934-26 Comparison of Intravascular Ultrasound and Coronary Angiography in the Assessment of Target Lesion Plaque Distribution in Coronary Artery Disease

Abstract

Pre-intervention intravascular ultrasound (IVUS) and coronary angiography were used to assess plaque distribution in 963 native vessel target lesions in 929 pts. Three definitions of lesion eccentricity (Ecc) were used: (1) pathologic: presence of an arc of normal or disease-free arterial wall within the lesion, (2) IVUS: Ecc index maximum/minimum plaque + media (P + M) thickness > 3.0, and (3) angiographic: one edge of the lesion in the outer one-quarter of the apparently normal lumen. (1) Only 162 lesions (16.8%) had an arc of disease-free arterial wall within the lesion. (2) The mean IVUS Ecc index was 3.4 ± 2.3; only 5 lesions (<1%) were completely concentric (Ecc index = 1.0). and 419 (43.5%) were Ecc. Ecc lesions had larger lumen cross-sectional areas, smaller P + M and external elastic membrane cross-sectional areas, and smaller arcs of calcium (compared to concentric lesions) suggesting that they represent less advanced disease. (3) By angiography 547 lesions (56.8%) were Ecc (p = 0.0182 vs IVUS). Angiographic Ecc lesions had a larger IVUS Ecc index that was the result of a thicker maximum P + M, not a thinner minimum P + M. Similarly, the angiographic classification of lesion Ecc tended to increase (to 68%) with a larger IVUS Ecc index (p = 0.0619). Using discriminant analysis, a predictive model of angiographic Ecc was constructed; it included lesion length and IVUS maximum P + M thickness, but correctly predicted angiographic Ecc in only 57.7%. (1) Target lesions that fit the pathologic definition of Ecc are unusual. (2) Lesions are less often Ecc than suggested by angiography, partly because longer lesions more often appear to be Ecc by angiography. (3) There is substantial disagreement between IVUS and angiography in the assessment of Ecc (concordance rate = 52.8%). Therefore, IVUS assessments should be the standard for evaluating plaque distribution if device therapy strategies are determined by target lesion eccentricity