Biodegradable Stents for Coronary Artery Disease treatment
Regular metal stents though successful in their purpose to treat coronary artery disease, present limitations such as stent thrombosis and restenosis. Drug-eluting stents are a step forward in the development of stents, since they significantly reduce restenosis rates and the need for repeat revascularization. However, they are still associated with subacute and late thrombosis, and necessitate prolonged antiplatelet therapy for at least 12 months. Further, the polymer used as a vehicle for drug delivery may induce vessel irritation, endothelial dysfunction, vessel hypersensitivity and chronic inflammation at the stent site.
As there is a pressing need for a stent that would cause less complications and that could be “removed” from the vessel after it is no longer needed, the biodegradable stent is a potential possibility to solve this issue. After completing their purpose, biodegradable stents are bioabsorbed leaving only the healed natural vessel behind. This decreases enormously (if not completely) the chance for late stent thrombosis since the stent is gone, and prolonged antiplatelet therapy is not necessary in this instance. Bioabsorbable stents can also be suitable for complex anatomy where stents impede on vessel geometry and morphology and are prone to crushing and fractures.
Also, these biodegradable stents can be use for drug and/or gene delivery such as transferring genes that code key regulatory pathways of cell proliferation inside the cells of the arterial wall. Regardless of which agent (drug or gene) will finally conquer restenosis, a polymer stent remains an optional vehicle for such delivery. What’s more, bioabsorbable stents are compatible with MRI and MSCT imaging.
Besides polymer biodegradable stents, also in consideration are metal bioabsorbable stents since they have the potential to perform similarly to stainless steel metal stents. So far, two bioabsorbable metal alloys have been proposed for this application: iron and magnesium. The biocompatibility of these stents depends on their solubility and their released degradation products. Their local toxicity is related to the local concentration of the elements over time. The tissue tolerance for physiologically occurring metals depends on the change of their tissue concentrations induced by corrosion. Thus metals with high tissue concentrations are the ideal candidates for bioabsorption stents.
This is a very interesting issue since biodegradable stents not only would facilitate the life of the patients after the stent is no longer needed by eliminating the chance of late stent thrombosis and thus the need for prolonged antiplatelate therapy but they would also be useful for other applications such as angiogenesis and gene transfer. Once they deposit the drug locally, the vehicle as a whole will disappear in the surrounding tissue. It would be an excellent medical progress if the biodegradable stents could replace the current practice in which many patients chronically carry metal prostheses in their coronary arteries.
The article can be found in http://www.invasivecardiology.com/article/5222
Geraldine Pena-Galea
As there is a pressing need for a stent that would cause less complications and that could be “removed” from the vessel after it is no longer needed, the biodegradable stent is a potential possibility to solve this issue. After completing their purpose, biodegradable stents are bioabsorbed leaving only the healed natural vessel behind. This decreases enormously (if not completely) the chance for late stent thrombosis since the stent is gone, and prolonged antiplatelet therapy is not necessary in this instance. Bioabsorbable stents can also be suitable for complex anatomy where stents impede on vessel geometry and morphology and are prone to crushing and fractures.
Also, these biodegradable stents can be use for drug and/or gene delivery such as transferring genes that code key regulatory pathways of cell proliferation inside the cells of the arterial wall. Regardless of which agent (drug or gene) will finally conquer restenosis, a polymer stent remains an optional vehicle for such delivery. What’s more, bioabsorbable stents are compatible with MRI and MSCT imaging.
Besides polymer biodegradable stents, also in consideration are metal bioabsorbable stents since they have the potential to perform similarly to stainless steel metal stents. So far, two bioabsorbable metal alloys have been proposed for this application: iron and magnesium. The biocompatibility of these stents depends on their solubility and their released degradation products. Their local toxicity is related to the local concentration of the elements over time. The tissue tolerance for physiologically occurring metals depends on the change of their tissue concentrations induced by corrosion. Thus metals with high tissue concentrations are the ideal candidates for bioabsorption stents.
This is a very interesting issue since biodegradable stents not only would facilitate the life of the patients after the stent is no longer needed by eliminating the chance of late stent thrombosis and thus the need for prolonged antiplatelate therapy but they would also be useful for other applications such as angiogenesis and gene transfer. Once they deposit the drug locally, the vehicle as a whole will disappear in the surrounding tissue. It would be an excellent medical progress if the biodegradable stents could replace the current practice in which many patients chronically carry metal prostheses in their coronary arteries.
The article can be found in http://www.invasivecardiology.com/article/5222
Geraldine Pena-Galea
posted by Geraldine at 3:12 PM
0 Comments:
Post a Comment
<< Home