2nd International Congress on Advances in Bioscience and Biotechnology (ICABB), 26 - 30 June 2018, no.550, pp.29-30
Early Degradation Problem of Biodegradable Stents
Intravascular stents used in clinics today are primarily made of stainless-steel, CoCr-alloy and NiTi-alloys known as intelligent materials. Additionally, drug-eluting-stents have been developed with drug-impregnated-polymer-coating on the metal substrate. Even though stents made of such materials function for a while, it is seen that they cause problems in long-term. Since they are interacting with corrosive body fluids, stents cause occlusion of the vessel when they are broken by corrosion. Additionally, researches have been continuing in recent years to overcome late restenosis caused by problems such as atherosclerosis and thrombosis.
In Biodegradable Stents (BS); problems which come up in permanent bare-metal or polymer-types will not be encountered. It is known that magnesium, poly-L-lactic-acid (PLLA), polyglycolic-acid (PGA), poly (D, L-lactide / glycolide) copolymer (PDLA) and polycaprolactone (PCL) are soluble in the body. Stents made of BS are called as "Biodegradable Stents". They begin to corrode and disappear in a few months in the vessel and leave no residue as other stents. Therefore, it is stated that they will cause no late-restenosis-risk which is seen in other stents. Thanks to the materials they contain, they do not create any obstacles to imaging with tomography and MR devices.
However, early degradation risk of bioabsorbable stents is a problem must be solved. Since these stents are thick braided, their flexibility is low and grabbing the vessel is not as sufficient as metals yet. Therefore, it is not appropriate that placing such stents in complicated structures.
In order to prevent restenosis risk, corroding in 12-18 months is expected from BS. However, this feature has not been accessed yet. Therefore, BS have not received approval for routine clinical use. As of 2017, they are only in use for clinical research in EU countries.
Our researches are still continuing to bring the BS’s corroding time to ideal values.
Key words: Biodegradable materials, stents, restenosis, degradable stents, bio-corrosion