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In previous research abdominal aortic aneurysm (AAA) wall stress analysis has proven to be more accurate in rupture risk prediction than the clinically used diameter criterion [1]. Together with Philips Medical Systems (Best, NL), a clinical software tool is created that automatically derives the AAA geometry from patient CT data and performs AAA wall stress analysis (Hemodyn package). Using this software package, the role of intraluminal thrombus (ILT) in AAA wall stress analysis is evaluated in this study.Copyright © 2007 by ASME

During coronary catheterization, the epicardial coronary arteries are visually assessed for stenoses on the coronary angiogram. However, the functional significance of disease in the coronary arterial tree, the increased resistance to blood flow, may easily be over- or underestimated by using a 2D projection.Copyright © 2007 by ASME

Aims: Early atherosclerosis is located in low wall shear-stress (WSS) regions, however plaques are also found in the high WSS sensing flowdivider walls of coronary bifurcations. We assessed the plaque distribution and morphology near bifurcations non-invasively with 64 slice computed tomography (MSCT) in relation to the WSS distribution. Methods and results: We inspected 65 cross-sections near coronary bifurcations for the presence of plaque. Cross-sections were divided into four equal parts, which we numbered according to expected levels of WSS, with part I the lowest WSS (outer wall) and increasing WSS’s in part II (inner bend), III (outer bend) and IV (flowdivider). Of the cross-sections 88% had plaque. Of all parts I, 72% contained plaque. This was 62%, 38% and 31% in parts II, III and IV. In cross-sections with only 1 or 2 parts inflicted, plaque was found in part I and/or II in 94%. In 93% of the cross-sections with the flowdivider inflicted, parts I and/or II were also inflicted. Plaque was never found exclusively in the flowdivider part IV. Conclusions: We demonstrated that plaque is mostly present in low WSS regions, whereas plaque in high WSS regions is accompanied by plaque in adjacent low WSS regions. It is therefore plausible that plaque grows from the outer wall (low WSS) of the bifurcation towards the flowdivider (high WSS).

Left-ventricular assist devices (LVADs) have evolved from being a bridge to total heart transplant to forming a bridge to recovery of the heart. With this development, the process of weaning has become more important, and consequently, the operation and control of the LVADs during this process is more important as well. To evaluate the function and the assist properties of LVADs, a mock circulation, featuring the properties of the (diseased) heart and the systemic circulation may prove to be a valuable tool.Copyright © 2007 by ASME

Culture of arteries has become increasingly important in studying atherosclerosis and the effect of clinical interventions [1]. Ideally, arterial culturing should imitate in vivo conditions within an ex vivo environment. Physiological wall shear stresses are important as they induce an atheroprotective endothelial phenotype [2], which is relevant for maintaining arterial wall integrity. The arteries in such ex vivo studies, however, are perfused with culture medium, which has a viscosity lower than blood. Previously, the culture medium has been supplemented with dextran to obtain physiological fluid viscosity and wall shear stresses. However, several researchers [3,4] reported side effects of dextran on the cells in the arterial wall independent of its effect on medium viscosity. Also, dextran increases medium osmolality to supraphysiological levels [5]. This suggests that dextran may not be the optimal substance to increase medium viscosity.