The aim of this study was to compare the residual diameter stenosis after PTCA with fractional flow reserve (FFR) and coronary flow reserve (CFR), and investigate the correlation between FFR and CFR in patients with acute myocardial infarction (AMI).

The study population consisted of twenty seven patients with myocardial infarction. Baseline and hyperemic average peak velocity (APV) were measured using Doppler wire 15 minutes after restoration of infarct-related artery (IRA). CFR was obtained by the ratio of distal hyperemic APV to baseline APV. Distal coronary arterial pressure (Pd) was measured with advancing the wire distal to the lesion of IRA. Simultaneous proximal aortic pressure (Pa) was measured using guiding catheter. Myocardial FFR was obtained by the ratio of hyperemic Pd to hyperemic Pa.

Post-interventional CFR and FFR were 0.85±0.44, 0.91±0.09. CFR did not show significant correlation with luminal diameter stenosis (%ST). There was no significant correlation between FFR and CFR with a correlation coefficient of 0.29 (p=.25). But, significant correlation was found between %ST and FFR, %ST and hyperemic PG (hPG) with correlation coefficient of -0.70 (p=.0012) and 0.68 (p=.0018).

In AMI patients, %ST has a significant correlation with FFR and hPG after PTCA. But, there was no significant correlation between FFR and CFR.