MIT engineers have been working on a mathematical model that can be used to map out the patterns of turbulence formed by drug eluting stents. With this knowledge it is possible to predict which designs will be less favorable to the formation of stent induced clots, and so let engineers work around potentially bad shapes.
From MIT press office:
Stents affect the fluid dynamics of blood flowing past them and cause drugs to accumulate in certain areas. Too much drug buildup promotes clot formation.
The MIT model shows that the dynamics of blood flowing around a stent is similar to whitewater rapids, said Edelman. When water in a river flows over a boulder, some of the water strikes the base of the boulder, flies up in the air and comes back down, instead of flowing over the rock. This water continuously recirculates in the same area.
The same thing happens when blood flows across a stent: Drugs tend to accumulate and spin around in the recirculation zone. This is most likely to happen with stents that protrude further into the artery. “Until now, the degree to which recirculation zones impact the distribution of drugs was not appreciated,” said Edelman.
This is the first time that a mathematical model has successfully predicted stent performance based on changes in arterial blood flow and design, and the researchers hope the model and concepts it establishes could aid efforts to design stents that allow drugs to be more evenly distributed throughout the area.
The model could also help the FDA in its approval processes, by helping regulators figure out which stents are most likely to be safe or harmful, based on their size and shape, which controls how they will affect blood flow.
More from MIT: Model predicts how to build a better stent …
Study abstract: Luminal flow patterns dictate arterial drug deposition in stent-based delivery