The study found that when a nurse checked in by telephone every few months after a stenting procedure, nearly all patients continued to take a combination of clopidogrel (Plavix) and aspirin as prescribed. Adherence to the medication regimen, known as dual anti-platelet therapy (DAPT), dropped by about 10 percentage points among a comparison group of patients who received no ongoing telephone follow-up after leaving the hospital.
“We should make every effort to make sure patients do not interrupt dual anti-platelet therapy once they’ve received a drug-eluting stent,” said Stéphane Rinfret, MD, FSCAI, a clinical and interventional cardiology researcher at the Quebec Heart and Lung Institute. “It’s absolutely crucial. If a patient stops taking clopidogrel or aspirin, it increases the stent thrombosis risk by 100 to 150 times, and that can lead to a heart attack, stroke or death.”
Drug-eluting stents act like scaffolding to prop open an artery after inflation of a tiny balloon clears away a blockage of cholesterol-laden plaque. Over time, these stents release medication that prevents fibrous scar tissue from growing through the stent’s metal mesh walls and obstructing the artery. In addition, patients typically must take dual anti-platelet therapy for a year to prevent platelet blood cells from clumping together on the inner surface of the stent, causing blood clots (stent thrombosis) that can completely block the stent and cut off blood flow to the heart.
For the study, known as the Early discharge After transradial Stenting of Coronary ArterY-IMProving Adherence to Clopidogrel Trial (EASY-IMPACT), Dr. Rinfret and his colleagues at the Quebec Hearth and Lung Institute recruited a total of 300 patients who had just been treated with a drug-eluting stent. Patients were randomly assigned to either standard care or special telephone follow-up. Both groups were briefed on the importance of dual anti-platelet therapy before leaving the hospital, but the telephone group also received phone calls from a nurse 7 days after stenting and again at one, six and nine months. During the telephone calls, the nurse checked to see whether the patient was taking dual anti-platelet medication as prescribed, inquired about any problems with excess bruising or bleeding and reinforced the importance of continuing therapy.
Researchers also collected pharmacy data for all patients to document whether prescriptions were filled and refilled on schedule, an indicator of whether patients were taking the medication each day as prescribed. They then calculated medication adherence, defined as the proportion of aspirin and clopidogrel pills each patient took over a 12-month period compared to the number they would be expected to have taken.
At the 12-month mark, median adherence to aspirin and clopidogrel were each 99.2 percent in the telephone support group, as compared to 90.2 percent for aspirin and 91.5 percent for clopidogrel in the usual care group (p <0.0001 for both aspirin and clopidogrel).
Researchers also calculated medication persistence, which they defined as having less than a 14-day gap between expected and actual prescription refill dates at any point in the study. They found that for aspirin, 91.2 percent of the telephone group and 72.3 percent of the usual care group remained persistent at six months (p<0.0001), while 87.8 percent and 39.0 percent, respectively remained persistent at one-year (p<0.0001). For clopidogrel, 90.5 percent of patients in the telephone group and 66.7 percent of patients in the usual care group were still persistent at six months (p<0.0001), while 87.2 percent and 43.1 percent, respectively, were still persistent at one year (p<0.0001).
“As physicians, we should remember that drugs only work in patients who take them,” Dr. Rinfret said. “There are ongoing debates about the best anti-platelet agent based on their biological effects, but new approaches to patient management may have an even stronger effect than new drugs on the prevention of heart attack and other complications following implantation of drug-eluting stents.”
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