The study was led by researchers at the University of Ulsan College of Medicine, Asian Medical Center in Seoul, Korea, who also called for more trials to confirm or refute the data.
Stents are inserted to prop open arteries that have become narrowed due to plaque build-up. Once in place, though, the stents - tiny mesh scaffolds - can help spur dangerous blood clots.
These new results come not from one study but from two initially separate studies which were combined because both had flagging enrollment.
In all, more than 2,700 Korean patients were randomly assigned to receive clopidogrel (Plavix) plus aspirin for at least 12 months. Patients were followed for a median of just over 19 months.
Not only were there few differences between the two groups, there was even a sign of benefit in the group taking aspirin alone after 12 months.
"This was surprising [that there was no difference between the arms] and that those on aspirin alone even seemed to do a little bit better with respect to heart attack, stroke and death," Garratt said.
Nor were bleeding complications, always a concern with blood-thinning medications, any different between the two groups.
It is conceivable, however, that the results would not hold up in a different study population.
For instance, Asian populations have a high prevalence of an enzyme which is not very good at metabolizing Plavix, Garratt pointed out. The individuals studied here were likely all or nearly all Asian.
"It's likely that the Plavix group didn't have the same effect biochemically that we would have expected in a North American, Caucasian or mixed population," he said.
"This study essentially shows that you need to continue aspirin and clopidogrel for one full year and after that, you can stop clopidogrel and just keep people on aspirin and that is what people have been doing in general," Sandhu said.
All rights reserved