Relationship between intravascular ultrasound parameters and fractional flow reserve in intermediate coronary artery stenosis of left anterior descending artery: intravascular ultrasound volumetric analysis.

Abstract

OBJECTIVES: The objective of this study was to assess the relationship between

intravascular ultrasound (IVUS) parameters, including volumetric analysis, and

fractional flow reserve (FFR). BACKGROUND: Although it is known that coronary

atherosclerosis burden measured by IVUS volumetric analysis is related with

clinical outcomes, its relationship with functional significance remains unknown.

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) >/= 4.0 mm2 had FFR >/= 0.80 in 91.4% of cases, while 50.9% of lesions with

MLA < 4.0 mm2 had FFR < 0.80. The independent predictors of FFR < 0.80 were IVUS

lesion length (odds ratio [OR]: 1.1, 95% confidence interval [CI] = 1.06-1.18, P

< 0.001) and MLA significance according to the lesion location (OR: 7.01, 95% CI

= 3.09-15.92, P = 0.001). 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.