REACTIVE THROMBOCYTOSIS - A LIPID DYSFUNC TION

Reactive thrombocytosis (RT, platelet counts >400 x 10(3)/mm(3)) follo wing coronary artery bypass grafting (CABG) has previously been report ed to occur frequently (20%) and is associated with thrombotic complic ations, e.g. vein graft occlusion. This prospective study was undertak en in an attempt to identify the underlying causes of RT following CAB G. 40 consecutive patients undergoing elective CABG entered the study between December 1 1994 and April 15 1995. Patient characteristics, op eration data, cardiopulmonary data and postoperative complications (30 parameters) were evaluated together with routine blood chemistry, hem atology, hemostasis and anti-inflammatory parameters (25 parameters/da y, preoperatively until the 9th postoperative day). 15 patients develo ped RT and 25 served as controls. Patient characteristics did not diff er. Operation data, cardiopulmonary bypass data and postoperative comp lications revealed no group differences, neither did preoperative labo ratory results, except that S-cholesterol was higher in the RT-group ( 6.2+/-0.9 vs. 5.3+/-0.9, p < 0.018). All blood findings were without g roup differences throughout the entire study period, except platelet c ounts, platelet size (PWD) and mean platelet volume (MPV), and AT III levels on the 7th postoperative day, which were significantly lower in controls compared to RT. RT patients had a less marked drop in platel et count immediately after cardiopulmonary bypass than non-RT, togethe r with an increased MPV, but without differences in PWD. There was a s ignificantly higher platelet count in the RT group on the 3rd postoper ative day, which remained higher throughout the study period. This stu dy has again found RT frequently occurring after CABG (30%). Preoperat ive S-cholesterol was significantly higher in the RT group, while othe r parameters did not differ in RT vs. non-RT. It is therefore possible that RT is linked to a lipid dysfunction, and further studies are ong oing.