Effects of balloon-based distal protection during primary percutaneous coronary intervention on early and late infarct size and left ventricular remodeling: A pilot study using serial contrast-enhanced magnetic resonance imaging

Background: Distal protection devices are effective in preventing distal embolization during primary percutaneous coronary intervention (PCI). We investigated whether balloon-based distal protection could reduce early and late infarct size and left ventricular (LV) remodeling using serial analysis of contrast-enhanced magnetic resonance imaging (CE-MRI). Methods: Patients undergoing primary PCI for ST-segment elevation myocardial infarction within 12 hours after symptom onset were randomized to a distal protection group (n = 19) or to a control group (n = 20). The primary end point was infarct size evaluated by the volume of delayed hyperenhancement on CE-MRI at 3 days. The secondary end point included infarct size on CE-MRI at 6 months and LV remodeling assessed by the change between LV end-diastolic volume on CE-MRI at 3 days (baseline) and 6 months (follow-up). Results: Percutaneous coronary intervention procedures were fully protected with balloon-based distal protection in all patients of the protection group. Infarct size was similar in the distal protection group and the control group at baseline (25.9 ± 7.8% vs 26.1 ± 8.2%; P = .93) and at follow-up (21.4 ± 9.1% vs 18.5 ± 9.1%; P = .51). The change in LV end-diastolic volume was 10.5 ± 32.2 mL in the distal protection group and 8.9 ± 40.7 mL in the control group (P = .86). There was no significant difference in the 6-month rate of major adverse cardiac events between groups (none in the distal protection group and 4 patients in the control group; P = .11). Conclusions: Serial CE-MRI showed that the balloon-based distal protection during primary PCI did not reduce early and late infarct size or prevent LV remodeling.