Features of disrupted plaques by coronary computed tomographic angiography: correlates with invasively proven complex lesions.

BACKGROUND This study was designed as a "proof-of-concept" to establish whether coronary computed tomographic angiography (CTA) has the capability to identify morphological features of plaque disruption. METHODS AND RESULTS In patients with unstable angina undergoing CTA and invasive coronary angiography within 30 days, quantitative CTA analysis was performed on all plaques for percent stenosis, volume, remodeling index, and volume of low-attenuation plaque (<50 Hounsfield units). Plaques with >25% stenosis were evaluated for CTA features of disruption, including ulceration and intraplaque dye penetration. Using invasive coronary angiography complex plaque as the reference standard for disruption, the sensitivity and specificity of ulceration and intraplaque dye penetration by CTA were determined. In 60 patients, 294 plaques were identified by CTA, of which 109 (37%) had features of disruption, including ulceration in 53 (18%) lesions and intraplaque dye penetration in 80 (27%). Compared with nondisrupted lesions, plaques with ulceration or intraplaque dye penetration by CTA were more voluminous (313±356 mm(3) versus 118±93 mm(3) P<0.0001), more often positively remodeled (94.5% versus 44.3%, P<0.0001), contained more low-attenuation plaque (99±161 mm(3) versus 19±18 mm(3), P<0.0001), and were more often complex by ICA (57.8% versus 8.1%, P<0.0001). CTA features of disruption demonstrated modest to good sensitivity (53% to 81%) and good specificity (82% to 95%) for complex plaque by invasive coronary angiography. CONCLUSIONS In this highly selected group of patients with unstable angina, CTA can delineate features of plaque disruption, including ulceration and intraplaque dye penetration, which are specific markers of invasively identified complex plaque. Further studies are needed to confirm the generalizability of the results and to explore the clinical and prognostic implications of these findings.