The field of biomedical science and technology has been actively working on improving vascular stents to solve problems relating to the body’s reaction to their presence. Advances in nanotechnology are leading to improved vascular stent coating materials, in some cases making the implantable medical device seem invisible to the body. This is helping vascular surgeons to carry out procedures with higher success rates and better outcomes for patients.
What is a Vascular Stent?
A stent is a small metal, wire mesh tube that is placed inside your blood vessel when it is totally or partially blocked. The stent expands the walls of the artery, keeping the blood vessel open so blood can flow through. Stent grafts, however, which are large stents with a polymer fabric lining, can be used to keep weakened or damaged arteries from bursting.
Stents and other intravascular prostheses are used on damaged or diseased vessels to treat a number of medical conditions. While stents are most often used to treat diseases that affect the arteries, such as coronary heart disease or peripheral artery disease, they can also be used to treat blocked veins caused by conditions like deep vein thrombosis (DVT), post-thrombotic syndrome and May-Thurner syndrome.
Why use Vascular Stents?
There are several types of vascular stents all with different purposes to aid a patient’s recovery from a variety of conditions. The common vascular stents are:
Coronary stents aid the arteries leading to the heart. If there is a buildup of plaque in the coronary arteries, it can reduce the blood flow to the heart, leading to blood clots, and more severe heart attacks.
Carotid artery stents help treat carotid artery disease by opening the arteries. Carotid arteries are in the neck and supply blood to the brain. With damage or plaque-blocked arteries, there is an increased risk of stroke.
The arteries in your arms and leg ensure good blood flow throughout the extremities of your body. Peripheral artery disease can lead to buildup of plaque or blood clots in these vessels causing pain and discomfort. If untreated, serious long-term complications of the disease include critical limb ischemia and amputation in very extreme cases.
Types Of Vascular Stents
Each stent category can be further separated into Drug-Eluting Stents (DES) and Bare Metal Stents (BMS).
Bare metal stents were the original stents used to treat blocked vessels, which is simply a metal stent with no coating, whereas drug-eluting stents are coated with a drug which is slowly released into the surrounding tissue.
Drug-eluting stents are more effective than bare-metal stents at reducing restenosis (the blockage of vessels), however, concerns have been raised about the long term effect of drug-eluting stents. Some early generation drug-eluting stents have a higher risk of causing stent thrombosis after implantation.
Most drug-coated stents approved for peripheral vascular disease are coated with paclitaxel, a very potent cytotoxic agent. While the drug is effective are mitigating restenosis, the implications of the drug delaying normal tissue repair are not well understood.
With drug-eluting stents under review by the U.S. Food and Drug Administration (FDA), there is a growing interest in drug-free stent coatings that can mitigate restenosis.
Invisible Implantable Medical Devices
There is the option to move away from drug-coated stents toward biomaterials that avoid the normal reactions of the body caused by the presence of the stent.
A hydrophilic polymer coating that is bonded to the surface of a device such as a stent, while acting as an invisible barrier to the body’s defenses, could be the solution needed to tackle both thrombosis and restenosis.
TekCyte has developed a nano-scale coating technology based on a hyperbranched polyglycerol (HPG) polymer (BIOINVISIBLE™) designed for stents and other endovascular devices to appear invisible to the human body.
This type of coated vascular medical device could be a vast improvement on existing vascular stents, with potential to improve the performance, safety and durability of short- and long-term implanted devices.
The new wave in vascular medical devices
The use of biomedical coatings to create better implantable devices is not restricted to vascular stents. These coating is being considered and applied to a variety of devices that are implantated into the body. TekCyte offers custom services that can integrate its BIOINVISIBLE™ coating with your implantable device. It can also investigate and design bespoke coatings that have tailored surface properties and functions, for your specific requirements.