ACCEL | Results from a 5-Year Landmark Analysis of Dual Antiplatelet Therapy: DAPT just keeps going and going and... but should it?
The French FAST-MI Registry was designed to evaluate the "real-world" management of patients with ACS. Along with its earlier counterparts, USIK 1995 and USIC 2000, the FAST-MI 2005 and FAST-MI 2010 registries were nationwide surveys of patients enrolled over a 1-month period. All participants were recruited consecutively from intensive care units following STEMI or NSTEMI with the aim of providing cardiologists and health authorities with national and regional data on acute MI management and outcomes every 5 years.
At ESC 2013, François Schiele, MD, PhD, of the Université de Franche Comté, Besançon, France, reported the results from an analysis of 3,319 patients who were discharged after acute MI. Of these patients, 9% received no antiplatelet therapy, 17% were on single antiplatelet therapy, and 73% on dual antiplatelet therapy (DAPT). At 2 years, fully 43% of patients were still on dual therapy and nearly one-third remained on DAPT at 3 years (31%) and 4 years (29%). The percentage of patients receiving no antiplatelet therapy was never higher than 14% (at 3 years) and averaged about 8%.
According to Dr. Schiele, it was good to see such high use of DAPT at 1 year but it was surprising to see the high use at 2 years and "quite unexpected" to see relatively high use at 3 and 4 years.
The predictors of prolonged dual antiplatelet therapy:
- At 1 year, DAPT use was lower in the elderly (>75 years of age) and in patients on chronic oral anticoagulation (OAC).
- At 2 years, DAPT was more likely to be used in males, diabetics, individuals with previous MI, no OAC, and PCI with drug-eluting stent (DES).
- Use of DAPT attenuated over time in the elderly, individuals with a GRACE score >140, and patients with renal failure.
Prolonged DAPT and MortalityDr. Schiele and colleagues believe theirs is the first report to show DAPT use across 4 years with 5 years of follow-up. With data on 95% of patients, univariate analysis shows a mortality benefit favoring DAPT: 19.3% for no DAPT versus 10.8% with DAPT (p = 0.0002). However, multivariate analysis showed no significant difference in mortality between the groups. "With matched groups," Dr. Schiele said, "no effect at all." Interestingly, mortality was not significantly different between DAPT and single antiplatelet therapy at 1 year (p = 0.20; HR = 0.92 [0.68-1.44]) or at 2 years (p = 0.30; HR = 1.35 [0.92-1.91]). Overall, Dr. Schiele said, DAPT use at 1 year was not a predictor of 5-year mortality. There were a number of predictors of mortality that were evident—such as age >75 years, previous MI, diabetes, etc.—but "not DAPT at 1 year; it was absolutely neutral" for mortality. This neutral effect associated with DAPT remained whether analyzed by age, presence or absence of diabetes, type of MI, or type of therapy (medical vs. bare-metal stent [BMS] vs. DES). The FAST-MI 2005 Registry data extend the results of the PARIS study with an identical rate of DAPT use at 2 years (47%).
Given that prolonged DAPT was seen mainly among patients <75 years of age, with diabetes, or following PCI with DES, Dr. Schiele said it likely reflects a conscious medical decision to target DAPT in patients with low bleeding and high thrombotic risk, possibly reflecting concerns regarding a rebound effect and increased risk of stent thrombosis soon after halting DAPT in the years studied (2006-2009). The results concur with previous observational analyses as well as randomized trials, but with longer follow-up in an unselected population of patients.
In conclusion, the FAST-MI 2005 Registry data do not support the use of prolonged DAPT beyond 1 year after acute MI, even in specific populations considered to be at high risk, such as patients with diabetes, STEMI, or PCI with DES.
To listen to an interview with François Schiele, MD, PhD, about the FAST-MI 2005, visit youtube.cswnews.org. The interview was conducted by Douglas P. Zipes, MD.
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