Serum neopterin and complex stenosis morphology in patients with unstable angina

OBJECTIVES We sought to assess the relation between serum neopterin concentration and complex coronary artery stenosis in patients with unstable angina. BACKGROUND Monocyte activation is associated with acute atheromatous plaque disruption and acute coronary syndromes. Angiographically demonstrated complex coronary stenosis is often an expression of plaque disruption. Increased serum concentration of neopterin, a pterydine derivative secreted by macrophages after stimulation by interferon-gamma, has been observed in patients with acute coronary syndromes as compared with control subjects and patients with stable angina pectoris. METHODS We studied 50 patients with unstable angina (32 men) who underwent coronary angiography after hospital admission. All coronary stenoses with ≥30% diameter reduction were assessed and classified as “complex” (irregular or scalloped borders, ulceration or filling defects suggesting thrombi) or “smooth” (absence of complex features). Serum neopterin levels were assessed within 24 h of hospital admission using a commercially available immunoassay (enzyme-linked immunosorbent assay kit, IBL, Hamburg, Germany). RESULTS Thirty-nine patients were classified in Braunwald class IIIb, four in class IIb and seven in class Ib. The number of complex lesions per patient was 2.6 ± 1.8 (mean ± SD). The mean neopterin concentration was 7.76 ± 3.62 nmol/liter. A significant correlation was observed between neopterin serum concentration and the presence of complex coronary stenoses (r = 0.35, p = 0.015). Multiple regression analysis showed that serum neopterin (p < 0.0001) was independently associated with the number of complex lesions. Other variables associated with complex lesions were the number of vessels with ≥75% stenosis (p < 0.0001), plasma creatinine (p = 0.003), triglycerides (p = 0.014) and a history of unstable angina (p = 0.032). CONCLUSIONS Serum neopterin concentration is associated with the presence of angiographically demonstrated complex lesions in patients with unstable angina and may represent a marker of coronary disease activity.