Activated protein C resistance in patients with arterial ischemic stroke

BACKGROUND

Activated C protein resistance (APC-R) has recently been reported to be a common cause of thrombophilia; it may be acquired or caused by a genetic defect (factor V Leiden mutation). It is clear that there is an association between APC-R and venous thrombosis. It has been suggested that there is a possible relationship of APC-R with arterial ischemic stroke (IS), but case-control studies have not given enough clues for considering APC-R as a main risk factor.

OBJECTIVES

To assess the incidence of APC-R in patients with IS of several ethiologies in Buenos Aires.

PATIENTS AND METHODS

Seventy-two patients with IS were assessed for signs or symptoms of previous clinical thrombophilia and the presence of vascular risk factors (RF). They were searched for APC-R (COATEST, APC resistance-V, with a predilution of the samples) test. Determinations were carried out between 1 to 4 months after the ischemic episode. The plasma of 50 healthy control subjects (blood donors) was used as controls.

RESULTS

None of the patients had signs of previous thrombophilia; 57 (79.2%) had RF for IS, and 3 (4.2%) had APC-R (all of them with RF). One subject in the control group (2%) showed a low APC response (1/50). The occurrence of APC-R among patients with stroke was not significantly higher when compared with the occurrence of APC-R among the control subjects.

CONCLUSIONS

In the present series, the incidence of factor V Leiden related APC-R in the group with IS was similar to the healthy population. Other risk factors were associated in patients showing APC-R.

Southern Buenos Aires stroke project

BACKGROUND

Ethnic differences and vascular risk factors are the major determinants of stroke subtypes. Nevertheless, specific data from undeveloped countries is difficult to obtain. Natives from South America may have a higher frequency of penetrating small vessel disease and hemorrhagic stroke. However, there are few studies in South America supporting these findings.

OBJECTIVE

We analyze demographic, ethnic, risk factors, clinical characteristics, and stroke subtypes in all patients with acute stroke admitted to our hospital.

METHODS

We studied all consecutive acute stroke patients admitted to the Ramos Mejia Hospital in Buenos Aires from 1997 to 1999. Our hospital serves a determined population of Southern Buenos Aires. Data were collected prospectively on patients' admission in a form especially designed for this study including vascular risk factors, clinical features, epidemiological characteristics, and neuroradiological findings. Stroke subtypes were determined according to the TOAST classification.

RESULTS

Among 361 acute stroke patients, 31% had hemorrhagic stroke. It was more frequent among Natives (34%) than Caucasians (27%) (P<0.002). Ischemic stroke subtypes were as follows: 105 (42%) patients had lacunar, 31 (12%) atherosclerotic stroke, 53 (21%) cardioembolic infarction, and 16 (6%) other causes of stroke. Forty-five (18%) patients were classified as undetermined. Small vessel disease was higher among Caucasians (35%) than Natives (24%).

CONCLUSIONS

Penetrating artery disease (42%) and intracranial hemorrhage (31%) were the most common stroke subtypes, being more frequent than reported in the literature. Natives had significantly higher frequency of hemorrhagic stroke than Caucasians.

Multiple simultaneous intracerebral hemorrhages: clinical features and outcome

BACKGROUND

The simultaneous occurrence of intracerebral hemorrhages in different arterial territories is an uncommon clinical event. Its predisposing factors and pathophysiological mechanisms are not clearly defined.

OBJECTIVE

To analyze the frequency, risk factors, clinical features, neuroimaging findings, and outcome of multiple simultaneous intracerebral hemorrhages (SIHs).

PATIENTS AND METHODS

We studied all patients with acute stroke admitted to our hospital from July 18, 1997, through December 18, 1999. Multiple SIHs were defined as the presence of 2 or more intracerebral hemorrhages affecting different arterial territories with identical computed tomographic density profiles. Patients with a history of traumatic brain injury were excluded from this study. Diagnostic investigation included routine blood and urine tests, coagulation studies, a chest radiograph, electrocardiogram, 2-dimensional transthoracic echocardiography, and computed tomography of the head without contrast medium. Disability was assessed using the National Institutes of Health Stroke Scale and Modified Rankin Scale.

RESULTS

Among 142 patients with hemorrhagic stroke, we found 4 (2.8%) with SIHs. All 4 patients had a history of uncontrolled arterial hypertension. We excluded other potential causes of multiple SIHs by using appropriate diagnostic tests. The most common clinical manifestations were headache and weakness. Localization of hematomas was supratentorial, except for one patient who had both infratentorial and supratentorial hemorrhages. The mean National Institutes of Health score on admission was 15 and the Modified Rankin Scale score was higher than 4 at 3 months.

CONCLUSIONS

In our study, all patients with multiple SIHs had arterial hypertension and a poor outcome. Additional analytic studies, including new imaging techniques, can help to elucidate the association between arterial hypertension and multiple SIHs, risk factors, and underlying mechanisms of this clinical condition.

[Fluctuation in bilateral thalamic infarction: diffusion study using magnetic resonance]

INTRODUCTION

Bilateral paramedian thalamic infarcts are uncommon. The most frequent clinical manifestations are acute impairment of consciousness, oculomotor abnormalities and cognitive disturbances. A fluctuating course has not been previously reported.

CLINICAL CASE

A 66 year-old woman with a past history of arterial hypertension and diabetes was admitted to our hospital presenting four episodes of decreased consciousness and vertical gaze paresis. Neurological examination between episodes was unremarkable. Diffusion-weighted magnetic resonance imaging revealed high-signal lesions in both paramedian thalamic areas.

CONCLUSIONS

Fluctuating impairment of consciousness may be a clinical presentation of bilateral paramedian thalamic infarction. Atheromatous occlusion of the mouth of the paramedian thalamic penetrating artery is the most common cause. Neurological findings and diffusion-weighted images may help to define the extension and the underlying pathophysiological mechanism.

Differences in stroke subtypes among natives and caucasians in Boston and Buenos Aires

BACKGROUND AND PURPOSE

Several issues regarding ethnic-cultural factors, sex-related variation, and risk factors for stroke have been described in the literature. However, there have been no prospective studies comparing ethnic differences and stroke subtypes between populations from South America and North America. It has been suggested that natives from Buenos Aires, Argentina, may have higher frequency of hemorrhagic strokes and penetrating artery disease than North American subjects. The aim of this study was to validate this hypothesis.

METHODS

We studied the database of all consecutive acute stroke patients admitted to the Ramos Mejia Hospital (RMH) in Buenos Aires and to the Beth Israel Deaconess Medical Center (BIMC) in Boston, Massachusetts, from July 1997 to March 1999. Stroke subtypes were classified according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. All information on patients (demographic, clinical, and radiographic) was recorded prospective to the assessment of the stroke subtype.

RESULTS

Three hundred sixty-one and 479 stroke patients were included at RMH and BIMC stroke data banks, respectively. Coronary artery disease was significantly more frequent in BIMC (P:<0.001), whereas tobacco and alcohol intake were significantly more frequent in RMH (P:<0.001). Intracerebral hemorrhage (P:<0.001) and penetrating artery disease (P:<0.001) were significantly more frequent in the RMH registry, whereas large-artery disease (P:<0.02) and cardioembolism (P:<0.001) were more common in the BIMC data bank.

CONCLUSIONS

Penetrating artery disease and intracerebral hemorrhage were the most frequent stroke subtypes in natives from Buenos Aires. Lacunar strokes and intracerebral hemorrhage were more frequent among Caucasians from Buenos Aires than Caucasians from Boston. Poor risk factor control and dietary habits could explain these differences.