COLLAGEN SCAR FORMATION AFTER ACUTE MYOCARDIAL-INFARCTION - RELATIONSHIPS TO INFARCT SIZE, LEFT-VENTRICULAR FUNCTION, AND CORONARY-ARTERY PATENCY

Background Left ventricular function after acute myocardial infarction (AMI) is determined by the expansion of the infarct zone and remodeli ng of the noninfarcted myocardium. An occluded infarct-related artery (IRA) is an independent risk factor for remodeling. Methods and Result s Changes in myocardial collagen metabolism were evaluated in 36 patie nts with suspected AMI. The plasma creatine kinase MB fraction and myo globin release curves were analyzed for assessment of early reperfusio n and infarct size. Collagen scar formation was evaluated by measureme nt of serum concentrations of the aminoterminal propeptide of type III procollagen (PIIINP), the aminoterminal propeptide of type I procolla gen (intact PINP), and the carboxyterminal propeptide of type I procol lagen (PICP). Plasma renin activity and urine excretion of cortisol an d aldosterone were also measured. Coronary angiography and left ventri cular cineangiography were performed during early hospitalization. The serum concentration of PIIINP increased from 3.50+/-0.20 to a maximum of 5.08+/-0.36 mu g/L (n=32) in the patients with AMI, whereas the co ncentrations of intact PINP and PICP tended to decrease. The area unde r the curve (AUC) of PIIINP during the first la postinfarction days wa s larger in patients with severe heart failure or ejection fractions l ess than or equal to 40% than in those with no heart failure or with a n ejection fraction >40% (P<.05 and P<.01, respectively), and it was a lso larger in the patients with TIMI grade 0 to 2 flows than in those with TIMI 3 flows (P<.05), despite similar enzymatically determined in farct sizes. No significant correlations between PIIINP and neurohumor al parameters were observed. The AUC of PIIINP and the change in PIIIN P during the first 4 days were significantly correlated with indices o f cardiac function. Conclusions Collagen scar formation after AMI can be quantified by measurement of serum PIIINP concentrations. Scar form ation is more prominent in large infarctions causing left ventricular dysfunction and in patients with occluded IRAs.