Significance of platelet volumetry

Since heterogeneity of circulating platelets is present, we have analyzed what kind of platelets and what factors in platelets do play an important role in thrombogenesis. Using 51 healthy young men and women (22.2±4.6 years in mean±SD), 17 patients in acute stage of thrombosis such as myocardial infarction or cerebral thrombosis (The two-week period following the onset of thrombosis was called the acute stage), 19 patients in the recovery stage of thrombosis and 8 DIC patients, their platelet volume, aggregability and adenine nucleotides content were measured. In healthy volunteers, platelet count was 30.1±5.9×104/μl, platelet mode volume was 4.21±0.56, mean volume was 5.32±0.42 and median volume was 4.66±0.47μ3. There was a significant correlation between platelet mode volume and 5 minutes aggregation induced by 3μM ADP (r=0.375, p<0.02). On the one hand, there was not significant correlation between platelet volume and slope of aggregation curve, intensity of primary and secondary aggregation. In acute stage of thrombosis, platelet volume (mode, mean and median) was significantly smaller than those of the healthy (p<0.05). In recovery stage of thrombosis, platelet volume, especially mode was larger than those of the healthy. In DIC, platelet mode volume was significantly smaller than that of the healthy (p<0.05), while the difference was not found in mean and median volume. ADP content in platelets was significantly decreased in acute thrombosis (p<0.05), while ADP and ATP contents were significantly decreased in DIC as compared to those in the healthy. There was a significant correlation between platelet volume and their adenine nucleotides contents (r=0.347, p<0.025 in ATP and r=0.537, p<0.05 in ADP). Platelet aggregation decreased in DIC and increased in acute thrombosis.These results suggest that large platelets have a large amount of adenine nucleotides and easily are consumed in thrombus formation. In thrombus formation, there may be an enhancement of release phenomenon in platelets.