A blood test for patients with coronary heart disease could help predict their risk for subsequent cardiovascular events or death.
Risk stratification for cardiovascular events among the general population and among high-risk individuals is of considerable interest because of the potential to help guide use of primary and secondary preventive therapies. Brain-type natriuretic peptide ( BNP; consisting of 2 or more amino acids ) and the amino terminal fragment of the prohormone BNP ( NT-proBNP; a type of peptide in the blood that is a cardiac biomarker ) appear to provide prognostic information in individuals following hospital admission for decompensated heart failure or acute coronary syndrome, and may also be important markers of long-term prognosis.
Kirsten Bibbins-Domingo, of the University of California, San Francisco, and colleagues assessed the association of plasma NT pro-BNP levels with subsequent cardiovascular events ( myocardial infarction, stroke, or heart failure ) and death in a group of 987 patients with coronary heart disease ( CHD ). The participants were followed up for an average of 3.7 years, during which 256 patients ( 26.2 percent ) had a cardiovascular event or died.
The researchers found that each increasing quartile of NT-proBNP level was associated with a greater risk of cardiovascular events or death, with individuals in the highest quartile ( 19.6 percent event rate ) having a nearly 8-fold increased rate of cardiovascular events or death compared with those in the lowest quartile ( 2.6 percent event rate ). Each incremental increase by a certain level of NT-proBNP was associated with a 2.3-fold increased rate of adverse cardiovascular outcomes, even after adjusting for other prognostic markers, including clinical factors, echocardiographic parameters, ischemia, serum biomarkers and functional limitations.
" We observed the strongest association between NT-proBNP level and risk of incident heart failure. The ability to identify individuals at risk for developing heart failure has considerable appeal because the early initiation of preventive therapies may alter the course of this disease with very high rates of morbidity and mortality, " the authors write.
" These findings suggest that a simple blood test for NT-proBNP level may aid in the risk stratification of high-risk patients, such as those with CHD, and may guide further testing and treatment strategies aimed at reducing future cardiovascular morbidity and mortality, " the researchers conclude.
In an accompanying editorial, Marvin A. Konstam, of the Tufts University School of Medicine and Tufts-New England Medical Center, Boston, comments on the findings of the study concerning peptides and cardiovascular events.
" Bibbins-Domingo et al suggest that NT-proBNP may be used to screen for patients to be considered for therapeutic intervention. Before accepting this proposal, it is important to remember that use of a biomarker for triggering or guiding therapy requires more than the demonstration of its correlation with worse clinical outcomes. Blood pressure and low-density lipoprotein cholesterol represent markers that are linked directly to the pathology that drives adverse outcomes. Clinical trial demonstration of a therapeutic impact on either of these markers has consistently been associated with improvement in cardiovascular outcomes. Likewise, clinical trial evidence also should be required to demonstrate that matching a treatment strategy to an elevated natriuretic peptide level improves clinical outcomes.
" Unlike low-density lipoprotein cholesterol and blood pressure, the natriuretic peptides predominantly mitigate disease rather than drive it. Nevertheless, as disease markers, assays for natriuretic peptides might represent instruments to aid decision making in initiation and guidance of treatment," Konstam writes.
Source: Journal of American Medical Association, 2007