Measurement of myocardial fractional flow reserve during coronary angioplasty in infarct-related and non-infarct related coronary artery lesions

Myocardial fractional flaw reserve (FFRmyo) has been demonstrated to be a u seful method for determining the physiologic importance of a given coronary lesion. However, the reliability of the FFRmyo measurement is unknown in i nfarct-related arteries (IRA). The aim of this study was to measure and cor relate the FFRmyo results of 14 consecutive patients who had recent acute m yocardial infarction (AMI) (Group 1) with 14 consecutive patients who didn' t have AMI (Group 2) before and after percutaneous transluminal coronary an gioplasty (PTCA). Quantitative coronary angiography (QCA) and FFRmyo measur ements were determined both before and after optimal PTCA for all patients. FFRmyo was measured by use of a 0.014 inch guidewire as the ratio of the p ressure distal to the target lesion to the aortic pressure taken during the maximal hyperemia induced by intracoronary adenosine. There were no differ ences between the two groups related to gender, target artery reference dia meter, minimal luminal diameter and percent diameter stenosis of the vessel both before and after PTCA. While FFRmyo results after PTCA were not diffe rent between the groups, they were statistically different before PTCA (Gro up 1: 77.6 +/- 5.1%, Group 2: 63.3 +/- 8.4%; p < 0.001). Although QCA-deter mined percent diameter stenosis revealed a significant degree of stenosis ( 66.5 +/- 10.5%) for Group 1, FFRmS a values were higher than 75% (77.6 +/- 5.1%), indicating insignificant stenosis. Thus, it was concluded that FFRmy o measurements before PTCA were significantly different between IRA. and no n-IRA and that the method may not be valid far the determination of stenosi s significance in IRA.