The Late Open Artery Hypothesis -- A Decade Later

Am Heart J. 2001;142(3) 

In This Article

Observational Clinical Studies on the Late Open Artery Hypothesis

Experimental studies indicated that late reperfusion reduces infarct expansion and LV remodeling in the absence of myocardial salvage.[16] Numerous clinical studies suggested that patients with a patent IRA late after AMI, regardless of reperfusion therapy, have a markedly lower mortality during follow-up than those with a persistently occluded IRA (Table I). In a study of 312 thrombolytic-treated patients by White et al,[5] a patent IRA at[]a mean of 28 days after AMI was independently associated with improved clinical outcome during follow-up. This independent association was only evident in patients with reduced LVEF or if the IRA supplied >25% of the left ventricle. Lamas et al[20] reported similar findings in the Survival and Ventricular Enlargement (SAVE) study population; the incidence of congestive heart failure (CHF) and death was significantly lower in those with an open IRA compared with those with a closed IRA. Further, this association was independent of other patient characteristics, including LVEF and coronary anatomy. Similar beneficial effects of a patent IRA have been noted in patients who underwent mechanical revascularization for post-MI angina.[21]

However, there are conflicting data. Puma et al[23] recently analyzed 11,228 patients in the Global Use of Streptokinase and Tissue Plasminogen Activator to Open Occluded Coronary Arteries (GUSTO-I) with data on the patency of the IRA. The unadjusted mortality rate in patients with an open IRA (3-6 days after AMI) was significantly lower at 30 days and 1 year compared with that of the group with an occluded IRA (1.5% and 3.3% vs 6.3% and 8.8%). Although an open IRA remained an independent predictor of 30-day mortality, after adjustment for clinical and angiographic variables including LVEF, patency was not independently associated with lower 1-year mortality rate. Thus the largest retrospective analysis of the open artery hypothesis refuted the positive results reported in smaller studies. Extensive data on revascularization of single- and double-vessel coronary artery disease for clinical reasons, including severe angina, have not shown significant mortality reduction compared with medical therapy.[24,25,26] Thus, at present, the totality of evidence does not support the routine opening of occluded IRAs in asymptomatic post-MI patients.