A new analysis published in JAMA shows that a combination of aspirin and another antiplatelet agent can prevent clotting after coronary artery bypass grafts but also increases the risk of potentially dangerous bleeding. This double-edged finding from investigators suggests physicians should carefully weigh the use of these medications after this procedure.
A Weill Cornell Medicine and NewYork-Presbyterian team led by Dr Mario Gaudino, a coronary artery bypass surgeon, examined data from 1668 grafts in which surgeons use a saphenous vein graft to circumvent blocked coronary arteries. It is common for blood clots to form within the grafted vein, for which patients are typically given aspirin. Some evidence suggests that aspirin along with a prescription strength antiplatelet agent such as ticagrelor can more effectively prevent this clotting.
“We found that, yes, this dual therapy significantly reduces the risk that the grafts will fail. However, for the first time, we have shown that this approach also carries a significant risk of clinically important bleeding,” said Dr Gaudino. “So, the benefit comes at a price.”
Taken together, these results indicate physicians should base their decisions on patients’ individual circumstances and avoid using this approach for those with conditions that put them at risk of bleeding, he said.
In more than 90% of coronary artery bypass grafts, surgeons take a graft from one of the patient’s saphenous veins, which return blood up the leg. However, within a year, up to a quarter of these grafts become obstructed.
While studies have examined the benefit of aspirin and ticagrelor, known as dual antiplatelet therapy (DAPT), these studies were small and had conflicting conclusions. The team contacted researchers on four such trials to obtain access to their raw data. They aggregated the data and effectively created a much larger study capable of generating more robust conclusions.
They found a failure rate of approximately 11% in patients who received a combination of aspirin and ticagrelor, while blockages occurred in 20% of grafts when patients received only aspirin. However, compared to aspirin alone, DAPT brought on more bleeding events that, while generally not life threatening, required medical attention.
In these previous trials, patients received DAPT for a full year. However, most graft failure occurs in the first few months after surgery. Dr Gaudino plans a further test of aspirin and ticagrelor over one to three months to see if a shortened course offers the same benefit with less risk of bleeding.
Source: Weill Cornell Medicine
