Restenosis Prevention

By Dr. Liji Thomas, MD

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

• http://eurheartj.oxfordjournals.org/content/ehj/21/21/1739.full.pdf
• http://www.radcliffecardiology.com/articles/treatment-stent-restenosis-past-present-and-future?page=9
• http://circ.ahajournals.org/content/105/22/2586.full

Further Reading

• All Restenosis Content
• What is Restenosis?
• Restenosis Causes
• Restenosis Physiology
• Restenosis Treatment