ORIGINAL ARTICLE
International patterns of dual antiplatelet therapy
duration after acute coronary syndromes
Héctor Bueno,1,2,3 Stuart Pocock,4 Nicolas Danchin,5 Lieven Annemans,6
John Gregson,4 Jesús Medina,7 Frans Van de Werf8
▸ Additional material is
published online only. To view
please visit the journal online
(http://dx.doi.org/10.1136/
heartjnl-2016-309509).
1Centro Nacional de
Investigaciones
Cardiovasculares (CNIC),
Madrid, Spain
2Cardiology Department,
Hospital Universitario 12 de
Octubre, and Instituto de
investigación i+12
3Universidad Complutense de
Madrid, Spain
4London School of Hygiene
and Tropical Medicine, London,
UK
5Hôpital Européen Georges
Pompidou & René Descartes
University, Paris, France
6I-CHER Interuniversity Centre
for Health Economics Research
UGent, VUB, Ghent, Belgium
7Medical Evidence and
Observational Research, Global
Medical Affairs, AstraZeneca,
Madrid, Spain
8University Hospitals, Leuven,
Belgium
Correspondence to
Dr Héctor Bueno, Centro
Nacional de Investigaciones
Cardiovasculares (CNIC),
Melchor Fernandez Almagro,
3, Madrid 28029, Spain;
hbueno@cnic.es
Received 18 February 2016
Revised 5 July 2016
Accepted 13 July 2016
Published Online First
8 August 2016
To cite: Bueno H, Pocock S,
Danchin N, et al. Heart
2017;103:132–138.
ABSTRACT
Objective To describe international patterns of dual
antiplatelet therapy (DAPT) duration after acute coronary
syndrome (ACS), and explore its determinants and
correlation with clinical events.
Methods EPICOR (long-tErm follow-uP of anti-
thrombotic management patterns In acute CORonary
syndrome patients) is a prospective, international,
observational study of 10 568 ACS hospital survivors
enrolled in 555 centres from 20 countries across Europe
and Latin America between 2010 and 2011, with
telephone follow-up at quarterly intervals up to
24 months to assess treatment continuation and clinical
events.
Results Of 8593 patients discharged on DAPT, 4859
(57%) remained on uninterrupted DAPT at end of
follow-up. There were minor differences in rates of DAPT
discontinuation according to age, gender, risk factors,
therapeutic strategy or region, but major differences
between countries. By study end, 555 of evaluable
patients (5.7%) died, 727 (10.0%) experienced new
cardiovascular (CV) events, 496 new coronary events
(6.82%) and 154 (2.11%) clinically relevant bleeding
(14 (6.7%) fatal). Most CV events and deaths (85%)
occurred while on DAPT. DAPT interruption was
associated with increased risk of CV events in the
following week (HR 2.29; 95% CI 1.08 to 4.84) but not
specifically with time to first coronary event or mortality.
Conclusions Despite guideline recommendations, most
patients with ACS in Europe and Latin America remained
on DAPT beyond 12 months, country being the most
important determinant of DAPT duration. Increase in
short-term CV risk was seen after switching from DAPT
to less medication, as compared with continued DAPT,
with no long-term effect on coronary or mortality risk.
Trial registration number NCT01171404; Results.
INTRODUCTION
Recent evidence shows that prolonging dual anti-
platelet therapy (DAPT) in patients treated with
coronary stents for longer than 12 months reduces
the rate of ischaemic events but increases bleeding
events.1 Although duration of DAPT for 12 months
following an acute coronary syndrome (ACS) was
an arbitrary period, selected on the basis of dur-
ation of follow-up in the Clopidogrel in Unstable
angina to prevent Recurrent Events (CURE) trial
and findings from two other major DAPT trials in
ACS,2–4 European and US ACS guidelines recom-
mended the use of DAPT for up to 12 months for
the majority of patients, treated with or without
stents.5 6 Despite this uniform recommendation,
information on DAPT duration from real-life prac-
tice is scarce, with some studies reporting observa-
tions from only a limited number of countries.7–9
The EPICOR (long-tErm follow-uP of anti-
thrombotic management patterns In acute CORonary
syndrome patients) study (NCT01171404) was
designed to describe real-life international patterns of
DAPT duration in patients with ACS. Secondary
objectives were identifying determinants for different
DAPT duration patterns and exploring the association
of changes in DAPT use with cardiovascular (CV) or
bleeding risk events.10
METHODS
Study design
Full details of the study design have been published
previously.10 Briefly, EPICOR is a prospective, ‘real-
life’, international, observational, cohort study,
which enrolled 10 568 consecutive survivors of an
ACS between September 2010 and March 2011
from 555 hospitals in 20 countries across Europe
and Latin America. Patients were enrolled at dis-
charge from hospital but details of their manage-
ment were recorded during the prehospital and
inhospital periods as well as during follow-up (by
3-monthly telephone interview) for up to 2 years
from discharge.
Study population
The main inclusion criteria were: hospitalisation
within 24 h of symptom onset of the index event
and a final diagnosis of ST-segment elevation myo-
cardial infarction (STEMI) or non-ST-segment ele-
vation ACS (comprising both non-STEMI and
unstable angina) at discharge, age ≥18 years, and
written informed consent. Patients were excluded if
they had a ‘secondary’ ACS (precipitated by or
occurring as a complication of surgery, trauma,
gastrointestinal bleeding or percutaneous coronary
intervention (PCI), or occurring during hospitalisa-
tion for other reasons). Other exclusion criteria
included any condition/circumstance considered
likely to limit completion of follow-up, any serious/
severe comorbidities limiting life expectancy to
<6 months, or previous enrolment in EPICOR or
another clinical trial. All other details (eg, site selec-
tion, patient enrolment and secondary objectives)
are provided in the design manuscript.10 Patient
baseline characteristics, and prehospital and inhos-
pital management have also been described
elsewhere.11
132 Bueno H, et al. Heart 2017;103:132–138. doi:10.1136/heartjnl-2016-309509
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Follow-up and event definition
Patients were followed up by centralised telephone interviews
by well trained native speakers of each patient’s language, and
interviewers were supervised by a direct patient contact
manager at 6 weeks after the index event, and then every
3 months up to 24 months. Interviews included questions
related to the occurrence of events, ischaemic and/or bleeding;
planned and unplanned hospitalisations, interventions or visits
to the emergency room or other physicians (including dentists);
treatment changes, including any planned/unplanned treatment
interruptions; other healthcare resource utilisation; and quality
of life measurement. For any changes in treatment, each drug of
interest was listed in turn — aspirin, ticlopidine, clopidogrel,
prasugrel, warfarin/acenocoumarol, dabigatran or any other to
be specified — and patients were asked to provide details of
when and why a current drug dose was changed, stopped and/
or restarted, or any new drug initiated. Patients were asked to
specify if the treatment change was due to a hospitalisation or
other physician visit, or at their own initiative. Events were
recorded through specific questionnaires in which hospitalisa-
tions or emergency department visits were first recorded. In
such cases, interviewers were asked to collect all relevant clinical
information (medical reports) from the patient, hospital physi-
cians or general practitioners. Whenever necessary, the primary
study investigator was contacted to obtain confirmation or any
clarification regarding the identified event.
The main reason for hospitalisation/visit was registered as CV,
bleeding or other. All CV and bleeding events reported by
patients, relatives or physicians were recorded together with spe-
cific information regarding each particular event but only events
in which a medical record with a specific diagnosis was available
were counted. Therefore, event rates were calculated according
to diagnoses reported in medical records.
Statistical analysis
Three groups were defined for antithrombotic patterns accord-
ing to patients’ discharge medication: (1) DAPT, comprising
patients discharged on aspirin plus one other oral antiplatelet
agent, such as clopidogrel, prasugrel or ticlopidine (ticagrelor
was not available in the majority of countries while the study
was conducted); (2) oral anticoagulation, participants discharged
on warfarin or dabigatran regardless of any other antithrombo-
tic drug prescribed, and (3) single antiplatelet therapy (SAPT),
which included all other patients. Characteristics across dis-
charge medication groups were compared using the χ2 test.
Event rates were calculated using the Kaplan-Meier method,
and Cox proportional hazards models were used to relate
change in DAPT to CV events. We did not use recurrent events
for the present analysis. Follow-up of each patient was divided
into time spent before and after change in DAPT. Change from
DAPT was entered in the model as a time-updated categorical
variable that enters the model on the day of change from
DAPT.12 HRs therefore compare the hazard of an event after a
change in DAPT to the hazard before a change in DAPT (which
includes the hazard in patients who do not change from DAPT
at any time). Time after change from DAPT was further split
into <7 days, 8–30 days and >30 days after the change. All ana-
lyses were performed in Stata V.11.2 (StataCorp, USA, 2009).
RESULTS
Patient characteristics
Of the 10 568 patients enrolled in EPICOR, 10 069 had known
medication status at discharge. Nineteen patients (0.18%) were
lost to follow-up, and 743 (7.03%) discontinued due to volun-
tary withdrawal or enrolment in another clinical trial during
follow-up. Of the 10 069 patients, most (8593, 85.3%) were dis-
charged on DAPT, 899 (8.9%) on SAPT and 537 (5.3%) on oral
anticoagulation (with or without antiplatelet agents) (table 1).
Forty patients were discharged on neither antiplatelets nor anti-
coagulants. Baseline characteristics, inhospital procedures and
medications and discharge therapies for the overall population
and the DAPT group have been described in detail elsewhere.11
There were small differences in the proportions of patients dis-
charged on each type of antithrombotic option across patient
characteristics except for age, initial management strategy and
type of ACS.
Change in medication
Complete follow-up with full information on antiplatelet treat-
ment was available for 8593 patients discharged on DAPT. A
large proportion of patients discharged on DAPT did not
change to another antiplatelet option at any time during the
first 12 months (6552, 76.2%) and up to the end of follow-up
(4859, 56.5%) (figure 1). In terms of specific antiplatelet treat-
ment, there was no difference at 12 months, but at 23 months
those on aspirin plus prasugrel were significantly more likely to
have been switched (p<0.0001). The most common reasons for
change of medication in patients on DAPT were instruction
from a physician (53.8%), programmed interventions (24.9%)
and physician instructions at discharge (9.6%). Older patients,
those with diabetes and those in Latin America or northern
Europe were significantly more likely to remain on DAPT, and
there was a borderline association with higher baseline haemo-
globin level (table 2). There were statistically significant,
although numerically minor, differences among regions in the
proportion of patients remaining on DAPT at the end of
follow-up, but major differences between countries were
observed within regions (p<0.001 for each region, figure 2).
Clinical events
By the end of follow-up, 559 (5.7%) patients had died, and 978
patients (9.8%) experienced 1173 CV events, of which 653
were coronary, including 252 myocardial infarctions (MIs)
(table 3, see online supplementary figure). ‘Non-coronary’
events included congestive heart failure, arrhythmias and
cerebrovascular events. A relatively small number of patients,
168 (1.7%), had one or more clinically relevant bleeding events
during follow-up, of which 14 (0.1% of study population) were
fatal (table 3, see online supplementary figure).
Most events and deaths (85%) during follow-up occurred
while patients were on DAPT. During the overall follow-up
period, there was no apparent association between medication
change and coronary or overall CV events (see online supple-
mentary table), but there was an increased rate of CV events
within the first 7 days after changing from DAPT to less medica-
tion (HR 2.29; 95% CI 1.08 to 4.84) (figure 3). Non-fatal CV
events within the first 7 days included two cases of unstable
angina, and one case each of congestive heart failure, stroke,
STEMI and ventricular arrhythmia. During that period, the inci-
dence of any CV event was 9.2 per 100 person-years at risk
compared with 5.9 during time on DAPT (HR 2.22; 95% CI
1.30 to 3.82) (see online supplementary table).
DISCUSSION
Our study shows that a high proportion (57%) of patients with
ACS in Europe and Latin America were receiving DAPT beyond
12 months, well before there was clear evidence of any
Bueno H, et al. Heart 2017;103:132–138. doi:10.1136/heartjnl-2016-309509 133
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advantage of such practice or any recommendations by contem-
porary clinical practice guidelines.5 6 Interestingly, we could not
find any strong patient-related determinant of longer DAPT dur-
ation, including initial revascularisation strategy, and use or type
of stents. Conversely, the largest variations were found in indi-
vidual country practices, suggesting local systems as more
important drivers of local DAPT duration. Moreover, while the
findings showed no overall correlation between switching from
DAPT to a lower antiplatelet level treatment and CV events,
they suggest an increased global CV risk within the first 7 days
after treatment change with no further increase in coronary or
mortality risk.
Currently, DAPT for longer than 12 months may be consid-
ered in patients after ACS, according to the most recent guide-
lines.13 However, this recommendation is based on findings
from the DAPT and PEGASUS-TIMI 54 (Prevention of
Cardiovascular Events in Patients with Prior Heart Attack Using
Ticagrelor Compared to Placebo on a Background of Aspirin-
Thrombolysis in Myocardial Infarction 54) trials,1 14 published
in December 2014 and March 2015, respectively, years after the
treatment decisions were made. Although surprising, our results
are not unique. The PARIS (Patterns of Non-Adherence to
Antiplatelet Regimens in Stented Patients) registry reported that
43% of patients with ACS and 57% of those who underwent
elective PCI remained on DAPTat the end of a 2-year follow-up
in a cohort of 5031 patients from the USA, France, Germany,
Italy and Greece.8 Similar results had been reported in France9
and the USA.7
Table 1 Antithrombotic medication at discharge in relation to characteristics of the study population
Distribution of antithrombotic medication at discharge by
characteristics of study population
Description Total number of patients in each category DAPT (n=8593) SAPT (n=899) Anticoagulants (n=537) p Value
Age, years; mean (SD) 61 (12) 64 (12) 67 (13) <0.0001
Group, years; n (%) <0.0001
<50 1691 1517 (89.7) 118 (7.0) 56 (3.3)
50–59 2821 2523 (89.4) 206 (7.3) 92 (3.3)
60–69 2794 2386 (85.4) 271 (9.7) 137 (4.9)
70–79 1962 1558 (79.4) 226 (11.5) 178 (9.1)
≥80 760 608 (80.0) 78 (10.3) 74 (9.7)
Female, n (%) 2467 2011 (81.5) 295 (11.9) 161 (6.5) <0.0001
Region, n (%) <0.0001
Northern Europe 3526 3008 (85.3) 283 (8.0) 235 (6.7)
Southern Europe 2290 1958 (89.4) 135 (6.2) 97 (4.4)
Eastern Europe 2291 1954 (85.3) 224 (9.8) 113 (4.9)
Latin America 2022 1673 (82.7) 257 (12.7) 92 (4.6)
Centre type, n (%) 0.0002
University general 3930 3370 (85.8) 362 (9.2) 198 (5.0)
Non-university general 2848 2487 (87.3) 212 (7.4) 149 (5.2)
Regional/community/rural 2137 1809 (84.7) 192 (9.0) 136 (6.4)
Private 1060 927 (87.5) 133 (12.5) 0 (0)
Diabetic 2256 1882 (83.4) 227 (10.1) 147 (6.5) 0.002
ACS type, n (%) <0.0001
STEMI 4747 4314 (90.9) 213 (4.5) 220 (4.6)
NSTE-ACS 5251 4253 (81.0) 681 (13.0) 317 (6.0)
Management strategy, n (%) <0.0001
PCI only 6572 6205 (94.4) 110 (1.7) 257 (3.9)
CABG 258 50 (19.4) 179 (69.4) 29 (11.2)
Medication only 3145 2292 (72.9) 603 (19.2) 250 (7.9)
Serum creatine, mg/dL; median (IQR) 9470 0.90 (0.79–1.08) 0.93 (0.80–1.11) 1.00 (0.83–1.20) <0.0001
Blood glucose, mg/dL; median (IQR) 8709 122.0 (104–150) 117.1 (101–151) 124.7 (104–162) <0.0001
Haemoglobin g/dL; median (IQR) 9358 14.3 (13.1–15.3) 13.9 (12.7–15.0) 13.9 (13.0–15.0) 0.20
Forty patients with known medication history were classified as in none of the above categories.
ACS, acute coronary syndromes; CABG, coronary artery bypass graft; DAPT, dual antiplatelet therapy; NSTE-ACS, non-ST elevation acute coronary syndrome; PCI, percutaneous coronary
intervention; SAPT, single antiplatelet therapy; STEMI, ST-elevation myocardial infarction.
Figure 1 Changes in medication status during follow-up among
patients with ACS discharged on DAPT. ACS, acute coronary syndrome;
DAPT, dual antiplatelet therapy; FU, follow-up.
134 Bueno H, et al. Heart 2017;103:132–138. doi:10.1136/heartjnl-2016-309509
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The reasons for such practices are unknown. In EPICOR, it is
surprising that there were only small differences in DAPT pat-
terns according to critical factors related to long-term risk, such
as age, diabetes, initial strategy or type of stent. Neither were
there any major differences among the four predefined regions
in the proportion of patients on DAPT at the end of follow-up,
ranging from 55.5% in southern Europe to 66% in Latin
America. However, there were major differences between coun-
tries within the same region. In fact, country represented the
most important determinant of the proportion of patients
remaining on DAPT at the end of follow-up. This suggests that
duration of DAPT may be mostly conditioned by local factors
rather than by an individual patient’s risk. Whether these factors
are cultural, economic or related to organisational factors within
Table 2 Characteristics of patients staying on DAPT during all follow-up
Characteristic
Number (%) of
patients remaining on
DAPT at 12 months (n=6552) p Value*
Number (%) of
patients remaining on
DAPT at the end of follow-up (n=4859) p Value*
Age, years† 0.55 0.018
<50 1147/1517 (75.6) 819/1517 (54.0)
51–59 1949/2523 (77.2) 1393/2523 (55.2)
60–69 1848/2386 (77.5) 1352/2386 (56.7)
70–79 1230/1558 (78.9) 916/1558 (58.8)
≥80 464/608 (76.3) 378/608 (62.2)
Sex 0.59 0.91
Male 5072/6582 (77.1) 3706/6582 (56.3)
Female 1567/2011 (77.9) 1153/2011 (57.3)
Region <0.001 <0.001
Northern Europe 2467/3008 (82.0) 1825/3008 (60.7)
Southern Europe 1495/1958 (76.4) 1005/1958 (51.3)
Eastern Europe 1372/1954 (70.2) 1002/1954 (51.3)
Latin America 1305/1673 (78.0) 1027/1673 (61.4)
Centre type <0.001 <0.001
University general 2540/3370 (75.4) 1913/3370 (56.8)
Non-university general 1921/2487 (77.2) 1335/2487 (53.7)
Regional/community/rural 1471/1809 (81.3) 1118/1809 (61.8)
Private 707/927 (76.3) 493/927 (53.2)
Type of ACS† 0.16 0.68
NSTE-ACS 3262/4253 (76.7) 2430/4253 (57.1)
STEMI 3360/4314 (77.9) 2415/4314 (56.0)
Diabetic status 0.034 0.008
Non-diabetic 5142/6711 (76.6) 3725/6711 (55.5)
Diabetic 1497/1882 (79.5) 1134/1882 (60.3)
Management strategy† <0.001 0.25
CABG (with/without PCI) 40/50 (80.0) 32/50 (64.0)
PCI only 1679/2292 (73.3) 3466/6205 (55.9)
Medication only 1679/2292 (73.3) 1339/2292 (58.4)
Unknown 29/46 (63.0) 22/46 (47.8)
Antiplatelet medication 0.99 <0.001
Aspirin+clopidogrel 5420/7829 (69.2) 4495/7829 (57.4)
Aspirin+prasugrel 500/705 (70.9) 333/705 (47.2)
Aspirin+clopidogrel+prasugrel 14/18 (77.8 10/18 (55.6)
Aspirin+ticlopidine 30/41 (73.2) 21/41 (51.2)
Glucose, mg/dL† 0.19 0.061
<160 4381/5709 (76.7) 3194/5709 (55.9)
≥160 1390/1763 (78.8) 1056/1763 (59.9)
Creatine, mg/dL† 0.17 0.88
<1.2 5455/7041 (77.5) 3959/7041 (56.2)
1.2–1.6 549/713 (77.0) 407/713 (57.1)
1.6–2.0 154/200 (77.0) 121/200 (60.5)
>2.0 129/167 (77.2) 113/167 (67.7)
Haemoglobin, g/dL† 0.68 0.055
<13 1321/1683 (78.5) 1020/1683 (60.6)
≥13 4892/6357 (77.0) 3512/6357 (55.2)
*p Values calculated using Cox model with time to first switch from DAPT as the outcome.
†Data unavailable in 1 patient for age, 14 for type of ACS, 22 for management strategy, 1560 for glucose level, 259 for creatine level and 327 for haemoglobin level.
ACS, acute coronary syndrome; CABG, coronary artery bypass graft; DAPT, dual antiplatelet therapy; NSTE-ACS, non-ST elevation acute coronary syndrome; PCI, percutaneous coronary
intervention; STEMI, ST-elevation myocardial infarction.
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local healthcare systems, requires further investigation. Given
the recent results from the DAPT and PEGASUS-TIMI 54
trials,1 14 extended DAPT use may increase even further in the
future. Postmarketing surveillance at both a national and an
international level will be needed to monitor patterns of DAPT
duration and, particularly, patient selection for long-term DAPT
duration.
In EPICOR, event rates continued to accrue throughout the
2-year follow-up period post discharge with higher rates in the
initial period and a steady increase during subsequent months
up to the end of follow-up. Interestingly, 85% of events and
85% of deaths during follow-up occurred while patients were
on DAPT; approximately half of non-fatal events were coronary,
and one in four patients who presented with an event died
during follow-up. The incidence of clinically relevant bleeding
recorded in EPICOR was relatively low (approximately 5%),
and less than half of the events were considered clinically rele-
vant. The PARIS registry showed an incidence of TIMI major
bleeding of 1.4% and 2.1% at 1 year and 2 years, respectively.8
Unfortunately, our findings cannot be compared here due to the
absence of a standardised bleeding definition.
Our study shows an association between DAPT discontinu-
ation (for any cause, including interruption or disruption) and
adverse events in the first 7 days. The DAPT trial showed a
modest increase in event rate between month 30, when the
P2Y12 inhibitor was terminated, and month 33 when follow-up
was terminated,1 suggesting a potential ‘rebound’ effect after
DAPT discontinuation, which was more obvious after prasugrel
withdrawal.15 The real-life PARIS registry also reported an
increased risk of major adverse CV events, spontaneous MI, def-
inite or probable stent thrombosis and cardiac death after DAPT
cessation, which was particularly relevant within the first
7 days.8 However, this hazard was only observed for DAPT dis-
ruptions; that is, cessations due to bleeding or patient non-
adherence, while DAPT discontinuations (those recommended
by physicians for patients thought to no longer need DAPT) or
interruptions (temporary cessations due to surgical necessity
with reinstitution of DAPT within 14 days) were not associated
with an increased event rate. It is worth noting that our defin-
ition of DAPT discontinuation does not align exactly with the
classification used in PARIS, which may explain at least part of
the differences in magnitude of effect. Moreover, despite the
large number of patients enrolled in EPICOR, the number who
effectively dropped DAPT was not large and the absolute
number of events recorded was low, limiting the power for
accurate risk estimations. Results for longer-term DAPT duration
Figure 2 Proportion of patients on DAPT at the end of follow-up by country. This analysis excluded patients who died or were lost to follow-up.
DAPT, dual antiplatelet therapy.
Table 3 Cardiovascular (CV) and bleeding events during
follow-up in the whole cohort (n=10 069)
Type of event
Patients with
event (%)*
Total number
of events (fatal)
All CV 978 (9.8%) 1173 (281)
Coronary 559 (5.7%) 653 (65)
MI 238 (2.5%) 252 (45)
Heart failure 104 (1.1%) 117 (30)
Arrhythmia 88 (0.9%) 93 (13)
Sudden death 8 (0.1%) 8 (8)
Chest pain 14 (0.1%) 18 (0)
Cerebrovascular 50 (0.5%) 56 (8)
Other 71 (0.7%) 75 (7)
Not classified 151 (1.5%) 153 (150)
Bleeding 366 (3.6%) 492 (14)
Clinically relevant bleeds 168 (1.7%) 223 (14)
Bleeds requiring hospitalisation 158 (1.5%) 212 (8)
Bleeds with haemodynamic
compromise
33 (0.3%) 37 (3)
Intracranial bleeds 15 (0.2%) 15 (6)
Other bleeds 226 (2.2%) 269 (0)
Deaths not due to CV or bleeding
Deaths of unknown cause 84 (0.9%) 84 (84)
*Percentages are Kaplan-Meier estimates at 23 months.
MI, myocardial infarction.
136 Bueno H, et al. Heart 2017;103:132–138. doi:10.1136/heartjnl-2016-309509
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are unknown as such trials are not available. The French registry
of Acute STelevation or non-ST-elevation Myocardial Infarction
2005 registry, however, reported similar outcomes in patients
with or without prolonged DAPT in the long term (up to
5 years of follow-up).9
The patterns found in our registry are more surprising in the
light of the later evidence, coming mostly from the results of the
two large randomised trials comparing either 12 months versus
30 months of DAPTwith aspirin and clopidogrel or prasugrel in
patients who had received a coronary stent (DAPT trial),1 or
aspirin versus aspirin plus ticagrelor starting between 12 months
and 36 months after a prior MI (either continuing DAPT at
12 months or restarting DAPT later) (PEGASUS-TIMI 54
trial).14 Both trials showed a reduction in ischaemic events (MI
in DAPT, and MI and stroke in PEGASUS-TIMI 54) with a sig-
nificant and clinically relevant increase in major bleeding and
diverging but non-significant trends for mortality. Together with
a number of smaller trials testing different durations of DAPT,
mostly in patients treated with stents, several meta-analyses have
confirmed that prolongation of DAPT beyond the first
12 months is a trade-off between reducing non-fatal ischaemic
events and non-fatal major bleeding events, with unclear results
on all-cause mortality, which may differ according to the reason
for DAPT indication (MI vs percutaneous intervention).16–18 For
this reason, the 2015 European Society of Cardiology guidelines
for the management of ACS in patients presenting without per-
sistent ST segment elevation state that P2Y12 inhibitor adminis-
tration in addition to aspirin beyond 1 year may be considered
after careful assessment of the ischaemic and bleeding risks of
the patient (indication class, IIb; level of evidence A).12
Several limitations should be considered when interpreting
the results of this study. As for any observational study, causal
relationships between patterns of care or DAPT interruption
and outcomes cannot be inferred. Some methodological issues
may have affected the accuracy of data collection or evaluation.
There was no prescription ascertainment and no confirmation
with supervising physician, so it may be possible that telephone
call answers do not detail actual tablets prescribed or taken.
Given the fact that telephone calls were only made every
3 months, recall bias leading to a reduced number of events
reported cannot be excluded. There is also a possibility that
some patients might have interpreted the telephone call as a
reminder to take the medication and could have felt tempted to
respond they were taking their medication, potentially leading
to an artefact in the direction of longer medication use. This is
particularly relevant for fatal events in which failure to identify
previous changes in medication may have been an issue that
could affect calculations of estimated risk. CV event rates may
also have been underestimated as no central adjudication of
events was done and only those events confirmed by physicians
with full event reports were counted in the analyses. Local adju-
dication might have been open to potentially differing interpre-
tations in different countries. Furthermore, cause of death was
not systematically recorded, and clinical events during follow-up
were not centrally adjudicated. Also, there was no standardised
classification of clinically relevant bleeding, limiting the compar-
ability of our results. Finally, there were ongoing changes in pre-
scription patterns of antiplatelet drugs during the study period.
CONCLUSIONS
International patterns of DAPT duration do not necessarily
align with guideline recommendations. Despite contemporary
evidence, patients with ACS remained on DAPT longer than
12 months, irrespective of clinical characteristics and ischaemic
Figure 3 Risk of CV or coronary events following interruption of DAPT versus remaining on DAPT. CV, cardiovascular; DAPT, dual antiplatelet
therapy.
Bueno H, et al. Heart 2017;103:132–138. doi:10.1136/heartjnl-2016-309509 137
Coronary artery disease
group.bmj.com on October 23, 2017 - Published by http://heart.bmj.com/Downloaded from 
risk, country being the most important determinant of DAPT
duration. This emphasises the importance of postmarketing sur-
veillance to monitor prescription patterns, patient selection and
clinical events related to long-term DAPT duration.
Key messages
What is already known on this subject?
Although guidelines recommend 12 months of DAPT following
an acute coronary syndrome (ACS) in the majority of patients,
relatively little is known about the duration of DAPT in a
real-world setting.
What might this study add?
This large international, prospective study shows that many
patients with ACS remain on DAPT beyond 12 months. There
were large differences in DAPT duration between countries, but
only small differences according to patient characteristics,
therapeutic strategy or region, suggesting local policies rather
than patient characteristics as key determinants of DAPT
prescription patterns. Discontinuation of DAPT was associated
with a short-term increase in overall cardiovascular risk but not
with any long-term increase in coronary events or mortality.
How might this impact on clinical practice?
The findings suggest that long-term duration of DAPT after ACS
was already common practice before it was recommended.
There is a need to follow compliance with guidelines
recommendations and develop interventions to improve these.
Acknowledgements The authors thank Liz Anfield, Prime Medica Ltd, for medical
writing support, Worldwide Clinical Trials for data management, and all the EPICOR
principal investigators.
Contributors All authors contributed to the design and conduct of the study,
analysis of the study data, and opinions, conclusions and interpretation of the data.
The lead author, HB, takes responsibility for the initial drafting and overall content
of the manuscript, and all authors contributed to the manuscript at each stage of
preparation, and approved the final version. Statistical analysis was performed by JG
and SP.
Funding The EPICOR study was funded by AstraZeneca.
Competing interests HB has received advisory/consulting fees from Abbott,
AstraZeneca, Bayer, BMS-Pfizer, Daichii-Sankyo, Eli-Lilly, Ferrer, Menarini, Novartis,
Sanofi and Servier, and research grants from AstraZeneca. SP has received research
funding from AstraZeneca. ND has received research grants from Amgen,
AstraZeneca, Bayer, Daiichi-Sankyo, Eli-Lilly, MSD and Sanofi, and consulting or
speaking fees from Amgen, AstraZeneca, Bayer, BMS, Boehringer-Ingelheim, GSK,
MSD-Schering Plough, Novartis, Pierre Fabre, Pfizer, Roche, Sanofi-Aventis, Servier
and The Medicines Company. LA has received consulting and lecture fees from
AstraZeneca. JM is an employee of AstraZeneca. JG has received research funding
from AstraZeneca. FVdW has received consulting fees and research grants from
Boehringer-Ingelheim and Merck, and consulting fees from Roche, Sanofi-Aventis,
AstraZeneca and The Medicines Company.
Ethics approval Local/national ethics committees for each participating centre/
country.
Provenance and peer review Not commissioned; externally peer reviewed.
Open Access This is an Open Access article distributed in accordance with the
Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which
permits others to distribute, remix, adapt, build upon this work non-commercially,
and license their derivative works on different terms, provided the original work is
properly cited and the use is non-commercial. See: http://creativecommons.org/
licenses/by-nc/4.0/
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syndromes
therapy duration after acute coronary 
International patterns of dual antiplatelet
Gregson, Jesús Medina and Frans Van de Werf
Héctor Bueno, Stuart Pocock, Nicolas Danchin, Lieven Annemans, John
doi: 10.1136/heartjnl-2016-309509
2017 103: 132-138 originally published online August 8, 2016Heart 
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