Babak B. Navi

Hypertonic saline versus mannitol for the treatment of elevated intracranial pressure: a meta-analysis of randomized clinical trials.

Objectives:Randomized trials have suggested that hypertonic saline solutions may be superior to mannitol for the treatment of elevated intracranial pressure, but their impact on clinical practice has been limited, partly by their small size. We therefore combined their findings in a meta-analysis. Data Sources:We searched for relevant studies in MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, and ISI Web of Knowledge. Study Selection:Randomized trials were included if they directly compared equiosmolar doses of hypertonic sodium solutions to mannitol for the treatment of elevated intracranial pressure in human subjects undergoing quantitative intracranial pressure measurement. Data Extraction:Two investigators independently reviewed potentially eligible trials and extracted data using a preformed data collection sheet. Disagreements were resolved by consensus or by a third investigator if needed. We collected data on patient demographics, type of intracranial pathology, baseline intracranial pressure, osms per treatment dose, quantitative change in intracranial pressure, and prespecified adverse events. Our primary outcome was the proportion of successfully treated episodes of elevated intracranial pressure. Data Synthesis:Five trials comprising 112 patients with 184 episodes of elevated intracranial pressure met our inclusion criteria. In random-effects models, the relative risk of intracranial pressure control was 1.16 (95% confidence interval, 1.00–1.33), and the difference in mean intracranial pressure reduction was 2.0 mm Hg (95% confidence interval, −1.6 to 5.7), with both favoring hypertonic saline over mannitol. A mild degree of heterogeneity was present among the included trials. There were no significant adverse events reported. Conclusions:We found that hypertonic saline is more effective than mannitol for the treatment of elevated intracranial pressure. Our meta-analysis is limited by the small number and size of eligible trials, but our findings suggest that hypertonic saline may be superior to the current standard of care and argue for a large, multicenter, randomized trial to definitively establish the first-line medical therapy for intracranial hypertension.

Risk of a Thrombotic Event after the 6-Week Postpartum Period

BACKGROUND The postpartum state is associated with a substantially increased risk of thrombosis. It is uncertain to what extent this heightened risk persists beyond the conventionally defined 6-week postpartum period. METHODS Using claims data on all discharges from nonfederal emergency departments and acute care hospitals in California, we identified women who were hospitalized for labor and delivery between January 1, 2005, and June 30, 2010. We used validated diagnosis codes to identify a composite primary outcome of ischemic stroke, acute myocardial infarction, or venous thromboembolism. We then used conditional logistic regression to assess each patients likelihood of a first thrombotic event during sequential 6-week periods after delivery, as compared with the corresponding 6-week period 1 year later. RESULTS Among the 1,687,930 women with a first recorded delivery, 1015 had a thrombotic event (248 cases of stroke, 47 cases of myocardial infarction, and 720 cases of venous thromboembolism) in the period of 1 year plus up to 24 weeks after delivery. The risk of primary thrombotic events was markedly higher within 6 weeks after delivery than in the same period 1 year later, with 411 events versus 38 events, for an absolute risk difference of 22.1 events (95% confidence interval [CI], 19.6 to 24.6) per 100,000 deliveries and an odds ratio of 10.8 (95% CI, 7.8 to 15.1). There was also a modest but significant increase in risk during the period of 7 to 12 weeks after delivery as compared with the same period 1 year later, with 95 versus 44 events, for an absolute risk difference of 3.0 events (95% CI, 1.6 to 4.5) per 100,000 deliveries and an odds ratio of 2.2 (95% CI, 1.5 to 3.1). Risks of thrombotic events were not significantly increased beyond the first 12 weeks after delivery. CONCLUSIONS Among patients in our study, an elevated risk of thrombosis persisted until at least 12 weeks after delivery. However, the absolute increase in risk beyond 6 weeks after delivery was low. (Funded by the National Institute of Neurological Disorders and Stroke.).

Pilot Randomized Trial of Outpatient Cardiac Monitoring After Cryptogenic Stroke

Background and Purpose— Observational studies indicate that outpatient cardiac monitoring detects previously undiagnosed atrial fibrillation (AF) in 5% to 20% of patients with recent stroke. However, it remains unknown whether the yield of monitoring exceeds that of routine clinical follow-up. Methods— In a pilot trial, we randomly assigned 40 patients with cryptogenic ischemic stroke or high-risk transient ischemic attack to wear a Cardionet mobile cardiac outpatient telemetry monitor for 21 days or to receive routine follow-up alone. After thorough investigation, we excluded patients with documented AF or other apparent stroke pathogenesis. We contacted patients and their physicians at 3 months and at 1 year to ascertain any diagnoses of AF or recurrent stroke or transient ischemic attack. Results— The baseline characteristics of our cohort broadly matched those of previous observational studies of monitoring after stroke. In the monitoring group, patients wore monitors for 64% of the assigned days, and 25% of patients were not compliant at all with monitoring. No patient in either study arm received a diagnosis of AF. Cardiac monitoring revealed AF in zero patients (0%; 95% confidence interval, 0%–17%), brief episodes of atrial tachycardia in 2 patients (10%; 95% confidence interval, 1%–32%), and nonsustained ventricular tachycardia in 2 patients (10%; 95% confidence interval, 1%–32%). Conclusions— In the first reported randomized trial of cardiac monitoring after cryptogenic stroke, the rate of AF detection was lower than expected, incidental arrhythmias were frequent, and compliance with monitoring was suboptimal. Our findings highlight the challenges of prospectively identifying stroke patients at risk for harboring paroxysmal AF and ensuring adequate compliance with cardiac monitoring. Clinical Trial Registration— URL: http://clinicaltrials.gov. Unique Identifier: NCT00715533

Application of the ABCD2 Score to Identify Cerebrovascular Causes of Dizziness in the Emergency Department

Background and Purpose— Dizziness can herald a cerebrovascular event. The ABCD2 score predicts the risk of stroke after transient ischemic attack partly by distinguishing transient ischemic attack from mimics. We evaluated whether this score would also identify cerebrovascular events among emergency department patients with dizziness. Methods— We retrospectively identified consecutive adults presenting to a university emergency department with a primary symptom of dizziness, vertigo, or imbalance. Two neurologists independently reviewed medical records to determine whether the presenting symptom was caused by a cerebrovascular event (ischemic stroke, transient ischemic attack, or intracranial hemorrhage). ABCD2 scores were then assigned using clinical information from the medical record. The ability of the score to discriminate between patients with cerebrovascular events and those with other diagnoses was quantified using the c statistic. Results— Among 907 dizzy patients (mean age, 59 years; 58% female), 37 (4.1%) had a cerebrovascular cause, the majority of which were ischemic strokes (n=24). The median ABCD2 score was 3 (interquartile range, 3–4). The ABCD2 score predicted ultimate diagnosis of a cerebrovascular event (c statistic, 0.79; 95% CI, 0.73–0.85). Only 5 of 512 (1.0%) patients with a score of ⩽3 had a cerebrovascular event compared to 25 of 369 patients (6.8%) with a score of 4 or 5 and 7 of 26 patients (27.0%) with a score of 6 or 7. Conclusions— The ABCD2 score may provide useful information on dizzy emergency department patients at low-risk for having a cerebrovascular diagnosis and may aid frontline providers in acute management if validated prospectively.

Paroxysmal Supraventricular Tachycardia and the Risk of Ischemic Stroke

Background and Purpose— It is unknown whether supraventricular arrhythmias other than atrial fibrillation or flutter are associated with stroke. Methods— To examine the association between paroxysmal supraventricular tachycardia (PSVT) and stroke, we performed a retrospective cohort study using administrative claims data from all emergency department encounters and hospitalizations at California’s nonfederal acute care hospitals in 2009. Our cohort comprised all adult patients with ≥1 emergency department visit or hospitalization from which they were discharged alive and without a diagnosis of stroke. Our primary exposure was a diagnosis of PSVT recorded at an encounter before stroke or documented as present-on-admission at the time of stroke. To reduce confounding, we excluded patients with diagnoses of atrial fibrillation. We defined PSVT, stroke, and atrial fibrillation using International Classification of Diseases, Ninth Revision, Clinical Modification codes previously validated by detailed chart review. Results— Of 4 806 830 eligible patients, 14 121 (0.29%) were diagnosed with PSVT and 14 402 (0.30%) experienced a stroke. The cumulative rate of stroke after PSVT diagnosis (0.94%; 95% confidence interval, 0.76%–1.16%) significantly exceeded the rate among patients without a diagnosis of PSVT (0.21%; 95% confidence interval, 0.21%–0.22%). In Cox proportional hazards analysis controlling for demographic characteristics and potential confounders, PSVT was independently associated with a higher risk of subsequent stroke (hazard ratio, 2.10; 95% confidence interval, 1.69–2.62). Conclusions— In a large and demographically diverse sample of patients, we found an independent association between PSVT and ischemic stroke. PSVT seems to be a novel risk factor that may account for some proportion of strokes that are currently classified as cryptogenic.

Association between incident cancer and subsequent stroke.

A study was undertaken to examine the association between incident cancer and the subsequent risk of stroke.

Intracerebral and subarachnoid hemorrhage in patients with cancer

Objective: To analyze the risk factors, presentation, etiologies, and outcomes of adult cancer patients with intracranial hemorrhage (IH). Methods: We analyzed 208 patients retrospectively with the diagnosis of IH from the Memorial Sloan-Kettering neurology database from January 2000 through December 2007. Charts were examined for clinical and radiographic data. Survival was calculated using the Kaplan-Meier method. Survival between groups was compared via the log-rank test. Logistic regression models were used to assess for prognostic indicators of 30- and 90-day mortality. Results: There were 181 intracerebral and 46 subarachnoid hemorrhages. Sixty-eight percent of patients had solid tumors, 16% had primary brain tumors, and 16% had hematopoietic tumors. Hemiparesis and headache were the most common symptoms. Intratumoral hemorrhage (61%) and coagulopathy (46%) accounted for the majority of hemorrhages, whereas hypertension (5%) was rare. Median survival was 3 months (95% confidence interval [CI] 2-4), and 30-day mortality was 31%. However, nearly one-half of patients were completely or partially independent at the time of discharge. Patients with primary brain tumors had the longest median survival (5.9 months, 95% CI 2.9-11.8, p = 0.05). Independent predictors of 30-day mortality were not having a primary brain tumor, impaired consciousness, multiple foci of hemorrhage, hydrocephalus, no ventriculostomy, and treatment of increased intracranial pressure. Conclusions: Intracranial hemorrhage in patients with cancer is often due to unique mechanisms. Prognosis is poor, but comparable to intracranial hemorrhage in the general population. Aggressive care is recommended despite high mortality, because many patients have good functional outcomes.

Rate and Predictors of Serious Neurologic Causes of Dizziness in the Emergency Department

OBJECTIVE To describe the rate and predictors of central nervous system (CNS) disease in emergency department (ED) patients with dizziness in the modern era of neuroimaging. PATIENTS AND METHODS We retrospectively reviewed the medical records of all adults presenting between January 1, 2007, and December 31, 2009, to an academic ED for a primary triage complaint of dizziness, vertigo, or imbalance. The final diagnosis for the cause of dizziness was independently assigned by 2 neurologists, with a third neurologist resolving any disagreements. The primary outcome was a composite of ischemic stroke, intracranial hemorrhage, transient ischemic attack, seizure, brain tumor, demyelinating disease, and CNS infection. Univariate and multivariate logistic regression were used to assess the association between clinical variables and serious CNS causes of dizziness. RESULTS Of 907 patients experiencing dizziness (mean age, 59 years; 58% women [n=529]), 49 (5%) had a serious neurologic diagnosis, including 37 cerebrovascular events. Dizziness was often caused by benign conditions, such as peripheral vertigo (294 patients [32%]) or orthostatic hypotension (121 patients [13%]). Age 60 years or older (odds ratio [OR], 5.7; 95% confidence interval [CI], 2.5-11.2), a chief complaint of imbalance (OR, 5.9; 95% CI, 2.3-15.2), and any focal examination abnormality (OR, 5.9; 95% CI, 3.1-11.2) were independently associated with serious neurologic diagnoses, whereas isolated dizziness symptoms were inversely associated (OR, 0.2; 95% CI, 0.0-0.7). CONCLUSION Dizziness in the ED is generally benign, although a substantial fraction of patients harbor serious neurologic disease. Clinical suspicion should be heightened for patients with advanced age, imbalance, or focal deficits.

Recurrent thromboembolic events after ischemic stroke in patients with cancer

Objective: To determine the cumulative rate and characteristics of recurrent thromboembolic events after acute ischemic stroke in patients with cancer. Methods: We retrospectively identified consecutive adult patients with active systemic cancer diagnosed with acute ischemic stroke at a tertiary-care cancer center from 2005 through 2009. Two neurologists independently reviewed all electronic records to ascertain the composite outcome of recurrent ischemic stroke, myocardial infarction, systemic embolism, TIA, or venous thromboembolism. Kaplan-Meier statistics were used to determine cumulative outcome rates. In exploratory analyses, Cox proportional hazard analysis was used to evaluate potential independent associations between a priori selected clinical factors and recurrent thromboembolic events. Results: Among 263 study patients, complete follow-up until death was available in 230 (87%). Most patients had an adenocarcinoma as their underlying cancer (60%) and had systemic metastases (69%). Despite a median survival of 84 days (interquartile range 24–419 days), 90 patients (34%; 95% confidence interval 28%–40%) had 117 recurrent thromboembolic events, consisting of 57 cases of venous thromboembolism, 36 recurrent ischemic strokes, 13 myocardial infarctions, 10 cases of systemic embolism, and one TIA. Kaplan-Meier rates of recurrent thromboembolism were 21%, 31%, and 37% at 1, 3, and 6 months, respectively; cumulative rates of recurrent ischemic stroke were 7%, 13%, and 16%. Adenocarcinoma histology (hazard ratio 1.65, 95% confidence interval 1.02–2.68) was independently associated with recurrent thromboembolism. Conclusions: Patients with acute ischemic stroke in the setting of active cancer (especially adenocarcinoma) face a substantial short-term risk of recurrent ischemic stroke and other types of thromboembolism.

Magnetic resonance angiography detection of abnormal carotid artery plaque in patients with cryptogenic stroke.

Background Magnetic resonance imaging of carotid plaque can aid in stroke risk stratification in patients with carotid stenosis. However, the prevalence of complicated carotid plaque in patients with cryptogenic stroke is uncertain, especially as assessed by plaque imaging techniques routinely included in acute stroke magnetic resonance imaging protocols. We assessed whether the magnetic resonance angiography–defined presence of intraplaque high-intensity signal (IHIS), a marker of intraplaque hemorrhage, is associated with ipsilateral cryptogenic stroke. Methods and Results Cryptogenic stroke patients with magnetic resonance imaging evidence of unilateral anterior circulation infarction and without hemodynamically significant (≥50%) stenosis of the cervical carotid artery were identified from a prospective stroke registry at a tertiary-care hospital. High-risk plaque was assessed by evaluating for IHIS on routine magnetic resonance angiography source images using a validated technique. To compare the presence of IHIS on the ipsilateral versus contralateral side within individual patients, we used McNemar’s test for correlated proportions. A total of 54 carotid arteries in 27 unique patients were included. A total of 6 patients (22.2%) had IHIS-positive nonstenosing carotid plaque ipsilateral to the side of ischemic stroke compared to 0 patients who had IHIS-positive carotid plaques contralateral to the side of stroke (P=0.01). Stroke severity measures, diagnostic evaluations, and prevalence of vascular risk factors were not different between the IHIS-positive and IHIS-negative groups. Conclusions Our findings suggest that a proportion of strokes classified as cryptogenic may be mechanistically related to complicated, nonhemodynamically significant cervical carotid artery plaque that can easily be detected by routine magnetic resonance imaging/magnetic resonance angiography acute stroke protocols.