Summary
Forty-seven patients presenting with acute chest pain had in vivo platelet activity
assessed by measuring plasma levels of the platelet-specific protein beta thromboglobulin
(BTG), and by screening for the presence of circulating platelet aggregates. Nineteen
patients with transmural myocardial infarction (MI), 21 patients with acute coronary
ischaemia (CI), and 7 patients with non-cardiac chest pain (NCCP) were investigated
in a serial study and compared with a normal control group. The means of all BTG determinations
in the MI (34, ± SD = 21-57) and CI (33, ± SD = 19-57) groups were significantly higher than those in the NCCP group (24, ± SD = 17-34; p Ã0.01) and normal subjects (22,5, ± SD = 14-37; p Ã0.001). There was no difference in BTG between those with MI or
CI, nor between the NCCP group and normal subjects. Raised numbers of circulating
platelet aggregates could not be detected in either MI or CI. The mean BTG levels
in both MI and CI patients were significantly raised, compared to normal subjects,
on the first day of admission to hospital and remained so on each of the subsequent
nine days. Neither heparin plus warfarin nor sulphinpyrazone had any significant effect
in lowering BTG levels. 15/40 patients (37.5%) following MI and CI had repeatedly
raised BTG levels throughout the study period, and it is suggested that these patients
represent an “at risk” group that may benefit from anti-platelet therapy in secondary
prevention studies.
Keywords
Platelets - Beta thromboglobulin - Myocardial infarction
