Association of calciprotein particles measured by a new method with coronary artery plaque in patients with coronary artery disease: A cross-sectional study

Abstract Background Calciprotein particles (CPPs) have been suggested to be associated with the degree of coronary atherosclerosis, and have also been established as a molecular marker for clinical outcome in patients with chronic kidney disease (CKD). However, there are several concerns with regard to conventional measurement of CPPs. We therefore developed a new CPP measurement system that can detect both smaller and lower-density CPPs. Methods We analyzed 71 consecutive patients who underwent percutaneous coronary intervention for acute coronary syndrome (ACS, n = 29) and/or stable angina pectoris (AP, n = 42) who did not have CKD of stage 4 or greater. CPP measurement was made using an infrared fluorescent bisphosphonate (OsteoSense, PerkinElmer, Waltham, MA, USA) and a gel filtration method. The coronary artery plaque was analyzed by gray-scale intravascular ultrasound (IVUS) and integrated backscatter (IB)-IVUS. Results The median CPP level (interquartile range) was 40,953 (19,171–74,131) arbitrary units (AU). When we divided the CPP level into quintiles, the total and lipid plaque volume were incrementally higher with increasing quintile from lowest to highest (both p  86,751 AU) had significantly higher total plaque (263 mm3 vs. 161 mm3; p = 0.001) and lipid plaque volume (156 mm3 vs. 89 mm3; p  Conclusions The results suggested that a high CPP level, as measured by the novel assay, is a surrogate marker for coronary atherosclerosis, especially in lipid-rich plaques, contributing to an increased risk of plaque vulnerability.