We investigated the platelet volume and other blood coagulation parameters in early postoperative periods in patients who underwent cardiac surgery. They were 11 (coronary artery bypass grafting, 5; prosthetic valve replacement, 6) in total numbers, and their mean age was 52.3 (41-61).
We tested their blood for platelet numbers, and mean platelet volume (MPV) as well as plasma levels of beta-thromboglobulin (β-TG), fibrinogen (Fbg), antithrombin III (ATIII) and plasminogen (Plg). The tests were done on the preoperative day, immediately after the operation, 1d, 2d, 5d, 1w, 2w, 3w and 4w after the operation.
The platelet number fell from 21.2±5.7×104 (M±SD)/μl to 7.9±2.1×104/μl immediately after the operation and showed its lowest value (5.3±3.1×104/μl) two days after the operation. Then it showed dramatic increase through 1st and 2nd weeks and reached its maximum value of 39.3±7.1×104/μl two weeks postoperatively. Plasma β-TG reached its highest value of 107.6±35.3ng/ml immediately after the operation. MPV changed from preoperative values of 8.96±0.73μm3 to 8.11±0.5μm3 immediately after the operation. MPV changed from preoperative values of 8.96±0.73μm3 to 8.11±0.5μm3 immediately after the operation and then gradually increased. The value reached its maximum value of 9.27±0.63μm3 on the fifth postoperative day. Fibrinogen levels increased mono-exponentially after the surgery and returned to its preoperative value very slowly.
These results suggested the destruction and consumption of the platelet within extracorporeal circulation circuit during cardiac surgery. Rapid rebound increase in platelet numbers and changes in coagulation parameters may explain the hypercoagulable state in the early postoperative period following cardiac surgery.