Expansive Growth of Atherosclerotic Plaques Assessed by VH-IVUS Association with TNF-α and OX-LDL Levels in Circulation C. Ramos 1 , P. Napoleão 2 , C. Fondinho 3 , M. Selas 3 , M. Mota Carmo 3,4 , R. Cruz Ferreira 3,4 and T. Pinheiro 1 1 IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa, E.N. 10, Sacavém, Portugal 2 Instituto de Medicina Molecular, Av. Prof. Gama Pinto, Lisboa, Portugal 3 Serviço de Cardiologia, Hospital de Santa Marta CHLC, Lisboa, Portugal 4 CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Campo Santana, Lisboa, Portugal Keywords: VH-IVUS, Biomarkers, Expansive Plaque, Plaque Vulnerability. Abstract: The identification of a vulnerable plaque through the quantification of soluble biomarkers would improve the diagnosis and treatment of coronary artery disease. Inflammation and LDL oxidative modification have been implicated in CAD. Disease severity and plaque vulnerability have recently been associated to expansive plaque growth, rather than constrictive growth which results in vessel stenosis. Forty CAD patients were admitted prospectively. VH-IVUS was performed and TNF-α and ox-LDL were quantified in the serum and plasma, respectively. Expansive plaques characterized by large EEL diameters and preserved luminal measures were associated to STEMI patients. Larger EEL diameter (≥4.6 mm 2 ) was significantly associated to increases of TNF-α concentrations whereas larger plaque areas (≥13.0 mm 2 ) associated with ox-LDL increases in the circulation. Hence, TNF-α and ox-LDL may be indicators of plaque vulnerability. 1 INTRODUCTION Coronary artery disease (CAD) has been studied for decades but many of the mechanisms underlying both the establishment and the development of this disease are yet to be understood. (Fayard and Fuster, 2001); (Choi et al., 2008); (Greco et al., 2010) It is generally accepted that oxidized low density lipoproteins (ox-LDL) and tumour necrosis factor - α (TNF-α) are involved in CAD. Oxidative modification of LDL plays a part in the formation of the fatty streak which constitutes the first step in atheroma formation. During the progress of atherosclerosis the inflammatory process is highly activated, involving many types of cells and cytokines, namely TNF-α. (Goldstein and Ross, 1987); (Hansson, 2005) The identification of vulnerable coronary atherosclerotic plaque is one of the ultimate goals of coronary imaging. There is increasing evidence suggesting the most vulnerable plaques are not associated with constrictive growth which causes vessel stenosis, but with outwards, expansive growth – positive remodelling. (Hong et al., 2012) IVUS is a widespread modality used for the direct visualization of coronary lumen, vessel wall, and atherosclerotic plaque. It allows the measurement of plaque area and any thickening of arterial walls (Amato et al., 2007); (Böse et al., 2007), which is an important advantage over coronary angiography, the golden standard method of coronary disease assessment. In addition to lumen diameter, IVUS provides plaque measures and histological structure by analysing the radiofrequency spectra. Noninvasive identification of rupture-prone plaques would dramatically improve risk stratification of both symptomatic and asymptomatic patients. Therefore, associations between the expansive growth of the atherosclerotic plaque and soluble bioindicators may provide important information that enhances the precision of clinical and laboratory variables used to assess patients at risk of CAD or of plaque rupture (Ramos et al., 2013); (Hong et al., 2012). 90 Ramos C., Napoleão P., Fondinho C., Selas M., Mota Carmo M., Cruz Ferreira R. and Pinheiro T.. Expansive Growth of Atherosclerotic Plaques Assessed by VH-IVUS - Association with TNF-α and OX-LDL Levels in Circulation. DOI: 10.5220/0004664500900094 In Proceedings of the International Congress on Cardiovascular Technologies (VisualCardio-2013), pages 90-94 ISBN: 978-989-8565-78-5 Copyright c  2013 SCITEPRESS (Science and Technology Publications, Lda.)