The difference in intraluminal intensity of blood speckle (IBS) on integrated backscatter intravascular ultrasound (IVUS) across the coronary stenosis was reportedly correlated with fractional flow reserve (FFR) in the left descending coronary artery. The aim of this study was to investigate the novel physiological assessment using IVUS in all coronary arteries.Patients and methods
Fifty-four patients with 57 coronary lesions underwent both FFR and IVUS. Intraluminal IBS was analyzed using integrated backscatter IVUS in cross-sections at the ostium and the distal site of the target vessel. ΔIBS was calculated as: (distal IBS)−(ostium IBS).Results
Both ΔIBS (r=−0.50, P<0.01) and minimum lumen area (MLA) (r=0.55, P<0.01) showed significant correlations with FFR. There were significant correlations between FFR and ΔIBS in the right and left descending coronary arteries (r=−0.60, P=0.02, and r=−0.58, P<0.01), but not in the left circumflex (r=0.30, P=0.44). In receiver operating characteristic curve analyses, ΔIBS predicted FFR less than or equal to 0.80 (area under the curve=0.82, P<0.01, best cutoff value=6.78), as with MLA (area under the curve=0.83, P<0.01, best cutoff value=2.38). FFR progressively decreased in association with ΔIBS greater than or equal to 6.78 and MLA less than or equal to 2.38, and was the lowest when these were combined.Conclusion
ΔIBS was correlated with FFR in right and left descending coronary arteries. IVUS may assess coronary artery stenosis anatomically and physiologically.