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

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Abstract
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 full 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.