Background— Effective myocardial reperfusion after primary percutaneous coronary intervention (PCI) may be limited by distal embolization. We tested the safety, feasibility, and efficacy of the FilterWire-Ex (FW), a distal embolic protection device, as an adjunct to primary PCI.

Methods and Results— Fifty-three consecutive patients undergoing primary PCI with FW protection were compared with a matched control group treated by primary PCI alone. Successful FW positioning was obtained in 47 patients (89%) without complications. Histological analysis of the content of the last 13 filters showed multiple embolic debris in all cases. FW use was associated with lower postinterventional corrected TIMI frame count (22±14 versus 31±19; P=0.005) and higher occurrence of grade 3 myocardial blush (66% versus 36%; P=0.006) and early ST-segment elevation resolution (80% versus 54%; P=0.006). At multivariate analysis, FW use was the only independent predictor of early ST-segment elevation resolution and of grade 3 myocardial blush. FW patients showed lower peak creatine kinase-MB release (236±172 versus 333±219 ng/mL; P=0.013) and greater improvement at 30 days in left ventricular wall motion score index (−0.30±0.19 versus −0.18±0.26; P=0.008) and ejection fraction (+7±4% versus +4±7%; P=0.012).

Conclusions— FW use during primary PCI is feasible and safe. Distal embolization prevention appears to exert a beneficial effect on markers of myocardial reperfusion and on left ventricular function improvement at 30 days.