Abstract P368: N-Terminal Pro Brain Natriuretic Peptide and Microsize Myocardial Infarctions in the REasons for Geographic And Racial Differences in Stroke (REGARDS) Study
Background: N-terminal pro brain natriuretic peptide (NT-proBNP) has been associated with myocardial infarctions (MI), but less is known about the relationship between NT-proBNP and very small non ST-elevation MIs now routinely detectable with modern troponin assays. Since these “microsize MIs” confer high long-term coronary heart disease (CHD) risks, we examined the association of NT-proBNP with incident acute CHD events, total MIs, and two MI subtypes: microsize and typical MIs.
Methods: REGARDS is a national cohort of 30,237 US community-dwelling black and white adults aged ≥45 recruited from 2003 to 2007. Expert-adjudicated outcomes included incident typical MIs (definite/probable MI with peak troponin ≥0.5 μg/L), incident microsize MIs (definite/probable MI with peak troponin <0.5 μg/L), and total incident acute CHD (nonfatal MIs or CHD deaths). Low-level troponin elevations with the peak at least twice the upper limit of normal which did not have a rising and/or falling pattern or which had a non-ischemic cause were not considered MIs. We assembled a case-cohort study comprised of 1) a stratified random sample of participants free of CHD at baseline and not on dialysis (n=849); and 2) all incident acute CHD cases through 12/31/2010. NT-proBNP was measured in case-cohort participants at baseline and was dichotomized on the sample’s median value (73.3 pg/mL). Adjusted weighted Cox proportional hazards regression models examined associations of NT-proBNP and CHD endpoints, controlling for sociodemographics and CHD risk factors.
Results: Over a median of 5.9 years follow-up, 139 microsize MIs, 315 typical MIs, and 146 non-MI CHD deaths occurred. NT-proBNP was associated with all CHD outcomes examined (Table).
Conclusions: Above-median NT-proBNP was independently and strongly associated with all CHD endpoints with a suggestion of greater risks of incident microsize MI. A better understanding of the pathophysiologic differences between typical and microsize MIs is needed.
Author Disclosures: R.W. Durant: None. Y.A. Khodneva: None. E.B. Levitan: None. T.M. Brown: None. S. Glasser: None. G. Howard: None. M.M. Safford: None.
- © 2014 by American Heart Association, Inc.