Abstract 4512: Is There an Intravascular Ultrasound Luminal Area Threshold That Correlates With Fractional Flow Reserve in Intermediate Coronary Artery Stenosis?
Background: Decision making in pts with intermediate coronary stenosis is still debated. Deferring intervention based on IVUS guidance of MLA ≥4 mm2 or FFR >0.8 is correlated with a low event rate.
Aim: To determine the cutoff MLA determined by IVUS that predicts physiological significance of FFR <0.8 in intermediate coronary stenosis.
Methods: The analysis included 69 intermediate lesions (64 pts) in a vessel diameter >2.5 mm. These lesions were evaluated by FFR and IVUS. Cutoff of positive FFR for ischemia was <0.8.
Results: The mean age was 63.8±12.3 years; 37 were male (56.9%). The mean FFR value was 0.84±0.1; 18 were <0.8 (30.5%). The mean MLA was 3.5±1.1 mm2 and the mean diameter stenosis by QCA was 47.6±10.5%. The MLD by IVUS was 1.8±0.3 mm and by QCA 1.78±0.5 mm. All 18 ischemic lesions (FFR <0.8) were treated and 7 (13.7%) of the non-ischemic lesions were treated. Regression analysis demonstrated strong correlation between FFR and MLA (r=0.4, p<0.001), as well as between FFR and MLD by IVUS (r=0.37, p=0.006) and by QCA (r=0.3, p=0.01). There was an inverse correlation between FFR and lesion length (r= −0.39, p=0.08). There was no correlation between FFR and diameter stenosis by QCA (r=0.1, p=0.2). ROC curve identified a MLA <3.2 mm2 (sensitivity 87.5%, specificity 78.3%) to be the best cutoff value to fit with a FFR <0.8.
Conclusion: Anatomic parameters of intermediate coronary lesions obtained by IVUS showed a significant correlation to the FFR values, however, the cutoff value of the IVUS parameter of MLA <4 mm2 does not always imply physiological ischemia. Therefore, functional assessment of intermediate lesions should remain the gold standard.