Leukocyte depletion during cardiac operation: A new approach through the venous bypass circuit

Background. Leukocyte depletion recently has been introduced for cardiac su rgical patients to attenuate leukocyte-mediated inflammation and organ repe rfusion injury. We evaluated the feasibility of a new leukocyte depletion m ethod in which systemic leukocyte depletion is achieved through the venous side of the cardiopulmonary bypass circuit under low blood flow. Methods. Forty cardiac surgical patients undergoing cardiopulmonary bypass were allocated randomly to a leukocyte depletion group (n = 20) and a contr ol group (n = 20). In the depletion group, leukocyte filtration was achieve d with two filter sets located between the venous drainage and the venous r eservoir, Leukocyte filtration was commenced after the start of rewarming b ut before the release of the aortic cross-clamp, and it was driven by a spa re roller pump of the heart-lung machine. Results. All the episodes of filtration went smoothly within a period of 10 minutes and with a blood now rate of 400 mL/min. The mean leukocyte remova l rate calculated at the end of filtration was 69%. Circulating leukocytes were reduced by 38% in the depletion group compared with the control group at the moment of crossclamp release (4.3 x 10(9)/L versus 6.8 x 10(9)/L, p < 0.05). The postoperative inflammatory response also was reduced as indica ted by less production of interleukin-8 (p < 0.05). Clinically, there was n o significant difference between the two groups in postoperative Pao(2) or pulmonary hemodynamics. Conclusions. It is technically feasible to deplete circulating leukocytes t hrough the venous side of the cardiopulmonary bypass-circuit with a low blo od now rate. Future studies should focus on the duration and timing of leuk ocyte depletion to optimize the methodology of leukocyte depletion for card iac surgical patients. (Ann Thorac Surg 1999;67:604-9) (C) 1999 by The Soci ety of Thoracic Surgeons.