Background/Objectives: The objective of this study was to assess the relationship between intravascular ultrasound (IVUS) parameters, including volumetric analysis, and fractional flow reserve (FFR). Methods: Both IVUS and FFR were performed in 206 cases of intermediate stenosis of the left anterior descending artery (LAD). Myocardial ischemia was assessed by FFR and maximal hyperemia was induced by continuous intracoronary adenosine infusion. FFR < 0.80 was considered as significant inducible myocardial ischemia. We performed standard IVUS parameter measurements and volumetric analyses. IVUS parameter comparison was performed in the presence (n=90) or absence (n=116) of significant myocardial ischemia. Results: Lesions with minimal lumen area (MLA) ≥4.0mm2 had FFR ≥0.80 in 91.4% of cases, while 50.9% of lesions with MLA <4.0mm2 had FFR <0.80. The multiple logistic regression analysis demonstrated that IVUS lesion length (odds ratio [OR]: 1.1, 95% confidence interval [CI] =1.1–1.2, p<0.001) and MLA significance according to lesion location (OR: 8.8, 95% CI = 4.4-17.8, p< 0.001) were independent predictors of functionally significant myocardial ischemia (FFR < 0.80). FFR correlated with plaque volume (r= -0.345, p<0.001) and percent atheroma volume (PAV) (r=-0.398, p<0.001). Lesions with significant ischemia (FFR <0.80) as compared to those with FFR >0.80 were associated with larger plaque volume (181.8±82.3 vs. 125.9±77.9 mm3, p<0.001) and PAV (58.9±5.6 vs. 53.8± 7.9 %, p<0.001).
Conclusions: IVUS parameters representing severity and extent of atheromatous plaque correlated with functional significance in LAD lesions with intermediate stenosis.
