| Objective: To investigate the relationships between preoperative blood glucose control and perioperative insulin resistance(IR) and operative prognosis in diabetic patients receiving conventional coronary artery bypass graft(CCABG).Methods: The research consisted of two parts. The first part was a prospective randomized controlled trial observing the degree of perioperative IR influenced by different levels of glucose control which was represented by glycosylated hemoglobin(Hb A1c) preoperatively. Patients were divided into three groups according to Hb A1 c levels and type 2 diabetes mellitus(T2DM) or not. NC group: Hb A1 c <5.6% non-diabetic(n=30), DM1 group: well controlled T2DM(Hb A1 c <6.5%)(n=30), DM2 group: badly controlled T2DM(Hb A1 c >6.5%)(n=30). Baseline characteristics were compared between each two groups. Serum insulin level and fasting blood glucose(FBG) were measured preoperatively,before cardiopulmonary bypass(CPB), before the end of CPB, 2, 6, 12 and 48 hours from the beginning of CPB, homeostatic model assessment of insulin resistance(HOMA-IR) were calculated to assess the extent of IR. IL-6 and TNF-α were measured 6 hours after CPB with ELISA.The second part is a retrospective study on the operative mortality and morbidity influenced by different levels of preoperative glucose control represented by Hb A1 c. 175 diabetic patients receiving CCABG were divide into three groups based on their Hb A1 c levels:Ⅰgroup(Hb A1 c <7.0%, n=47),Ⅱgroup(Hb A1 c 7.0-8.0%, n=57), Ⅲgroup(Hb A1 c >8.0%, n=71). Baseline characteristics were compared. The incidence of perioperative mortality and morbidity(myocardial infarction, low cardiac output syndrome, transient ischemic attack, stroke, respiratory failure, acute kidney injury, reoperation and wound infection) were compared between Ⅰgroup andⅡgroup and Ⅲgroup respectively.Results:(1) The baseline characteristics between group NC, DM1 and DM2 showed no difference except for preoperative Hb A1 c and FBG(P<0.05). DM2 group showed a significantly higher rate of application of oral antidiabetic drugs and insulin compared with DM1 and NC group.(2) FBG and HOMA-IR of DM1 and DM2 at every time points showed significantly high level compared with those of group NC(P<0.05), and FBG and HOMA-IR of DM2 were higher than the corresponding points of DM1(P<0.05). In all groups, FBG and HOMA-IR increased slowly from anesthesia and high level emerged at the end of CPB. Peak values appeared 6h after the initiation of CPB. IR maintained at a higher level compare with preoperative value even at the 48 h after CPB. The level of IL-6 and TNF-α showed significant difference among 3 groups, DM2>DM1>NC(P<0.05).(3) The 2nd part: The incidence of hyperlipdemia and application of insulin was higher in Ⅲgroup compared withⅠandⅡ(P<0.05). and Ⅲ Ⅱgroups showed a significantly higher rate of application of oral antidiabetic drugs compared withⅠgroup.The rest baseline characteristics showed no difference between different glucose control groups. The incidence of postoperative cerebrovascular attack was significantly higher in Ⅲgroup compared with Ⅰand Ⅱgroups(P=0.042). The incidence showed an increasing inclination in perioperative myocardial infarction, reoperation and wound infection in Ⅲgroup with no statistical significance(P>0.05).Conclusion:(1) Preoperative glucose control represented by Hb A1 c level significantly correlated with the the severity of IR in diabetic CCABG patients.(2) Preoperative glucose control level had influence on the outcomes of diabetic patients undergoing CCABG.(3) Uncompensated diabetic patients with poor preoperative glucose control were in high risk of poor prognosis of CCABG. |
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