Patients who received six months of clopidogrel after coronary artery stenting had better outcomes than those treated for the standard 24 months in a study presented at a Hot Line session at the European Society of Cardiology congress.
The results “question the validity of current guideline recommendations”, said Marco Valgimigli from the University Hospital of Ferrara, Italy. Presenting the data on behalf of the PRODIGY (Prolonging dual antiplatelet treatment after grading stent-induced intimal hyperplasia study) group, he said that 24 months dual antiplatelet therapy was no better than six months antiplatelet therapy in preventing adverse cardiac events. However, patients who were treated for longer had a consistently greater risk of bleeding and haemorrhage.
“We were really surprised to see there was absolutely no difference in any ischemic endpoint if you prolong treatment,” Valgimigli said. “You just get more bleeding. Patients are twice as likely to need blood transfusion, so it is a real hazard.”
PRODIGY is a multicentre study which included 2,000 patients scheduled for elective or emergency coronary angioplasty. They were randomised to receive one of four stent types: everolimus-eluting, paclitaxel-eluting, zotarolimus-eluting or a thin-strut bare metal stent. At 30 days, patients in each stent group were then further randomised to either six or 24 months of dual antiplatelet treatment.
At two years, cumulative risk of the primary endpoint, a composite of overall death, myocardial infarction or stroke, was 10.1% with the 24 month treatment, and 10% with the six-month (HR 0.98, CI 0.74–1.29; p=0.91). Risk of bleeding was doubled in the 24-month group: the hazard ratio for type 5, 3, or 2 bleeding events (Bleeding Academic Research Consortium classification) was 2.17 (CI 1.02–3.13; p=0.037).
Valgimigli said that the study had “failed to show” that treatment for 24 months is superior to six months, and added: “While we cannot rule out the possibility that a smaller than previously anticipated benefit may exist, the clear increase in bleeding, transfusion and net adverse clinical events, suggests that current recommendations may have overemphasised the benefit over the risk of combined long-term aspirin and clopidogrel.”
Other groups presented studies with similar findings at the ACC meetings this year and last, though neither has yet published. Valgimigli said: “I am aware of three different studies giving more or less the same type of findings. I do not know how the guidelines committees will adapt their recommendations based on those findings.”