Measurement of Myocardial Fractional Flow Reserve During Coronary Angioplasty in Infarct-related and Non-infarcet-related Coronary Artery Lesions

Myocardial fractional flow reserve (FFR) has been demonstrated to be a useful method for determining the physiologic importance of a given coronary lesion. However, the reliability of the FFR measurement is unknown in infarct related arteries (IRA). The aim of this study was to measure and correlate the FFR findings of 14 consecutive patients who had recent acute myocardial infarction (AMI) (Group1) with 14 consecutive patients who did not have AMI (Group2) before and after percutaneous transluminal coronary angioplasty (PTCA). Quantitative coronary angiography (QCA) and FFR measurements were determined both before and after optimal PTCA for all patients. FFR was measured by use of a 0.014 inch guidewire as the ratio of the pressure distal to the target lesion to the aortic pressure taken during the maximal hyperemia induced by intracoronary adenosine. There were no differences between the two groups related to gender, target artery reference diameter, minimal luminal diameter and percent diameter stenosis of the vessel both before and after PTCA. While FFR findings after PTCA were not different between the groups, they were statistically different before PTCA (Group1 %77.6±5.4, Group2 %63.3±8.4, p<0.001). Although QCA determined percent diameter stenosis was significant (%66.5±10.5) for Group 1, FFR values were higher than 75% (%77.6±5.4) indicating insignificant stenosis. Thus, it was concluded that FFR measurements before PTCA are different between IRA and non-IRA and the cut-off point of 75% may not be valid for IRA.