusted risk ratios (RRs) of pc-ASPECTS dichotomized at ≥8 versus <8. Primary outcome measure was favorable outcome (modified Rankin Scale scores 0–3). Secondary outcome measures were mortality and functional independence (modified Rankin Scale scores 0–2). Results— Of 158 patients included, 78 patients had a CT angiography source images pc-ASPECTS ≥8. Patients with a pc-ASPECTS ≥8 more often had a favorable outcome than patients with a pc-ASPECTS <8 (crude RR, 1.7; 95% CI, 0.98–3.0). After adjustment for age, baseline National Institutes of Health Stroke Scale score, and thrombolysis, pc-ASPECTS ≥8 was not related to favorable outcome (RR, 1.3; 95% CI, 0.8–2.2), but it was related to reduced mortality (RR, 0.7; 95% CI, 0.5–0.98) and functional independence (RR, 2.0; 95% CI, 1.1–3.8). In post hoc analysis, pc-ASPECTS dichotomized at ≥6 versus <6 predicted a favorable outcome (adjusted RR, 3.1; 95% CI, 1.2–7.5). Conclusions— pc-ASPECTS on CT angiography source images independently predicted death and functional independence at 1 month in the CT angiography subgroup of patients in the BASICS registry.

“Paradoxical” transtentorial herniation due to CSF drainage in the presence of a hemicraniectomy

Decompressive hemicraniectomy can be a life-saving treatment for uncontrolled elevations in intracranial pressure (ICP) due to trauma or space-occupying ischemic or hemorrhagic stroke.1 Herniation in the direction opposite the site of the craniectomy—paradoxical herniation—is an underrecognized and potentially fatal complication of this procedure. It can occur spontaneously or may be precipitated by a lumbar puncture (LP) or a CSF shunt. It is critical to recognize this treatable entity because standard interventions aimed at lowering ICP are harmful. A 24-year-old man with a right-sided subdural hemorrhage (SDH) and temporal contusion from head trauma underwent SDH evacuation, anterior temporal lobectomy, and a right-sided hemicraniectomy. Subsequently, a medium pressure ventriculoperitoneal shunt (VPS) was placed for hydrocephalus. Two months later, he followed simple commands and had a left-sided hemianopsia and hemiparesis. At this time, his scalp was slightly sunken over the skull defect. He was transferred to our hospital for rehabilitation, where he developed fevers and decreased responsiveness. An LP revealed an opening pressure of 11 cm H2O. …

Predicting outcome after acute basilar artery occlusion based on admission characteristics.

Objective: To develop a simple prognostic model to predict outcome at 1 month after acute basilar artery occlusion (BAO) with readily available predictors. Methods: The Basilar Artery International Cooperation Study (BASICS) is a prospective, observational, international registry of consecutive patients who presented with an acute symptomatic and radiologically confirmed BAO. We considered predictors available at hospital admission in multivariable logistic regression models to predict poor outcome (modified Rankin Scale [mRS] score 4–5 or death) at 1 month. We used receiver operator characteristic curves to assess the discriminatory performance of the models. Results: Of the 619 patients, 429 (69%) had a poor outcome at 1 month: 74 (12%) had a mRS score of 4, 115 (19%) had a mRS score of 5, and 240 (39%) had died. The main predictors of poor outcome were older age, absence of hyperlipidemia, presence of prodromal minor stroke, higher NIH Stroke Scale (NIHSS) score, and longer time to treatment. A prognostic model that combined demographic data and stroke risk factors had an area under the receiver operating characteristic curve (AUC) of 0.64. This performance improved by including findings from the neurologic examination (AUC 0.79) and CT imaging (AUC 0.80). A risk chart showed predictions of poor outcome at 1 month varying from 25 to 96%. Conclusion: Poor outcome after BAO can be reliably predicted by a simple model that includes older age, absence of hyperlipidemia, presence of prodromal minor stroke, higher NIHSS score, and longer time to treatment.

Symptomatic and Asymptomatic Retinal Embolism Have Different Mechanisms

Purpose— To investigate differences between symptomatic and asymptomatic retinal embolism regarding the frequency and source of cerebral microemboli. Methods— Thirty-seven patients with transient monocular blindness or retinal infarction and 27 patients (29 eyes) with asymptomatic retinal embolism were prospectively enrolled. Patients underwent a transcranial Doppler study and noninvasive imaging of the cervical internal carotid arteries (ICA). The middle cerebral artery (MCA) ipsilateral to the affected eye was monitored for 30 minutes for microembolic signals (MES), which were saved and analyzed offline. Age-matched controls (n=15) had no history of retinal or brain ischemia, <50% ICA stenosis, and normal ophthalmologic examinations. Results— MES were detected in 0/15 (0%) controls, 11/37 (30%) MCAs in the symptomatic group (P =0.02), and 3/29 (10%) MCAs in the asymptomatic group (P =0.54). Nine of 11 (82%) symptomatic eyes with MES had ipsilateral ICA stenosis of ≥50%, as compared with 0/3 (0%) eyes in the asymptomatic group with MES (P =0.03). Both MES and ICA stenosis of >50% were present in 9/37 (24%) cases in the symptomatic and in 0/29 (0%) cases of the asymptomatic group (P =0.0036). Conclusions— The frequency and potential source of cerebral microemboli in symptomatic and asymptomatic retinal embolism are different. Cerebral microemboli are more frequent in symptomatic patients and are associated with ICA stenosis.