Platelet function, coagulation and fibrinolysis in patients with previous coronary and cerebrovascular ischemic events

OBJECTIVES: Ischemic stroke (IS) or transient ischemic attack (TIA) history is present in 4-17% of patients with coronary artery disease (CAD). This subgroup of patients is at high risk for both ischemic and bleeding events. The aim of this study was to determine the role of platelet aggregability, coagulation and endogenous fibrinolysis in patients with CAD and previous IS or TIA. METHODS: A prospective case-control study that included 140 stable CAD patients divided into two groups: the CASE group (those with a previous IS/TIA, n=70) and the CONTROL group (those without a previous IS/TIA, n=70). Platelet aggregability (VerifyNow Aspirin® and VerifyNow P2Y12®), coagulation (fibrinogen and thromboelastography by Reorox®) and endogenous fibrinolysis (D dimer and plasminogen activator inhibitor-1) were evaluated. RESULTS: Patients in the CASE group presented significantly higher systolic blood pressure levels (135.84±16.09 vs 123.68±16.11, p<0.01), significantly more previous CABG (25.71% vs 10%, p=0.015) and significantly higher calcium channel blocker usage (42.86% vs 24.29%, p=0.02) than those in the control group. In the adjusted models, low triglyceride values, low hemoglobin values and higher systolic blood pressure were significantly associated with previous IS/TIA (CASE group). Most importantly, platelet aggregability, coagulation and fibrinolysis tests were not independently associated with previous cerebrovascular ischemic events (CASE group). CONCLUSION: Platelet aggregability, coagulation and endogenous fibrinolysis showed similar results among CAD patients with and without previous IS/TIA. Therefore, it remains necessary to identify other targets to explain the higher bleeding risk presented by these patients.

Plasma antithrombin III deficiency in ischaemic stroke in the young.

A deficiency of plasma antithrombin III has been identified as a potential risk factor for thrombosis. In a pilot study of 56 patients aged less than 40 years who presented with ischaemic stroke of unknown etiology, we detected only one case of plasma antithrombin III deficiency. Antithrombin III activity was estimated by a chromogenic assay. Hence, antithrombin III deficiency, though rare, should be considered while evaluating young patients with stroke of unknown etiology.

Platelet functions & lipid profile within 24 hours following an attack of TIA, thrombotic & haemorrhagic stroke.

The present study was undertaken to evaluate comparatively the lipid profile and platelet functions within 24 h of the three most frequent types of stroke encountered in clinical practice. Twenty patients of transient ischaemic attacks, 22 of thrombotic stroke and 26 of haemorrhagic stroke (hypertensive putaminal haemorrhage), all within 24 h of the acute event, and 21 control subjects were studied. Spontaneous platelet aggregation, platelet aggregation induced with adenosine diphosphate (2.5, 3.75 and 5.0 microM) and lipid profile (serum cholesterol, triglycerides, high density lipoprotein, low density lipoprotein and very low density lipoprotein) estimations were performed in all the subjects. Mean platelet aggregation values were significantly lower in haemorrhagic stroke patients as compared to controls. Serum cholesterol, triglycerides and very low density lipoprotein levels in ischaemic groups i.e., transient ischaemic attacks and thrombotic stroke patients, were significantly elevated, more so in the former group. It appears that platelet hypofunction has a role in the pathogenesis of hypertensive putaminal haemorrhage while in patients of transient ischaemic attack and thrombotic stroke, lipids may be a contributing factor in cerebral atherogenesis.

Lipoproteínas del suero de la enfermedad cerebrovascular isquémica / Serum lipoproteins in the ischemic cerebrovascular disease

Se estudiaron las lipoproteinas del suero de 103 pacientes con enfermedad cerebrovascular isquémica (66 con infarto cerebral y 37 con ataques transitorios ded isquemia cerebral) y de 101 controles. Ambos grupos se distribuyeron en 2 subgrupos de edad: de 40 a 59 años y de 60 a 79 añs. Para la separación de las lipoproteínas del suero se empleó la electrofóresis engel de poliacrilamida, con la que se observó un porciento menor de fracción alfa y un mayor porciento de fracción prebeta en todos los grupos de pacientes: un porciento menor de fracción beta en pacientes masculinos de ambos grupos de edad y un mayor porciento de fracción de densidad intermedia en todos los grupos de pacientes con excepción de las mujeres entre 60 y 79 años de edad. Se concluye que el método es de utilidad para el estudio de las alteraciones del metabolismo lipídico en pacientes con enfermedad cerebrovascular isquémica

Risk factors in extracranial carotid disease.

One hundred patients with ischaemic cerebro vascular disease (TIA/RIND--67% and completed stroke--33%) were evaluated for various clinical and biochemical risk factors. Evidence of extra-cranial carotid vascular disease (ECCVD) was looked for by using Doppler scan and carotid angiography. Of the 28 patients with abnormal Dop scan, 27 were confirmed to have ECCVD by angiography. Though the history of hypertension was elicited in 40%, only 28% had BP of 160/95 mm Hg or more during hospital stay. Hypertension was twice more common in ECCVD group compared to the group with normal carotid vessels. Obesity was seen in 15%, diabetes mellitus in 10% and 1% had hyperuricaemia. Total cholesterol was elevated in 29% and HDL cholesterol fraction was decreased (less than 35 mg%) in 43%. The reduction of HDL cholesterol was more frequent in ECCVD group (63%) and in hypertensive (73%) patients. Lipoproteins, triglycerides, free fatty acids and phospholipids were not significantly affected.

An in vivo assessment of stenotic disease using the instantaneous mean velocity curves generated at sites near the vessel wall

Investigaçöes efetuadas anteriormente "in vitro" demonstraram que o registro da velocidade média instantânea do fluxo sangüíneo arterial, obtida por meio de instrumentaçäo ultrasônica "Doppler", podem ser indicadores bastante úteis na detecçäo de perturbaçöes de fluxo geradas através de modelos de estenoses. Os modelos testados foram desenhados para reduzir o lúmen arterial de até 15%. Säo descritos aqui os resultados obtidos "in vivo", usando-se um sistema rastreador de velocidades minimas, o qual é conectado a um instrumento ultrasônico Doppler pulsátil de múltiplos canais. Esta investigaçäo demonstrou que este sistema permite a detecçäo de perturbaçöes do fluxo sangüíneo, as quais näo säo percebidas outros métodos näo invasivos usados como comparaçäo