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Objective: To compare the effects of a bolus of milrinone, 50 microg/kg, versus placebo on flow in coronary artery bypass grafts after cardiopulmonary bypass (CPB)., Design: A prospective, randomized, double-blind study., Setting: A university hospital., Participants: Forty-four patients with stable angina and left ventricular ejection fraction >30% scheduled for elective coronary artery bypass graft (CABG) surgery were included., Intervention: Patients were randomized to receive 50 microg/kg of milrinone (n = 22) or placebo (n = 22) after aortic declamping., Measurements and Main Results: The flow in coronary artery bypass grafts was measured with a transit time flow meter at 10 minutes and 30 minutes after termination of CPB. The hemodynamic evaluation included transesophageal echocardiography, mean arterial pressure (MAP), heart rate, and intracavitary measurement of left ventricular end-diastolic pressure (LVEDP). The flow in the saphenous vein grafts was significantly higher in the milrinone group when compared with the placebo group both at 10 and 30 minutes after termination of CPB (p < 0.001). At 10 minutes, the flow was 64.5 +/- 37.4 mL/min (mean +/- standard deviation) and 43.6 +/- 25.7 mL/min in nonsequential vein grafts for milrinone and placebo, respectively. Corresponding values at 30 minutes were 54.8 +/- 29.9 mL/min and 35.3 +/- 22.4 mL/min. The left internal thoracic artery (LITA) flow was higher in the milrinone group but did not reach statistical significance. The fractional area change was higher, and the MAP and calculated pressure gradient (MAP-LVEDP) were lower at 10 minutes in the milrinone group., Conclusion: Milrinone significantly increases the flow in anastomosed saphenous vein grafts after CPB, and has beneficial effects on left ventricular function.

Cardiopulmonary bypass (CPB) causes activation of cascade systems. Although heparin coating of CPB circuits improves biocompatibility, the effects on coagulation remain controversial. Theoretically, heparin coating should permit the reduction of systemic anticoagulation during CPB. We investigated influences on haemostatic variables in animal CPB, comparing heparin-coated circuits and reduced systemic heparinization (group HC) with uncoated circuits and full heparinization (group C). Twenty pigs underwent 2-h CPB. Seven (HC, n = 4; C, n = 3) were weaned from CPB and studied for up to 4 h. Total administered heparin was 470 +/- 6 IU/kg (mean +/- SEM) in group C and 100 +/- 0 IU/kg in group HC. Protamine dosage was significantly reduced in group HC. In group C, levels of prothrombin complex, factor VIII and adhesive platelets were reduced significantly during CPB, and postoperatively there were significantly lower values of prothrombin complex, fibrinogen, antithrombin III, factor VIII and adhesive platelets but a significantly increased concentration of von Willebrand factor and cumulative bleeding after 4 h. In conclusion, heparin-coated CPB circuits combined with lowered heparin dosage reduced coagulation factor consumption and preserved platelet function, possibly contributing to improved postoperative haemostasis.

In a randomized, double-blind study of patients undergoing elective coronary artery grafting, the effect of heparin-coated circuit combined with 50% reduction of systemic heparin bolus was investigated. Ten patients comprised group HC (heparin-coated) and ten group C (controls). The mean total doses of heparin were 172 IU/kg in group HC and 416 IU/kg in group C and the respective protamine doses were 0.96 and 3.96 mg/kg (both p < 0.001). Activated clotting times during cardiopulmonary bypass were significantly shorter in group HC, and both intra- and postoperative bleeding was significantly less than in group C (7.7 vs. 11.7 ml/kg, p = 0.036, and 6.9 vs. 9.7 ml/kg, p = 0.004). Hemoglobin loss via the drains was 22.5 g in group HC and 43.7 g in group C (p < 0.005). Hemolysis at the end of bypass was significantly greater in group C. Apart from one perioperative myocardial infarction in group HC the postoperative course was uneventful. Use of a heparin-coated circuit is concluded to permit complication-free reduction of heparin and protamine doses and to decrease both intra- and postoperative bleeding, which may favorably influence the outcome of coronary artery grafting.

Blood cell trauma and postoperative bleeding remain important problems in cardiopulmonary bypass (CPB). We compared heparin-coated with non-coated circuits in the pig. Twenty animals were perfused for 2 h at normothermia using membrane oxygenators (Bentley Bos 50). Two groups were studied. In the non-coated group (NC, n = 11) the CPB circuits used were without a heparin coating. This group had systemic heparinization of 400 IU/kg to maintain an ACT (activated clotting time) of over 400 s during CPB. In the coated group (C, n = 9), all surfaces exposed to blood in the CPB circuits were heparin-coated. This group had the heparin dose reduced to 25% (100 IU/kg) without further administration regardless of ACT. During CPB, group C displayed shorter ACT (per definition), higher platelet count, platelet adhesion and lower fibrinolysis and haemolysis (P less than 0.05) as compared to group NC. No thromboembolic events were detected during CPB. Three animals in group NC and 4 animals in group C were weaned from CPB and protaminized. Four hours postoperatively, the leucocyte consumption was two-fold greater and blood loss about four-fold greater in group NC as compared with group C (P less than 0.05). Perfusion with heparin-coated surfaces reduces blood cell trauma. The decreased postoperative blood loss observed in group C is probably explained by the reduced dosages of heparin and protamine.

Complement activation was studied during cardiopulmonary bypass (CPB) in the pig. One group of animals was perfused for 2 h using a standard extracorporeal circuit including a hollow fiber membrane oxygenator with full systemic heparinization. Another group was treated in the same way, except that bypass was performed through a heparin-coated CPB circuit (Carmeda Bio-Active Surface, CBAS) and systemic heparinization was reduced by 75%. It was found that complement activation during CPB, measured as changes in the ratio C3d/C3, was significantly less in the CBAS group, most probably reflecting a better biocompatibility.

Examines the establishment of cardiopulmonary bypass (CBP), anaesthetic and monitoring considerations for minimally invasive direct coronary artery bypass (MIDCAB) procedures. Importance of MIDCAB; Monitoring conditions for port-access cardiac surgery; Distinction between MIDCAB and coronary artery bypass grafting.