The irrelevance of adhesive platelet estimations after thrombosis

Abstract

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).

Platelet Consumption in Cardiovascular Disease

“…Spain and Bradess 292 Adelson et al 3 Spain and Bradess 293 Jørgensen et al 149 Scott and Briggs 275 Roberts and Buja 253 Friedman et al 94 Haerem 109 Myers Murphy and Mustard 207 Moolten et al 197 Poplawski et al 237 Badawi et al 8 Danta 64 Besterman et al 18 O'Brien et al 223 Chaudhuri 48 Sharma and Seth 278 Aznar et al 7 Eisen et al 82 Sjogren et al 285 Stormorken 310 Eastham 80 Danta 65 Fitzgerald et al 88 Besterman et al 18 Sullivan et al 312 Steele et al 304 Bygdeman and Eliasch 41 Aznar et al 7 Yamazaki et al 345 No unknown. There is no evidence that tests of platelet adhesion are of value as markers of in vivo platelet activation or consumption in ischemic heart disease.…”

“…The low frequency of elevated levels in patients with symptomatic deep vein thrombosis may be related to the time the samples are drawn in relation to the onset of the thrombotic event. 140 Negus et al 214 Eastham 80 Isacson and Nilsson 143 Becker 16 Steele et al 304 O'Brien et al 228 Warlow et al 331 Platelet Aggregate Ratio Schmidt 272 Wu et al 344…”