Minimised closed circuit coronary artery bypass grafting in the elderly is associated with lower levels of organ-specific biomarkers: a prospective randomised study.

ABSTRACT

BACKGROUND: Restrictive fluid management may protect organ function and improve postoperative outcome in elderly coronary artery bypass grafting (CABG) patients. OBJECTIVE: We assessed organ-specific biomarker release to study the contribution of a fluid restrictive closed circuit concept to organ protection in elderly CABG patients. Cardiac, respiratory and abdominal organ injury was measured during and following minimal fluid coronary artery bypass grafting (mCABG), off-pump coronary artery bypass (opCAB) surgery and conventional CABG with high volume prime and cold crystalloid cardioplegia (cCABG). The results were related to differences in clinical outcome. DESIGN: Prospective randomised trial. SETTING: Dutch tertiary single centre study. PATIENTS Sixty patients over 70 years of age (38 men and 22 women) were randomised to one of the three different techniques. Inclusion criteria were as follows first time CABG, elective surgery, ejection fraction more than 30% and multivessel disease. Acetylsalicylic acid and clopidogrel administration or requiring less than three distal anastomoses were an exclusion. MAIN OUTCOME MEASURES: Organ-specific markers of the heart--heart fatty acid binding protein (HFABP), troponin T, pro-brain natriuretic peptide (pro-BNP) and creatinine phosphokinase (CPK), lung clara cell 16 protein, pneumoprotein (CC16), intestinal fatty acid binding protein (IFABP) and liver glutathione S-transferase (α-GST)--were measured perioperatively. Postoperative PaO2 levels, ventilation time, blood product consumption and adverse events were noted. RESULTS: Myocardial organ-specific biomarker troponin T showed significantly lower median levels during mCABG compared with the cCABG and opCAB groups [troponin 0.25 mg l(-1) (interquartile range, IQR 0.18 to 0.40), 0.39 mg l(-1) (IQR 0.23 to 0.49) and 0.36 mg l(-1) (IQR 0.23 to 0.50), respectively (P<0.003)]. HFABP, IFABP and α-GST levels were significantly higher during cCABG compared with opCAB and mCABG [HFABP 38.6 mg l(-1) (IQR 29.6 to 47.1), 23.3 mg l(-1) (IQR 16.5 to 31.0) and 21.1 mg l(-1) (IQR 15.7 to 28.8; P<0.001), IFABP 0.57 mg l(-1) (IQR 0.37 to 1.11), 0.44 mg l(-1) (IQR 0.16 to 0.74) and 0.37 mg l(-1) (IQR 0.13 to 1.05; P<0.02) and α-GST 11.5 mg l(-1) (IQR 7.7 to 15.7), 7.0 mg l(-1) (IQR 4.5 to 13.8) and 7.3 mg l(-1) (IQR 6.2 to 11.2), respectively (P<0.009)]. There was a trend towards higher median CC16 levels in the cCABG group (P<0.07). CPK and pro-BNP were not significantly different. On the first postoperative day, PaO2 levels and duration of mechanical ventilation were significantly improved, and there was lower use of blood products in the mCABG group than in the cCABG and opCAB groups (P<0.05). CONCLUSION: Following mCABG with low volume myocardial preservation and restrictive fluid management, early respiratory performance was improved and consumption of blood products reduced compared with opCAB and cCABG.