AHA 2015: Antiplatelet agent switching is uncommon in heart attack patients in the year after discharge

November 8, 2015 – Switching is more frequent in patients discharged on ticagrelor and prasugrel than in those on clopidogrel, but rarely triggered by bleeding, report the DCRI’s Tracy Wang, MD, MHS, MSc, and others.

Randomized clinical trials of antiplatelet therapies, which prevent platelets from clumping and blood clots from forming and growing, show efficacy based on participants being treated consistently with a single agent. Examples of such products are the ADP receptor inhibitors (ADPri), ticagrelor, prasugrel and clopidogrel.

tracy-wang-newsIn routine clinical practice, heart attack patients treated with percutaneous coronary intervention – also known as angioplasty – may switch ADPri therapies due to adverse events, inability to afford the medication, or based on their physician’s advice. A previous study showed that switching occurs already in 12 percent of patients during their initial hospitalization following a heart attack.  However, the extent of post-discharge switching in community practice – its incidence, timing, and reasons for switching – have not been previously described.

The results of the study were presented in a poster session Sunday at the 2015 American Heart Association Scientific Sessions in Orlando, Florida.

This analysis involved heart attack patients undergoing percutaneous coronary intervention and treated with an ADPri at hospitals in the United States between 2010 and 2012  enrolled in the TRANSLATE-ACS (TReatment with ADP receptor iNhibitorS: Longitudinal Assessment of Treatment Patterns and Events after Acute Coronary Syndrome) study. Enrolled patients were interviewed at six weeks, six months and 12 months to obtain information on medications and events.

Among patients continued on ADPri throughout the first year after a heart attack, 7.6 percent of patients switched ADPri agents. The majority of switching occurred within the first two months post-discharge, and took place more frequently in patients discharged on ticagrelor (28.3 percent) and prasugrel (15.4 percent), compared with those discharged on clopidogrel (3.6 percent). Switching was preceded by a major adverse cardiovascular event or stent thrombosis in 29.6 percent of clopidogrel patients who switched. However, bleeding events did not appear to be a major driver of switching in prasugrel or ticagrelor patients (1.3 percent and 1.6 percent). Patients who switched from prasugrel or ticagrelor most often cited cost as a reason for the switch, while most patients switching from clopidogrel attributed the switch to a physician decision.

“Switching between ADPri therapies is a reality of community practice, and the most commonly cited reasons for switching are cost and physician advice,” said the DCRI’s Tracy Y. Wang, MD, the senior author of the study. “Fortunately drug related side-effects such as bleeding do not seem to be a major driver of switching.”

In addition to Wang, DCRI co-authors were Eric D. Peterson, MD, MPH; Lisa A. McCoy, MS; and Kevin J. Anstrom, Ph.D.