CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 2, March/April 2022 AFRICA 77 Pre-operative IPC and IPF were also found to be significantly correlated with postoperative drainage at the 12th and 24th hour. However, neither pre-operative IPC nor IPF were associated with the length of hospital stay. Postoperative IPC was however associated with the length of hospital and ICU stay. Parallel to the increase in technical advances and number of angiographies performed to diagnose the presence of coronary artery disease, the number of patients scheduled for CABG has increased in recent years.8,9 The CABG procedure is currently the standard of care for treatment of multivessel coronary artery disease, particularly in subjects with concomitant diabetes and left ventricular systolic dysfunction.10-12 However, it still has an in-hospital mortality rate of about 3% and it has been established that intra- and postoperative bleeding events account for a considerable portion of the mortality associated with CABG procedures.13 Several factors, including reduced coagulation factors and a low platelet count, may lead to coagulopathy following CABG. Previous data have shown that platelet counts after CABG are independent predictors of excessive blood loss.14 A prolonged closure time, which indicates platelet dysfunction, has been shown to predict blood product transfusion in children undergoing cardiac surgery.15 Studies utilising multiple electrode impedance aggregometry and light transmission aggregometry demonstrated significant platelet dysfunction after CABG, with partial recovery within 24 hours of surgery.16 In a study of patients with immune thrombocytopenia, it was found that high IPC in patients with low platelet counts protected against life-threatening bleeding.17 The negative correlation of pre-operative IPC with intra-operative blood use in our results supports this study. IPC and IPF, which represent the young cells that have recently been released into the circulation, are considered to be associated with platelet function. These young platelets have a greater number of granules and higher volume than older ones, and therefore may be more effective in facilitating homeostasis in the case of bleeding.6 Although platelet count and platelet dysfunction measured with different techniques have been shown to precipitate excessive bleeding after CABG, there are currently no data concerning the impact of IPC and IPF on postoperative bleeding in patients undergoing CABG.18-20 Our study is the first to demonstrate Table 5. Platelet IPC, IPF and MPV changes Markers Postoperative Postoperative day 1 Postoperative day 3 Postoperative day 5 Platelet count Mean % change from pre-operative –17.81 –13.77 –13.14 +16.23 p-value* < 0.0001 < 0.0001 < 0.0001 0.001 IPC Mean % change from pre-operative –7.77 +10.91 +7.64 +31.15 p-value* < 0.001 0.020 0.003 0.045 IPF Mean % change from pre-operative +14.29 +32.12 +31.44 +21.12 p-value* 0.382 0.206 0.463 0.378 MPV Mean % change from pre-operative +4.03 +6.94 +4.80 +1.12 p-value* < 0.001 < 0.001 < 0.001 0.435 IPC: immature platelet count, IPF: immature platelets fraction, MPV: mean platelet volume. *Wilcoxon test. PREOP PLT PO 0 PLT PO 1 PLT PO 3 PLT PO 5 PLT 600 500 400 300 200 100 0 Platelet count (×103 cells/μl) MPV (f/l) PREOP MPV PO 0 MPV PO 1 MPV PO 3 MPV PO 5 MPV 14 12 10 8 IPF (×109 cells/l) PREOP IPF PO 0 IPF PO 1 IPF PO 3 IPF PO 5 IPF 20 15 10 5 0 * * * * *** IPC (%) PREOP IPC PO 0 IPC PO 1 IPC PO 3 IPC PO 5 IPC 50 40 30 20 10 0 * * * * Fig. 1. Postoperative trends in platelet count and immature platelet markers following CABG. (A) Platelet count, (B) MPV, (C) IPF and (D) IPC in patients undergoing CABG. PREOP: pre-operative, PO: postoperative , IPC: immature platelet count , IPF: immature platelets fraction , MPV: mean platelet volume. A C B D
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