A method of bioassay for the quantification of peptide fragments comprising a neo-epitope formed by cleavage of a protein of an atherosclerotic plaque such as lumican, versican, perlecan, decorin, biglycan, collagen type III, CRP, ApoE, or elastin, by a proteinase, said comprises contacting a sample such as urine or serum with an antibody reactive with the neo-epitope and determining the level of binding of said immunological binding partner to peptide fragments in said sample. The assay is predictive of risk of cardiovascular disease events.