Patients with diabetes are less likely to have a heart attack or dieif they stay on anti-clotting medication for a full year after astenting procedure.
A stent is a very small metal mesh cylinder that's inserted into acardiac artery after it's become choked off by atherosclerosis. Thestent acts like a scaffold to prop open the artery, allowing ahealthy volume of blood flow. To prevent tissue from growing overthe stent and re-blocking the blood vessel, stents are often coatedwith slow-release drugs that keep the growth from occurring; theseare called drug-eluting (drug washing-out) stents. Stents that arenot coated with drugs are called bare metal stents.
Patients who've had a stent inserted must take an anti-clottingagent such as aspirin and clopidogrel (Plavix). In general, themedication is prescribed for six or more months after the stenting,to prevent the blood from reacting to the stent by thickening andclogging up the newly expanded artery (thrombosis). The hope is thata smooth, thin layer of endothelial cells (the inner lining of theblood vessel) grows over the stent during this period andincorporates it into the artery, reducing the tendency for clotting.
Now research has shown that a full year of treatment with theanti-clotting agent clopidogrel, twice as long as the standardsix-month treatment, offers significant benefit to people withdiabetes. In the study, 671 diabetic patients who had a stentingprocedure were followed. A year after the procedure, patients wereless likely to have suffered a heart attack or died if they hadcontinued to take clopidogrel for the full year. Even with baremetal stents, long-term clopidogrel significantly reduced the riskof death or heart attack.
The researchers speculated that year-longclopidogrel therapy is helpful because it prevents blood clots fromforming on inflamed plaques throughout the diseased coronaryarteries, not just on the stent itself. Continuing the therapylonger than a year did not further reduce risk.
Source: Society for Cardiovascular Angiography and Intervention