REACTIVE THROMBOCYTOSIS FOLLOWING CORONARY-ARTERY BYPASS-SURGERY - A POSSIBLE LINK TO A LIPID DYSFUNCTION

Reactive thrombocytosis (RT, Platelet counts >400x 10(3)/mm(3)) follow ing coronary artery bypass grafting (CABG) has earlier been described to occur. frequently (20%) and is associated with thrombotic complicat ions eg. vein graft occlusion. This prospective study was undertaken i n an attempt to identify the underlaying causes of RT following CABG. Forty 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) mere entered into a database together with routine broo d chemistry and hematology results, hemostasis and antiinflammatory (e g.IL-6) parameter (25 parameters/day, preoperatively until the 9th pos toperative day. Fifteen patients developed RT and the remaining 25 ser ved as controls (C). Fourteen patients, chosen at random, received Asp irin, 100 mg daily, starting from the 3rd postoperative day, all patie nts were anticoagulated postoperatively with heparin and later coumari ne. Patient characteristics, except a larger number of patients with h yperlipidemia in the RT group, did not differ. Operation data, cardiop ulmonary bypass data as well as postoperative complications revealed n o group differences, neither did preoperative laborations, except that S-Cholesterol was higher in the RT-group, 6.2+/-0.9 vs 5.3+/-0.9, p<0 .018. All blood laborations were without group differences throughout the entire study period, except platelet counts, platelet size (PWD) a nd mean platelet volume (MPV), and AT III levels at the 7th postoperat ive day, which was significantly lower in controls compared to RT. RT patients had a less marked drop in platelet count immediately after ca rdiopulmonary bypass than non-RT together with an increased MPV, but w ithout differences in the PWD. There was a significantly higher platel et count in the PT-group on the 3rd postoperative day, which remained higher throughout the study period and RT was established on the 7th p ostoperative day. Additional treatment with Aspirin postoperatively di d not influence studied parameters. This study has again found RT freq uently occurring after CABG (30%). It was found that the preoperative S-Cholesterol level was significantly higher in the RT group, while he mostasis and anti-inflammatory parameters did not differ RT vs non-RT. It could therefore be possible that RT is linked to a lipid dysfuncti on and further studies are on-going.