P1801Comparison between minimum lumen area and integrated backscatter intravascular ultrasound derived intraluminal ultrasonic intensity for detecting functionally significant coronary artery stenosis

Abstract

Background: Intravascular ultrasound (IVUS), which can assess detailed morphological information compared to coronary angiography, is useful for the guidance of percutaneous coronary intervention. Although previous studies reported the cut-off value of minimum lumen area (MLA) for predicting myocardial ischemia using fractional flow reserve (FFR) was 3.0mm2, it may be different according to the vessel sizes. Recent study reported the step-up of intraluminal integrated backscatter (IB) value beyond coronary artery stenosis (CAS) was useful for predicting myocardial ischemia based on FFR. Purpose(s): We compared the diagnostic ability between IVUS derived MLA and intraluminal ultrasonic intensity using IB-IVUS for detecting functionally significant CAS based on FFR. Method(s): We included 53 patients (60 lesions) who had intermediate CAS which diagnosed by coronary angiography. After angiographic diagnosis, we undergo both FFR and IVUS measurements during catheterization procedure. FFR were measured at maximal hyperemia induced by intravenous adenosine 5'- triphosphate infusion (180 mug/kg/min). We measured IVUS derived MLA at the segment of CAS and intraluminal IB values at both coronary ostium and distal to the stenosis. IB values were obtained at the intraluminal area (lumen area removing IVUS catheter area), then the average IB value was calculated automatically by off-line quantitative IVUS analysis software (VISI-ATLAS).We defined that DELTAIB was distal IB value - ostial IB value. We compared the diagnostic ability of functionally significant CASs based on FFR between MLA and DELTAIB. Result(s): A total of 60 (40 LADs, 12 LCXs, and 8 RCAs) lesions were analyzed. Mean FFR, MLA, DELTAIB were 0.78+/-0.08, 2.44+/-0.91 mm2, and 22.3+/-12.5, respectively. There was no significant correlation between FFR and MLA in all lesions (r=0.17, p=0.20), however, there was a moderate correlation between FFR and MLA in LAD lesions (r=0.31, p=0.05). On the other hand, there was a significant correlation between FFR and DELTAIB in all lesions (r=-0.43, P<0.01), and a more stronger correlation between FFR and DELTAIB especially in LAD lesions (r=- 0.58, p<0.001). Diagnostic ability using MLA <3.0mm2 for predicting FFR 17 for predicting FFR