Impact of serum erythropoietin level on collateral vessel development in patients with coronary artery disease

Objective: Experimental data have shown that Erythropoietin (EPO) stimulates angiogenesis and neovascularization which may result in improved collateral development. The aim of this study was to investigate the association between serum EPO levels and the extent of coronary collaterals. Patient characteristics possibly related with coronary collaterals were also sought. Methods: A total of 256 patients with high grade coronary stenosis or occlusion were evaluated for the extent of coronary collaterals using Rentrop classification. Patients with grade 0 or 1 collaterals were grouped as poor collaterals, while grade 2 or 3 collaterals were grouped as good collaterals. Results: Mean age of the study population was 63 years, 77% were males. Subjects with good collaterals were significantly more likely to have anemia (p=0.038) and stable angina pectoris as clinical presentation (p=0.40). Serum EPO levels were not different among good and poor collateral groups (10.4 +/- 9.4 mU/mL vs. 9.7 +/- 11 mU/mL, p=0.397). The prevalence of all other cardiovascular risk factors, medications, and angiographic characteristics were similar between the two groups. After adjusting for age, gender, and clinical presentation with stable angina pectoris, presence of anemia persisted to be a significant correlate of the good collateral formation (OR: 1.95; 95%; CI: 1.07-3.54, p=0.029). Conclusion: There has been conflicting results from trials studying the effects of serum EPO on coronary collateral development. The present study, with the largest patient population studying this topic, suggests that presence of anemia, but not serum EPO level, is associated with good collateral development.