Delayed Post-Myocardial Infarction Invasive Measures, Helpful or Harmful?: A Subgroup Analysis

Abstract

In patients who have experienced acute myocardial infarction (MI), primary percutaneous coronary intervention (PCI) has been shown to be of benefit in terms of clinical outcomes. However, the value of performing routine PCI in patients with early MI (ie, an MI occurring > 12 h to < or = 7 days before patient presentation) or recent MI (ie, an MI occurring > or = 8 days to < 30 days before patient presentation) has not been established. The purposes of this prospective observational study were to evaluate the impact of PCI on outcomes, and to delineate the predictors of lack of response to reperfusion and the prognostic determinants in patients with this clinical condition. A total of 377 consecutive unselected patients who had experienced early or recent MI underwent PCI. Successful reperfusion (ie, Thrombolysis in Myocardial Infarction flow grade 3 of the infarct-related artery [IRA]) was achieved in 90.2% of patients. By multiple stepwise logistic regression analysis, high-burden thrombus formation (odds ratio [OR], 15.53; 95% confidence interval [CI], 6.09 to 39.60; p < 0.0001) in the IRA, early PCI (ie, < or = 3 days) [OR, 4.10; 95% CI, 1.79 to 7.36; p = 0.0008], advanced congestive heart failure (CHF) [OR, 4.10; 95% CI, 1.70 to 9.91; p = 0.002], and diabetes (OR, 3.03; 95% CI, 1.03 to 7.06; p = 0.010) were independent predictors for lack of response to reperfusion. The 30-day mortality rate was 6.8%. The only variables that were independently related to the 30-day mortality rate were advanced CHF (OR, 29.85; 95% CI, 7.84 to 113.7; p < 0.0001), lack of response to reperfusion (OR, 7.57; 95% CI, 2.29 to 25.07; p = 0.0009), early PCI (OR, 4.81; 95% CI, 1.60 to 14.41; p = 0.005), and multivessel disease (OR, 9.22; 95% CI, 1.63 to 52.04; p = 0.0119). The surviving 351 patients were discharged from the hospital and followed-up for a mean (+/- SD) 38.9 +/- 14.2 months. Coronary angiographic follow-up was performed in 285 patients (81.2%). Restenosis of the IRA was found in 101 patients (35.4%). Reinterventions of the IRA were required in 69 patients (24.2%). Follow-up measurements of left ventricular ejection fraction (LVEF) showed significantly more improvement than the initial LVEF (59.3 +/- 13.8% vs 50.4 +/- 13%; p < 0.0001). The total cumulative mortality rate after hospital discharge was 6.5% for the entire group. Only advanced CHF (OR, 3.46; 95% CI, 1.26 to 9.52; p = 0.016) and old age (ie, > or = 70 years of age) [OR, 4.41; 95% CI, 1.59 to 12.24; p = 0.004] were independent predictors of long-term mortality. The performance of PCI on > or = day 4 in patients after they had experienced an MI was safe and had a high rate of success. The clinical benefits of a relative low mortality rate associated with successful PCI for patients with early and recent MI was maintained during the long-term follow-up. However, patients with advanced CHF along with old age continued to have a poor prognosis.