An Abnormal Pattern of Adenosine Diphosphate-Induced Platelet Aggregation in Acute Myocardial Infarction

Summary

Platelet aggregation as induced by A.D.P. has been studied using the fragiligraph. With this instrument continuous registration for 60 min of the aggregation - disag gregation - behaviour of platelet rich plasma (P.R.P.) has become practicable and a number of parameters of the curves could then be defined and analysed. Specimens from 24 male patients with acute myocardial infarction and 14 normal controls were compared. P.R.P. of the controls exhibited a short phase of an initial rise in optical density (O.D.) lasting 10-20 sec, a phase of decreasing O.D. (5 min), pointing to platelet aggregation and a phase of disaggregation afterwards. The samples of the myocardial patients differed clearly in several aspects : in most of them (18) the initial rise in O.D. was absent and aggregation started immediately; it was though slower but reached a greater extent. The time of maximum aggregation was significantly greater in the patients and there was no overlap with the controls. Coarse aggregates were clearly visible. Final disaggregation was either minimal or absent. At a concen tration of A.D.P. 0.59 γ/ml, the aggregation curve was biphasic in most patients, whereas it was monophasic in the controls. The curves obtained were mathematically analysed including the definition of a parameter called “aggregation time”, τ, and an attempt was made to clarify several of the properties of the curves in terms of platelet behaviour.

• References

• 1 O’Brien J. R. Platelet stickiness. Ann. Rev. Med 17: 275 1966;
• 2 Born G. V. R. Aggregation of blood platelets by adenosine diphosphate and its reversal. Nature (Lond) 194: 927 1962;
• 3 O’Brien J. R. Platelet aggregation. II. Some results from a new method of study. J. clin. Path 15: 446 1962;
• 4 O’Brien J. R. A comparison of platelet aggregation produced by seven compounds and a comparison of their inhibitors. J. clin. Path 17: 275 1964;
• 5 Mitchell J. R. A, Sharp A. A. Platelet clumping in vitro. Brit. J. Haemat 10: 78 1964;
• 6 Hovig T. Release of a platelet - aggregating substance (adenosine disphosphate) from rabbit blood platelets induced by saline “extract” of tendons. Thrombos. Diathes. haemorrh. (Stuttg) 09: 264 1963;
• 7 O’Brien J. R. The effect of the alkyl tins on platelet aggregation. Thrombos. Diathes. haemorrh. (Stuttg) 09: 330 1963;
• 8 Haslam R. J. Role of adenosine diphosphate in the aggregation of human blood platelets by thrombin and by fatty acids. Nature (Lond) 202: 765 1964;
• 9 Rozenberg M. C, Firkin B. G. The rate, of platelet aggregation in haemorrhagic disease and thrombosis. Scand. J. Haemat 03: 5 1966;
• 10 Ardlie N. G, Kinlough R. H, Schwartz G. J. In vitro thrombosis and platelet aggregation in myocardial infarction. Brit. Med. J I: 888 1966;
• 11 Danon D. A rapid method for recording red cell osmotic fragility by continuous decrease of salt concentration. J. clin. Path 16: 377 1963;
• 12 Brecher G, Schneiderman M, Gronkite E. P. The reproducibility and constancy of the platelet count. Amer. J. clin. Path 23: 15 1953;
• 13 Defares J. G, Sneddon I. N. An introduction to the mathematics of medicine and biology. 417 North-Holland Publishing Company; Amsterdam: 1960
• 14 Born G. V. R, Cross M. J. The aggregation of blood platelets. J. Physiol. (Lond) 168: 178 1963;
• 15 O’Brien J. R. Variability in the aggregation of human platelets by adrenaline. Nature (Lond) 202: 188 1964;
• 16 Emmons P. R, Mitchell J. R. A. Postoperative changes in platelet clumping activity. Lancet I: 71 1965;
• 17 Harrison M. J. G, Emmons P. R, Mitchell J. R. A. The variability of human platelet aggregation. J. atheroscler. Res 07: 197 1967;
• 18 Bolton C. H, Hampton J. R, Mitchell J. R. A. Nature of transferable factor which causes abnormal platelet behaviour in vascular disease. Lancet I: 1101 1967;