To the Editor:
It is with great interest that we read the excellent review of biomarkers in cardiovascular medicine by Martin-Ventura et al.1 They reviewed the biomarkers most commonly reported in the existing literature and assessed their links with atherogenic mechanisms, atheromatous plaque disruption, endothelial dysfunction, inflammation, oxidative stress, and thrombosis. In their scholarly review, however, the authors do not mention neopterin, a marker of macrophage activation2 which over the last few years has gained particular importance due to its role in cardiovascular risk stratification.3
Neopterin is a pteridine derivative, produced by activated macrophages stimulated by interferon gamma. Studies by our group4-9 and others10-13 have shown that neopterin can be a useful prognostic marker in the risk stratification of patients with coronary artery disease. The serum concentration of neopterin has been shown to correlate with the presence of vulnerable atheromatous plaques7 and acute coronary syndrome.4,9-11
High neopterin levels predict risk in patients with chronic stable angina,6 and in hypertensive patients without obstructive coronary disease,5 diabetics13 and patients undergoing coronariography.12 Moreover, neopterin predicts the rapid progression of coronary disease in patients with chronic stable angina.8 As this marker predicts cardiovascular events independently of the extension and severity of the coronary disease,6,14 it is reasonable to suggest that high neopterin concentrations identify patients with a "vulnerable phenotype."15
Given the scientific evidence accumulated in the literature over recent years, we believe that neopterin should be considered as a promising prognostic marker that may find a practical application in the clinical setting.