Biomarkers in heart failure.

Copyright © 2008 Massachusetts Medical Society. Heart failure, a major and growing public health problem, appears to result not only from cardiac overload or injury but also from a complex interplay among genetic, neurohormonal, inflammatory, and biochemical changes acting on cardiac myocytes, the cardiac interstitium, or both. An increasing number of enzymes, hormones, biologic substances, and other markers of cardiac stress and malfunction, as well as myocyte injury — collectively referred to as biomarkers — appear to have growing clinical importance. Although biomarkers include genetic variants, clinical images, physiological tests, and tissuespecimen biopsies, this review focuses on biomarkers derived from the blood or urine other than serum levels of hemoglobin, electrolytes, liver enzymes, and creatinine, which are routinely determined as part of clinical care. Morrow and de Lemos1 have set out three criteria a biomarker should fulfill to be useful clinically. First, accurate, repeated measurements must be available to the clinician at a reasonable cost and with short turnaround times; second, the biomarker must provide information that is not already available from a careful clinical assessment; and finally, knowing the measured level should aid in medical decision making. Although relatively few of the biomarkers discussed in this review satisfy all three criteria, many appear to provide important information regarding the pathogenesis of heart failure or the identification of subjects at risk for heart failure or appear to be useful in risk stratification, in the diagnosis of heart failure, or in monitoring therapy. Many biomarkers may be risk factors themselves and therefore may be potential targets of therapy. Although no specific classes for biomarkers are accepted, I propose that they could be divided into six categories, as well as a seventh category of new biomarkers that have not yet been fully characterized (Table 1).