Comparative study of the effect on clinical outcome of the use of an open circuit and the use of a closed circuit in cardiopulmonary bypass for a graft replacement of the descending thoracic or thoracoabdominal aorta.

Purpose: We studied the benefits of reduced systemic heparinization in a heparin-coated cardiopulmonary bypass (CPB) system for graft replacement of the descending thoracic (TA) or thoracoabdominal aorta (TAA).

Methods: Fifty-five patients were assigned to two groups: one group in which closed CPB circuits with reduced heparinization by elimination of the hard shell reservoir were used (group A, n = 36) and one group in which open circuits with full heparinization were used (group B, n = 19).

Results: The transfusion requirement tended to be greater as the duration of CPB increased, even in group A. The incidences of renal dysfunction in two groups were not significantly different. Only the incidence of pulmonary dysfunction was significantly higher in group B. A reduction of systemic heparinization had no benefit for perioperative bleeding. In the TAA operation, the total amount of hemorrhaging in group A was greater than that in group B, but the difference was not significant.

Conclusions: No beneficial effects of the use of heparin-coated CPB circuits on the amount of perioperative bleeding and postoperative organ damage, including renal dysfunction, were found in this study. However, our findings suggest that it may be better to avoid the use of closed CPB circuits in operations with a prolonged duration of CPB, such as a TAA operation.