Branch points in the arteries are a common area of atherosclerotic disease, resulting in the occlusion of both branches. These branch points can generally be defined as a main branch and a side branch, and, in treating the disease, the question of what is the optimal course of action, opening the main branch, the side branch, or both, remains uncertain.
Studies have shown that using a stent to open a blocked blood vessel is generally more successful that balloon angioplasty, when one is treating a lesion in non-bifurcated area. Current data, however, indicate no such superiority in the use of stents to treat lesions in branching passages. Yoram Richter and colleagues, from Harvard–M.I.T. Division of Health Sciences and Technology, provide a hemodynamic analysis (an analysis of the forces of blood flow) in the region of the bifurcated vasculature to show that stenting of both passages results in a blood flow pattern that is inherently harmful to the main branch, and results in rapid re-occlusion of the main branch. To investigate this system, the authors developed a new dynamic bench top fluid mechanical model system.
This system provides a major advance over previous static models by allowing not only the prediction of areas in the blood vessels likely to be damaged, but also by reflecting the true active nature of the arterial system that compensates for and minimizes any disturbance. The authors further tested their in vitro predictions in an animal model, and, in seeing in the animals what was predicted to occur from their bench top model, established the strength of their in vitro modeling system. This study provides an explanation for why stenting in forked blood vessel regions has had a low success rate, and also provides a direction for appropriate treatment of these commonly blocked regions.
An accompanying commentary from R. Wayne Alexander at Emory University, provides a detailed look at the stent methodologies for treating occluded arteries, and describes how the study by Richter and colleagues advances our understanding of how best to treat these occluded branch sites by stenting only the main branch for optimal healing and maintenance of open vasculature.
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