The characterization of patients who have acute coronary syndrome (ACS) without critical stenosis is unclear. First, we wanted to learn more about the angiographic and demographic characteristics of patients with non-ST-segment-elevation myocardial infarction who were not in need of percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). Second, we wanted to look for further cardiac events during follow-up.

We retrospectively analyzed all patients with ACS plus ischemic-marker elevation from May 2002 through September 2005. Follow-up was obtained primarily by telephone interviews. Of the 1,437 ACS patients who were screened, 127 (8.8%) had noncritical stenosis (study group), and 509 (35.4%) had sufficient stenosis (>50%) to warrant PCI (control group). Patients with noncritical stenosis (≤50%) were significantly younger, were more frequently women, and had fewer risk factors. Myocardial infarction or PCI/CABG occurred in no patients with noncritical stenosis (follow-up, 12.2 mo) and in 5.1% or 16.1% (respectively) of patients with critical stenosis (follow-up, 11.1 mo; P <0.05 for revascularization). Cardiac death was more likely in patients without critical stenosis, but insignificantly so (2.4% vs 1.8%, P=0.6).

Subanalysis: Of patients without critical stenosis, 52.8% had smooth coronary arteries, and 47.3% had mild-to-moderate atherosclerosis (stenosis ≤50%). Follow-up revealed no deaths in the 1st subgroup and 3 cardiac deaths (5%) in the 2nd (P=0.06).

We conclude that the prognosis of patients without significant stenosis was significantly better in regard to revascularization, but statistically the same in regard to mortality.