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DOI: 10.1055/s-2006-925809
Off-Pump coronary artery bypass grafting does not alter hemostasis compared to cardiopulmonary bypass and Impella assisted surgery in a porcine model
Objectives: Mediastinal bleeding after coronary bypass surgery contributes to perioperative morbidity and mortality. In an adult porcine model the influence of different surgical techniques for myocardial revascularisation on hemostatic parameters and chest drainage output following internal mammarian to left anterior descending coronary artery bypass grafting were investigated.
Methods: Three different surgical techniques were applied: normothermic high flow cardiopulmonary-bypass (CPB) with cold crystalloid cardioplegic arrest (n=8), off-pump grafting (n=8), Impella®elect100 assisted beating-heart revascularisation (n=8). Eight animals underwent a sham operation. Anticoagulation was performed with Heparin (500 IU/kg) and reversed with an equivalent dose of protamine in either group. Coagulation and platelet-function were evaluated by intrinsic and extrinsic rotational-thrombelastography, platelet-aggregation induced by 3 and 10µmol Adenosinediphosphat, hemoglobin-concentration (Hb) and platelet-count. These variables were analysed before, several times during the procedure and further 4 hours of reperfusion.
Results: CPB caused significant coagulation disorder resulting in increased chest-tube drainage and decreased Hb-concentration after 4 hours (6.8±0.2mg/dl 371.7±82.0ml, p<0.05). Most markedly platelet-function and count were significantly diminished during and even after CPB (p<0.05). OPCAB-surgery didn't significantly disturb platelet function and plasmatic coagulation. Chest tube output and Hb-concentration were not altered compared to control animals (OPCAB: 8.7±0.4mg/dl 201.7±41.5ml control: 7.9±0.3mg/dl 174.0± 42.2ml). Impella-assistance generated significant platelet and plasmatic coagulation disorder, chest-tube output was severely increased after 4 hours (494.6±154.3ml p<0.05). Howerver Hb-concentration was not significantly diminished (8.1±0.3mg/dl).
Conclusion: CPB resulted in pronounced coagulation disorder. Especially platelet-function was affected. Impella assistance created significant hemostasic disorder with the most markedly increased chest-tube output. OPCAB only minimally influenced hemostasis and caused no significant mediastinal bleeding.