Setting priorities for stroke care and research

Recent publications describing the sobering global increase in stroke mortality and global life years lost due to stroke despite improvements in developed countries have drawn focus on the severe impact of stroke in the developing world. At the same time, three recent interventional trials that failed to demonstrate an important role for catheter-based therapies in acute stroke have called into question this expensive use of technology. Coupling all of this new data leads to the natural conclusion that a focus on stroke prevention for the developing world, and for the poor in developed countries, should be where we set our priorities for the foreseeable future.

Symptom differences and pretreatment asymptomatic interval affect outcomes of stenting for intracranial atherosclerotic disease

BACKGROUND AND PURPOSE

Different types of symptomatic intracranial stenosis may respond differently to interventional therapy. We investigated symptomatic and pathophysiologic factors that may influence clinical outcomes of patients with intracranial atherosclerotic disease who were treated with stents.

MATERIALS AND METHODS

A retrospective analysis was performed of patients treated with stents for intracranial atherosclerosis at 4 centers. Patient demographics and comorbidities, lesion features, treatment features, and preprocedural and postprocedural functional status were noted. χ(2) univariate and multivariate logistic regression analysis was performed to assess technical results and clinical outcomes.

RESULTS

One hundred forty-two lesions in 131 patients were analyzed. Lesions causing hypoperfusion ischemic symptoms were associated with fewer strokes by last contact [χ(2) (1, n = 63) = 5.41, P = .019]. Nonhypoperfusion lesions causing symptoms during the 14 days before treatment had more strokes by last contact [χ(2) (1, n = 136), 4.21, P = .047]. Patients treated with stents designed for intracranial deployment were more likely to have had a stroke by last contact (OR, 4.63; P = .032), and patients treated with percutaneous balloon angioplasty in addition to deployment of a self-expanding stent were less likely to be stroke free at point of last contact (OR, 0.60; P = .034).

CONCLUSIONS

More favorable outcomes may occur after stent placement for lesions causing hypoperfusion symptoms and when delaying stent placement 7-14 days after most recent symptoms for lesions suspected to cause embolic disease or perforator ischemia. Angioplasty performed in addition to self-expanding stent deployment may lead to worse outcomes, as may use of self-expanding stents rather than balloon-mounted stents.

Endovascular mechanical thrombectomy for the treatment of acute ischemic stroke due to arterial dissection

Arterial dissections account for 2% of strokes in all age groups, and up to 25% in patients aged 45 years or younger. The safety of endovascular intervention in this patient population is not well characterized. We identified all patients in the Merci registry - a prospective, multi-center post-market database enrolling patients treated with the Merci Retriever thrombectomy device - with arterial dissection as the most likely stroke etiology. Stroke presentation and procedural details were obtained prospectively; data regarding procedural complications, intracerebral hemorrhage (ICH), and the use of stenting of the dissected artery were obtained retrospectively. Of 980 patients in the registry, ten were identified with arterial dissection (8/10 ICA; 2/10 vertebrobasilar). The median age was 48 years with a baseline NIH stroke scale score of 16 and median time to treatment of 4.9 h. The procedure resulted in thrombolysis in cerebral ischemia (TICI) scores of 2a or better in eight out of ten and TICI 2b or better in six out of ten patients. Stenting of the dissection was performed in four of nine (44%). The single complication (1/9; 11%) - extension of a dissected carotid artery - was treated effectively with stenting. No symptomatic ICH or stroke in a previously unaffected territory occurred. A favorable functional outcome was observed in eight out of ten patients. Despite severe strokes on presentation, high rates of recanalization (8/10) and favorable functional outcomes (8/10) were observed. These results suggest that mechanical thrombectomy in patients with acute stroke resulting from arterial dissection is feasible, safe, and may be associated with favorable functional outcomes.

Higher degrees of recanalization after mechanical thrombectomy for acute stroke are associated with improved outcome and decreased mortality: pooled analysis of the MERCI and Multi MERCI trials

BACKGROUND AND PURPOSE

Although the combined end point of partial and complete recanalization is a well-established predictor of good outcome following acute stroke intervention, few investigations have evaluated the effect of the degree of recanalization. We hypothesized that greater degrees of recanalization would be associated with a higher likelihood of favorable functional outcomes.

MATERIALS AND METHODS

Data from MERCI and Multi MERCI-prospective single-arm trials of endovascular mechanical thrombectomy for acute stroke-were pooled. The TIMI score was used to define the degree of recanalization, and a favorable outcome was defined as an mRS score of 0-2 at 90 days.

RESULTS

A total of 305 patients were included. Age, stroke severity, and site of arterial occlusion did not differ among groups stratified by the TIMI score. The unadjusted OR for a favorable outcome increased significantly as the TIMI score increased from 0 to 1 (OR, 5.9; 95% CI, 1.7-20.0; P = .007) and from 2 to 3 (OR. 2.3; 95% CI, 1.2-4.5; P = .01) and the likelihood of death decreased significantly as the TIMI score increased from 2 to 3 (OR, 2.2; 95% CI, 1.1-4.3; P = .05). In multivariate analysis, each increase in TIMI grade increased the odds of a good outcome 2.6-fold (95% CI, 1.9-3.4, P < .0001).

CONCLUSIONS

Increases in the TIMI score were highly associated with improved outcomes. This finding not only provides additional evidence that restoration of blood flow improves clinical outcomes in ischemic stroke but also suggests that interventionalists should strive for complete revascularization when they provide endovascular treatment for acute ischemic stroke.

Functional contrast-enhanced CT for evaluation of acute ischemic stroke does not increase the risk of contrast-induced nephropathy

BACKGROUND AND PURPOSE

Concerns have recently grown regarding the safety of iodinated contrast agents used for CTA and CTP imaging. We tested whether the incidence of AN, defined by a >or=25% increase in the post-contrast scan creatinine level, was higher among patients with ischemic stroke who underwent a functional contrast-enhanced CT protocol compared with those who had no iodinated contrast administration.

MATERIALS AND METHODS

The contrast-exposed group consisted of 575 patients with acute ischemic stroke who underwent CTA (n = 313), CTA/CTP (n = 224), or CTA/CTP followed by conventional angiography (n = 38) within 24 hours of stroke onset and were consecutively enrolled in a prospective cohort study. The nonexposed group consisted of 343 patients with ischemic stroke, consecutively admitted to the same institution, who did not receive iodinated contrast material. Patients were stratified by baseline eGFR. In the primary analysis, the Fisher exact test was used to compare the incidence of AN between the contrast-exposed and the nonexposed patients at 24, 48, and 72 hours and on a cumulative basis. A secondary analysis compared the incidence of AN in patients who underwent conventional angiography following CTA/CTP versus patients who underwent CTA/CTP only.

RESULTS

The incidence of AN was 5% in the exposed and 10% in the nonexposed group (P = .003). Patients who underwent conventional angiography after contrast CT were at no greater risk of AN than patients who underwent CTA/CTP alone (26 patients, 5%; and 2 patients, 5%, respectively; P = .7).

CONCLUSIONS

Administration of a contrast-enhanced CT protocol involving CTA/CTP and conventional angiography in selected patients does not appear to increase the incidence of CIN.

The triple rule-out for acute ischemic stroke: imaging the brain, carotid arteries, aorta, and heart

BACKGROUND AND PURPOSE

Ischemic stroke is commonly embolic, either from carotid atherosclerosis or from cardiac origin. These potential sources of emboli need to be investigated to accurately prescribe secondary stroke prevention. Moreover, the mortality in ischemic stroke patients due to ischemic heart disease is greater than that of age-matched controls, thus making evaluation for coronary artery disease important in this patient population. The purpose of this study was to evaluate the image quality of a comprehensive CTA protocol in patients with acute stroke that expands the standard CTA coverage to include all 4 chambers of the heart and the coronary arteries.

MATERIALS AND METHODS

One hundred twenty patients consecutively admitted to the emergency department with suspected cerebrovascular ischemia undergoing standard-of-care CTA were prospectively enrolled in our study. We used an original tailored acquisition protocol using a 64-section CT scanner, consisting of a dual-phase intravenous injection of iodinated contrast and saline flush, in conjunction with a dual-phase CT acquisition, ascending from the top of the aortic arch to the vertex of the head, then descending from the top of the aortic arch to the diaphragm. No beta blockers were administered. The image quality, attenuation, and CNRs of the carotid, aortic, vertebral, and coronary arteries were assessed.

RESULTS

Carotid, aorta, and vertebral artery image quality was 100% diagnostic (rated good or excellent) in all patients. Coronary artery image quality was diagnostic in 58% of RCA segments, 73% of LAD segments, and 63% of LCX segments. When we considered proximal segments only, the diagnostic quality rose to 71% in the RCA, 83% in the LAD, and 74% in the LCX.

CONCLUSIONS

Our stroke protocol achieved excellent opacification of the left heart chambers, the cervical arteries, and each coronary artery, in addition to adequate carotid and coronary artery image quality.

The fish community of the Sorocaba River Basin in different habitats (State of São Paulo, Brazil)

A fish assemblage study was accomplished in different habitats of the Sorocaba River Basin. Fish were caught with gillnets, were weighed (weight total - g) and measured (standard length - mm). Several abiotic variables of selected sampling sites were measured in order to characterise their habitats in order to attempt establishing correlations with fish community traits. Fish numbers per species were adjusted to the lognormal and logseries species/abundance models The fish community totaled 38 species, distributed in 28 genera, 14 families and 4 orders. Diversity was calculated both in number and in weight and both presented higher values in better preserved sites. We did not detect any statistical differences between dry and rainy seasons. We also concluded that the abundance distribution was not influenced by abiotic variables.

Optimal brain perfusion CT coverage in patients with acute middle cerebral artery stroke

BACKGROUND AND PURPOSE

PCT has emerged as an alternative to MR imaging for the assessment of patients with suspected acute stroke. However, 1 disadvantage of PCT is its limited anatomic coverage, which may impact the characterization of hemispheric ischemic strokes. The purpose of this study was to determine the optimal brain CT coverage required to accurately estimate the size of the infarct core relative to the MCA territory and the infarct-penumbra mismatch, by using a criterion standard of these parameters measured on PCT with 80-mm z-axis coverage.

MATERIALS AND METHODS

Fifty-one patients with acute ischemic hemispheric stroke underwent PCT scanning (2 boluses, total coverage of 80 mm, 16 x 5 mm sections) within the first 24 hours of symptom onset and a follow-up NCCT of the brain between 3 days and 3 months after the initial stroke CT study. The volumes of PCT infarct and penumbra for each possible extent of z-axis coverage derived from the individual PCT sections were recorded (beginning with 5 mm of z-axis coverage above the orbits and then increasing the coverage in 5-mm increments in the z-axis up to 80 mm above the orbits). The infarct-penumbra mismatch and the size of the infarction relative to the MCA territory were calculated for each extent of z-axis coverage. Using the 80-mm z-axis coverage as the criterion standard, we calculated the accuracy of the values of the relative PCT infarct size and mismatch that were obtained by using more limited z-axis coverage. The impact of different levels of PCT z-axis coverage on the eligibility for reperfusion treatment was assessed.

RESULTS

On the admission PCT, by using 80-mm of z-axis coverage, the mean perfusion infarct core volume was 45.9 +/- 44.0 cm(3) (range, 0-170 cm(3)) and the mean penumbra volume was 64.5 +/- 64.4 cm(3) (range, 0-226 cm(3)). The mean perfusion infarct core/MCA territory ratio was 19.6% +/- 16.2% (range, 0.1%-56%). The penumbra / (infarct + penumbra) ratio was 68.6% +/- 23.6% (range, 16.4%-100%). The final infarct volume on follow-up NCCT was 115.4 +/- 157.3 cm(3) (range, 1.79-647.4 cm(3)). The minimal z-axis PCT coverage required to obtain values similar to those obtained with 80-mm z-axis coverage was 75 mm for a mismatch of 0.5, fifty millimeters for a mismatch of 0.2, and 55 mm for a size of PCT infarct relative to the MCA territory.

CONCLUSIONS

Seventy-five millimeters is the minimal PCT coverage required to use PCT as a tool to select patients with acute stroke for reperfusion therapy by using a mismatch of 0.5. A z-axis coverage of 50 mm was sufficient for a mismatch of 0.2; and 55 mm, for the size of PCT infarct relative to MCA territory (one-third or more).

Synaptic linkages between corticomotoneuronal cells affecting forelimb muscles in behaving primates

To elucidate the cortical circuitry controlling primate forelimb muscles we investigated the synaptic interactions between neighboring motor cortex cells that had postspike output effects in target muscles. In monkeys generating isometric ramp-and-hold wrist torques, pairs of cortical cells were recorded simultaneously with independent electrodes and corticomotoneuronal ("CM") cells were identified by their postspike effects on target forelimb muscles in spike-triggered averages (SpTAs) of electromyographs (EMGs). The response patterns of the cells were determined in response-aligned averages and their synaptic interactions were identified by cross-correlograms of action potentials. The possibility that synchronized firing between cortical cells could mediate spike-correlated effects in the SpTA of EMG was examined in several ways. Sixty-two pairs consisted of one CM cell and a non-CM cell; 15 of these had correlogram peaks of the same magnitude as that of other pairs, but the synchrony peaks did not mediate any postspike effect from the non-CM cell. Twelve pairs of simultaneously recorded CM cells were cross-correlated. Half had features (usually synchrony peaks) in their cross-correlograms and the cells of these pairs also shared some target muscles in common. The other half had flat correlograms and, in most of these pairs, the CM cells affected different muscles. The latter group included pairs of CM cells that facilitated synergistic muscles. These results indicate that common synaptic input specifically affects CM cells that have overlapping muscle fields. Reconstruction of the cortical locations of CM cells affecting 12 different muscles showed a wide and overlapping distribution of cortical colonies of forelimb muscles.

Synaptic interactions between forelimb-related motor cortex neurons in behaving primates

We investigated the synaptic interactions between neighboring motor cortex cells in monkeys generating isometric ramp-and-hold torques about the wrist. For pairs of cortical cells the response patterns were determined in response-aligned averages and their synaptic interactions were identified by cross-correlation histograms. Cross-correlograms were compiled for 215 cell pairs and 84 (39%) showed significant features. The most frequently found feature (65/84 = 77%) was a central peak, straddling the origin and representing a source of common synaptic input to both cells. One third of these also had superimposed lagged peaks, indicative of a serial excitatory connection. Pure lagged peaks and lagged troughs, indicative of serial excitatory or inhibitory linkages, respectively, both occurred in 5% of the correlograms with features. A central trough appeared in 13% of the correlograms. The magnitude of the synaptic linkage was measured as the normalized area of the correlogram feature. Plotting the strength of synaptic interaction against response similarity during alternating wrist torques revealed a positive relationship for the correlated cell pairs. A linear fit yielded a positive slope: the pairs with excitatory interactions tended to covary more often than countervary. This linear fit had a positive offset, reflecting a tendency for both covarying and countervarying cells to have excitatory common input. Plotting the cortical location of the cell pairs showed that the strongest interactions occurred between cells separated by <400 microns. The correlational linkages between cells of different cortical layers showed a large proportion of common input to cells in layer V.

Perfusion CT Imaging Follows Clinical Severity in Left Hemispheric Strokes

OBJECTIVE

The purpose of this study was to assess how imaging findings on admission perfusion CT (PCT) and follow-up noncontrast CT (NCT), and their changes over time, correlate with clinical scores of stroke severity measured on admission, at discharge and at 6-month follow-up.

METHODS

Fifty-two patients with suspected hemispheric acute ischemic stroke underwent a PCT within the first 24 h of symptom onset and a follow-up NCT of the brain between 24 h and 3 months after the initial stroke CT study. NIH Stroke Scale (NIHSS) scores were recorded for each patient at admission, discharge and 6 months; modified Rankin scores were determined at discharge and 6 months. Baseline PCT and follow-up NCT were analyzed quantitatively (volume of ischemic/infarcted tissue) and semiquantitatively (anatomical grading score derived from the Alberta Stroke Program Early CT Score). The correlation between imaging volumes/scores and clinical scores was assessed. Analysis was performed for all patients considered together and separately for those with right and left hemispheric strokes.

RESULTS

Significant correlations were found between clinical scores and both quantitative and semiquantitative imaging. The volume of the acute PCT mean transit time lesion showed best correlation with admission NIHSS scores (R2 = 0.61, p < 0.001). This association was significantly better for left hemispheric strokes (R(2) = 0.80, p < 0.001) than for right hemispheric strokes (R2 = 0.39, p = 0.131). Correlation between imaging and NIHSS scores was better than correlation between imaging and modified Rankin scores (p = 0.047). The correlation with discharge clinical scores was better than that with 6-month clinical scores (p = 0.012).

CONCLUSIONS

Baseline PCT and follow-up NCT volumes predict stroke severity at baseline, discharge and, to a lesser extent, 6 months. The correlation is stronger for left-sided infarctions. This finding supports the use of PCT as a surrogate stroke outcome measure.

Risk factors for hemorrhagic presentation in patients with dural arteriovenous fistulae

OBJECTIVE

Intracranial dural arteriovenous fistulae (DAVFs) can present as disabling intracranial hemorrhage. The aim of this study was to investigate the independent effects of specific demographic and clinical variables on hemorrhagic presentation in patients with DAVFs.

METHODS

All patients with DAVFs evaluated at the University of California at San Francisco from July 1988 through June 2004 were identified. Clinical and radiographic characteristics were recorded using a detailed abstraction form.

RESULTS

A total of 402 patients with DAVFs were identified, 73 (18%) of whom presented with intracranial hemorrhage. Men were twice as likely to present with hemorrhage (men 70% versus women 30%, P < 0.001). Cortical venous drainage (85 versus 22%; P < 0.001), retrograde venous drainage (59 versus 36%; P < 0.001), and sinus occlusion (33 versus 18%; P = 0.004) were also more common in patients with DAVF with hemorrhagic presentation. In multivariate logistic regression analysis, cortical venous drainage (odds ratio [OR], 10.5; P < 0.001), focal neurological deficits (OR, 4.7; P < 0.001), DAVFs in the posterior fossa (OR, 4.0; P = 0.005), male sex (OR, 3.4, P = 0.001), and age older than 50 years were found to be independently associated with hemorrhagic presentation.

CONCLUSION

Although DAVFs are less frequent in men than in women, they are more likely to present with hemorrhage. In addition to cortical venous drainage, a well-known risk factor for intracranial hemorrhage, posterior fossa location, older age at presentation, and focal neurological deficits were independently associated with hemorrhagic presentation in patients with DAVFs.

Contrast extravasation on CT predicts mortality in primary intracerebral hemorrhage

BACKGROUND AND PURPOSE

Recent studies of intracerebral hemorrhage (ICH) treatments have highlighted the need to identify reliable predictors of hematoma expansion. The goal of this study was to determine whether contrast extravasation on multisection CT angiography (CTA) and/or contrast-enhanced CT (CECT) of the brain is associated with hematoma expansion and increased mortality in patients with primary ICH.

MATERIALS AND METHODS

All patients with primary ICH who underwent CTA and CECT, as well as follow-up noncontrast CT (NCCT) before discharge/death from January 1, 2003, to September 30, 2005, were retrospectively identified. One neuroradiologist reviewed admission and follow-up NCCT for hematoma size and growth. A second neuroradiologist independently reviewed CTA and CECT for active contrast extravasation. Univariate and multivariate logistic regression analyses were performed to evaluate the significance of clinical and radiologic variables in predicting 30-day mortality, designated as the primary outcome. Hematoma growth was considered as a secondary outcome.

RESULTS

Of 56 patients, contrast extravasation was seen in 17.9% of patients on initial CTA and in 23.2% of patients on initial CECT following CTA. Univariate analysis showed that the presence of extravasation on CT, large initial hematoma size (>30 mL), the presence of "swirl sign" on NCCT, the Glasgow Coma Scale and ICH scores, and international normalized ratio were associated with increased mortality. On multivariate analysis, only contrast extravasation on CT (P = .017) independently predicted mortality. Contrast extravasation on CT (P < .001) was also an independent predictor of hematoma growth on multivariate analysis.

CONCLUSION

Active contrast extravasation on CT in patients with primary ICH independently predicts mortality and hematoma growth.

Monitoring serial change in the lumen and outer wall of vertebrobasilar aneurysms

BACKGROUND AND PURPOSE

Estimation of the stability of fusiform aneurysms of the basilar artery requires precise monitoring of the luminal and outer wall volumes. In this report we describe the use of MR imaging and 3D postprocessing methods to study the evolution of those aneurysms.

MATERIALS AND METHODS

Nine patients with fusiform basilar artery aneurysms underwent MR imaging studies covering at least 2 different time points (mean delay between studies, 7.1 +/- 4.6 months). Imaging included multisection 2D T1-weighted fast spin-echo and/or 3D steady-state imaging to assess the outer wall and contrast-enhanced MR angiography to study the lumen. The outer and inner walls were extracted using, respectively, a manual delineation (made by 2 observers) and a thresholding technique. The 2 studies were subsequently coregistered at each time point, as well as between differing time points. Volumes of each vessel component were calculated.

RESULTS

Mean volume was 6760 +/- 6620 mm(3) for the outer wall and 2060 +/- 1200 mm(3) for the lumen. Evolution of the lumen and outer wall was highly variable from 1 patient to another, with a trend toward increase of the vessel wall for the largest aneurysms. Interobserver reproducibility for outer wall delineation was on the order of 90%.

CONCLUSION

Combining MR imaging methods to study both the outer wall and lumen with 3D registration tools provides a powerful method for progression of fusiform basilar aneurysmal disease.

Safety of mechanical thrombectomy and intravenous tissue plasminogen activator in acute ischemic stroke. Results of the multi Mechanical Embolus Removal in Cerebral Ischemia (MERCI) trial, part I

BACKGROUND

The MERCI (Mechanical Embolus Removal in Cerebral Ischemia) trial reported efficacy of the Merci Retriever for opening intracranial vessels in patients ineligible for intravenous (IV) tissue plasminogen activator (tPA). Patients who receive IV tPA but do not recanalize may also benefit from thrombectomy, but the revascularization efficacy and safety of this strategy has not been reported.

METHODS

Multi MERCI is an ongoing international, multicenter, prospective, single-arm trial of patients with large vessel stroke treated within 8 hours of symptom onset. Patients were enrolled who had received IV tPA but did not recanalize or who were ineligible for IV tPA. Primary outcome was vascular recanalization (Thrombolysis in Myocardial Infarction [TIMI] score II/III) and safety.

RESULTS

One hundred eleven patients received the thrombectomy procedure. Mean age +/- SD was 66.2 +/- 17.0 years, and baseline National Institutes of Health Stroke Scale (NIHSS) score was 19 +/- 6.3. Thirty patients (27%) received IV tPA before intervention. Treatment with the Retriever alone resulted in successful recanalization in 60 of 111 (54%) treatable vessels and in 77 of 111 (69%) after adjunctive therapy (IA tPA, mechanical). Symptomatic intracranial hemorrhage (ICH) occurred in 10 of 111 (9.0%). Clinically significant procedural complications occurred in 5 of 111 (4.5%) patients. The symptomatic ICH rate was 2 of 30 (6.7%) in patients pretreated with IV tPA and 8 of 81 (9.9%) in those without (P > .99).

CONCLUSIONS

Mechanical thrombectomy after IV tPA seems as safe as mechanical thrombectomy alone. Mechanical thrombectomy with both first- and second-generation Merci devices is efficacious in opening intracranial vessels during acute ischemic stroke in patients who are either ineligible for IV fibrinolytic therapy or have failed IV fibrinolytic therapy.

Vasospasm after subarachnoid hemorrhage: utility of perfusion CT and CT angiography on diagnosis and management

PURPOSE

To evaluate the utility of perfusion CT (PCT) combined with CT angiography (CTA) for the diagnosis and management of vasospasm, by using conventional digital subtraction angiography (DSA) as the gold standard.

METHODS

We retrospectively identified 27 patients with acute subarachnoid hemorrhage who had undergone CTA/PCT, DSA, and transcranial Doppler (TCD) ultrasonography within a time interval of 12 hours of one another. The patients' charts were reviewed for treatment of vasospasm. CTA, PCT, TCD, and DSA examinations were independently reviewed and quantified for vasospasm. PCT thresholds, CTA findings, noncontrast CT (NCT) hypodensities, and TCD thresholds were evaluated for accuracy, sensitivity, and specificity, as well as for negative (NPV) and positive predictive values (PPV) in the prediction of angiographic vasospasm and endovascular treatment, considering DSA as the gold standard.

RESULTS

Thirty-five CTA/PCT, TCD, and DSA examinations were performed on these 27 patients. A total of 123 arterial territories in 11 patients demonstrated angiographic vasospasm. Six patients underwent endovascular therapy. CTA qualitative assessment and PCT-derived mean transit time (MTT) with a threshold at 6.4 seconds represented the most accurate (93%) combination for the diagnosis of vasospasm, whereas MTT considered alone represented the most sensitive parameter (NPV, 98.7%). A cortical regional cerebral blood flow value </=39.3 (mL x 100 g(-1)x min(-1)) represented the most accurate (94.8%) indicator for endovascular therapy. PCT had significantly higher PPV (89.9%) than TCD (62.9%).

CONCLUSIONS

A CT survey combining CTA and PCT represents an accurate screening test in patients with suspected vasospasm. However promising, the value of PCT for selecting the best management strategy in such patients will need to be further investigated.

Long-term outcome of endovascular stenting for symptomatic basilar artery stenosis

Eighteen patients underwent stenting for symptomatic basilar artery stenosis. There were three major periprocedural complications (16.7%) without fatality. At a mean 26.7 +/- 12.1-month follow-up, 15 patients (83.3%) had an excellent long-term outcome. Only one patient (5.6%) had moderate disability from recurrent stroke, and two patients died of medical illness at 30 and 36 months after stenting. In this uncontrolled study, stenting appeared to be effective in reducing stroke risk and death and worthy of further scrupulous trial.

Evaluation of carotid stenosis using CT angiography in the initial evaluation of stroke and TIA

BACKGROUND

Imaging of the carotid arteries is important for the evaluation of patients with ischemic stroke or TIA. CT angiography (CTA) of the head and neck is readily available and can be part of the routine imaging of stroke patients. To evaluate the accuracy of CTA, the authors compared the degree of stenosis found using CTA with digital subtraction angiography (DSA) in consecutive patients during a 3-year period.

METHODS

The authors included all patients with interpretable CTA and DSA of the cervical carotid arteries from April 2000 to November 2002 at a single academic medical center. This yielded a total of 81 vessels. Stenosis on CTA of the internal carotid artery was measured in the axial plane at the point of maximum stenosis and referenced to the distal cervical internal carotid by two blinded readers. Two blinded readers measured stenosis from the DSA using the North American Symptomatic Carotid Endarterectomy Trial method.

RESULTS

Using a 70% cutoff value for stenosis, CTA and DSA were in agreement in 78 of 81 (96%; 95% CI, 90 to 99%) vessels. CTA was 100% sensitive (n = 5) and 63% specific (95% CI, 25 to 88%), and the negative predictive value of a CTA demonstrating <70% stenosis was 100% (n = 73).

CONCLUSIONS

In this consecutive series of patients with CT angiography of the neck and digital subtraction angiography, the authors found that CT angiography has a high sensitivity and high negative predictive value for carotid disease. CT angiography appears to be an excellent screening test for internal carotid artery stenosis, and the authors advocate its use for the initial imaging of patients with suspected stroke or TIA.

Endovascular embolectomy of acute basilar artery occlusion

Acute basilar artery occlusion has a mortality rate approaching 90%. The authors describe a case of acute basilar artery occlusion managed successfully with endovascular embolectomy. A 31-year-old man sought treatment for confusion, dysarthria, and right-sided weakness. He soon became unresponsive and was found to have a vertebral artery dissection and an associated basilar artery embolism. The dissection was managed with endovascular stenting, and the basilar artery embolus was removed with a clot retriever at 7 hours. The patient recovered without neurologic deficit.

Spinal manipulative therapy is an independent risk factor for vertebral artery dissection

OBJECTIVE

To determine whether spinal manipulative therapy (SMT) is an independent risk factor for cervical artery dissection.

METHODS

Using a nested case-control design, the authors reviewed all patients under age 60 with cervical arterial dissection (n = 151) and ischemic stroke or TIA from between 1995 and 2000 at two academic stroke centers. Controls (n = 306) were selected to match cases by sex and within age strata. Cases and controls were solicited by mail, and respondents were interviewed using a structured questionnaire. The medical records of interviewed patients were reviewed by two blinded neurologists to confirm that the patient had stroke or TIA and to determine whether there was evidence of arterial dissection.

RESULTS

After interview and blinded chart review, 51 patients with dissection (mean age 41 +/- 10 years; 59% female) and 100 control patients (44 +/- 9 years; 58% female) were studied. In univariate analysis, patients with dissection were more likely to have had SMT within 30 days (14% vs 3%, p = 0.032), to have had neck or head pain preceding stroke or TIA (76% vs 40%, p < 0.001), and to be current consumers of alcohol (76% vs 57%, p = 0.021). In multivariate analysis, vertebral artery dissections were independently associated with SMT within 30 days (OR 6.62, 95% CI 1.4 to 30) and pain before stroke/TIA (OR 3.76, 95% CI 1.3 to 11).

CONCLUSIONS

This case-controlled study of the influence of SMT and cervical arterial dissection shows that SMT is independently associated with vertebral arterial dissection, even after controlling for neck pain. Patients undergoing SMT should be consented for risk of stroke or vascular injury from the procedure. A significant increase in neck pain following spinal manipulative therapy warrants immediate medical evaluation.

Deaths from stroke in US children, 1979 to 1998

BACKGROUND

Studies have documented declining mortality from stroke in adults over the past two decades, with black adults at greater risk of death from stroke than whites in all years. As these findings have been attributed to control of stroke risk factors that are less important in children, trends and demographics of childhood stroke mortality are of interest, but have not been explored.

METHODS

The authors analyzed death certificate data for ischemic and hemorrhagic stroke (subarachnoid hemorrhage [SAH] and intracerebral hemorrhage [ICH]) in children under 20 years of age in the United States for the years 1979 through 1998, covering approximately 1.5 billion person-years.

RESULTS

Childhood mortality from stroke declined by 58% overall, with reductions in all major subtypes (ischemic stroke decreased by 19%; SAH, by 79%; ICH, by 54%). Black ethnicity was a risk factor for mortality from all stroke types (relative risk 1.74 for ischemic stroke; 1.76 for SAH; 2.06 for ICH; p < 0.0001 for all types). Male sex was a risk factor for mortality from SAH (relative risk 1.30, p < 0.0001) and ICH (relative risk 1.21, p < 0.0001), but not from ischemic stroke (relative risk 1.02, p = 0.76).

CONCLUSIONS

Mortality from stroke in US children has decreased dramatically over the last 20 years. Black children are at greater risk of death from all stroke types than are white children. As control of known stroke risk factors is unlikely to account for declining stroke mortality and ethnic differences in children, unrecognized stroke risk factors may be important.

Arterial dissection and stroke in children

OBJECTIVE

To describe the clinical characteristics of dissections of cerebral arteries in children.

METHODS

Searches of MEDLINE (1966-2000) and bibliographies were systematically performed for English-language publications that described patients <18 years old with anterior circulation arterial dissections (ACAD) or posterior circulation arterial dissections (PCAD).

RESULTS

A total of 2,027 studies were reviewed; 118 patients were identified in 79 studies. Seventy-four percent of patients with ACAD (n = 73) and 87% with PCAD (n = 47) were male (p < 0.0001). When patients with preceding trauma were excluded, this male predominance persisted. All patients had evidence of cerebral ischemia at the time of diagnosis. Headache was reported in approximately half of patients. Sixty percent of ACAD were intracranial. ACAD with no preceding trauma were more commonly intracranial than those preceded by significant trauma (86 vs 25%, p = 0.002). The most common location for PCAD was the vertebral artery at the level of the C1-C2 vertebral bodies (53%). Recurrent ischemic events after the diagnosis of dissection were reported in 15% of PCAD and 5% of ACAD cases. None of the PCAD group and 10% of the ACAD group had recurrent dissections.

CONCLUSIONS

There is a marked male predominance among children with cerebral arterial dissections that is not explained by trauma. Unlike adult ACAD, childhood ACAD are most commonly intracranial. Spontaneous ACAD, in particular, tend to be intracranial, while post-traumatic ACAD are more often extracranial. The vertebral artery segment most susceptible to dissection is similar between children and adults.

Advanced imaging of melorheostosis with emphasis on MRI

OBJECTIVE

To describe the CT and MR imaging appearance of both osseous and extraosseous manifestations of melorheostosis.

DESIGN AND PATIENTS

We retrospectively reviewed the CT (n=7) and/or MR imaging findings (n=12) of 17 patients with characteristic radiographic findings of melorheostosis (undulating cortical hyperostosis with marked uptake on radionuclide bone scintigraphy).

RESULTS

CT and MR imaging revealed cortical hyperostosis as high attenuation and low signal intensity on all MR pulse sequences, respectively. Encroachment on the marrow space was seen in all cases resulting from endosteal involvement. Thirteen patients demonstrated 14 soft tissue masses with infiltrative margins in 80% of cases and seven showed extensive mineralization on CT or MR imaging (low intensity on all pulse sequences). Seven soft tissue masses were predominantly nonmineralized with intermediate signal intensity on T1-weighted and intermediate to high signal on T2-weighted MR images corresponding to vascularized fibrous tissue with variable collagen content pathologically. Enhancement after intravenous gadolinium was seen in all patients imaged with soft tissue masses (n=2). Two patients demonstrated muscle atrophy resulting from nerve involvement.

CONCLUSIONS

The osseous abnormalities in melorheostosis are identical on advanced imaging and radiographs. Mineralized or nonmineralized soft tissue masses should be recognized as another manifestation of this disease as opposed to a more ominous finding, making biopsy unwarrranted.

Dural arteriovenous fistula associated with prothrombin gene mutation

An association between dural arteriovenous fistula and cerebral sinus thrombosis is reported. It is clear in several cases that thrombosis precedes the development of the fistula while it is unclear that it occurs in every case. The authors report a case of a woman with sinus thrombosis and presence of prothrombin gene mutation who subsequently developed a large dural arteriovenous fistula. Various possible factors involved in the pathogenesis of a dural fistula are discussed, with emphasis on underlying thrombophilia and oral contraceptive use in this patient.

Reporting terminology for brain arteriovenous malformation clinical and radiographic features for use in clinical trials

“If you wish to converse with me,” said Voltaire, “define your terms.” How many a debate would have been deflated into a paragraph if the disputants had dared to define their terms!

Will Durant: The Story of Philosophy

Multisection dynamic CT perfusion for acute cerebral ischemia: the "toggling-table" technique

A new CT perfusion technique providing extended anatomic coverage was evaluated in 12 patients with suspected acute middle cerebral artery ischemia. With a multidetector CT scanner, scans were obtained in an alternating fashion at two distinct "toggling" table positions (two 1-cm sections each) during a 40-mL contrast agent bolus (approximately 5 seconds per image), and perfusion parameter maps were created. The CT perfusion results were compared with follow-up images. Nine patients showed focal perfusion abnormalities in at least one section, most commonly on mean transit time maps. Using a single table location would have underestimated or missed the involved tissue in most cases. In three of 12 patients, perfusion maps failed to delineate any abnormality. In two patients, perfusion and diffusion MR imaging confirmed the absence of perfusion abnormality and tissue injury, respectively. In one case, a small ischemic injury was revealed by diffusion MR imaging. By using the toggling-table approach, perfusion images can be obtained over an extended anatomic area and, thus, reveal the presence and the extent of presumed tissue injury.

Utilization of intravenous tissue-type plasminogen activator for ischemic stroke at academic medical centers: the influence of ethnicity

BACKGROUND AND PURPOSE

We sought to measure the overall rate of usage of tissue-type plasminogen activator (tPA) for ischemic stroke at academic medical centers, and to determine whether ethnicity was associated with usage.

METHODS

Between June and December 1999, 42 academic medical centers in the United States each identified 30 consecutive ischemic stroke cases. Medical records were reviewed and information on demographics, medical history, and treatment were abstracted. Rates of tPA use were compared for African Americans and whites in univariate analysis and after adjustment for age, gender, stroke severity, and type of medical insurance with multivariable logistic regression.

RESULTS

Complete information was available for 1195 ischemic stroke patients; 788 were whites and 285 were African Americans: Overall, 49 patients (4.1%) received tPA. In the subgroup of 189 patients without a documented contraindication to therapy, 39 (20.6%) received tPA. Ten (20%) of those receiving tPA had documented contraindication. African Americans were one fifth as likely to receive tPA as whites (1.1% African Americans versus 5.3%; P=0.001), and the difference persisted after adjustment (OR 0.21, 95% CI 0.06 to 0.68; P=0.01). When comparison was restricted to those without a documented contraindication to tPA, the difference remained significant (OR 0.24, 95% CI 0.06 to 0.93; P=0.04). Medical insurance type was independently associated with tPA treatment. After adjustment for ethnicity and other demographic characteristics, those with Medicaid or no insurance were one ninth as likely to receive tPA as those with private medical insurance (OR 0.11, 95% CI 0.02 to 0.17; P=0.003).

CONCLUSIONS

tPA is used infrequently for ischemic stroke at US academic medical centers, even among qualifying candidates. African Americans are significantly less likely to receive tPA for ischemic stroke. Contraindications to treatment do not appear to account for the difference.

Pacing during ventricular fibrillation: factors influencing the ability to capture

INTRODUCTION

Recent studies showed that pacing atrial and ventricular fibrillation (VF) is possible. The studies presented here determined which parameters influence the efficacy of a pacing train to capture fibrillating ventricular myocardium. Electrode type, current strength, order of pacing trains, polarity, and VF morphology preceding the pacing trains were investigated.

METHODS AND RESULTS

A 504-electrode recording plaque sutured to the right ventricle of pig hearts was used to record the activations of VF and those resulting from the pacing stimulation. Capture of VF by pacing was determined by observing an animated display of the first temporal derivative of the electrograms. A series of electrodes in a line captured the heart more frequently during VF than did a point electrode. Increasing the current strength to 10 x diastolic pacing threshold increased the incidence of capture, but increasing this strength further did not. The second or third train of 40 stimuli had greater capture rates than did the first train during the same VF episode. Anodal and cathodal unipolar, and bipolar stimulation were equally efficacious in capturing VF. VF activation during the 1-second interval preceding pacing was more organized for pacing trains that captured than those that did not. The highest incidence of capture, 46% to 61% of pacing trains, occurred with a line of electrodes at 10 x diastolic pacing threshold delivered by the second or third train.

CONCLUSION

The probability of a pacing train capturing fibrillating myocardium can be influenced by the pacing protocol parameters.

Stent angioplasty for cervical carotid artery stenosis in high-risk symptomatic NASCET-ineligible patients

BACKGROUND AND PURPOSE

Although the North American Symptomatic Carotid Endarterectomy Trial (NASCET) has shown carotid endarterectomy (CEA) to be protective compared with medical therapy alone, its stringent eligibility criteria excluded patients with severe medical, angiographic, and neurological risk factors. We sought to determine the safety and efficacy of stent angioplasty in this high-risk subset for whom the perioperative morbidity and mortality of surgery are elevated.

METHODS

Twenty-eight consecutive symptomatic NASCET-ineligible patients (10 female; median age, 72.2 years) underwent microcatheter-based carotid stent angioplasty. Half of the patients had sustained a previous stroke. Classification of surgical risk by Sundt criteria yielded no patients in grade 1, 3 patients in grade 2 (10.7%), 8 in grade 3 (28.6%), and 17 (60.7%) in grade 4. Stratification of stroke risk for medical therapy according to the European Carotid Surgery Trial (ECST) 5-point score showed 8 patients with a score of 3 (28.6%), 12 with 4 (42.8%), and 8 with 5 (28.6%). Follow-up was obtained in all patients at a median of 14 months.

RESULTS

The procedure was technically successful in all cases (100%), with immediate stenosis reduction from a mean of 80.3% to 2.7%. There were no periprocedural deaths, 1 major stroke (3.6%), no minor strokes, and 3 transient ischemic attacks (10.7%). In-hospital complications included 2 nonfatal myocardial infarctions, 1 case of acute renal failure, and 1 groin hematoma requiring transfusion. There were 5 deaths during the follow-up period, all beyond 30 days after the procedure: 3 from cardiac causes, 1 from lung cancer, and 1 following unrelated surgery. The patient with major stroke died at 7.8 months during rehabilitation. No surviving patients had further strokes, and all except 1 (95.5%) remained asymptomatic. Anatomic follow-up in 20 patients showed occlusion in 2 (10%) (1 symptomatic, 1 asymptomatic) and intimal hyperplasia in 3 asymptomatic patients (15%).

CONCLUSIONS

The clinical results and sustained freedom from symptoms and stroke during the short available follow-up period suggest that stent angioplasty may be useful in the treatment of symptomatic cervical carotid stenosis in high-risk patients despite a notable incidence of restenosis.

The ichthyofauna of the marginal lagoons of the Sorocaba River, SP, Brazil: composition, abundance and effect of the anthropogenic actions

The marginal lagoons of the Sorocaba River fulfil important functions in their lotic ecosystems and for its fish communities, providing shelter, food, and area for fish early stages of development. The lagoons are also an escape from the river pollution since the physical-chemical characteristics of their water are more stable than the river water. Nevertheless, these lagoons are under a series of impacts that contribute to reduce their diversity and stability such as water pollution, deforesting and river dumping. These impacts decrease habitat availability, and modify the fish community structure by reducing the number of species in the Sorocaba River, the floodplains and its marginal lagoons.

Endovascular management of extracranial carotid artery dissection achieved using stent angioplasty

BACKGROUND AND PURPOSE

Dissection of the carotid artery can, in certain cases, lead to significant stenosis, occlusion, or pseudoaneurysm formation, with subsequent hemodynamic and embolic infarcts, despite anticoagulant therapy. We sought to determine the therapeutic value of stent-supported angioplasty retrospectively in this subset of patients who are poor candidates for medical therapy.

METHODS

Five men and five women (age range, 37-83 years; mean age, 51.2 years) with dissection of the internal (n=9) and common (n=1) carotid artery were successfully treated with percutaneous endovascular balloon angioplasty and stent placement. The etiology was spontaneous in five, iatrogenic in three, and traumatic in two. Seven of the treated lesions were left-sided and three were right-sided.

RESULTS

The treatment significantly improved dissection-related stenosis from 74+/-5.5% to 5.5+/-2.8%. Two occlusive dissections were successfully recanalized using microcatheter techniques during the acute phase. Multiple overlapping stents were needed in four patients to eliminate the inflow zone and false lumen and establish an angiographically smooth outline within the true lumen. There was one case of retroperitoneal hemorrhage, but there were no procedural transient ischemic attacks (TIAs), minor or major strokes, or deaths (0%). Clinical outcome at latest follow-up (16.5+/-1.9 months) showed significant improvements compared with pretreatment modified Rankin score (0.7+/-0.3 vs 1.8+/-0.44) and Barthel index (99.5+/-0.5 vs 80.5+/-8.9). One delayed stroke occurred in a treated patient with contralateral carotid occlusion following a hypotensive uterine hemorrhage at 8 months; the remaining nine patients have remained free of TIA or stroke.

CONCLUSION

In select cases of carotid dissection associated with critical hemodynamic insufficiency or thromboembolic events that occur despite medical therapy, endovascular stent placement appears to be a safe and effective method of restoring vessel lumen integrity, with good clinical outcome.

Modulation of CTP:phosphocholine cytidylyltransferase by membrane curvature elastic stress

The activity of CTP:phosphocholine cytidylyltransferase, a rate-limiting enzyme in phosphatidylcholine biosynthesis, is modulated by its interaction with lipid bilayers [Kent, C. (1997) Biochim. Biophys. Acta 1348, 79-90]. Its regulation is of central importance in the maintenance of membrane lipid homeostasis. Here we show evidence that the stored curvature elastic stress in the lipid membrane's monolayer modulates the activity of CTP:phosphocholine cytidylyltransferase. Our results show how a purely physical feedback signal could play a key role in the control of membrane lipid synthesis.

Patient presentation, angiographic features, and treatment of strangulation-induced bilateral dissection of the cervical internal carotid artery. Report of three cases

Domestic violence leading to strangulation by an abusive spouse can cause carotid artery dissection. This phenomenon is rare and has been described in only three previous instances. The authors present their management strategies in three additional cases. Three young women aged 24 to 43 years were victims of manual strangulation committed by their spouses 3 months to 1 year before presentation. Two of the patients suffered delayed cerebral infarctions before presentation and angiography demonstrated focal, mirror-image severe residual stenoses in the high-cervical internal carotid artery (ICA), which were characteristic of a healed chronic dissection; there was no evidence of fibromuscular dysplasia. One of these patients underwent unilateral percutaneous angioplasty with stent placement, and the other underwent bilateral percutaneous angioplasty. Both patients have recovered from their strokes and remain clinically stable at 8 and 20 months posttreatment, respectively. The third patient presented with bilateral ischemic frontal watershed infarctions resulting from an occluded left ICA and a severely narrowed right ICA. Given the extent of the established infarctions, this case was managed with a long-term regimen of anticoagulation medications, and the patient remains neurologically impaired. These cases illustrate the susceptibility of the manually compressed ICA to traumatic injury as a result of domestic violence. They identify bilateral symmetrical ICA dissection as a consistent finding and the real danger of delayed stroke as a consequence of strangulation. Endovascular therapy in which percutaneous angioplasty and/or stent placement are used can be useful in treating residual focal stenoses to improve cerebral perfusion and to lower the risk of embolic or ischemic stroke.

Dynamic CT perfusion to assess the effect of carotid revascularization in chronic cerebral ischemia

We present the case of a female patient who was studied with dynamic contrast-enhanced CT perfusion before and after carotid revascularization. Before treatment, there was decreased perfusion in the ipsilateral insula, which was shown to be resolved on the scan obtained 1 day after treatment, indicating the technical success of the revascularization. In the ipsilateral basal ganglia, there was delayed contrast agent clearance from the tissue, which was attributed to vasodilation; after revascularization, there remained a subtle stenotic effect. The observed changes in the dynamic CT perfusion study suggest that this technique may be a useful tool in the evaluation of patients with asymmetrical cerebral blood flow.

Subclavian arteritis and pseudoaneurysm formation secondary to stent infection

Technically uncomplicated percutaneous angioplasty and stent placement of a left subclavian artery stenosis was performed in a 56-year-old man for treatment of subclavian steal syndrome and vertebrobasilar insufficiency. Six days later the patient was readmitted with Staphylococcus aureus bacteremia and stigmata of septic emboli isolated to the ipsilateral hand. Nine days later he had computed tomography (CT) evidence of a contrast-enhancing phlegmon surrounding the stent. Despite clinical improvement and resolution of bacteremia on intravenous antibiotic therapy, the phlegmon progressed, and at day 21 a pseudoaneurysm was angiographically confirmed. The patient underwent surgical removal of the stented arterial segment and successful autogenous arterial reconstruction. The possible contributory factors leading to stent infection were prolonged right femoral artery access and an infected left arm venous access. Although the role of prophylactic antibiotics remains to be defined, it may be important in cases where the vascular access sheath remains in place for a prolonged period of time.

Practice variability in management of transient ischemic attacks

To define practice patterns in the management of transient ischemic attacks (TIAs), we surveyed practicing neurologists attending an educational conference in San Francisco, evaluating management decisions in 2 TIA case vignettes. In a vignette describing a hemispheric TIA 1 day prior with ipsilateral bruit, 53% chose admission, 47% elected an outpatient work-up, 28% treated with intravenous heparin and 70% chose aspirin, reflecting the disagreement about medical management of carotid stenosis in the literature. There was more agreement in the second case, a posterior circulation TIA 1 day prior with atrial fibrillation, in which 84% chose hospital admission, 74% chose intravenous heparin and 90% treated with some form of anticoagulation. There are areas of important practice variability in the management of TIAs. Further research is justified to guide patient care decisions in TIA patients.

From the archives of the AFIP. Imaging of musculoskeletal neurogenic tumors: radiologic-pathologic correlation

Numerous neurogenic tumors can affect the musculoskeletal system, including traumatic neuroma, Morton neuroma, neural fibrolipoma, nerve sheath ganglion, neurilemoma, neurofibroma, and malignant peripheral nerve sheath tumors (PNSTs). The diagnosis of neurogenic tumors can be suggested from their imaging appearances, including lesion shape and intrinsic imaging characteristics. It is also important to establish lesion location along a typical nerve distribution (eg, plantar digital nerve in Morton neuroma, median nerve in neural fibrolipoma, large nerve trunk in benign and malignant PNSTs). Traumatic and Morton neuromas are commonly related to an amputation stump or are located in the intermetatarsal space, respectively. Neural fibrolipomas show fat interspersed between nerve fascicles and are often associated with macrodactyly. Nerve sheath ganglion has a cystic appearance and commonly occurs about the knee. Radiologic characteristics of neurilemoma, neurofibroma, and malignant PNST at computed tomography (CT), ultrasonography, and magnetic resonance imaging include fusiform shape, identification of entering and exiting nerve, low attenuation at CT, target sign, fascicular sign, split-fat sign, and associated muscle atrophy. Although differentiation of neurilemoma from neurofibroma and of benign from malignant PNST is problematic, recognition of the radiologic appearances of neurogenic tumors often allows prospective diagnosis and improves clinical management of patients.

Improved paramedic sensitivity in identifying stroke victims in the prehospital setting

OBJECTIVE

The authors have previously shown that San Francisco paramedics without specific training in stroke recognition identified acute stroke victims with a 61% sensitivity and a 77% positive predictive value (PPV). The authors implemented an educational program on stroke to improve paramedic accuracy in stroke recognition.

METHODS

Twenty-two paramedics volunteered to attend a four-hour seminar about stroke and then were followed prospectively for six months. All encounters with adult patients who were evaluated by both trained and untrained paramedics and were transported to two university hospitals were reviewed. Subjects were identified by paramedic assessment as stroke/transient ischemic attack (TIA) and/or final hospital discharge diagnosis of stroke/TIA after detailed chart review. Sensitivity and PPV for paramedic identification of stroke were calculated.

RESULTS

During the prospective six-month phase, 84 confirmed stroke patients were transported to the target hospitals. Of the 32 who were transported by trained paramedics, all but three were identified as having stroke/TIA, resulting in a sensitivity of 91%. This is significantly higher than the 61% previously found (p=0.01). Nontrained paramedics also increased their sensitivity to 90%. Thirty-eight false-positive patients were identified, resulting in PPVs of 64% for trained paramedics and 69% for all other paramedics.

CONCLUSIONS

Institution of an educational stroke program was associated with a significant increase in sensitivity in stroke identification by the paramedics; however, educational influences outside this training program may have contributed to the increased sensitivity. Better education for paramedics, combined with rapid response to stroke victims once identified, may result in improved care for victims of acute stroke.

Emergency medical services dispatcher identification of stroke and transient ischemic attack

OBJECTIVE

Certain forms of stroke can be treated if access to medical care is expeditious. Since many stroke victims first enter medical care through emergency medical services (EMS) access, minimizing delays in the EMS system may translate to improved neurologic outcome. Because EMS dispatchers determine the response priority for these calls, dispatchers should be able to recognize the signs and symptoms of stroke based on their brief phone interviews. The authors studied the abilities of dispatchers in a major urban area to correctly identify stroke and transient ischemic attack (TIA) in victims who access 911 and describe what is communicated in the 911 call.

METHODS

A retrospective review was conducted of the medical records of patients treated for stroke or TIA at two urban hospitals during 1996. The tape-recorded 911 calls from patients using EMS were transcribed and analyzed. Information regarding dispatcher classification and triage of these calls was collected and described.

RESULT

The records of 182 patients with acute stroke or TIA were reviewed. Fifty-three percent of patients used EMS. Dispatchers coded 31% of their 911 calls as stroke. The word "stroke" was used without prompting by 51% of callers, yet fewer than half of these calls were coded as stroke by dispatchers. Many callers reported symptoms characteristic of stroke, including impaired communication (36%), weakness (30%), and decreased ability to stand or walk (25%). Only 41% of ambulances were sent at high priority.

CONCLUSION

People who activate EMS for stroke frequently use the word "stroke" and/or describe symptoms compatible with stroke in their calls. EMS dispatch protocols should be sensitive for these symptoms to ensure more accurate and timely ambulance dispatch.

Embolization of the meningohypophyseal trunk as a cause of diabetes insipidus

We present an unusual case of diabetes insipidus occurring after selective embolization of 50% dextrose and pure ethanol into an enlarged left meningohypophyseal trunk (MHT) supplying a dural carotid cavernous fistula. The inferior hypophyseal artery was not opacified during the selective preembolization MHT injection; however, diabetes insipidus developed abruptly a few hours after the procedure. The patient required intranasal 1-deamino-(8-D-arginine)-vasopressin for approximately 3 months, after which his symptoms resolved. The hazards of using liquid embolic agents, especially ethanol, in the cavernous branches of the internal carotid artery should always be borne in mind.

Endovascular recanalization with balloon angioplasty and stenting of an occluded occipital sinus for treatment of intracranial venous hypertension: technical case report

OBJECTIVE AND IMPORTANCE

Dural sinus thrombosis can lead to intracranial venous hypertension and can be complicated by intracranial hemorrhage. We present a case report of a patient who underwent endovascular recanalization and stenting of a thrombosed occipital sinus.

CLINICAL PRESENTATION

A 13-year-old patient with a history of chronic sinus thrombosis refractory to anticoagulant therapy presented with acute onset of aphasia and hemiparesis. Computed tomography and magnetic resonance imaging revealed hydrocephalus and cerebral edema. Angiography delineated multiple dural arteriovenous fistulae and persistent occlusion of the posterior sagittal, occipital, and bilateral transverse dural sinuses with retrograde cortical venous drainage.

INTERVENTION

After embolization of the dural arteriovenous fistulae, a transvenous approach was used to recanalize and perform balloon angioplasty of the right internal jugular vein and the occipital and left transverse sinuses, resulting in subsequent clinical improvement. The patient's condition deteriorated 3 days later with reocclusion of both balloon-dilated sinuses. Repeat angioplasty and then deployment of an endovascular stent in the occipital sinus were performed, and reestablishment of venous outflow was achieved, resulting in a decrease of intracranial venous pressure from 41 to 14 mm Hg and neurological improvement. At the 3-month follow-up examination, the stented occipital sinus remained patent and served as the only conduit for extracranial venous outflow; the patient remained neurologically intact at the 12-month follow-up examination.

CONCLUSION

This is the first report of mechanical recanalization, balloon angioplasty, and stent deployment in the occipital sinus to provide sustained venous outflow for the treatment of venous hypertension with retrograde cortical venous drainage in a patient with dural pansinus thrombosis refractory to anticoagulant therapy.

Endovascular stenting of an acutely thrombosed basilar artery: technical case report and review of the literature

OBJECTIVE AND IMPORTANCE

The goal of this report was to describe the successful percutaneous endovascular use of a Gianturco-Roubin-2 coronary stent in the treatment of an acute atherothrombotic occlusion of the basilar artery. To our knowledge, the percutaneous endovascular deployment of an intra-arterial stent for the treatment of an acute atherothrombotic occlusion of the basilar artery and the percutaneous endovascular placement of a Gianturco-Roubin-2 stent in the basilar artery have not been previously reported.

CLINICAL PRESENTATION

An 83-year-old man presented with a recurrent, transient, locked-in syndrome resulting from a lower basilar artery occlusion caused by vertebrobasilar thrombosis superimposed on severe proximal basilar artery atheromatous stenosis.

INTERVENTION

After successful superselective intra-arterial thrombolysis of the vertebrobasilar clot, balloon angioplasty of the underlying basilar artery stenosis was performed, without significant angiographic improvement. Percutaneous endovascular deployment of a Gianturco-Roubin-2 coronary stent of 4-mm diameter was subsequently performed, with excellent angiographic results.

CONCLUSION

The patient made a very good neurological recovery but unfortunately died as a result of cardiogenic shock and sepsis. Detailed neuropathological follow-up results are presented; stent patency was revealed in the postmortem examination. The anatomic and pathophysiological considerations of basilar artery stent placement for the treatment of acute basilar artery occlusion related to atherosclerotic stenosis are discussed.