Abstract 378: Plaque Composition on Virtual Histology Intravascular Ultrasound in Relation to the Angiographic Degree of Stenosis and Myocardial Perfusion
Background: Other factors than degree of stenosis are known to influence myocardial perfusion. However, the relation between plaque composition and perfusion abnormalities is still unclear.
to evaluate plaque composition with virtual histology intravascular ultrasound (VH IVUS) in relation to degree of stenosis.
to evaluate plaque composition with VH IVUS in relation to presence of abnormal perfusion.
Methods: 46 patients underwent myocardial perfusion imaging (MPI), followed by conventional coronary angiography with quantitative coronary angiography and VH IVUS. Degree of luminal narrowing of severest stenosis was evaluated. On VH IVUS, plaque burden, minimal lumen area and % of fibrotic tissue, fibro-fatty tissue, necrotic core and dense calcium were determined. Plaques were classified into 4 types; pathological intimal thickening, fibrocalcific, fibroatheroma, thin cap fibroatheroma (TCFA).
Results: Significant stenosis (>50%) was present in 21 plaques. Plaques corresponding to significant stenosis had significantly more dense calcium and less fibrotic tissue. However, necrotic core (marker for vulnerability) was not different and TCFA were equally distributed (24% vs. 17%, p=0.45). In total, 18 plaques corresponded to abnormal perfusion. These plaques had significantly higher plaque burden, more dense calcium, less fibro-fatty tissue and smaller minimal lumen area. Plaques corresponding to abnormal perfusion had significantly more necrotic core and more TCFA were identified (35% vs. 15%, p=0.04).
Conclusion: Potentially vulnerable plaques may be related to the presence of abnormal perfusion rather than with significant stenosis.