Assessment of a Normal versus Tailored dose of prasugrel after stenting in patients Aged >75 years to Reduce the Composite of bleeding, stent Thrombosis, and Ischemic Complications - ANTARCTIC

Contribution To Literature:

The ANTARCTIC trial failed to show that tailored antiplatelet therapy improves outcomes after percutaneous coronary intervention.

Description:

The goal of the trial was to evaluate tailored antiplatelet therapy compared with conventional therapy among patients with acute coronary syndrome undergoing stenting.

Study Design

  • Randomized
  • Parallel

Patients with acute coronary syndrome undergoing stenting were randomized to tailored antiplatelet therapy (n = 435) versus conventional therapy (n = 442). All patients were started on prasugrel 5 mg daily.

Patients in the tailored arm received 14 days of prasugrel 5 mg, followed by platelet function tests at 14 days and 28 days. If platelet reactivity unit (PRU) was ≥208, prasugrel was increased to 10 mg daily and if ≤85, prasugrel was changed to clopidogrel 75 mg daily. 

Inclusion criteria:

  • Patients >75 years of age with acute coronary syndrome (ST- or non–ST-elevation myocardial infarction) undergoing stenting
  • Total number of enrollees: 877
  • Duration of follow-up: 12 months
  • Mean patient age: 81 years
  • Percentage female: 41%
  • Percentage diabetics: 28%

Exclusion criteria:

  • Stroke or transient ischemic attack
  • Fibrinolytic therapy in the last 48 hours
  • Chronic anticoagulation therapy
  • Concomitant medical illness with reduced survival
  • Allergy/intolerance to aspirin or thienopyridines
  • Active bleeding or history of bleeding abnormality
  • Thrombocytopenia
  • Severe hepatic disease
  • Any condition associated with poor adherence

Other salient features/characteristics:

  • In the tailored antiplatelet therapy group, 3.7% were increased to prasugrel 10 mg daily, while 39.3% were converted to clopidogrel 75 mg daily.

Principal Findings:

The primary outcome, incidence of cardiovascular death, myocardial infarction, stroke, stent thrombosis, urgent revascularization, or bleeding complication at 1 year, occurred in 27.6% of the tailored therapy group versus 27.8% of the conventional therapy group (p = 0.98).

Secondary outcomes, cardiovascular death, myocardial infarction, stent thrombosis, or urgent revascularization, occurred in 9.9% versus 9.3% (p = 0.80), respectively, for tailored versus conventional therapy.

Interpretation:

Among elderly patients with acute coronary syndrome undergoing stenting, tailored antiplatelet therapy did not improve outcomes compared with conventional antiplatelet therapy. Tailored antiplatelet therapy resulted in a large proportion of patients that were down-titrated to clopidogrel therapy. The results of this trial complement the ARCTIC trial, which also failed to demonstrate benefit for tailored antiplatelet therapy.

References:

Cayla G, Cuisset T, Silvain J, et al., on behalf of the ANTARCTIC Investigators. Platelet function monitoring to adjust antiplatelet therapy in elderly patients stented for an acute coronary syndrome (ANTARCTIC): an open-label, blinded-endpoint, randomized controlled superiority trial. Lancet 2016;Aug 29:[Epub ahead of print].

Editorial Comment: Sibbing D, Massberg S. Antiplatelet strategies in elderly people: still a long way to go. Lancet 2016;Aug 29:[Epub ahead of print].

Presented by Dr. Gilles Montalescot at the European Society of Cardiology Congress, Rome, Italy, August 28, 2016.

Keywords: Acute Coronary Syndrome, Blood Coagulation Tests, Blood Platelets, ESC Congress, Geriatrics, Myocardial Infarction, Myocardial Revascularization, Percutaneous Coronary Intervention, Platelet Activation, Platelet Function Tests, Stents, Stroke, Thrombosis


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