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Background Altered activity of the matrix metalloproteinases (MMP-2 and -9), has been implicated in the left ventricular (LV) remodeling process occurring after myocardial infarction (MI). In the acute phase, a relation between plasma MMP-9 levels and parameters of LV dysfunction has been demonstrated. The relationship in long-term survivors has not been investigated. We studied the relationships of these biochemical markers, and N-terminal pro-B-type natriuretic peptide (N-BNP), with measures of long-term LV remodeling. Methods and Results Plasma levels of N-BNP, MMP-2, and MMP-9 were measured at randomization, 1 month, 1 year, and >4 years after complicated AMI. Contrast-enhanced cardiac magnetic resonance (CMR) was performed at 4.4 (±0.4) years in 52 clinically stable long-term survivors of the index AMI. We assessed the relationships of plasma N-BNP, MMP-2, and MMP-9 with myocardial scarring, and measures of long-term LV remodeling. Compared with a reference population, N-BNP and MMP-9 levels were increased at all time points from the acute phase until >4 years after MI. Plasma N-BNP and MMP-9 correlated only in the subacute phase (randomization, mean 3.3 days after MI) days after acute MI ( r = 0.38, P = .006). At CMR assessment ≥4 years, log MMP-9 level was inversely related to LV ejection fraction ( P = .002) and nonscarred myocardial mass ( P = .008). This relationship was independent of MMP-2. Log N-BNP was related to end diastolic volume index ( P = .0002). There was no correlation between log MMP-9 and LV volumes. Conclusion There is a time-dependent relationship between plasma N-BNP and MMP-9 levels, these peptides correlating only in the acute phase after MI. In long-term follow-up, plasma MMP-9 and N-BNP levels were related to different parameters of LV remodeling. These findings suggest that in long-term survivors of complicated MI, different mechanisms modulate plasma levels of MMP-9 and N-BNP.

Background Few studies have compared the relative prognostic value of different natriuretic peptides after acute myocardial infarction (AMI). None has described peptide levels beyond the early post-AMI period. This study describes temporal profiles of 4 natriuretic peptides to 2 years after AMI and relationship with outcome. Methods and Results We assessed profiles of N-terminal proANP (N-ANP), B-type natriuretic peptide (BNP), N-terminal proBNP (N-BNP), and C-type natriuretic peptide (CNP) (study entry, 1 month, 1 year, and 2 years) in 236 patients with AMI complicated by clinical or radiologic evidence of heart failure. We assessed the prognostic value for baseline levels of each peptide for death or reinfarction. We observed distinct natriuretic peptide profiles. BNP and N-BNP levels were highest at baseline and fell thereafter. N-ANP levels increased from baseline to 30 days and fell thereafter. During follow-up (mean 938 days), 34 patients died and a further 25 suffered nonfatal AMI. Baseline natriuretic peptide levels did not have independent predictive power for outcome. N-BNP levels fell from baseline to 30 days in patients surviving to the end of follow-up ( P = .005) but were similar at both times ( P = .76) for those dying after 30 days. Age ( P P = .026) had independent predictive value for death after 30 days. Conclusion N-ANP, BNP, N-BNP, and CNP show distinct plasma profiles after AMI. Failure of plasma N-BNP to fall in the 30 days after AMI indicates adverse prognosis.