Asymptomatic Carotid Trial I - ACT I

Mar 17, 2016
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Author/Summarized by Author:
Anthony A. Bavry, MD, MPH, FACC
Summary Reviewer:
Deepak L. Bhatt, MD, MPH, MBA, FACC
Trial Sponsor:
Abbott Vascular
Date Published:
02/17/2016
Original Posted Date:
03/17/2016
References

Description:

The goal of the trial was to evaluate treatment with carotid artery stenting with embolic protection compared with carotid endarterectomy among asymptomatic patients with carotid artery stenosis.

Contribution to the Literature: The ACT I trial showed that carotid artery stenting for asymptomatic carotid artery stenosis was noninferior to carotid endarterectomy.

Study Design

  • Randomized
  • Parallel

Asymptomatic subjects with carotid artery stenosis were randomized to carotid artery stenting with embolic protection (n = 1,089) versus carotid endarterectomy (n = 364). All patients received aspirin and those who underwent stenting received clopidogrel 3 days before and 30 days after.

  • Total number of enrollees: 1,453
  • Duration of follow-up: 4 years
  • Mean patient age: 68 years
  • Percentage female: 39%
  • Percentage diabetics: 36%

Inclusion criteria:

  • Asymptomatic subjects with carotid artery stenosis (70-99% stenosis)
  • 79 years of age or younger
  • Considered not to be at high risk for operative complications

Exclusion criteria:

  • Stroke, transient ischemic attack (TIA), or amaurosis fugax within 180 days prior to enrollment

Principal Findings:

The primary outcome—death, stroke, or myocardial infarction within 30 days or ipsilateral stroke within 1 year—occurred in 3.8% of the carotid stent group versus 3.4% of the carotid endarterectomy group (p for noninferiority = 0.01).

Secondary outcomes:

  • Death or major stroke: 0.6% vs. 0.6%
  • Freedom from ipsilateral stroke from 30 days to 5 years: 97.8% vs. 97.3% (p = 0.51), respectively for stenting vs. surgery
  • Overall survival: 93.1% vs. 94.7% (p = 0.21), respectively for stenting vs. surgery

Interpretation:

Among asymptomatic patients with carotid artery stenosis, carotid artery stenting with embolic protection was noninferior to carotid endarterectomy. Long-term outcomes were similar between the groups. This trial is distinct from the CREST trial, which enrolled symptomatic and asymptomatic patients, but also documented similar results between treatment strategies. Among asymptomatic patients who are low risk for adverse events, current guidelines support carotid revascularization. An important limitation of the current trial is lack of a control arm treated with contemporary medical therapy. This is an important consideration because the risk of stroke from asymptomatic carotid stenosis on optimal medical therapy is <1% per year.

References:

Rosenfield K, Matsumura JS, Chaturvedi S, et al. Randomized Trial of Stent Versus Surgery for Asymptomatic Carotid Stenosis. N Engl J Med 2016;374:1011-20.

Keywords: Aspirin, Cardiac Surgical Procedures, Carotid Stenosis, Constriction, Pathologic, Endarterectomy, Carotid, Ischemic Attack, Transient, Myocardial Infarction, Myocardial Revascularization, Secondary Prevention, Stents, Stroke, Ticlopidine, Vascular Diseases


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