Deborah R. Horowitz

Volume of ventricular blood is an important determinant of outcome in supratentorial intracerebral hemorrhage.

OBJECTIVE To determine the prognostic significance and pathophysiologic implication of intraventricular extension of supratentorial intracerebral hemorrhage. DESIGN Prospective study. SETTING Acute stroke and neurointensive care units of a tertiary care hospital. PATIENTS One hundred twenty-nine patients with supratentorial intracerebral hemorrhage, managed medically. INTERVENTIONS Two patients had intraventricular catheters placed for external drainage. No patient received thrombolytics or surgical evacuation of clot. MEASUREMENTS AND MAIN RESULTS Of the 129 patients, 47 had intraventricular extension of their hemorrhages. These patients had larger intraparenchymal hemorrhages (36.6 cm3 vs. 15.0 cm3) and lower initial Glasgow Coma Scale scores (mean, 9.6 vs. 13.7). Their 30-day mortality rate was 43% compared with only 9% among those without ventricular extension. Univariate and multivariate logistic regression modeling was used to assess the prognostic significance of various measures of intraventricular hemorrhage. The presence of intraventricular hemorrhage, the number of ventricles containing blood, fourth ventricular blood, and intraventricular hemorrhage volume were each related to 30-day mortality in a univariate analysis, but only intraventricular hemorrhage volume contributed significantly to outcome prediction in the presence of Glasgow Coma Scale score. CONCLUSIONS Volume of intraventricular hemorrhage is an important determinant of outcome in supratentorial intracerebral hemorrhage.

Elevated Anticardiolipin Antibody Titer Is a Stroke Risk Factor in a Multiethnic Population Independent of Isotype or Degree of Positivity

BACKGROUND AND PURPOSE Previous studies have produced conflicting results regarding the putative association between anticardiolipin antibodies (aCL) and infarction in the general stroke population. These inconsistencies may be a function of sample size and methodological differences among the studies. The purpose of the present study, the largest case-control study of this issue to date, was to assess aCL status as an independent risk factor for ischemic stroke in a multiethnic, urban population. METHODS We obtained aCL titers in 524 hospitalized acute stroke patients and 1020 community controls enrolled in the Minorities Risk Factors and Stroke Study. The results were interpreted as negative (</=22.9 IgG phospholipid [GPL] or 10.9 IgM phospholipid [MPL] units), low positive (22.9 to 30.0 GPL or 10.9 to 15.0 MPL units), or high positive (>30.0 GPL or 15.0 MPL units). Odds ratios (ORs) were adjusted for age, sex, race/ethnicity, history of diabetes, hypertension, atrial fibrillation, coronary artery disease, and current cigarette smoking. RESULTS A positive aCL titer was present in 11% (111/1020) of controls and 34% (180/524) of cases. The adjusted OR for any positive aCL titer was 4.0 (95% CI, 3.0 to 5.5). For any positive IgG aCL titer this value was 3.9 (95% CI, 2.8 to 5.5), and for any positive IgM aCL titer it was 3.4 (95% CI, 2.1 to 5.5). There were no significant differences in ORs associated with high- or low-positive IgG or IgM aCL titers. CONCLUSIONS In the largest study of its kind to date, aCL antibodies were demonstrated to be independent stroke risk factors across the 3 ethnic groups studied, conferring a 4-fold increased risk of ischemic stroke. IgG and for the first time IgM aCL were each shown to be associated with increased stroke risk. The prevalence of these antibodies and the stroke risk associated appear greater than previously reported.

Validation and comparison of models predicting survival following intracerebral hemorrhage.

OBJECTIVE To compare the performance of two previously reported logistic regression models using data independent from those data used to derive the models. DESIGN Prospective. SETTING Acute stroke unit of a tertiary care hospital. PATIENTS One hundred twenty-nine patients with supratentorial intracerebral hemorrhage. MEASUREMENTS AND MAIN RESULTS Model 1 contains the initial Glasgow Coma Scale score, hemorrhage size, and pulse pressure. The more complex model 2 includes, in addition to those three variables, the presence or absence of intraventricular hemorrhage and a term representing the interaction of intraventricular hemorrhage and Glasgow Coma Scale score. The areas under the receiver operating characteristic curves generated for each model were statistically indistinguishable. CONCLUSIONS Model 1 predicts 30-day patient status as well as the more complex model 2. Model 1 provides a valid, easy-to-use means of categorizing supratentorial intracerebral hemorrhage patients in terms of their probability of survival.

Mechanisms in lacunar infarction.

Background and Purpose Lacunes are thought to occur in patients with hypertension or diabetes mellitus as a result of small-vessel disease. This study evaluated the importance of other stroke mechanisms in a population of patients with lacunar infarction. Methods We evaluated 108 consecutive patients with a lacune in the lenticulostriate distribution for other stroke risk factors such as carotid and cardiac disease. Results Hypertension was present in 68% of the patients and diabetes mellitus in 37%; both occurred in 28% and neither occurred in 23%. Noninvasive carotid studies identified atherosclerotic plaque as a possible embolic source in 23%. By previously established criteria, 18% were at high risk for cardioembolism. Of those with hypertension or diabetes mellitus, 36% were at risk for a carotid or cardiac embolus. Of those without hypertension or diabetes mellitus, 32% had a possible carotid or cardiac etiology. Conclusions The high incidence of carotid and cardiac disease in those with and without hypertension or diabetes mellitus suggests the importance of other stroke mechanisms in this population. Patients with lacunar infarction should therefore be evaluated for other causes of stroke that may be treatable.

Aortic plaque in patients with brain ischemia: diagnosis by transesophageal echocardiography.

We evaluated 183 patients with brain ischemia for an embolic source, using transesophageal echocardiography with extensive imaging of the thoracic aorta. There were mobile, frond-like projections of aortic plaque in seven (4%) patients. The plaque originated on a wide base on the posterior aspect of the ascending aorta at its junction with the transverse arch in six patients, and on the aortic root in one. The acute event was a cerebral infarction in five patients, and a transient ischemic attack in two. This type of aortic plaque could be a previously underdiagnosed source of cerebral embolism that is now easily visualized by transesophageal echocardiography.

Antiphosphatidyl serine antibodies are independently associated with ischemic stroke

OBJECTIVE To determine whether elevated titers of antiphosphatidyl serine antibodies (aPS) are associated with an increased risk of ischemic stroke in a general stroke population. BACKGROUND aPS are members of the family of antiphospholipid antibodies that has been associated with increased stroke risk. Although aPS have been demonstrated to occur in 18% of a group of young patients with cerebrovascular symptoms, their prevalence in the general stroke population is unknown, and no controlled study to assess the strength of their association with ischemic stroke has been undertaken previously. METHODS A case-control study comparing 267 acute ischemic stroke patients and 653 community controls. Sera were obtained immediately after acute stroke in patients. Titers of IgG aPS >16 IgG phospholipid units or IgM aPS >22 IgM phospholipid units were considered positive. Odds ratios (ORs) were obtained by logistic regression, adjusting for age, gender, race/ethnicity, history of hypertension, diabetes mellitus, cardiovascular disease, and cigarette smoking. RESULTS The adjusted OR was 5.6 (95% confidence interval [CI] 1.8, 18.0) for IgG aPS and 2.9 (95% CI 1.6, 5.3) for IgM aPS. The adjusted OR for either an elevated IgG or IgM aPS was 3.2 (95% CI 1.8, 5.5). CONCLUSIONS This study demonstrates that elevated IgG and IgM antiphosphatidyl serine antibodies titers are associated with increased risk of ischemic stroke. The prevalence of these antibodies is lower, but the associated stroke risk is comparable with that of anticardiolipin antibodies.

Autoregulatory cerebral vasodilation occurs during orthostatic hypotension in patients with primary autonomic failure

It is unclear whether patients with autonomic failure autoregulate cerebral blood flow during hypotension. The objective in this study was to examine cerebral autoregulatory capacity in patients with autonomic failure by studying changes in middle cerebral artery blood flow velocity using transcranial Doppler ultrasonography before, during, and after tilt-induced hypotension. Nine patients with primary autonomic failure were evaluated. Mean arterial pressure and middle cerebral artery blood flow velocity were simultaneously recorded while the patients were in the supine position, during 60o head-up tilt, and after they were returned to the horizontal position. The results were as follows: during tilt-induced hypotension, mean arterial pressure decreased significantly more than middle cerebral artery mean blood flow velocity (58% versus 36%, p<0.0002). After return to the horizontal position, mean arterial pressure returned to baseline, and middle cerebral artery blood flow velocity transiently increased above pretilt value (p<0.02). It is concluded that cerebral autoregulatory vasodilation occurs in patients with autonomic failure. This was demonstrated by a more pronounced decline in mean arterial pressure than in middle cerebral artery blood flow velocity during hypotension and by a transient increase in middle cerebral artery blood flow velocity (ie, hyperemic response) after blood pressure was restored.

Stroke mechanisms and clinical presentation in large subcortical infarctions

Large subcortical infarctions may be due to cerebral embolism and cause cortical signs more frequently than small subcortical infarctions, which usually result from small-vessel disease and are not associated with cortical findings. We evaluated 51 consecutive patients with a subcortical infarct on CT that was 1.5 cm or larger for a potential carotid or cardiac source of embolism and determined how frequently aphasia, hemineglect, or gaze paresis occurred. A carotid or cardiac embolic source was identified in 63% of the total population with a carotid source occurring in 23% and a cardiac source occurring in 49%. More than one-half of the patients with hypertension or diabetes mellitus had an embolic source, whereas all patients without these risk factors had a possible carotid or cardiac source of embolism. Aphasia or hemineglect occurred in 39% of patients and gaze paresis occurred in 41%. Large subcortical strokes frequently result in a different clinical syndrome and from a different mechanism than small subcortical strokes

Transesophageal echocardiography: Diagnostic and clinical applications in the evaluation of the stroke patient

OBJECTIVES Transesophageal echocardiography (TEE) is superior to transthoracic echocardiography (TTE) in diagnosing cardiac abnormalities that may result in cerebral embolism. The clinical importance of these abnormalities is unclear. METHODS We classified 96 consecutive stroke patients into high- or low-risk groups for cardioembolism based on historical criteria. The presence of left atrial thrombus, atrial smoke, patent foramen ovale, atrial septal aneurysm, and plaque in the ascending aorta was assessed with TEE. Stroke type and other possible stroke mechanisms were evaluated. RESULTS Left atrial thrombus occurred only in the high-risk group. Patent foramen ovale, atrial septal aneurysm, and most cases of left atrial smoke occurred in the presence of another embolic source or were associated with a stroke related to hypertensive small vessel disease. Protruding atherosclerotic plaque in the ascending aorta and aortic arch was the most significant cause of stroke diagnosed by TEE because it frequently occurred in those without other risk factors for stroke. TEE identified aortic plaque in one and left atrial smoke in two patients with lacunar infarction without risk factors for small vessel disease. CONCLUSIONS TEE should be considered in both lacunar and nonlacunar stroke that occur in the absence of stroke risk factors, although optimal management of most TEE findings is yet to be determined.

Abductive localization of brain damage: incorporating spatial adjacency relations

An important problem in neurology is to localize the site of damage to the nervous system given a patients examination findings. While the reasoning processes involved in this neurologic localization task are a type of diagnostic reasoning, they are distinguished by their heavy use of anatomical (spatial) relationships. Previous attempts to automate neurological localization have met with limited success. This paper describes an abductive problem-solving method for neurological localization based on parsimonious covering theory (PCT). Basic PCT is augmented by adding spatial relationships between elementary anatomic units. Our models localization for 100 stroke patients was compared to that of a neurologist specializing in stroke who was not involved with the models development. In 99 cases, the problem-solving system based on the augmented PCT algorithm identified the location of nervous system damage (brainstem or either hemisphere) found by the stroke expert. In the one case of complete disagreement, the problem-solving system was proven correct. Examination of the detailed localizations in terms of the elementary anatomical units involved indicated a number of interesting differences between human and automated inference processes. These results demonstrate that an augmented PCT approach has substantial promise for neurological localization.