A combined approach for improving cardiopulmonary bypass in coronary artery surgery: a pilot study

Background: This is a pilot study carried out to assess the feasibility and the clinical impact of a combined approach of cardiopulmonary bypass (CPB) with reduced anti-coagulation. Methods: We used a retrospective, non-randomized analysis of 45 consecutive patients undergoing coronary artery bypass using standard CPB with fell anticoagulation (activated clotting time, ACT, > 450 s) (Group 1; n=23) or closed, heparin-coated CPB with low anticoagulation (ACT>250 s), precise heparin and protamine titration, controlled suction, and retrograde autologous prime (Group 2; n=22). Results: Patients were similar except for a higher incidence of three-vessel disease in Group 2 (77.3% versus 47.8%; p < 0.03). Heparin was reduced by 41% in Group 2 and protamine by 56% (p < 0.0001). Total postoperative blood loss was similar between Groups 1 and 2 (429 +/- 149 versus 435 +/- 168 ml, respectively). However, the operative hematocrit decrease was lower in Group 2 (-1.6 +/- 7.5% versus -6.9 +/- 4.8%; p=0.007), although hemodilution was similar, as reflected by the blood protein level. The need for postoperative inotropic support was less frequent in Group 2 (36.4% versus 65.2%; p=0.05). Within the subgroup of patients weaned from CPB without requiring inotropic support (n=35), the cardiac index dropped significantly in Group 1 (p=0.003) 6 h after the start of CPB, whereas it remained stable in Group 2 (p=0.92). Using multivariate analyses, Group 2 was found to be more protected than Group 1 against myocardial cellular injury (p=0.046) and need for postoperative inotropic support (p=0.014). Conclusion: The pejorative postoperative outcome in coronary artery surgery was attenuated through a combined approach aimed at improving CPB.