Restenosis is a re-narrowing of a blood vessel due to growth of tissue at the site of angioplasty or stent implementation. This re-narrowing of the blood vessel may lead to the return of symptoms associated with coronary artery disease.

More than 1.5 million people worldwide undergo coronary angioplasty and related procedures each year. However, 30 to 50 percent of these patients experience re-blockages within six months of their initial procedure. Coronary stents, which are tiny metal tubes that function as scaffolding to hold the previously blocked arteries open, have been very successful in reducing restenosis. Restenosis still develops in approximately 20 percent of patients with implanted stents.

Restenosis is generally treated with a second balloon angioplasty and/or stent implementation procedure. Sometimes there is no other option than to treat with coronary bypass surgery.

Once a patient experiences restenosis, there is a 50 percent chance the patient will experience it again in the future. This recurrence generally occurs within six months of initial treatment and patients often return to their doctor every few months with debilitating symptoms. Physicians have had limited treatment options for these patients.