Renal Function and Urinary Biomarkers in Cardiac Bypass Surgery: A Prospective Randomized Trial Comparing Three Surgical Techniques.

Background Cardiopulmonary bypass procedure is associated with an increased risk of renal impairment. To which extent structural damage causes functional decline is unknown. We evaluated perioperative kidney injury and function in patients treated with conventional extracorporeal circulation (CECC), minimized extracorporeal circulation (MECC), and off-pump coronary artery bypass grafting (OPCAB). Methods Blood and urine samples, collected at baseline and up to 72 hours after surgery from patients of the HEPCON trial (DRKS00007580, 120 patients randomized for heparin management and for surgical technique), were analyzed for differences in renal injury and function. Neutrophil gelatinase-associated lipocalin, α glutathione S-transferase, liver fatty acid-binding protein, and kidney injury molecule-1 were measured as urinary protein markers of renal tubular injury. Serum creatinine, blood urea levels, and estimated glomerular filtration rate were determined to monitor renal function. Results Markers of tubular injury differed significantly between surgical technique groups early after surgery, indicating the most detrimental effect in CECC. Hemolysis and hemodilution correlated with these early changes. A late rise did not show intergroup differences. Time courses of renal function parameters, as well as the development of acute kidney injury in 15 patients (13.5%), were irrespective of surgical technique. Heparin management did not influence renal parameters. Conclusion During coronary artery bypass grafting, CECC temporarily induces more tubular injury than MECC or OPCAB. However, late changes of renal function parameters occur irrespective of extracorporeal perfusion mode and even in off-pump surgery.

Similarity of coagulation and inflammation despite different surgical revascularization strategies - a prospective randomized trial.

BACKGROUND:: Supposedly, minimized extracorporeal circulation or off-pump revascularization as alternatives to conventional extracorporeal circulation (ONCAB) reduce inflammation and coagulation disturbances. METHODS:: One hundred and twenty coronary artery bypass graft (CABG) patients were prospectively randomized for three surgical techniques. Coagulation and inflammation markers were measured up to 72 hours postoperatively. RESULTS:: Coagulation factors I, II, V, X, antithrombin III and C-reactive protein did not differ perioperatively between the groups and increased, as did several other markers, 12 to 72 hours postoperatively. Compared to its alternatives, ONCAB showed the most obvious transient increase in thrombin-antithrombin complexes (p<0.0001), D-dimers (p=0.0059), tissue factor pathway inhibitor (p=0.0005), factor VIII (p=0.0041) and tumor necrosis factor α (p=0.0300) during the operation and up to 12 hours postoperatively. Furthermore, ONCAB generated lower leukocyte and platelet counts and higher values of soluble P-selectin and soluble intercellular adhesion molecule 1 at some time points. CONCLUSIONS:: With similarity in pivot coagulation factors, a specific detrimental influence of ONCAB on common coagulation pathways was excluded. Higher perioperative concentrations of products from the coagulation cascade most likely indicate activation of pericardial blood - recirculated only in ONCAB. Furthermore, with only temporary differences in markers of inflammation, the alternatives to ONCAB altogether were without advantage at 72 hours postoperatively. In the general answer to surgical trauma, the part of modern extracorporeal circulation is possibly overestimated. The study is registered at the German Clinical Trial Registry. Registration number DRKS00007580. URL: https://drks-neu.uniklinik-freiburg.de/drks_web/ URL: http://apps.who.int/trialsearch/.