Dual Ticagrelor Plus Aspirin Antiplatelet Strategy After Coronary Artery Bypass Grafting - DACAB

Contribution To Literature:

The DACAB trial showed that DAPT with aspirin + ticagrelor results in superior SVG patency at 1 year following CABG compared to low-dose aspirin monotherapy, with similar rates of major bleeding.

Description:

The goal of the trial was to assess the safety and efficacy of aspirin monotherapy, ticagrelor monotherapy, or dual antiplatelet therapy (DAPT) with aspirin and ticagrelor among patients undergoing coronary artery bypass grafting (CABG).

Study Design

Patients scheduled for CABG were randomized in a 1:1:1 fashion to either aspirin 100 mg daily (n = 166), ticagrelor 90 mg BID (n = 166), or DAPT (n = 168). Antiplatelet therapy was resumed within 24 hours post-CABG.

  • Total number of enrollees: 500
  • Duration of follow-up: 1 year
  • Mean patient age: 64 years
  • Percentage female: 19%
  • Percentage with diabetes: 42%

Inclusion criteria:

  • Age 18-80 years
  • Indication for CABG

Exclusion criteria:

  • Cardiogenic shock or hemodynamic instability
  • Need for urgent or other concomitant cardiac surgery
  • Indication for DAPT or vitamin K antagonist
  • Risk of serious bleeding
  • Contraindication to study medications

Other salient features:

  • Unstable angina or non−ST-segment elevation myocardial infarction: 65%
  • Median left ventricular ejection fraction: 62%
  • SYNTAX score 23 or higher: 87%
  • Cardiopulmonary bypass use: 24%
  • Mean number of vein grafts/patient: 2.9

Principal Findings:

The primary outcome, saphenous vein graft (SVG) patency at 1 year on computed tomography/coronary angiography for aspirin monotherapy vs. ticagrelor monotherapy vs. DAPT, was 76.5% vs. 82.8% vs. 88.7% (p for ticagrelor vs. aspirin = 0.096, p for DAPT vs. aspirin = 0.0006).

SVG nonocclusion was 80.6% vs. 86.1% vs. 89.9% (p for ticagrelor vs. aspirin = 0.13, p for DAPT vs. aspirin: 0.006).

Secondary outcomes for aspirin monotherapy vs. ticagrelor monotherapy vs. DAPT:

  • Major adverse cardiac events: 5.4% vs. 2.4% vs. 1.8%
  • Myocardial infarction: 1.8% vs. 1.2% vs. 1.2%
  • Stroke: 2.4% vs. 1.2% vs. 0%
  • Non–CABG-related bleeding: 9% vs. 12.1% vs. 30.4%
  • Major bleeding: 0% vs. 1.2% vs. 1.8%

Interpretation:

The results of this trial indicate that DAPT with aspirin + ticagrelor results in superior SVG patency at 1 year following CABG compared to low-dose aspirin monotherapy. Although there is an increase in all bleeding with this strategy, major bleeding rates were similar. It is important to note that more than three-quarters of the patients underwent off-pump CABG.

This is an important trial, but there are several caveats. Routinely, patients post-CABG receive 81-325 mg aspirin for 1 year, with most operators using 325 mg daily to preserve vein graft patency. Thus, by using a lower dose of aspirin in this study, vein graft patency in the control arm may be lower than observed in clinical practice. Indeed, most contemporary CABG trials report 1-year SVG patency rates between 85-95%, compared with 76.5% in this trial in the low-dose aspirin arm.

There have been a few small trials assessing the role of DAPT with aspirin and clopidogrel compared with aspirin monotherapy in post-CABG patients. There appears to be some benefit with this strategy, particularly among patients undergoing off-pump CABG. Moreover, the CABG subgroup in the PLATO trial also showed significant improvements in clinical outcomes with ticagrelor + aspirin compared with aspirin alone, with no differences in non-CABG bleeding, similar to this trial. Finally, nearly two-thirds of the patient population was enrolled post–acute coronary syndrome, who would have an indication for DAPT even in the absence of percutaneous coronary intervention.

References:

Presented by Dr. Qiang Zhao at the American Heart Association Annual Scientific Sessions (AHA 2017), Anaheim, CA, November 12, 2017.

Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Interventions and ACS, Interventions and Imaging, Angiography, Computed Tomography, Nuclear Imaging

Keywords: Acute Coronary Syndrome, AHA17, AHA Annual Scientific Sessions, Angina, Unstable, Aspirin, Cardiac Surgical Procedures, Cardiopulmonary Bypass, Coronary Angiography, Coronary Artery Bypass, Hemorrhage, Myocardial Infarction, Platelet Aggregation Inhibitors, Saphenous Vein, Stroke, Tomography, X-Ray Computed


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