Effects of timing, location and definition of reinfarction on mortality in patients with totally occluded infarct related arteries late after myocardial infarction

Background: The Occluded Artery Trial (OAT) randomized stable patients (n=2201)>24 h (calendar days 3-28) after myocardial infarction (MI) with totally occluded infarct-related arteries (IRA), to percutaneous coronary intervention (PCI) with optimal medical therapy, or optimal medical therapy alone (MED). PCI had no impact on the composite of death, reinfarction, or class IV heart failure over extended follow-up of up to 9 years. We evaluated the impact of early and late reinfarction and definition of MI on subsequent mortality.

Methods and results: Reinfarction was adjudicated according to an adaptation of the 2007 universal definition of MI and the OAT definition (≥2 of the following--symptoms, EKG and biomarkers). Cox regression models were used to analyze the effect of post-randomization reinfarction and baseline variables on time to death. After adjustment for baseline characteristics the 169 (PCI: n=95; MED: n=74) patients who developed reinfarction by the universal definition had a 4.15-fold (95% CI 3.03-5.69, p<0.001) increased risk of death compared to patients without reinfarction. This risk was similar for both treatment groups (interaction p=0.26) and when MI was defined by the stricter OAT criteria. Reinfarctions occurring within 6 months of randomization had similar impact on mortality as reinfarctions occurring later, and the impact of reinfarction due to the same IRA and a different epicardial vessel was similar.

Conclusions: For stable post-MI patients with totally occluded infarct arteries, reinfarction significantly independently increased the risk of death regardless of the initial management strategy (PCI vs. MED), reinfarction definition, location and early or late occurrence.