Prolonged DAPT confers ischemic benefit in patients with MI; DAPT Score improves prediction of benefit

CHICAGO — In analyses of the DAPT study, researchers determined that prolonged dual antiplatelet therapy after stenting offers ischemic benefit in patients with prior or index MI, and the DAPT Score improves prediction of benefit from prolonged dual antiplatelet therapy.

In the DAPT study, all patients (n = 11,648) were treated with aspirin plus clopidogrel or prasugrel (Effient, Daiichi Sankyo/Eli Lilly) for 12 months after stenting, then randomly assigned to aspirin plus continued thienopyridine therapy or placebo for 12 to 30 months after stenting.

Benefit in prior MI

In the poster presentation, Dean Kereiakes, MD, FACC, FSCAI, medical director for The Christ Hospital Heart and Vascular Center and the Carl and Edyth Lindner Center for Research and Education at The Christ Hospital, Cincinnati, and professor of clinical medicine at The Ohio State University, Columbus, compared the 21.1% of participants in the DAPT study who had prior MI (n = 2,456; median time before stenting, 891 days) with the 30.7% of participants who had index MI (n = 3,576).

Dean Kereiakes

A previous analysis from the DAPT study found that patients with index MI had lower late MI rates if assigned prolonged DAPT, but it was not known if the same was true in patients with prior MI.

The researchers found that patients with index or prior MI had reduced rates of stent thrombosis (0.5% vs. 1.8%; P < .001) and MI (2.5% vs. 5.2%; P = .001) and increased rates of bleeding (2.1% vs. 1.1%; P = .01) if assigned to prolonged DAPT.

According the Kereiakes and colleagues, risk for late MI was reduced after assignment to prolonged DAPT in those with index MI (2.2% vs. 5.2%; HR = 0.42; 95% CI, 0.29-0.62) and prior MI (3.5% vs. 6%; HR = 0.56; 95% CI, 0.37-0.83).

Accurate prediction of benefit

In the JACC study, Kereiakes and colleagues assessed whether the DAPT Score predicted benefit or harm with prolonged DAPT therapy. A DAPT Score of 2 or more indicates potential benefit from DAPT longer than 1 year, whereas a DAPT Score of less than 2 indicates potential harm from it.

Rates of late MI were higher in those with any MI compared with those with no MI (3.8% vs. 2.4%; P = .01), but prolonged DAPT was associated with reduction of late MI regardless of MI history (HR for any MI = 0.46; P < .001; HR for no MI = 0.6; P = .003), they found.

Participants from the DAPT study with a DAPT Score of at least 2 had less MI or stent thrombosis on continued DAPT vs. aspirin and placebo regardless of prior MI status (any MI, 2.7% vs. 6%; P < .001; no MI, 2.6% vs. 5.2%; P = .002). In that population, rates of late bleeding did not differ by assignment to prolonged DAPT or aspirin plus placebo (any MI, 1.5% vs. 1.1%; P = .24; no MI, 2.2% vs. 2%; P = .68).

However, among participants with a DAPT Score of less than 2, regardless of MI history, prolonged DAPT was associated with increased risk for bleeding (any MI, 3.2% vs. 1.2%; P = .01; no MI, 2.9% vs. 1.6%; P = .004) but no significant difference in late MI or stent thrombosis (any MI, 2.1% vs. 3.2%; P = .17; no MI, 1.5% vs. 2%; P = .21).

“The DAPT Score improves prediction of patient benefit and harm from continued [DAPT] beyond assessment of MI history alone,” the researchers wrote. – by Erik Swain

References:

Kereiakes DJ, et al. J Am Coll Cardiol. 2016;doi:10.1016/j.jacc.2016.03.485.

Mauri L, et al. Poster 1174-117. Presented at: American College of Cardiology Scientific Session; April 2-4, 2016; Chicago.

Disclosure: Kereiakes reports consulting for and receiving research funding from Abbott Vascular, Boston Scientific and Sanofi. Please see the full study for a list of the other researchers’ relevant financial disclosures.