Clinical relevance of homocysteine levels in patients receiving coronary stenting for unstable angina.

Although stents reduce the incidence of angiographic and clinical restenosis following percutaneous coronary interventions, they do not abolish restenosis altogether1. Epidemiological and clinical studies have identified moderately raised concentrations of plasma homocysteine (HCY) as an important and potentially modifiable risk factor for coronary artery disease2-4. In particular, raised concentrations of this non-essential amino acid produced by the demethylation of methionine appear to be a strong predictor of late adverse cardiac events in patients admitted with acute coronary events5. As seen in homocystinuria, elevated HCY levels increase thrombogenicity6 and induce vascular damage7. Recently, plasma HCY concentrations were correlated with restenosis after percutaneous transluminal coronary angioplasty (PTCA)8,9. Unstable angina, as previously reported, is a wellknown independent predictor of restenosis after coronary artery stenting10. However, little is known about the relevance of HCY levels for the prediction of in-stent restenosis in patients, who owing to their unstable clinical conditions, are at increased risk of restenosis and thrombotic complications. We therefore prospectively investigated whether plasma HCY concentrations are related to the rate of clinical in-stent restenosis (target lesion revascularizationTLR) in this specific subset of patients.