Incomplete protective effect of coronary collateral circulation for acute myocardial infarction patients

The short-term and long-term effects of coronary collateral circulation (CCC) discovered after acute myocardial infarction (AMI) are still debatable. This retrospective cohort study aimed to explore the clinical significance of CCC for AMI patients. A consecutive series of 323 AMI patients with CCC and 1339 AMI subjects without CCC were enrolled, most of them received percutaneous coronary intervention after AMI. Comparisons between CCC subjects and non-CCC population and between CCC sub-groups were applied regarded to basic clinical characteristics, stenosis extent indicated by Gensini score, myocardial infarction size estimated by peak concentration of troponin I (TnI), and left ventricular function evaluated by peak value of N-terminal pro-brain natriuretic peptide (NT-proBNP). Multiple linear regressions for NT-proBNP and TnI, and Kaplan-Meier curves for 5-years’ main cardiovascular event (MACE) were also analyzed. (1).. CCC patient had a greater extent of stenosis and a worse heart function while the estimated infarction size was not larger than non-CCC group; (2).. sub-group analyses showed, for good CCC circulation patient, stenosis extent was heavier, heart function was poorer while estimated infarction size was lower; (3).. regression analyses further indicated: for poorer heart function, stenosis extent and CCC (non, poor, good) were promotive factors; b) for infarction size, stenosis extent was a promotive factor in non-CCC group while it was an inhibitive factor in CCC group, good CCC was an inhibitive factor in CCC sub-group. (4).. Kaplan-Meier curves showed CCC had no obvious protective effect on 5-years’ MACE for AMI patients. CCC might provide incomplete protection by preventing excessive myocardial infarction but not a poorer heart function during AMI and CCC had no obvious protective effect on 5-years’ MACE for AMI patients. More attentions should be paid to heart function for CCC patients during AMI.