New computer models to predict physiologically realistic drug delivery patterns from stents in branched arterial vessels have been developed by researchers at Massachusetts Institute of Technology (MIT).
Scientists including Elazer R. Edelman, the Thomas D. and Virginia W. Cabot Professor of Health Science and Technology (HST), and HST postdoctoral associate Vijaya B. Kolachalama, conducted the study.
They simulated several arterial settings to show that drug distribution in these situations is determined by a complex calculation of the stent's position relative to arterial branches and constant blood flow changes caused by the branching.
"We now demonstrate for the first time that spatial variation in drug distribution can be significant when appreciated from a three-dimensional perspective and this viewpoint can only be gained with the use of these model systems," said Edelman.
Drug-eluting stents are now widely used all over the world to treat obstructive arterial disease, yet some patients with the stents have suffered life-threatening side effects- an increase risk of blood clotting and heart attacks.
Predicting drug distribution is complicated by the branching of arteries into two or more vessels, which establishes alterations in flow, wall shear stress and geometries.
"By observing the arterial drug distribution patterns for various settings, we understood that drug released from the stent does not reach uniformly to all regions of the vessel and this non-uniformity depends on where the stent is placed in the artery as well as the blood flow that is entering the vessel," said Edelman.
"Appreciating this phenomenon for more complex cases like branched vessels is non-intuitive, but now we have a computer model that gave us the much needed insight," he added.
"Modelling stent-based drug delivery in branched vessels is critically important because these are frequent sites of arterial disease and yet there are no dedicated devices that are FDA-approved or efficient strategies using multiple stents to specifically treat these locations. Our computer model shows that for some arterial settings, a single stent in the main-branch of the fork can provide drug to the side-branch. This observation could be important to consider, especially when one has to place stents in both branches," said Kolachalama.
The researchers generated the computer model by combining principles of digital image processing and parametric computer-aided geometry design with computational fluid dynamics and mass transport.
The authors believe this modelling technique can be extended to simulate several settings with various stent designs as well as complex arterial geometries with and without disease, altered flow environments and other boundary conditions.