Role of leukocyte depletion during cardiopulmonary bypass and cardioplegic arrest

Background. Leukocyte depletion (LD) has been shown to be beneficial during the reperfusion of acutely ischemic myocardium; however, its role during cardiopulmonary bypass (CPB) in hearts protected with blood cardioplegia (BCP) is unknwon. This experimental study sought to determine whether LD filters inserted in the CPB circuit before cardioplegic arrest and in the BCP circuit during arrest would decrease ischemic myocardial damage. Methods. In 20 pigs, the second and third diagonal vessels were occluded for 90 minutes, followed by 45 minutes of BCP arrest and 180 minutes of reperfusion on CPB. In 5 pigs, LD filters were inserted in both the CPB and BCP circuits (LD-CPB+BCP). Five pigs had LD during BCP (LD-BCP), 5 pigs had LD during CPB (LD-CPB), and 5 pigs had no LD. Ischemic damage was assessed by wall motion scores using two-dimensional echocardiography and the area of necrosis/area of risk. Results. The LD-CPB and LD-CPB+BCP groups had the highest wall motion scores and the lowest area of necrosis/area of risk. The addition of LD to BCP alone did not significantly alter wall motion scores or the area of necrosis/area of risk. Conclusions. Leukocyte depletion filters significantly reduce ischemic damage during acute surgical revascularization and appear to be most effective when placed in the CPB circuit before cardoplegic arrest.