Lumen and wall morphology of mild coronary dilatation assessed by in vivo intravascular ultrasound.

The in vivo features of the wall and lumen of mild coronary dilatation associated with atherosclerosis and the relationship with coronary ectasia were investigated by intravascular ultrasound (IVUS) imaging of 11 patients with angiographically-proven mild coronary dilatation. Maximal luminal diameter, thickness of the inner echogenic layer and echolucent zone, and frequency of calcification of the dilatation sites were compared with those of proximal adjacent normal sites. The results showed that : luminal diameter by angiography was significantly larger at the dilatation site and the ratio of dilatation/normal diameter was 1.27 +/- 0.07; the maximal luminal diameter of the dilatation site by IVUS was greater than that of the normal site (4.56 +/- 0.87 vs 3.94 +/- 0.61 mm, p< 0.01); the thickness of the inner echogenic layer and echolucent zone increased significantly at the dilatation site over the normal site (0.48 +/- 0.12 vs 0.17 +/- 0.14 mm and 0.53 +/- 0.17 vs 0.10 +/- 0.10 mm, p< 0.001, respectively); calcification occurred more frequently at the dilatation site (54.5% vs 9.1%, p< 0.05). The thickened inner echogenic layer and echolucent zone and a high frequency of calcification were observed by in vivo IVUS in the wall of angiographically-defined mild coronary dilatation lesions caused by atherosclerosis.