Principal component analysis of elements in atherosclerotic human coronary arteries

Principal component analysis was applied to identify normal and pathological structures using combinations of levels of phosphorus, sulphur, chlorine, potassium and calcium in early stages of atherosclerotic coronary arteries. An inverse correlation was found between the combination of Ca-P, and that of S-Cl-K. This finding points towards the presence of smaller calcified deposits in an early phase of atherosclerosis in the human coronary artery. A possible location of cholesterol or some other carbon-based materials could also be identified. Further, a histogram method proved to be useful for characterising calcified structures of Ca/P mass ratio lower than that of hydroxyapatite. An empirical formula of (1−n)Ca3(PO4)2 · nAm(PO4) is suggested to explain composition of these calcified structures.