Low variation and high reproducibility in plaque volume with intravascular ultrasound

Intravascular ultrasound (IVUS) has several advantages compared to angiography when evaluating coronary atherosclerosis in the vessel wall.

The accuracy, reproducibility, and short-time spontaneous variation in volume of vessel, plaque and lumen were studied by electrocardiographic-gated three-dimensional (3D) IVUS in 20 male patients with ischaemic heart disease (IHD).

The study lesions were angiographically insignificant, with a length of the analysed segment on 11.4+/-5.9 mm. At baseline the mean minimal lumen diameter was 2.41+/-0.59 mm, minimal lumen area 4.82+/-2.38 mm2, and maximal plaque burden 65.61+/-9.57%. Mean reference diameter was 3.1+/-0.6 mm. No significant changes were observed in volumes of total vessel, lumen or plaque. The coefficient of variation (CV) for two volume measurements at baseline was: vessel 0.8%, plaque 1.3%, and lumen 1.4%. For measurements recorded at baseline and after 12.6+/-1.5 weeks, CV was respectively 3.5%, 3.3% and 6.6%. Reproducibility and interobserver and intraobserver variation showed very high correlations. A linear correlation was present in percent changes over 12.6+/-1.5 weeks between vessel volume and lumen volume (r=0.804; p<0.001) and between percent changes in plaque volume and vessel volume (r=0.581; p=0.007). No correlation was found between changes in plaque volume and lumen volume (r=0.015; p=0.950).

ECG-gated 3D IVUS is a highly reproducible method when applied on coronary artery atherosclerosis. CV for lumen volume over 12.6+/-1.5 weeks is twice that of plaque volume indicating the superiority of the 3D IVUS compared to coronary angiography (CAG).