OBJECTIVES: This study was designed as a “proof-of-concept” to establish whether CTA has the capability to identify morphologic features of plaque disruption.
METHODS: In patients with unstable angina undergoing CTA and invasive coronary angiography (ICA) within 30 days, quantitative CTA analysis was performed on all plaques for percent stenosis, volume, remodeling index, and volume of low attenuation plaque (LAP, <50 HU). Plaques >25% stenosis were evaluated for CTA features of disruption, including ulceration and intra-plaque dye penetration. Using ICA complex plaque as the reference standard for disruption, the sensitivity and specificity of ulceration and intra-plaque dye penetration by CTA were determined.
RESULTS: In 60 patients, 294 plaques were identified by CTA, of which 109 (37%) had features of disruption, including ulceration in 53 (18%) lesions and intra-plaque dye penetration in 80 (27%). Compared to non-disrupted lesions, plaques with ulceration or intra-plaque dye penetration by CTA were more voluminous (313 Â± 356 mm(3) vs 118 Â± 93 mm(3) p<0.0001), more often positively-remodeled (94.5% vs 44.3%, p<0.0001), contained more LAP (99 Â± 161 mm(3) vs 19 Â± 18 mm(3), p<0.0001), and were more often complex by ICA (57.8% vs 8.1%, p<0.0001). CTA features of disruption demonstrated modest to good sensitivity (53-81%), and good specificity (82-95%) for complex plaque by ICA.
CONCLUSIONS: In this highly selected group of patients with unstable angina, CTA can delineate features of plaque disruption, including ulceration and intra-plaque 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.