Development of collateral vessels (CV) of the coronary artery in ischemic heart disease (IHD) differs in each individual. We tried to determine the relationship between the presence of CV and clinical characteristics and CAG findings, and the clinical impact of CV on prognosis.

Seventy-one patients with acute myocardial infarction (AMI) treated with percutaneous coronary intervention (PCI) within 24 hours after symptom onset were included. The relationships between the presence of CV and risk factors of IHD and the findings of CAG, and influences of CV on 3-year mortality and cardiac events were evaluated.

CV was absent in 35 patients (group A) and was observed in 36 (group B). There was no significant difference between these two groups in clinical characteristics or CAG findings. Risk factors of IHD, other than diabetes and high density lipoprotein-cholesterol (HDL-C), were not different. All seven cases of diabetes were in group A (p=0.005) and HDL-C was higher in group B than group A (41.6±12.0 mg/dL versus 50.1±17.3 mg/dL, p=0.021). There was a trend of higher mortality (14.3% versus 2.8%, p=0.056), whereas the higher rate of composite cardiac events in group A during follow-up was statistically significant (45.7% versus 22.2%; hazard ratio, 5.13; 95% confidence interval, 1.05-25.04; p=0.043).

CV was more frequently observed in the non-diabetic patients and in the patients with higher HDL-C level. The presence of CV in patients with AMI treated with PCI was a favorable prognostic factor.