| 1. |
- Smedby, Örjan
(författare)
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Geometric risk factors for atherosclerosis in the aortic bifurcation : a digitized angiography study.
- 1996
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Ingår i: Annals of Biomedical Engineering. - 0090-6964 .- 1573-9686. ; 24:4, s. 481-488
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Tidskriftsartikel (refereegranskat)abstract
- To clarify the relationship between arterial geometry and atherosclerosis at the aortic bifurcation, angiograms of 84 patients with slight or moderate atherosclerosis were studied by computerized image analysis. The degree of atherosclerosis involvement was assessed as angiographic edge roughness. The branching angles were found to be related to edge roughness of the left outer wall and the right side of the aorta. The position of the flow divider was related to edge roughness of the medial wall of the right common iliac and the right side of the aorta. For these two locations, there were also significant relationships to the area ratio, i.e., the ratio between cross-sectional areas distal and proximal to the bifurcations. On the basis of these findings, the concept of "geometric risk factors" for atherosclerosis and the potential influence of blood flow on atherogenesis are discussed.
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| 2. |
- Smedby, Örjan
(författare)
-
Geometrical risk factors for atherosclerosis in the femoral artery : a longitudinal angiographic study.
- 1998
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Ingår i: Annals of Biomedical Engineering. - 0090-6964 .- 1573-9686. ; 26:3, s. 391-397
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Tidskriftsartikel (refereegranskat)abstract
- In order to study the evolution of atherosclerosis in the superficial femoral artery in relation to local factors of vascular geometry, image processing of digitized angiograms was carried out in 237 hyperlipidemic patients before and after a three-year period of lipid-lowering treatment. The degree of atherosclerosis was measured as edge roughness, which was calculated separately for inner curves, outer curves, and straight segments and, in a subgroup of 110 patients, for segments with and without branches on either side of the artery. Initially, inner curves had significantly higher roughness values than outer curves, and outer curves higher than straight segments. After three years, there was an increase of borderline significance in the outer curves, and the difference between inner and outer curves was no longer significant. In several subpopulations, the increase in outer curve roughness was clearly significant. When branched and nonbranched segments were compared, the only significant difference was at the second examination where segments with a lateral branch had higher roughness of the medial edge than those without such a branch. It is concluded that curves are more likely than bifurcations to constitute a geometric risk factor for atherosclerosis, but it remains to explain the causal mechanism for this factor.
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| 3. |
- Smedby, Örjan, et al.
(författare)
-
Tortuosity and atherosclerosis in the femoral artery : what is cause and what is effect?
- 1996
-
Ingår i: Annals of Biomedical Engineering. - 0090-6964 .- 1573-9686. ; 24:4, s. 474-480
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Tidskriftsartikel (refereegranskat)abstract
- Earlier studies have demonstrated a correlation between tortuosity and atherosclerosis in the femoral artery. One conceivable explanation is that atherosclerosis causes an elongation of the artery, resulting in vessel tortuosity, another is that blood flow phenomena (such as flow separation) due to the vessel geometry may affect the progression of atherosclerosis. To determine which of these hypotheses is most likely, a group of 232 hyperlipidemic patients was followed with angiography for 3 years during lipid-lowering treatment. After digitization of the films, a tortuosity value and an atherosclerosis measure (edge roughness) were computed. In the group with lower tortuosity values, there was a significant (p < 0.0001) decrease in edge roughness, but not in the group with a higher tortuosity values. On the other hand, neither the group with higher edge roughness values nor that with lower edge roughness values displayed a significant change in tortuosity. When tortuosity, roughness, and treatment were studied simultaneously, only the effect of tortuosity on roughness change was significant. These findings are more consistent with tortuosity influencing the development of atherosclerosis than with its being a consequence of atherosclerosis.
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| 4. |
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