Assessment of Angiographic Coronary Calcification and Plaque Composition in Virtual Histology Intravascular Ultrasound

ObjectivesWe assessed the relation between coronary plaque composition and angiographic calcification by using virtual histology intravascular ultrasound (VH-IVUS). BackgroundThe plaque vulnerability according to angiographic calcification is unclear. MethodsSubjects were 140 consecutive patients (145 lesions) undergoing VH-IVUS before percutaneous coronary intervention. Subjects were divided into 4 groups: no calcification group (n=27), spotty group (n=65) that had calcium deposits under 90 degrees in grayscale IVUS, intermediate group (n=37) had calcium deposits with 90 degrees or more and under 180 degrees, and extensive group (n=16) had calcium deposits with 180 degrees or more. ResultsThe number of VH thin-cap fibroatheromas in spotty group was significantly larger than no calcification group, intermediate group, and extensive group (0.660.71 vs 0.22 +/- 0.42 [P<0.01], 0.32 +/- 0.48 [P<0.05], 0.13 +/- 0.34 [P<0.01], respectively). Spotty group without angiographic calcification had significantly larger %necrotic core than with angiographic calcification (24.5 +/- 6.7% vs 19.9 +/- 7.2%, P<0.05). Intermediate group without angiographic calcification had significantly larger necrotic core area than with angiographic calcification (2.5 +/- 0.9mm(2) vs 1.7 +/- 0.9mm(2), P<0.05). Extensive group with angiographic calcification had significantly larger %dense calcium than without angiographic calcification (18.3 +/- 4.0% vs 13.4 +/- 4.4%, P<0.05). ConclusionsLesions with spotty calcification was highly vulnerable in VH-IVUS. Spotty or intermediate plaque calcification without angiographic calcification was more vulnerable than those with angiographic calcification. Extensive plaque calcification with angiographic calcification had more dense calcium than those without angiographic calcification.