Intravascular ultrasound-based left main coronary artery assessment : comparison between pullback from left anterior descending and circumflex arteries

OBJECTIVE: We compared continuous pullback from the left anterior descending artery (LAD) with pullback from the circumflex artery (CX) for the assessment of the left main coronary artery (LMCA) by intravascular ultrasound (IVUS). BACKGROUND: Gray-scale IVUS and virtual histology by IVUS (IVUS-VH) overcome many shortcomings of contrast angiography in diagnostic assessment of the LMCA. IVUS of LCMA can be acquired by continuous pullback from LAD or CX. Equivalence of the two pullback methods has not been investigated. METHODS: LMCA morphology was assessed by IVUS in 65 patients referred for elective or rescue coronary angiography. In each patient IVUS was performed once using pullback from the LAD and once using pullback from the CX. Intraclass correlation coefficients (ICC) were calculated to measure the degree of reliability. RESULTS: The mean age of patients was 60.4 +/- 9.5 years (range 40-84). The IVUS-determined degree of stenosis in the LMCA was a mean of 30% +/- 8% (range 15-52%). The ICC showed excellent reliability (ICC < 0.8) for volume measurements within the plaque (lipid volume, fibrolipidic volume, lipid core volume and calcified volume) and for the measurement of large or averaged diameters (maximal vessel diameter, average vessel diameter, average lumen diameter). The ICC was intermediate (ICC 0.5-0.8) for the measurement of small diameters (minimal vessel diameter, minimal lumen diameter, maximal lumen diameter) and for area calculations (minimal lumen area) based on small diameters. CONCLUSIONS: Overall, there was excellent reliability between IVUS-based LMCA morphology assessment using pullback from either the LAD or the CX.