Processed B-Type Natriuretic Peptide Is a Biomarker of Postinterventional Restenosis in Ischemic Heart Disease

BACKGROUND: Restenosis, a condition in which the lesion vessel renarrows after a coronary intervention procedure, remains a limitation in management. A surrogate biomarker for risk stratification of restenosis would be welcome. B-type natriuretic peptide (BNP) is secreted in response to pathologic stress from the heart. Its use as a biomarker of heart failure is well known; however, its diagnostic potential in ischemic heart disease is less explored. Recently, it has been reported that processed forms of BNP exist in the circulation. We hypothesized that circulating processed forms of BNP might be a biomarker of ischemic heart disease. METHODS: We characterized processed forms of BNP by a newly developed mass spectrometry-based detection method combined with immunocapture using commercial anti-BNP antibodies. RESULTS: Measurements of processed forms of BNP by this assay were found to be strongly associated with presence of restenosis. Reduced concentrations of the amino-terminal processed peptide BNP(5-32) relative to BNP(3-32) [as the index parameter BNP(5-32)/BNP(3-32) ratio] were seen in patients with restenosis [median (interquartile range) 1.19 (1.11-1.34), n = 22] vs without restenosis [1.43 (1.22-1.61), n = 83; P < 0.001] in a cross-sectional study of 105 patients undergoing follow-up coronary angiography. A sensitivity of 100% to rule out the presence of restenosis was attained at a ratio of 1.52. CONCLUSIONS: Processed forms of BNP may serve as viable potential biomarkers to rule out restenosis.