The restenosis after coronary angioplasty is the unresolved problem even if the improvement of interventional skills and pharmacological therapies. Nitric oxide, known as endothelial derived relaxing factor (EDRF), regulates the vascular tone and inhibits the proliferation of vascular smooth muscle cells and platelet adhesions and endothelium-leukocyte interactions. Nitric oxide is produced by endothelial nitric oxide synthase (eNOS). We studied the significance of eNOS gene polymorphism for the prediction of restenosis after coronary angioplasty in Koreans with ischemic heart disease.

We analyzed the two eNOS poly-morphisms using PCR (eNOS A/B polymorphism is the VNTR in intron 4 and eNOS T/G polymorphism is a missense mutation in exon 7) in 199 Korean patients who had 257 lesions undergoing percutaneous coronary angioplasty (ballooning=152, stenting=105). The angiography was repeated 6 months later to assess the relation between the rate of restenosis and types of eNOS gene polymorphism.

We found no significant differences of restenosis rate in eNOS A/B and T/G polymorphism in those with balloon angioplasty or with stent (restenosis rate of A/A, A/B, B/B, respectively (n=257): 25% (1/4), 26% (14/53), 31% (62/200) (p=not significant), and T/T, T/G, G/G (n=249): 0% (0/3), 36% (16/44), 29% (58/202)(p=not significant)) Patients with A allele (non BB) or GG phenotype had lower restenosis rate, so we analyzed protective effect of non BB and GG phenotype on restenosis, but there was no significant statistical difference (restenosis rate of non BB and GG, BB and non GG respectively: 20% (15/57), 34% (16/47)(p=not significant)).

eNOS A/B and T/G polymorphism is not associated with a significantly elevated risk of restenosis after coronary angioplasty.