Risk of Death Not Lowered With Asprin, Ticagrelor Versus Aspirin in ACS Treatment

Although current guidelines recommend dual anti-platelet therapy after coronary artery bypass grafting (CABG) for patients with acute coronary syndrome (ACS), there is little evidence mainly derived from non-CABG populations.

As a result, a team of investigators investigated if the adjusted risk of ischemic events and major bleeding after CABG differed between patients with ACS treated with acetylsalicylic acid (ASA) and ticagrelor or with ASA monotherapy.

The team, led by Anders Jeppsson, MD, PhD, Department of Cardiothoracic Surgery, Sahlgrenska University Hospital, found no significant difference in risk of death or ischemic event between ASA plus ticagrelor and patients treated with ASA alone.

Study

Investigators identified the study population in the Swedish Cardiac Surgery Registry, as part of the SWEDEHEART registry.

Patients included in the study were ≥18 years old who underwent isolated first-time CABG from January 2006 - December 2017, with a diagnosis of ACS within 6 weeks before CABG and were treated postoperatively with ASA plus ticagrelor or ASA monotherapy.

Follow-up was 15 days after discharge and end of follow-up was considered death, emigration, or after December 31, 2017.

They noted the primary outcomes included time to first major adverse cardiovascular event (MACE; all-cause mortality, myocardial infarction, and stroke) and major bleeding within the first 12 months.

Further, a multivariable Cox regression model was used for the main analysis and propensity score-matched models were performed as sensitivity analysis. Investigators analyzed data from May - September 2020.

Results

The study included 6.558 patients, consisting of 5281 men (80.5%) and a mean age of 67.6 years. Within that total, 4745 patients (72.4%) were treated with ASA monotherapy, compared to 1813 patients (27.6%) treated with ASA and ticagrelor at baseline.

Median follow up was 2.9 years (1.4 - 4.4) with a total follow-up time of 19,111 patient-years.

Data show the percentage of patients treated with ASA plus ticagrelor increased from 4.2% in 2012 to 49.2% in 2017, while the percentage treated with ASA monotherapy decreased from 82.6% to 46.5%.

In addition, data from follow-up show 670 patients (10.2%) suffered a MACE, 366 patients (5.6%) died, 207 patients (3.2%) had a myocardial infarction, 160 patients (2.4%) had a stroke, and 197 patients (3.0%) experienced a major bleeding event.

The crude MACE rate was 3.0 per 100 person-years (95% CI, 2.5 - 3.6 per 100 person-years) in the ASA plus ticagrelor group and 3.8 per 100 person-years (95% CI, 3.5 - 4.1 per 100 person-years) in the ASA group.

All-cause mortality found the event rate to be 1.3 (95% CI, 1.0 - 1.7) per 100 person-years in the ASA plus ticagrelor group and 2.1 (95% CI, 1.8-2.3) per 100 person-years in the ASA group.

Further, the crude event for major bleeding during the first-year of follow-up was 2.2 (95% CI, 1.5 - 3.1) per 100 person-years in the ASA plus ticagrelor group and 1.3 (95% CI, 1.0 - 1.7) in the ASA group.

Following adjustment, investigators found no significant difference in the MACE risk between ASA plus ticagrelor versus ASA only in both the first 12 months (adjusted hazard ratio aHR, 0.84; 95% CI, 0.58 - 1.21, P = .34) or during total follow-up (aHR, 0.89; 95% CI, 0.71 - 1.11, P = .29).

Data show the use of ASA plus ticagrelor associated with a significantly increased risk for major bleeding during the first 12 months (aHR 1.90; 95% CI, 1.16 - 3.13, P = .011).

Conclusion

Investigators concluded adherence to guidelines for DAPT after CABG in patients with ACS is limited, noting event rates of CABG in patients with ACS who survive 2 weeks after hospital discharge is low independent of platelet inhibition strategy.

“Sufficiently powered prospective randomized trials with clinically important end points that compare different antiplatelet strategies after CABG are warranted,” investigators wrote.

The study, “Comparison of Midterm Outcomes Associated With Aspirin and Ticagrelor vs Aspirin Monotherapy After Coronary Artery Bypass Grafting for Acute Coronary Syndrome,” was published online in JAMA Network Open.