SPONTANEOUS PLATELET-AGGREGATION IN WHOLE-BLOOD IN DIABETIC AND NON DIABETIC SURVIVORS OF ACUTE MYOCARDIAL-INFARCTION

There is increasing evidence that platelet thrombi play an important r ole in the pathogenesis of acute myocardial infarction (AMI). We compa red ''spontaneous'' platelet aggregation in whole blood in 17 non-diab etic and 12 diabetic subjects on admission with AMI. There was no sign ificant difference in the fall in platelet count between the two group s, expressed as platelets remaining (75.2 +/- 7.9% vs 77.3 +/- 6.9% at 10 min, 66.6 +/- 8.9% vs 68.5 +/- 6.3% at 20 min, 63.5 +/- 8.2% vs 64 .9 +/- 6.7% at 30 min and 59.4 +/- 10.3% vs 61.3 +/- 7.6% at 60 min). The rate of ''spontaneous'' aggregation was increased in subjects with evidence of heart failure on admission compared to those without (59. 9 +/- 7.9% vs 66.2 +/- 6.6% at 30 min [p = 0.05] and 55.4 +/- 9.6% vs 63.1 +/- 7.7% at 60 min [p = 0.04]). There was no correlation between the fall in platelet count and admission plasma glucose, glycated haem oglobin or peak aspartate aminotransferase. The subjects studied on ad mission with AMI had greater rates of ''spontaneous'' aggregation than 8 subjects studied between 6 and 12 months after acute myocardial inf arction (75.9 +/- 7.4% vs 85.8 +/- 5.4% at 10 min; p = 0.001 and 64.3 +/- 7.5% vs 75.0 +/- 7.8% at 30 min; p = 0.006) and compared to normal controls (90.7 +/- 4.4% at 10 min; p <0.001 and 83.4 +/- 6.5 at 30 mi n; p <0.001). This study provides evidence of increased ''spontaneous' ' platelet aggregation in subjects admitted with acute myocardial infa rction but no difference between diabetic and non-diabetic subjects wa s observed.