Abstract 1208: Plaque Components in Coronary Artery Disease Increase at Different Rates: A Virtual Histology Intravascular Ultrasound Report from the Global VH-IVUS Registry
Virtual histology (VH) uses radiofrequency intravascular ultrasound (IVUS) to classify plaque composition as calcified (Ca), fibrotic (Fib), fibrofatty (FF), or necrotic core (NC). The global VH Registry (42 sites) collects VH IVUS data from unselected pts with coronary artery disease. Clinical parameters, biomarkers, and conventional IVUS parameters and VH plaque composition analysis of the entire pullback length has been performed on 880 pts.
Results: Mean plaque volume measured 470mm3; mean plaque cross-sectional area (pCSA) measured 6.9mm2; and mean plaque burden (plaque/vessel CSA) measured 44% over an average vessel length of 6.7cm. The mean areas of all four plaque components (2.0mm2 for Fib, 0.8mm2 for FF, and 0.4mm2 for Ca and NC) correlated with mean pCSA; however, each plaque component had a very different profile (Figure⇓). The growth of Fib plaque was greatest and correlated best with the increase in overall pCSA (2mm2/5mm2, r2=0.90, p<0.001)); the growth of FF plaque was intermediate in amount and variability (0.8mm2/5mm2, r2=0.63, p<0.001); and the growths of Ca plaque and NC were least (both increased 0.5mm2/5mm2 overall increase in pCSA), but the growth of Ca was most variable (r2=0.36, p<0.001 for Ca and r2=0.64, p<0.001 for NC).
Conclusions: While all plaque components increase in proportion to overall plaque growth, each component increases in a different proportion. The increase in fibrotic plaque is greatest and most consistent while the increase in lesion calcium is least and most inconsistent.