Effect of clopidogrel on platelet aggregation and plasma concentration of fibrinogen in subjects with cerebral or coronary atherosclerotic disease.

Acetylsalicylic acid inhibits thromboxane A2 production and reduces the risk of vascular occlusive events by 20% to 25%. Ticlopidine inhibits ADP-dependent platelet aggregation and reduces the same risk by 30% to 35%, but produces some adverse effects. Clopidogrel is a ticlopidin-related antiplatelet drug, with the same mechanism of action; it reduces the expression of the glycoprotein IIb/IIIa, the fibrinogen receptor on the platelet surface. Clopidogrel has the same clinical efficacy of ticlopidin and has a decreased incidence of adverse effects. The effect of one daily dose of 75 mg of clopidogrel on platelet function in 90 subjects was evaluated; 41 with coronary artery disease and 49 with cerebral vascular disease. Before treatment and after 6 and 12 weeks, bleeding time and fibrinogen plasma concentration were also evaluated. There was a reduction in 5-microM ADP-induced platelet aggregation of 38%+/-27% at 6 weeks and 44%+/-29% at 12 weeks in patients with coronary artery disease; 35%+/-41%, 29%+/-59% in the cerebral vascular disease group; and 36%+/-36% and 35%+/-49% in the total group. Reduction of 20 microg/mL collagen-induced platelet aggregation was not significant in any group. Plasma fibrinogen levels did not vary during treatment. Bleeding time was significantly prolonged in all studied groups. There were no hemorrhagic complications; only digestive discomfort in less than 3% of patients. Clopidogrel efficiently reduces ADP-induced platelet aggregation and prolongs bleeding time and is a safe and efficacious antiplatelet drug.

[Cardiovascular risk factors and carotid atherosclerosis detected by ultrasonography]. / Factores de riesgo cardiovascular y aterosclerosis carotídea detectada por ultrasonografía.

OBJECTIVES: To assess the frequency of carotid atherosclerosis and its relation to cardiovascular risk factors in a general elderly population of Mexico City. MATERIAL AND METHODS: B-mode ultrasonography was performed to investigate carotid atherosclerosis in 145 CUPA (a research project) participants, between July 1993 and January 1996. The outcome was then related to cardiovascular risk factors. RESULTS: Prevalence of ultrasound-detected carotid atherosclerosis was 64.8%. Intimal-medial thickening was detected in 64 subjects (44.1%) and carotid plaques in 82 (56.5%); Fifty-two subjects had both intimal-medial thickening and plaques. However, only 8 subjects had carotid plaques with severe stenosis (5.5%). There were no significant differences in the prevalence of atherosclerotic lesions (male 61.9%, female 66.0%). Carotid atherosclerosis was significantly associated with age (p < 0.0001), high blood pressure (p < 0.001), isolated systolic hypertension (p = 0.01), hypercholesterolemia (p = 0.04), and diabetes mellitus (p = 0.06). Prevalence of carotid atherosclerosis increased progressively with the number of vascular risk factors. CONCLUSIONS: There was a high prevalence of carotid atherosclerosis in this general elderly population of Mexico City, and was almost equal to that reported in developed western countries. Age, hypertension, hypercholesterolemia, and diabetes were the strongest predictors of atherosclerosis.

[Sonographic patterns by transcranial Doppler in acute cerebral infarction]. / Patrones sonográficos por Doppler transcraneal en el infarto cerebral agudo.

AIM: To evaluate the correlations between the patterns of Transcranial Doppler (TCD) and the extent and pathophysiologic mechanism of the ischemia as well as the prognosis of patients with acute ischemic stroke. METHODS: 37 patients with ischemic stroke within the first 24 hours of evolution were examined using TCD, neuroimaging, and neurologic state at admission and disarcharge. The TCDs were grouped into four categories: normal, stenotic, hemispheric asymmetry and trunk occlusion of the middle cerebral artery (MCA); they were correlated with the extent of brain damage, pathophysiologic mechanism of the stroke and prognosis. RESULTS: Normal TCD was highly predictive of lacunar infarction secondary to small vassels disease (p = 0.01) and good recovery (p < 0.02). The stenotic and hemispheric asymmetry patterns correlated highly with a cortical infarctions (p < 0.05) and a cardioembolic mechanism. The occlusion of the MCA was highly correlated with a large infarction (p < 0.01) and with poor outcome and death (p = 0.004). CONCLUSIONS: Our data show that TCD has a value in predicting the prognosis and the severity, location and pathophysiologic mechanism of cerebral strokes.

[Prevalence of carotid atherosclerosis in a cohort of Mexico City]. / Prevalencia de aterosclerosis carotídea en una población de la ciudad de México.

In order to investigate the prevalence of atherosclerosis in Mexico, high resolution ultrasound and color Doppler flow imaging of carotid arteries were carried out in a group of participants in CUPA project, a cohort study started in 1989 among persons 60 years and older living permanently in a high rise in México City. Imaging studies included identification of 4 atherosclerosis related abnormalities: 1) intima media thickness; 2) kinkings and tortuousness; 3) non-stenosing plaques; and 4) significant carotid stenosis (> 50%). Analysis of 198 Doppler ultrasonographic studies in 56 males and 142 females showed an overall prevalence of atherosclerosis related lesions of 65.6%, with increasing frequency by age groups: 33% in younger than 65 year-old, 71% in 65-74 years, and up to 88% in the 75 years and older group. The prevalence of high grade stenosis was low (6%) whereas the overall frequency of non-stenosing plaques and intima-media thickness was higher than 60%. Intima-media thickness was more common in males while non-stenosing plaques and high grade stenosis were more frequent in females. However, there were not significant differences among women and men when atherosclerotic lesions were analyzed by age groups. This is the first report on the prevalence of atherosclerosis in a Mexican population using ultrasonography. Findings of the investigation document the high prevalence of atherosclerosis among elderly resident in Mexico City.