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Objective Metabolism management plays an essential role during cardiopulmonary bypass (CPB). There are different metabolic management devices integrated to heart–lung machines; the most commonly used and accepted metabolic target is indexed oxygen delivery (DO2i) (280 mL/min/m2) and cardiac index (CI) (2.4 L/min/m2), which can be managed independently or according to other metabolic parameters. Our objective was to compare lactate production during CPB procedures using different metabolic management: DO2i in relation to indexed oxygen extraction ratio (O2ERi) and CI in relation to mixed venous oxygen saturation (SvO2). Methods Data on 500 CPB procedures were retrospectively collected in a specialized regional tertiary cardiac surgery center in Italy between September and 2012 and November 2019. In group A, the DO2i with 280 mL/min/m2 target in relation to O2ERi 25% was used; in group B, CI with 2.4 L/min/m2 target in relation to SvO2 75% was used. During CPB, serial arterial blood gas analyses with blood lactate and glucose determinations were obtained. Hyperlactatemia (HL) was defined as a peak arterial blood lactate concentration >3 mmol/L. The postoperative outcome of patients with or without HL was compared. Results Eight pre- and intraoperative factors were found to be significantly associated with peak blood lactate level during CPB at univariate analysis. HL (>3 mmol/L) was detected in 15 (6%) patients of group A and in 42 (16.8%) patients of group B (P = .022); hyperglycemia (>160 mg/dL) was found in 23 (9.2%) patients of group A and in 53 (21.2%) patients of group B (P = .038). Patients with HL during CPB had a significant increase in serum creatinine value, higher rate of prolonged mechanical ventilation time and intensive care unit stay. A cutoff of DO2i 35% in group A and a cutoff of CI 290 mL/min/m2 in relation to O2ERi 24% in group A and a cutoff of CI >2.4 L/min/m2 in relation to SvO2 >75% in group B were found to have a negative predictive value of 78% and 62% for HL, respectively. Conclusions This retrospective observational analysis showed that management of DO2i in relation to O2ERi was 16% more specific in terms of negative predictive value for HL during CPB compared with the use of CI in relation to SvO2. Group A reported a significant reduction in the incidence of intraoperative lactate peak, correlated with postoperative reduction of serum creatinine value, mechanical ventilation time, and intensive care unit stay, compared with group B., Graphical abstract

Background We used a large patient-level data set including 6 angiographic randomized controlled trials (RCTs) on coronary artery bypass conduits to explore incidence and determinants of coronary graft failure. Methods Patient-level angiographic data of 6 RCTs comparing long-term outcomes of the radial artery and other conduits were joined. Primary outcome was graft occlusion at maximum follow-up. The analysis was divided as (1) left anterior descending coronary (LAD) distribution and (2) non-LAD distribution (circumflex and right coronary artery). Mixed-model multivariable Cox regression including all baseline characteristics with stratification by individual trials was used to identify predictors of graft occlusion. Results Included were 1091 patients and 2281 grafts, consisting of 921 left internal mammary arteries, 74 right internal mammary arteries, 710 radial arteries, and 576 saphenous veins. All left internal mammary arteries were used on the LAD, the other conduits were used on the non-LAD distribution. Mean angiographic follow up was 65 ± 29 months. Occlusion rates were 2.3% for the left internal mammary arteries, 13.5% for the left internal mammary arteries, 9.4% for the right internal mammary arteries, and 17.5% for the saphenous veins. At multivariable analysis, type of conduit used, age, female sex, left ventricular ejection fraction of less than 0.50, and use of the Y graft were significantly associated with graft occlusion in the non-LAD distribution. Conclusions Our analyses showed that failure of the left internal mammary arteries-to-LAD bypass is a very uncommon event. For the non-LAD distribution, the nonuse of radial artery, age, female sex, left ventricular ejection fraction of less than 0.50, and use of the Y graft configuration were significantly associated with midterm graft failure.