New practice guidelines for use of biomarkers in ACS and heart failure. July 22, 2007

July 22, 2007 By Benjamin A. Olenchock, M.D. Ph.D. [mailto:bolenchock@partners.org]

New practice guidelines have been published for the use of biomarkers in the diagnosis, risk stratification, and management of patients with acute coronary syndrome (ACS) or heart failure (HF). Clinical trials of novel cardiac biomarkers pack the cardiology literature with exciting but sometimes contrary findings, and clinicians are faced with the difficult task of determining the most appropriate, evidence-based use of these markers. The new guidelines, published in the journal Circulation, focus on the role of natriuretic peptides, C-reactive protein (hsCRP), and cardiac troponin. These three markers are the most rigorously validated from among the more than twenty markers studied in the current literature.

The ACS guidelines stress two main points. First, cardiac troponin is recommended as the preferred biomarker for diagnosing acute myocardial infarction. Creatine kinase MB (CK-MB) measured by mass assay is an acceptable alternative. Second, natriuretic peptides (BNP or NT-proBNP) and high sensitivity CRP add prognostic information in ACS and are useful for risk stratification. However, there is insufficient evidence to make therapeutic recommendations based on these biomarkers.

The HF guidelines focus on the appropriate use of natriuretic peptides. Measurement of BNP or NT-proBNP is recommended for diagnostic purposes in patients with suspected HF in the acute setting. In the non-acute setting, routine measurement is not recommended when the diagnosis of HF is obvious; however, natriuretic peptide levels can be useful in the non-acute setting to exclude HF when the presentation is unclear. Other uses of natriuretic peptide measurement are more controversial and are not recommended, including use in screening patients for HF post-myocardial infarction or during annual health screenings, or use as a routine measure with which to guide HF management decisions.

These new guidelines come at a time when new, exciting biomarker trials are published with increasing frequency. The evidence-based recommendations should help physicians navigate the complexity of the biomarker literature.