SNOWMASS, COLO. – U.S. cardiologists are glaringly out of touch with the guidelines on maintenance aspirin dosing in patients with acute coronary syndrome, American College of Cardiology President Dr. Patrick T. O’Gara said at the Annual Cardiovascular Conference at Snowmass.
The latest AHA/ACC guidelines state that maintenance aspirin therapy at 81 mg/day to be continued indefinitely is preferred over 325 mg/day in patients with ACS, regardless of whether they have received a coronary stent or noninvasive medical management (Circulation 2014 Dec 23;130(25):e344-426).
Dr. Patrick T. O'Gara
“This statement has been out there in the guidelines for several years now. Yet the last time we interrogated the NCDR [National Cardiovascular Data Registry], 70% of patients with ACS were discharged on 325 mg/day of aspirin in the U.S.,” said Dr. O’Gara, professor of medicine at Harvard Medical School and director of clinical cardiology at Brigham and Women’s Hospital, Boston.
The recommendation in the guidelines is based on several solid studies, including OASIS 7, which in more than 25,000 randomized patients showed no difference in outcomes when aspirin at 75-100 mg/day was compared with 300-325 mg/day, but an increased incidence of bleeding at the higher dose (N. Engl. J. Med. 2010;363:930-42).
“Aspirin at 81 mg/day is not inferior with respect to clinical efficacy and it’s superior with respect to its safety outcome. But here in the United States we are still very much wedded to using 325 mg of aspirin. I’m not exactly sure of the reasons for that. Maybe it’s a catch up phenomenon,” Dr. O’Gara commented.
In the setting of percutaneous coronary intervention with a bare metal or drug-eluting stent for patients with either non–ST-elevation ACS or ST-elevation MI, the AHA/ACC guidelines give a class I recommendation for at least 12 months of dual-antiplatelet therapy (DAPT) with aspirin and a P2Y12 inhibitor. Either ticagrelor (Brilinta) at 90 mg twice daily or prasugrel (Effient) once daily at 10 mg is recommended over clopidogrel at 75 mg/day in patients who can take those medications safely; this guidance is based on ticagrelor’s superior efficacy compared with clopidogrel as shown in TRITON TIMI-38 (N. Engl. J. Med. 2007;357:2001-15) and prasugrel’s superiority in the PLATO trial (N. Engl. J. Med. 2009;361:1045-57).
The AHA/ACC guidelines give a relatively tepid level IIb recommendation that continuation of DAPT beyond 12 months may be considered in stent recipients. Many observers expect a stronger endorsement in the next iteration of the guidelines on the strength of the recent DAPT study, which showed that 30 months of DAPT was better than 12 in terms of major adverse cardiac and cerebrovascular events (N. Engl. J. Med. 2014;371:2155-66).
“Interestingly enough, the mechanism of benefit had less to do with prevention of stent thrombosis than it did with prevention of recurrent MI and stroke. This renders into much sharper focus the question of whether we’re treating the patient or we’re treating the stent. This result would imply that we’re treating the patient,” Dr. O’Gara observed.
The guidelines also include a bail-out option which states that if the risk of bleeding outweighs the anticipated benefit, it’s reasonable to discontinue DAPT before 12 months.
“I don’t know a single practitioner who’s not had to withdraw one or both elements of DAPT because of bleeding or because of the need for unanticipated noncardiac surgery. It’s a fact of life, and sometimes you have to just hope for the best,” the cardiologist said.
He reported having no financial conflicts of interest.