Effect of a leukocyte-platelet removal filter on ischemia induced reperfusion injury. The effect of leukocyte and platelet depletion on reperfusion injury using a leukocyte-platelet removal filter (LRF) in intracoronary thrombolysis is reported. To better define the usefulness of LRF in evaluating the effectiveness of intracoronary thrombolysis with this device, several cardiovascular variables were examined in rabbits during ischemia followed by reperfusion. The rabbits underwent cytoapheresis with LRF (n = 5) and were compared with controls without LRF (n = 5). LRF was composed of a nonwoven polyester fabric (1.8 microns, 4.6 gm). Removal of leukocytes and platelets by LRF was 98% for both. A period of 30 min equilibration was allowed before any experimental intervention, at which time the diagonal artery was occluded for 20 min and then reperfused. All arrhythmias were defined and quantified in accordance with the Lambeth Convention. Regional wall thickening was examined by a pulsed Doppler dimension system. No significant differences were observed in hemodynamic variables between the two groups; however, rabbits treated with a LRF demonstrated greater regional wall thickening (LRF group: 17 +/- 0.9%, control group: 11 +/- 0.3%, p less than 0.01), as well as significant improvement in the frequency of ventricular arrhythmias (LRF group: 12.5%, control group: 47.2%, p less than 0.01). The data suggest that LRF may help prevent arrhythmias, and preserve left ventricular contraction, during and after intracoronary thrombolysis. 