January 1, 2017Journal of the American College of Cardiology
Dual Antiplatelet Therapy Versus Aspirin Monotherapy in Diabetics With Multivessel Disease Undergoing CABG
Key result
DAPT post-CABG in diabetics is not linked to fewer major events versus aspirin alone.
- HR 0.83
- 95% CI 0.54-1.27
- P=0.39
- n=795
Why the study?
Guidelines recommend post-operative DAPT after CABG for ACS, but DAPT utilization rates and associated outcomes among post-CABG patients with diabetes needed evaluation.
Does dual antiplatelet therapy improve cardiovascular outcomes compared to aspirin monotherapy in diabetic patients with multivessel disease undergoing CABG?
Key Points
- This research aims to evaluate outcomes associated with dual antiplatelet therapy in diabetic patients post-CABG.
- Post hoc nonrandomized analysis from the FREEDOM trial
- Comparison of DAPT (aspirin plus thienopyridine) and aspirin monotherapy
- Assessment of primary and safety outcomes at 30 days and 5 years post-operative.
- No significant difference in 5-year primary composite outcome between DAPT (12.6%) and aspirin monotherapy (16.0%), adjusted HR: 0.83, 95% CI: 0.54 to 1.27, p=0.39.
- Safety outcomes for major bleeding (5.6% DAPT vs. 5.7% aspirin) and blood transfusions (4.8% DAPT vs. 4.5% aspirin) showed no differences, p=0.99 and p=0.82 respectively.
- DAPT did not show clinical benefits over aspirin monotherapy in terms of cardiovascular or bleeding outcomes.
Study Design
Type
Cohort (n=795)
Structured PICO
Does dual antiplatelet therapy improve cardiovascular outcomes compared to aspirin monotherapy in diabetic patients with multivessel disease undergoing CABG?
P
Population
795 patients with diabetes mellitus and multivessel disease who underwent coronary artery bypass grafting (CABG)
I
Intervention
Dual antiplatelet therapy (aspirin plus thienopyridine) at 30 days post-operatively, with a median clopidogrel therapy duration of 0.98 years
C
Comparator
Aspirin monotherapy at 30 days post-operatively
O
Outcome
Risk adjusted 5-year composite of all-cause mortality, nonfatal myocardial infarction, or strokecomposite
Main Result
Effect estimate: HR 0.83 (95% CI 0.54-1.27)
Absolute Event Rate: 12.6% vs 16%
p-value: p=0.39
In diabetic patients undergoing CABG for multivessel disease, routine use of DAPT did not significantly improve 5-year cardiovascular outcomes or increase bleeding compared to aspirin monotherapy.
Limitations
- post hoc analysis
- nonrandomized analysis
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Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“In a secondary analysis of the FREEDOM trial, we observed that use of DAPT in patients with diabetes post-CABG was high, and, compared with aspirin monotherapy, no significant associations were observed with all-cause mortality, MI or stroke.”
“Compared with aspirin monotherapy, no associated differences were observed in cardiovascular or bleeding outcomes, suggesting that routine use of DAPT may not be clinically warranted.”
“There is modest but not definitive data on potential benefits of DAPT post-CABG, including in patients with ACS and patients with diabetes.”
Implication
Does not support routine DAPT post-CABG in diabetics; leaves open optimal antiplatelet therapy pending dedicated RCTs.
Abstract
BACKGROUND: Clinical practice guidelines recommend post-operative dual antiplatelet therapy (DAPT) in patients who undergo coronary artery bypass grafting (CABG) following acute coronary syndromes (ACS). OBJECTIVES: The authors have evaluated DAPT utilization rates and associated outcomes among post-CABG patients with diabetes. METHODS: In a post hoc, nonrandomized analysis from the FREEDOM (Future REvascularization Evaluation in patients with Diabetes mellitus: Optimal management of Multivessel disease) trial, we compared patients receiving DAPT (aspirin plus thienopyridine) and aspirin monotherapy at 30 days post-operatively. The primary outcome was the risk adjusted 5-year FREEDOM composite of all-cause mortality, nonfatal myocardial infarction, or stroke. Safety outcomes included major bleeding, blood transfusion, and hospitalization for bleeding. RESULTS: At 30 days post-CABG, 544 (68.4%) patients received DAPT and 251 (31.6%) patients received aspirin alone. The median (25th, 75th percentile) duration of clopidogrel therapy was 0.98 (0.23 to 1.91) years. There was no significant difference in the 5-year primary composite outcome between DAPT- and aspirin-treated patients (12.6% vs. 16.0%; adjusted hazard ratio [HR]: 0.83; 95% confidence interval [CI]: 0.54 to 1.27; p = 0.39). The 5-year primary composite outcomes were similar for patients receiving DAPT versus aspirin monotherapy respectively, in subgroups with pre-CABG ACSs (15.2% vs. 16.5%; HR: 1.06; 95% CI: 0.53 to 2.10; p = 0.88) and those with stable angina (11.6% vs. 15.8%; HR: 0.82; 95% CI: 0.50 to 1.343; p = 0.42). The composite outcomes of both treatment groups were also similar by SYNTAX score, duration of DAPT therapy, completeness of revascularization, and in off-pump CABG. No treatment-related differences in major bleeding (5.6% vs. 5.7%; HR: 1.00; 95% CI: 0.50 to 1.99; p = 0.99), blood transfusions (4.8% vs. 4.5%; HR: 1.09; 95% CI: 0.51 to 2.34; p = 0.82), or hospitalization for bleeding (2.6% vs. 3.3%; HR: 0.85; 95% CI: 0.34 to 2.17; p = 0.74) were observed between aspirin- and DAPT-treated patients, respectively. CONCLUSIONS: The use of DAPT in patients with diabetes post-CABG in our cohort was high. Compared with aspirin monotherapy, no associated differences were observed in cardiovascular or bleeding outcomes, suggesting that routine use of DAPT may not be clinically warranted. (Future REvascularization Evaluation in patients with Diabetes mellitus: Optimal management of Multivessel disease [FREEDOM]; NCT00086450).
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Cite This Study
Diepen et al. (2017) conducted a cohort in Diabetes mellitus with multivessel disease undergoing CABG (n=795). Dual antiplatelet therapy (aspirin plus thienopyridine) vs. Aspirin monotherapy was evaluated on Risk adjusted 5-year FREEDOM composite of all-cause mortality, nonfatal myocardial infarction, or stroke (HR 0.83, 95% CI 0.54-1.27, p=0.39). Dual antiplatelet therapy post-CABG in diabetics was not associated with a significant difference in 5-year mortality, MI, or stroke compared to aspirin alone (HR 0.83; 95% CI 0.54-1.27; p=0.39).