The variability of human platelet aggregation

Harrison, M. J. G.; Emmons, Patricia; Mitchell, J. R. A.

doi:10.1016/s0368-1319(67)80081-4

Cited by 58 publications

(15 citation statements)

References 15 publications

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“…Our results do not confirm those of Harrison et al [6] who reported that 'plasma instability' was increased by exercise: the changes in platelet aggregation with increasing time interval after venepuncture occurred at the same rate in pre-and post-exercise PRP.…”

Section: Discussioncontrasting

confidence: 99%

Effect of Exercise on Platelet Count, Adhesion, and Aggregation

Warlow¹,

Ogston²

1974

Acta Haematol

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15 min of strenuous exercise caused a highly significant rise in the venous platelet count without altering platelet adhesion to glass. It also produced a significant increase in the rate of the second phase of ADPand adrenaline-induced aggregation, 5-HT-induced aggregation and disaggregation, and collagen-induced aggregation. These changes in platelet number and function following exercise should be taken into account when anti-platelet drugs are assessed in human subjects, and when changes in these parameters are sought in disease states.

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Section: Discussioncontrasting

confidence: 99%

Effect of Exercise on Platelet Count, Adhesion, and Aggregation

Warlow¹,

Ogston²

1974

Acta Haematol

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“…28,29 However, no reports of the method's reproducibility (or lack thereof) detail measures taken to minimize such within-individual variability as we have in this study. 25,30,31 Furthermore, we are unaware of previous reproducibility studies that have used submaximal agonist concentrations as we have. Such differences in study methodology may partially explain why the reproducibility of some of the aggregation assays we performed appears adequate in spite of widely held concerns and previous reports to the contrary.…”

Section: Reproducibility Of Platelet Hyperreactivitymentioning

confidence: 99%

“…Such differences in study methodology may partially explain why the reproducibility of some of the aggregation assays we performed appears adequate in spite of widely held concerns and previous reports to the contrary. 25,30 Association of platelet hyperreactivity with other variables Platelet hyperreactivity to 0.4 M epinephrine was significantly associated with female sex and higher fibrinogen levels. Compared with platelets from men, platelets from women have been previously shown to display increased reactivity to standard concentrations of agonists.…”

Section: Reproducibility Of Platelet Hyperreactivitymentioning

confidence: 99%

Aggregometry detects platelet hyperreactivity in healthy individuals

Yee

Sun

Bergeron

et al. 2005

Blood

176

177

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Aggregometry is widely used to assess platelet function, but its use in identifying platelet hyperreactivity is poorly defined. We studied platelet aggregation in 359 healthy individuals using the agonists adenosine diphosphate (ADP), epinephrine, collagen, collagen-related peptide, and ristocetin. We also assessed the reproducibility of these assays in 27 subjects by studying them repeatedly on at least 4 separate occasions. Healthy subjects exhibited considerable interindividual variability in aggregation response to agonists, especially at concentrations lower than those typically used in clinical laboratories. For each agonist tested at these submaximal concentrations, a small proportion of individuals demonstrated an unusually robust aggregation response. Subjects who exhibited such in vitro hyperreactivity to one agonist tended to demonstrate a similar response to others, suggesting that hyperreactivity is a global characteristic of platelets. Epinephrine and collagen-related peptide were especially reliable and efficient in detecting hyperreactivity. For epinephrine, excellent reproducibility persisted for up to 3 years, and hyperreactivity was associated with female sex and higher fibrinogen levels (P < .02). We recommend these assays as appropriate candidates for future studies requiring accurate assessment of increased platelet reactivity. These include clinical studies to improve risk assessment for arterial thrombosis, as well as genetic studies to establish determinants of the hyperreactive platelet phenotype. (Blood. 2005;106:2723-2729)

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“…Further evidence of humoral control of platelet adhesiveness, either with added ADP or without added ADP, is that platelet adhesiveness increases within four hours of surgical operation, especially when the method of estimation includes erythrocytes from the patient (Bennett, 1968), and it is of interest that platelet adhesiveness and red cell electrophoretic migration rates are directly correlated (Davies and Lloyd, 1967). Similarly plasma obtained from subjects after exercise or stress shows that these factors grossly enhance platelet aggregation (Harrison, Emmons, and Mitchell, 1967). Although ADP is released from platelets.…”

Section: Discussionmentioning

confidence: 99%

The irrelevance of adhesive platelet estimations after thrombosis

Eastham

1970

J Clin Pathol

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SYNOPSIS It has been found that adhesive platelet counts are not of clinical use either after surgical operation or during long-term anticoagulant therapy in the detection of thrombosis. Calculation of the theoretical risk of development of platelet thrombi related to the platelet count suggests a possible reason for this absence of clinical significance. The evidence that platelet adhesiveness alters because of uncontrollable platelet variables and is controlled at least in part by plasma factors is discussed. The possibility of measuring the plasma factors is considered briefly.Estimation of platelet adhesiveness has not been found to be clinically useful either during longterm anticoagulant therapy (Eastham, 1966;Eastham and Avis, 1966) or in the detection of venous thrombosis after surgery (Negus, Pinto, and Brown, 1969). A reassessment of this absence of obvious clinical significance has now been attempted, as there is evidence that the degree of platelet adhesiveness can change rapidly without any variation in the total platelet count, and because it now appears that platelet adhesiveness is greatly influenced by plasma factors (Bennett, 1968; Besterman, Myat, and Travadia, 1967;Bolton, Hampton, and Mitchell, 1967). Methods and MaterialsTotal platelet counts and adenosine diphosphate (ADP)-induced adhesive platelet counts were performed on a total of 650 blood samples from six male volunteers and from 57 patients during long-term anticoagulant therapy over a period of six to 24 months, using the methods of Eastham (1963 and1964 deep vein thrombosis and a history of attacks of pulmonary embolism, and 45 men and one woman who had suffered from myocardial infarction. All these patients were being treated with oral anticoagulants.In addition, total and adhesive platelet counts were obtained daily from a 24-year-old woman suffering from idiopathlc thrombocytopenic purpura, who underwent spienectomy to relieve this condition. ResultsThe mean adhesive platelet count for the whole group was 56% (1 SD = 88%) of the total platelet count. Mean values for the adhesive platelet counts in the six volunteers not taking oral anticoagulants (545 %), nine patients with venous thromboses (55-2%), and 46 patients following myocardial infarction (56-2 %) were not significantly different from the total mean value. Pegrum, Shaw, and Wolff (1967), using the same method, obtained a mean value of 60-5 ± 6-35 % from 67 normal control subjects. This result is significantly different from the mean value for these patients on oral anticoagulants (P < 0-01).

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The variability of human platelet aggregation

Cited by 58 publications

References 15 publications

Effect of Exercise on Platelet Count, Adhesion, and Aggregation

Effect of Exercise on Platelet Count, Adhesion, and Aggregation

Aggregometry detects platelet hyperreactivity in healthy individuals

The irrelevance of adhesive platelet estimations after thrombosis

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