Relationship of sustained brain natriuretic peptide release after reperfused acute myocardial infarction with gated SPECT infarct measurements and its connection with collagen turnover and left ventricular remodeling

Background. The relationship among plasma brain natriuretic peptide (BNP), markers of extracellular matrix (ECM) remodeling, and left ventricular (LV) dilation after reperfused acute myocardial infarction is poorly known. Methods and Results. Echocardiogram, plasma BNP, and ECM degradation markers (serum amino-terminal telopeptide of type I procollagen and type III procollagen and carboxy-terminal telopeptide of type I procollagen [ICTP]) were evaluated in 34 patients at days 1, 3, and 30 after first reperfused acute myocardial infarction. At 1 month, infarct size and severity and LV volume were measured by sestamibi gated single photon emission computed tomography. Patients were stratified according to day 3 BNP levels into 2 groups: group 1 (n=17) had BNP values over the median value, and group 2 (n=17) had BNP values under the median value. Infarct size and severity were similar in the 2 groups. LV volumes increased in group 1 but decreased in group 2 (P<.01). BNP values, LV volume/mass index, and infarct size were independent predictors of 1-month LV dilation (β=.58 [P=.001], β=.41 [P=.01], and β=.32 [P=.03], respectively). Levels of serum amino-terminal propeptide of type I procollagen and type III procollagen were similar in both groups. The level of ICTP increased significantly in group 1 only, and after 3 days, it was higher (P<.01) than in group 2. In group 1 ICTP significantly interacted with the relationship between BNP release and serial changes in LV volumes (F=4.87, P=.03). Conclusions. ICTP is related to elevated BNP level independently of infarct size and severity and interacts with the relationship between BNP and LV dilation. BNP levels could play a role in LV remodeling by favoring ECM degradation. (J Nucl Cardiol 2008;15:644-54.) This study was supported by a research grant from the A.R. CARD ONLUS Foundation, Florence, Italy, and by an unrestricted grant from the Cassa di Risparmio Foundation of Florence, Italy.