Effects of Fractional Flow Reserve on Coronary Artery Bypass Graft Flow to Left Anterior Descending Artery

Abstract

of the target left anterior descending artery (LAD), referred to as FFRLAD, on the intraoperative transit time flow measurement (TTFM) of both in situ left internal thoracic artery (LITA) grafts and aortocoronary saphenous vein grafts (SVGs). The aim of this study was to gain a better understanding of TTFM analysis of CABG graft flow, which is recommended in the European guidelines, 7,8 as a less invasive, more highly reproducible, and less timeconsuming method. MethodsThis retrospective study, using clinical data from routine medical practice for CABG patients, was approved by the Fujita Health University Ethics Committee (HM19-323, October 15, 2019), including a waiver for the need for informed consent for the retrospective use of patient data. The study was conducted according to the ethical guidelines for clinical studies published by the Ministry of Health 9 and in accordance with the Declaration of Helsinki. Study PatientsThis study enrolled 101 patients who received CABG F ractional flow reserve (FFR), an index calculated by dividing the distal coronary pressure by the proximal pressure measured under conditions of maximum hyperemia, has been well validated as a determinant of lesion-specific myocardial ischemia from epicardial coronary artery disease. 1,2 An FFR threshold ranging from 0.75 to 0.80 is used to distinguish functionally significant coronary artery stenosis. 3 The FFR Versus Angiography for Multivessel Evaluation (FAME) study demonstrated the superiority of FFR-guided percutaneous coronary intervention (PCI) to conventional angiography-guided PCI. 2 Furthermore, the subsequent FAME-2 trial showed that FFR-guided PCI surpasses medical therapy alone, 4 primarily by prudently deferring treatment for lesions that may appear stenotic but do not result in lesion-specific ischemia according to FFR measurements. Therefore, current guidelines recommend the use of FFR to complement coronary angiography. 5,6 Under these circumstances, the strategy of coronary artery bypass grafting (CABG) is also shifting to FFR guidance, although its advantage over angiography-guided CABG remains undetermined. 3 To validate the roles of FFR in CABG, our investigation aimed to assess the impact of preoperative FFR values