Journal Club Ani Balmanoukian and Peter Benjamin November 9, 2006 by termo

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									Journal Club
Ani Balmanoukian and
   Peter Benjamin

 November 9, 2006
   Endarterectomy versus
  Stenting in Patients with
Symptomatic Severe Carotid
          Stenosis
             Mas et al.
    NEJM 355;16 October 19, 2006
Background
   Carotid Endarterectomy is the standard
    treatment for symptomatic or asymptomatic
    high-grade(> 60% or 70%) internal carotid
    artery stenosis.

   Carotid artery stenting has become another
    option
Carotid Endarterectomy
   NASCET and ECST
    trials have demonstrated
    the efficacy in
    symptomatic patients

   Complications include
    local nerve injury and
    stroke


                               www.vascular.co.nz
Carotid Stenting
   Less invasive than CEA
   Can be done under local
    anesthesia and sedation
   Less costly than CEA
   Risk of stroke and local
    complications
   Long term efficacy not
    well known yet

                         http://radinfo.musc.edu/~stringes/carotidimage25.jpg
   Hypothesis/Goal: Evaluate whether stenting is
    not inferior to endarterectomy with regard to
    the risks of the procedure and long-term efficacy
    in patients with symptomatic carotid stenosis.

   Design: Randomized, noninferiority trial.

   Setting: 20 academic and 10 non-academic
    centers in France.
   Investigators: Each center had to have a team of
    physicians consisting of
       1 Neurologist
       1 Vascular surgeon: had to have performed at least
               25 CEAs
       1 Interventional physician: had to have performed
               at least 12 carotid stenting procedures or at
               least 35 stenting procedures in the
               supraaortic trunks, of which 5 were in the
               carotid artery.
   Participants: 527 patients >18 y/o, with history of a
        hemispheric or retinal TIA or a nondisabling stroke
        within 120 days before enrollment.
        Stenosis of 60-99% in the symptomatic carotid
    artery.

        Exclusion: disabling stroke, nonatherosclerotic
    carotid disease, previous revascularization, bleeding
    disorder, uncontrolled HTN or diabetes, unstable
    angina, life expectancy <2 years.
Figure 1.
Mas et al, Endarterectomy vs. stenting in
patients with symptomatic severe carotic
stenosis. NEJM 2006;355:1660-71
   Data Collection: Evaluation by Neurologist at 48 hrs, 30 days,
    6 months after treatment and 6 months thereafter.


   Outcome:
         Primary: Any stroke or death occurring within 30 days after
    treatment.
         Secondary: MI, TIA, cranial nerve injury, major local
    complications, and systemic complications within 30 days.


   Analysis: Kaplan-Meier method, intention to treat principle.
Table 1. Baseline Characteristics of the Patients.

Key Points
• Patients overall very similar
• Only differences:
      • More patients older than 75 yo in CEA group (40.5%
        vs. 32.2%)
      • More patients with h/o stroke in CEA group
        (20.1% vs 12.6%)
      • Higher proportion of contralateral carotid occlusion
        in stenting group (none of these had a stroke after
        stenting)
Table 3: Risk of stroke or death and other outcomes
within 30 days

Key Points:
• Unadjusted RR of stroke/death is 2.5 for stenting vs CEA
  (Number Needed to Harm: 17)

• No significant correlation between RR of stroke/death and
  number of patients treated at each center

• No significant difference in stroke/death outcomes
  between interventionalists who were experienced, tutored
  during training, tutored after training

• Decreased incidence in stroke/death in pts who had
  cerebral protection along with stenting vs stenting alone

• RR stroke/death adjusted for age was 2.4, h/o stroke 2.6

• Cranial nerve injury much more likely with CEA (7.7% vs
  1.1%)
       Conclusions/Implications
   In pts with symptomatic carotid stenosis >60%,
    CEA has lower rates of stroke/death through 6
    months
   These results agree with some (e.g. SPACE), but
    not all (e.g. SAPPHIRE) prior studies
   Taken together, pending further evidence,
    stenting should be limited to symptomatic pts
    with >70% stenosis who are high surgical risk
Strengths
   Large, Multicenter RCT
   All patients accounted for at conclusion
   Groups were similar at start of trial
Weaknesses
   Required minimal experience for
    interventionalists doing procedure
   Didn’t indicate differences in complications
    based on experience
   Anesthesiology or periop differences?
   No standardization of stenting device used (5
    different stents, 7 different cerebral protection
    systems used)
Discussion
   What are unique aspects of a noninferiority trial
   What is the significance of an intention to treat
    analysis
   Intricacies in a surgical rct that are unique
     How to minimize differences in
      surgeon/interventionalist experience?
     How to minimize effects of other aspects (e.g.
      anesthesia, postop care, etc)
     Can you standardize experience level differences
      between CEA and carotid stenting?
     Any way to blind such a trial?
References
   Mas JL et al. Endarterectomy versus stenting in
    patients with symptomatic severe carotid
    stenosis. N Engl J Med. 2006 Oct
    19;355(16):1660-71.

   North American Symptomatic Carotid
    Endarterectomy Trial Collaborators. Beneficial
    effect of carotid endarterectomy in symptomatic
    patients with high-grade carotid stenosis. N Engl
    J Med 1991; 325:445-53.

								
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