Plasma MMP-2, MMP-9 and N-BNP in long-term survivors following complicated myocardial infarction: relation to cardiac magnetic resonance imaging measures of left ventricular structure and function.

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 > or = 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.