Platelet aggregation in acute coronary syndromes: use of a new aggregometer with laser light scattering to assess platelet aggregability

Eto, Koji; Takeshita, Satoshi; Ochiai, Masahiko; Ozaki, Yukio; Sato, Tomohide; Isshiki, Takaaki

doi:10.1016/s0008-6363(98)00114-x

Cited by 63 publications

(44 citation statements)

References 21 publications

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“…30 It has been reported that platelet hyperaggregability during acute coronary syndrome may exist only during the primary aggregation process. 31 In recent reports, predictors of stent thrombosis have been premature antiplatelet therapy discontinuation, renal failure, bifurcation lesions, diabetes, small vessels, and a lower ejection fraction. 16,32 In the present study, however, there was no relationship between SAT and patient characteristics.…”

Section: Discussionmentioning

confidence: 99%

Predictors of Sub-Acute Stent Thrombosis in Acute Myocardial Infarction Patients Following Primary Coronary Stenting With Bare Metal Stent

Katayama

Nakashima

Takagi

et al. 2006

Circ J

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Section: Discussionmentioning

confidence: 99%

Predictors of Sub-Acute Stent Thrombosis in Acute Myocardial Infarction Patients Following Primary Coronary Stenting With Bare Metal Stent

Katayama

Nakashima

Takagi

et al. 2006

Circ J

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“…Our results showed that the reactions of platelet aggregation were clearly divided by 1 and 2 pM ADP. The concentration of 1 pM ADP is just the same as physiologic concentration [6,26,27]. Up to physiologic concentration of ADP (i.e., -.…”

Section: Discussionmentioning

confidence: 99%

Sex Difference in Platelet Aggregation Detected by New Aggregometry Using Light Scattering.

et al. 2001

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Abstract.Earlier studies in platelet aggregation have shown that females seemed to have greater aggregability than males as detected by conventional aggregometry which used light transmission (LT), but controversy still remains. This study was performed to determine whether sex difference exists in platelet aggregation by using the recently developed laser light scattering (LS) method, which can detect small aggregates (i.e., two or three platelets). Blood was drawn from healthy volunteers (10 male and 10 female in follicular phase after menstruation), and platelet aggregation was detected by either LT or LS method in platelet rich plasma.Platelet aggregation was stimulated by increasing concentration of adenosine 5 diphosphate (ADP, 0, 0.5, 1 and 2 pM). To detect the effect of sex hormones, platelets were incubated with estradiol (10 nM) or testosterone (40 nM) for 30 min, then platelet aggregation studies were performed.LT method revealed that female had greater aggregability than male. With weak stimuli (<_ 1,iM ADP), LS method showed that females had more medium aggregates than males, and that testosterone decreased small aggregates, and that estradiol decreased all sizes of aggregates. These data suggest that the female is more conductive to platelet aggregation than the male at a physiologic concentration of ADP (<-1 reM), but that both estradiol (10 nM) and testosterone (40 nM) have countereffects on platelet aggregation at the same condition. Therefore, the reason why females have greater aggregability than males may partly be explained by their lack of testosterone, but the mechanism still remains to be elucidated. has life-threatening bleeding during perinatal period. Some studies, however, have pointed out that the results in aggregometry between female and male are controversial [3,4]. The recently developed light scattering (LS) method has greater sensitivity than conventional LT method [5], since the LT method cannot detect small aggregates with less than 100 platelets, whereas the LS method can detect aggregates as small as two or three platelets [b, 7] . We applied this new method to exploring the sex differences in platelet aggregation. Sex hormones are the major difference between female and male, and the effect of estrogen on coagulation is sometimes discussed, but controversy still remains. High estrogen level is associated with

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“…Subsequent linkage of platelets to one another by fibrinogen or by vWF bound to the activated GP IIb/IIIa complex 22 may then lead to arterial thrombosis. 2,23,24 Recent data indicate that plasma vWF and platelet GPIb are essential in the response to varying hemodynamic conditions and that vWF-dependent platelet aggregation mediated by the vWF-GPIb interaction is necessary to functionally complement the activated GPIIb/IIIa in the presence of elevated fluid dynamic forces. 25 In contrast, it has been shown that high shear-induced aggregation of washed platelets increases as a function of the concentration of exogenous purified vWF.…”

Section: Discussionmentioning

confidence: 99%

AJvW-2, an Anti-vWF Monoclonal Antibody, Inhibits Enhanced Platelet Aggregation Induced by High Shear Stress in Platelet-Rich Plasma From Patients With Acute Coronary Syndromes

Eto

Isshiki²,

Yamamoto³

et al. 1999

ATVB

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Abstract-The platelet aggregation that is dependent on von Willebrand factor (vWF) is important in the thrombogenesisthat occurs under conditions of high shear stress, eg, during acute coronary syndromes (ACSs). A monoclonal antibody, AJvW-2, directed against the A1 domain of human vWF specifically blocks the interaction between plasma vWF and platelet glycoprotein (GP) Ib. To evaluate the association between the vWF-GPIb interaction and the enhanced shear-induced platelet aggregation (SIPA) observed in ACSs, we tested the effect of this antibody on platelet aggregation. Platelet-rich plasma was prepared from the citrated blood of 12 patients with unstable angina (UAP) and 20 patients with acute myocardial infarction (AMI) who were admitted within 3 hours of the onset of cardiac symptoms and from 18 controls. We observed the following: (1) 1.7-fold higher plasma levels of vWF and ristocetin cofactor activity in UAP patients and (2) 2.8-fold higher levels in the AMI group than in controls. Using a cone-and-plate viscometer, we measured the mean value of SIPA under high-shear conditions (108 dyne/cm 2 ) and found them to be 1.3-fold higher in the UAP group and 2.0-fold higher in the AMI group than in controls. The high SIPA in all groups was completely inhibited by 10 g/mL AJvW-2. Under low-shear conditions (12 dyne/cm 2 ), platelet aggregation was increased only in the AMI group, but this was unaffected by AJvW-2. We observed a significant correlation in both ACS groups between high SIPA and the plasma vWF level or vWF larger multimers. These findings suggest that the vWF-GPIb interaction is important in coronary occlusion and that inhibition of this interaction (with the use of AJvW-2) may prevent further events in the coronary arteries. A ctivation of platelets induced by physical shear stress or by physiological agonists is important in arterial thrombogenesis. 1,2 Increased levels of plasma von Willebrand factor (vWF) in patients with thrombotic disorders have suggested that this protein may be involved in thrombosis. For example, in survivors of acute myocardial infarction (AMI), the level of plasma vWF may be an index of the increased risk for reinfarction and mortality. 3 In addition, an enhanced plasma vWF concentration is thought to be an independent predictor of such acute coronary syndromes (ACSs) as unstable angina (UAP). 4 Most importantly, high physiological and/or pathological shear stress can induce vWF-mediated platelet aggregation in vitro 1,2,5,6 and may stimulate the interaction between plasma vWF and glycoprotein (GP) Ib on platelets in vivo, eg, in animal models with coronary artery occlusion. 7 To further clarify the molecular mechanism for arterial thrombogenesis and to seek an effective strategy for its prevention or treatment, efforts have focused on developing simple methods for monitoring vWFplatelet interactions in the blood of patients with ACSs. 2 The recent development of a cone-and-plate viscometer to monitor platelet aggregation under various shear conditions in the absence of an...

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Platelet aggregation in acute coronary syndromes: use of a new aggregometer with laser light scattering to assess platelet aggregability

Cited by 63 publications

References 21 publications

Predictors of Sub-Acute Stent Thrombosis in Acute Myocardial Infarction Patients Following Primary Coronary Stenting With Bare Metal Stent

Predictors of Sub-Acute Stent Thrombosis in Acute Myocardial Infarction Patients Following Primary Coronary Stenting With Bare Metal Stent

Sex Difference in Platelet Aggregation Detected by New Aggregometry Using Light Scattering.

AJvW-2, an Anti-vWF Monoclonal Antibody, Inhibits Enhanced Platelet Aggregation Induced by High Shear Stress in Platelet-Rich Plasma From Patients With Acute Coronary Syndromes

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