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Previous studies reported a cut-off value of intravascular ultrasound (IVUS) derived minimum lumen area (MLA) for predicting fractional flow reserve (FFR) ≦0.75 showed MLA≦3.0 mm2. Furthermore, the recent study reported the step-up of intraluminal integrated backscatter (IB) value beyond coronary artery stenosis had a significant correlation with FFR.
We included 52 patients (60 lesions) who had intermediate coronary artery stenosis. We undergo both FFR and IVUS during catheterization procedure and measured anatomic information and intraluminal IB value both a coronary ostial site and distal site at the same position of the pressure sensor. We defined the difference of IB value between both sites labeled ΔIB.
A total of 60 (39 LADs, 12 LCXs, and 9 RCAs) were analyzed. Mean FFR, MLA, ΔIB were 0.78 ± 0.09, 2.44 ± 0.91, and 22.1 ± 12.6, respectively. There was significant correlation between FFR and ΔIB in overall lesions (r=-0.43, p<0.01), and stronger correlation between FFR and ΔIB in LAD lesions (r=-0.58, p<0.001). Diagnostic accuracy using MLA≦3.0 for predicting FFR≦0.75 showed 47% (sensitivity 72%, specificity 19%, PPV 42%, NPV 70%). On the other hand, diagnostic accuracy using ΔIB for predicting FFR≦0.75 showed 65% (sensitivity 92%, specificity 47%, PPV 54%, NPV 89%).
IVUS-derived intraluminal IB analysis (ΔIB) might be useful to evaluate as a diagnosis of myocardial ischemia before percutaneous coronary interventional procedures.