Blood rheology in patients with transient ischemic attacks.

Abstract

A complete ischemic stroke is associated with a significant hemorheologic disturbance leading to a rise of the viscous component of the peripheral resistance. This abnormality represents a consequence of the acute event. Nonetheless, it could be causally related to ischemia. In an attempt to clarify this question, 26 patients suffering from transient ischemic attacks were compared with controls in terms of blood and plasma viscosity, hematocrit, blood cell filterability, and erythrocyte aggregation. In patients there was a significant impairment of blood fluidity comprising plasma viscosity, blood cell filterability, and erythrocyte aggregation, suggesting that the flow properties of blood are jeopardized even before an acute stroke. Most likely this is due to the underlying arteriosclerotic process. Our results open the way to speculating that hemorheologic mechanisms might predispose to the development of a stroke by decreasing cerebral blood flow. If this hypothesis were true, it would have important therapeutic implications. (Stroke 1988;19:634-636) T here is ample information on the flow properties of blood after an acute ischemic stroke. 1 " 6 These studies unanimously agree that both cellular and plasmatic abnormalities lead to a marked limitation of blood fluidity. Such changes may be looked upon as a consequence of a stroke; however, they could also contribute to the development of ischemia by virtue of their detrimental influence on cerebral blood flow.7 - 8A transient ischemic attack (TLA) with hemodynamicalry relevant stenosis of the internal carotid artery represents a precursor of stroke.*" 11 Little is known about the flow properties of blood in this condition. Our study was aimed at investigating the blood rheology of TLA patients and testing the hypothesis that blood fluidity is impaired not only after, but also before, an ischemic stroke. Subjects and MethodsTwenty-six consecutive outpatients (12 women, 14 men; aged 50 ± 15 years) with a history of TIAs (a minimum of one attack within the last 4 weeks) and ultrasonic evidence of a stenosis of the internal carotid artery of at least 75% were investigated. A control group (n -26) was selected to match the age (47 ± 14 years) and sex distributions (12 women, 14 men) of the patients. The frequency and distribution of cardiovascular risk factors (hypertension, smoking, hyperlipidemias, diabetes, obesity) were comparable in both groups (Table 1). The control group

Cushing`s disease: Fibrinogen and D-dimer levels fail to normalize despite early postoperative remission — a prospective, controlled study

“…High fibrinogen levels have been observed in patients with myocardial infarction, stroke, and transient ischaemic attacks, i.e. in conditions characterised by an undeniable thrombotic aspect [18][19][20][21]. Fibrinogen levels have been demonstrated to be higher with age, in smokers, in the obese, in diabetes, and in hypertension [18,19].…”

“…in conditions characterised by an undeniable thrombotic aspect [18][19][20][21]. Fibrinogen levels have been demonstrated to be higher with age, in smokers, in the obese, in diabetes, and in hypertension [18,19]. Fibrinogen is very likely to be a mediator of the prothrombotic effect of other cardiovascular risk factors [17,18,22].…”

“…The pathophysiological mechanisms involved in this effect include its impact on platelet aggregation and vascular endothelial function. Fibrinogen also affects the fluidity of blood by increasing blood viscosity and platelet aggregation [18][19][20][21]23].…”

Effects of the coadministration of Huatuo Zaizao pills and aspirin on hemorrheology and blood coagulation in rabbits

“…Recent data also demonstrated that >80% of strokes are ischemic and the main factors underlying the pathomechanism of brain ischemia are arterial obstruction and microcirculatory stasis. Previous studies reported a significantly elevated PV, erythrocyte aggregation and impaired red blood cell deformability in ischemic stroke patients (11). Data obtained from several studies confirmed that all ischemic strokes are associated with significant rheological abnormalities, independent of the subtype (12,13).…”

Viscoelastic properties of pediatric blood

“…These include high RBC count, inherited RBC abnormalities, altered RBC membrane properties and any other RBC property that can alter blood viscosity [Andrews, et al 1999] • Ischemia of the heart, brain and limbs -This kind of ischemia is defined as a temporary deficiency of blood flow to the heart, brain or limbs. Plasma viscosity and RBC aggregation is indicated to be increased in this condition [Ernst, et al 1988] leading to a Transient Ischemia Attack.…”