Stents have dramatically reduced the incidence of stenosis following percutaneous angioplasty. However, they are also known to restenose within months. Prevention of restenosis therefore depends on several factors:
- Accurate stent placement and expansion, which avoids the occurrence of empty spaces for scar buildup
- Use of targeted treatments to reduce neointimal hyperplasia and restenosis, which include:
- Drug-eluting stents
- Perivascular delivery which delivers the drug into the space around the artery
- Delivery catheters
- Antibody or peptide-linked drugs
- Gene-based therapies
- Cell-based therapies
- Nanoparticle-based drug delivery
- Lifestyle modifications as advised by the cardiologist, including regular exercise, lowering of blood pressure, quitting smoking and cutting down to one drink of alcohol, and a low-fat diet.
- Use of appropriate medication to prevent platelet clots from forming
There are several categories of drugs for restenosis:
- Drugs which inhibit coagulation, such as anticoagulants, antithrombotic agents and antiplatelet agents like clopidogrel and heparin
- Anti-inflammatory agents such as dexamethasone and tranilast
- Drugs which inhibit proliferation and oppose growth factors, such as ACE inhibitors, trapidil, tyrphostin
- Cytostatic drugs which inhibit cell growth, like paclitaxel and rapamycin
- Lipid-lowering agents such as statins
- Antioxidants such as probucol or resveratrol
Vascular brachytherapy
Vascular brachytherapy is another technique used to prevent or treat a restenotic lesion. Here short-range ionizing therapy is used to inhibit neointimal hyperplasia, so as to prevent shrinkage of the arterial lumen after angioplasty. The radiation produces:
- Inhibition of smooth muscle cell proliferation
- Increased number of cells that enter the apoptosis pathway
- Less fibrosis
- Less negative remodeling, or healing which results in a shrunken lumen
Characteristic changes in irradiated vessels include:
- Persistent absence of endothelium over the irradiated part of the vessel
- Fibrin deposition over the bare area
- Inflammatory cell infiltration of the vessel wall
Vascular brachytherapy can be used alone or following angioplasty of a restenotic lesion. This is performed through a special catheter placed for 10 minutes inside the blocked segment, and containing a source of short-term radiation.
References
Further Reading
Last Updated: Aug 23, 2018