The Confounding Effects of Non-cardiac Pathologies on the Interpretation of Cardiac Biomarkers

Marin Nishimura, Alison Brann, Kay-Won Chang, Alan S Maisel

Cardiac biomarkers play important roles in routine evaluation of cardiac patients. But while these biomarkers can be extremely valuable, none of them should ever be used by themselves-without adding the clinical context. This paper explores the non-cardiac pathologies that can be seen with the cardiac biomarkers most commonly used. High-sensitivity troponin assay gained FDA approval for use in the USA, and studies demonstrated its diagnostic utility can be extended to patients with renal impairment. Gender-specific cut points may be utilized for high-sensitivity troponin assays. In the realm of the natriuretic peptides, studies demonstrated states of natriuretic peptide deficiency in obesity and in subjects of African-American race. Regardless, BNP and NT-proBNP both retained prognostic utilities across a variety of comorbid conditions. We are rapidly gaining clinical evidence with use of soluble ST2 and procalcitonin levels in management of cardiac disease states. In order to get the most utility from their measurement, one must be aware of non-cardiac pathologies that may affect the levels of biomarkers as although many of these are actually true values, they may not represent the disease we are trying to delineate. A few take-home points are as follows: 1. A biomarker value should never be used without clinical context 2. Serial sampling of biomarkers is often helpful 3. Panels of biomarkers may be valuable.