Do established biomarkers such as B-type natriuretic peptide and troponin predict rejection?

Purpose of review: Acute cardiac allograft rejection surveillance has historically been based on serial endomyocardial biopsy (EMB). Limitations with this approach have stimulated interest in identifying noninvasive surrogate markers of rejection. This review summarizes the evidence assessing the use of direct cardiac markers B-type natriuretic peptide (BNP) and cardiac troponins in detecting acute allograft rejection. Recent findings: BNP, its amino-terminal fragment NT-proBNP, and cardiac troponins T and I have all been extensively evaluated for this purpose, and so far have demonstrated inadequate diagnostic accuracy to replace EMB. Longitudinal surveillance of BNP and NT-proBNP appears to offer promise for improved accuracy, but has not been adequately evaluated in prospective studies. Preliminary investigations into highly sensitive troponin assays suggest a potential role in rejection surveillance, but prospective validation in larger studies is needed. Summary: EMB remains the gold standard for cardiac allograft rejection surveillance. However, recent data indicate potential clinical utility for serial monitoring of natriuretic peptides. If further investigation into highly sensitive troponin assays confirms the positive data so far reported, further efforts directed toward a longitudinal-based rejection surveillance algorithm incorporating both troponin and BNP may identify a strategy that could serve as an alternative to EMB.