Platelet aggregation response and adenosine triphosphate secretion after abdominal total hysterectomy.

This study was designed to clarify the quantitative relationship between platelet aggregation and the secretion of adenosine triphosphate (ATP) after surgery. Peripheral blood was collected from 41 patients who underwent abdominal total hysterectomy. Platelet count, volume, aggregation and the amount of secreted ATP were determined using live platelets before, one day after and two weeks after surgery. Platelet aggregation and ATP secretion were investigated using a lumi-aggregometer. The aggregating reagents used were 5 microM of adenosine diphosphate (ADP) (final concentration) and 5 microg/ml of collagen. Structural alterations of platelets at these time points were also investigated by electron microscopy. Platelet aggregation induced by collagen was significantly lower (p<0.05) one day after surgery. ADP-induced aggregation two weeks after surgery was more intense than before (p<0.05) and one day after (p<0.05) surgery. The amount of secreted ATP induced by each of ADP and collagen was significantly lower (p<0.05-0.01) one day after surgery and correlation coefficients between platelet aggregation and secretion of ATP showed lower values in both ADP- and collagen-induced aggregation. One day after surgery electron microscopy showed that granule concentrations were markedly reduced in platelets. In conclusion, after consumption of circulating platelets at the site of operation, in addition to being lost by bleeding, the remaining platelets in circulation consist of platelet subpopulations different from those present before surgery, exhibiting low values of correlation coefficients between platelet aggregation and secretion of ATP and low concentrations of granules.