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.

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.

Ischemic preconditioning reduces peripheral oxidative damage associated with brain ischemia in rats.

Brain ischemia followed by reperfusion causes neuronal death related to oxidative damage. Furthermore, it has been reported that subjects suffering from ischemic cerebrovascular disorders exhibit changes in circulating platelet aggregation, a characteristic that might be important for their clinical outcome. In the present investigation we studied tert-butyl hydroperoxide-initiated plasma chemiluminescence and thiol content as measures of peripheral oxidative damage in naive and preconditioned rats submitted to forebrain ischemia produced by the 4-vessel occlusion method. Rats were submitted to 2 or 10 min of global transient forebrain ischemia followed by 60 min or 1, 2, 5, 10 or 30 days of reperfusion. Preconditioned rats were submitted to a 10-min ischemic episode 1 day after a 2-min ischemic event (2 + 10 min), followed by 60 min or 1 or 2 days of reperfusion. It has been demonstrated that such preconditioning protects against neuronal death in rats and gerbils submitted to a lethal (10 min) ischemic episode. The results show that both 2 and 10 min of ischemia cause an increase of plasma chemiluminescence when compared to control and sham rats. In the 2-min ischemic group, the effect was not present after reperfusion. In the 10-min ischemic group, the increase was present up to 1 day after recirculation and values returned to control levels after 2 days. However, rats preconditioned to ischemia (2 + 10 min) and reperfusion showed no differences in plasma chemiluminescence when compared to controls. We also analyzed plasma thiol content since it has been described that sulfhydryl (SH) groups significantly contribute to the antioxidant capacity of plasma. There was a significant decrease of plasma thiol content after 2, 10 and 2 + 10 min of ischemia followed by reperfusion when compared to controls. We conclude that ischemia may cause, along with brain oxidative damage and cell death, a peripheral oxidative damage that is reduced by the preconditioning phenomenon.

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

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

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