[Reactive thrombocytosis, a lipid dysfunction?]

Reactive thrombocytosis (RT, platelet counts > 400 x 10(3)/mm3) following coronary artery bypass grafting (CABG) has previously been reported to occur frequently (20%) and is associated with thrombotic complications, e.g. vein graft occlusion. This prospective study was undertaken in an attempt to identify the underlying causes of RT following CABG. 40 consecutive patients undergoing elective CABG entered the study between December 1 1994 and April 15 1995. Patient characteristics, operation data, cardiopulmonary data and postoperative complications (30 parameters) were evaluated together with routine blood chemistry, hematology, hemostasis and anti-inflammatory parameters (25 parameters/ day, preoperatively until the 9th postoperative day). 15 patients developed RT and 25 served as controls. Patient characteristics did not differ. Operation data, cardiopulmonary bypass data and post-operative complications revealed no group differences, neither did preoperative laboratory 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 group differences throughout the entire study period, except platelet counts, 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 platelet count immediately after cardiopulmonary bypass than non-RT, together with an increased MPV, but without differences in PWD. There was a significantly higher platelet count in the RT group on the 3rd postoperative day, which remained higher throughout the study period. This study has again found RT frequently occurring after CABG (30%). Preoperative S-cholesterol was significantly higher in the RT group, while other 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 ongoing.