Percutaneous Intervention for Concurrent Chronic Total Occlusions in Patients With STEMI: The EXPLORE Trial

Background: In 10% to 15% of patients with ST-segment elevation myocardial infarction (STEMI), concurrent coronary chronic total occlusion (CTO) in a non-infarct-related artery is present and is associated with increased morbidity and mortality.

Objectives: The EXPLORE (Evaluating Xience and Left Ventricular Function in Percutaneous Coronary Intervention on Occlusions After ST-Elevation Myocardial Infarction) trial evaluated whether patients with STEMI and concurrent CTO in a non-infarct-related artery benefit from additional percutaneous coronary intervention (PCI) of CTO shortly after primary PCI.

Methods: From November 2007 through April 2015, we enrolled 304 patients with acute STEMI who underwent primary PCI and had concurrent CTO in 14 centers in Europe and Canada. A total of 150 patients were randomly assigned to early PCI of the CTO (CTO PCI), and 154 patients were assigned to conservative treatment without PCI of the CTO (no CTO PCI). Primary outcomes were left ventricular ejection fraction (LVEF) and left ventricular end diastolic volume (LVEDV) on cardiac magnetic resonance imaging after 4 months.

Results: The investigator-reported procedural success rate in the CTO PCI arm of the trial was 77%, and the adjudicated success rate was 73%. At 4 months, mean LVEF did not differ between the 2 groups (44.1 ± 12.2% vs. 44.8 ± 11.9%, respectively; p = 0.60). Mean LVEDV at 4 months was 215.6 ± 62.5 ml in the CTO PCI arm versus 212.8 ± 60.3 ml in the no-CTO PCI arm (p = 0.70). Subgroup analysis revealed that patients with CTO located in the left anterior descending coronary artery who were randomized to the CTO PCI strategy had significantly higher LVEF compared with patients randomized to the no-CTO PCI strategy (47.2 ± 12.3% vs. 40.4 ± 11.9%; p = 0.02). There were no differences in terms of 4-month major adverse coronary events (5.4% vs. 2.6%; p = 0.25).

Conclusions: Additional CTO PCI within 1 week after primary PCI for STEMI was feasible and safe. In patients with STEMI and concurrent CTO, we did not find an overall benefit for CTO PCI in terms of LVEF or LVEDV. The finding that early CTO PCI in the left anterior descending coronary artery subgroup was beneficial warrants further investigation. (Evaluating Xience and Left Ventricular Function in Percutaneous Coronary Intervention on Occlusions After ST-Segment Elevation Myocardial Infarction; NTR1108).