Bioabsorbable stents: Difference between revisions
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Bioabsorbable stents can be broadly classified as two types-Polymeric and metallic types. The key features to be considered while selecting a polymer or an alloy for a bioabsorbable stent are: | |||
* Strength - to avoid potential immediate recoil | |||
* Rate of degradation and corrosion | |||
* Biocompatibility with the vessel wall | |||
* Lack of toxicity | |||
Polymers have been widely used in Cardiovascular devices and are now primarily used as delivery vehicles for drug coatings. Among the polymers suggested for bioabsorbable stents are Poly-L-Lactic acid(PLLA), polyglycolic acid(PGA),Poly(D,L-lactide/glycolide) copolymer(PDLA) and polycaprolactone. The use of bioabsorbable polymer coating reduces the need for extended dual anti-platelet therapy and in turn late thrombotic events. | |||
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Revision as of 17:54, 19 April 2012
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Associate Editor(s)-In-Chief Raviteja Reddy Guddeti, M.B.B.S.
Overview
Bioabsorbable stents also known as the disappearing stents are a promising new discovery in the field of Interventional Cardiology.They have been an interesting field of research over the past decade and half and as the name suggests they get absorbed completely over a period of time after their work has been done.The concept of bioabsorbable stents came into existence as there have been some unmet needs by the traditional bare metal stents, such as stent thrombosis,no drug platform,interfering with MRI-CT imaging,life long presence of implant and not facilitating reintervention.
Types
Bioabsorbable stents can be broadly classified as two types-Polymeric and metallic types. The key features to be considered while selecting a polymer or an alloy for a bioabsorbable stent are:
- Strength - to avoid potential immediate recoil
- Rate of degradation and corrosion
- Biocompatibility with the vessel wall
- Lack of toxicity
Polymers have been widely used in Cardiovascular devices and are now primarily used as delivery vehicles for drug coatings. Among the polymers suggested for bioabsorbable stents are Poly-L-Lactic acid(PLLA), polyglycolic acid(PGA),Poly(D,L-lactide/glycolide) copolymer(PDLA) and polycaprolactone. The use of bioabsorbable polymer coating reduces the need for extended dual anti-platelet therapy and in turn late thrombotic events.
| Company | Polymer | Features |
| Igaki Medicals | Poly-L-Lactic acid | Contains no drug, self expanding |
| REVA Medical | Poly(DTE carbonate) with Iodine on the backbone | Slide and lock design, paclitaxel drug eluting stent |
| Biotronic | Magnesium-alloy | Pimecrolimus drug eluting stent,Balloon expanding |
| Abbott Vascular | Poly-L-Lactic acid | Everolimus drug eluting stent,self expanding |
Advantages
The main advantages these Bioabsorbable stents can offer over the traditional bare metal stents are:
- No late stent thrombosis - the stent being absorbed completely leaves behind no stimulus to ignite a chronic inflammatory process and thus in turn reducing the rate of late stent thrombosis which is a major concern of the traditional stents.
- Short duration of post-stenting use of dual anti-platelet drugs.
- Obviates metal implants in vessels, leaves only healed natural vessel
- Facilitates reintervention (PCI and CABG)
- Prevents the constrictive vascular remodeling postdilatation due to the scaffolding effect of the stent and after being absorbed completely allows late expansive luminal and vessel remodeling.
- Increased drug loading capabilities that will enable chronic drug release strategies.
- In the long run, eliminates mechanical stent deformity and strut fractures
- Can be used in peripheral arteries like the tibial artery,femoral artery etc.
- It's feasible to transfer genes that code key regulatory pathway inside the cells of the arterial wall using polymer stents as vehicles.