Limitations of using a GuardWire temporary occlusion and aspiration system in patients with acute myocardial infarction: multicenter investigation of coronary artery protection with a distal occlusion device in acute myocardial infarction (MICADO).

BACKGROUND: The benefits of using distal protection during percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) remain unknown. The prevention of no-reflow in PCI is considered a challenge and could be a contributing factor for long-term prognosis.

OBJECTIVES: This study evaluated the efficacy of distal protection with the GuardWire distal protection device in PCI at the time of AMI revascularization.

METHODS: The study was conducted as a prospective, randomized, multicenter trial. Patients with AMI within 24 hours from onset were randomized into either PCI combined with a GuardWire, or PCI without distal protection. The primary endpoints were TIMI perfusion grade (TMP) and no incidence of reflow. Secondary endpoints were major cardiac events (MACE) during 6-month follow up.

RESULTS: The incidence of no-reflow was similar between the GuardWire group and the control group (4% vs. 3%). TMP 3 was seen at a higher rate in the GuardWire group, but was not statistically significant (58% vs. 44%; p = 0.054). Multivariate analysis revealed that diabetes and hyperlipidemia, but not GuardWire use, were predictors of failure to achieve TMP 3. Older age and right coronary artery (RCA) infarction were associated with achieving TMP 3. MACE was observed in similar incidences between the two groups after 6-month follow up.

CONCLUSIONS: From our randomized study of distal protection in PCI at the time of AMI, elderly patients or those with RCA infarction were considered good candidates for distal protection; however, we could not demonstrate an improvement in long-term outcome with the use of GuardWire distal protection.