Asymptomatic Carotid Stenosis

  • Both symptomatic and asymptomatic Carotid Artery Stenosis were treated.
  • Only highly experienced interventionist did the procedure
  • Study looked for CAS vs CEA; No medical therapy alone arm was present
  • During periprocedural period:
    • CAS: Higher risk of stroke
    • CEA: Higher risk of MI 
  • Long term no difference in 4 yrs
  • Also, observed was 
    • Older patient had increased risk with CAS; CEA better in older patient; Similar observation in SPACE trial as well. 
    • Mechanisms underlying the increased risk with carotid-artery stenting in very elderly patients probably include vascular tortuosity and severe vascular calcification 

CREST 10 yr Follow Up : NEJM 2016

ACT 1 Study NEJM 2016
  • Asymptomatic patient only
  • With Severe Stenosis 
  • CEA vs CAS; Medical therapy arm was not included
  • No Difference at upto 5 yr follow up 
ACT 1 NEJM 2016

Editorial Summary of CREST 10 yr follow up and ACT 1
  • 5 yr risk of ipsilateral stroke (excluding the perioperative period) was 0.4% per year after stenting and 0.5 % per year  after endarterectomy
  • CREST 10 yr follow up: 0.7% per year after CAS, and 0.6% per year after CEA
  • CREST 10 yr follow up resolves the question of long term outcome in CAS vs CEA, and that it does not differ 
  • Note: Perioperative risk was very low in these studies as they used the best interventionist. That is not the case in real world. Thus for symptomatic patient, is CEA or CAS better, will depend on the preoperative risk of these procedure. 
  • ACT 1 did not include the medical therapy arm. No true data to say either is better than Medical therapy alone 
  • Evidence now suggests that the annual rate of ipsilateral stroke may be as low as 0.5 to 1% — a rate that is very similar to that observed in ACT I and CREST after successful stenting or endarterectomy 
  • Hence, editors point out - "interventions may be appropriate if they can be performed with a risk of less than 3%, are based on historical data from randemised trials that were completed decades ago and that should now be considered obsolete" 
  • Outside clinical trials, endarterectomy and stenting should be reserved for patients with symptomatic severe stenosis or for asymptomatic patients who are shown to be at higher risk for stroke with medical therapy than with intervention. Such patients (approximately 10 to 15% of patients with asymptomatic stenosis of 70 to 99%) may be identified by an algorithm that in- corporates information about micro emboli detected by means of transcranial Doppler and in the future by imaging strategies that identify the vulnerable plaque 
  • Ref

Stroke Risk: 4 % per annum. 
  • Hence, not a urgent referral. Referral to a center of excellence is reasonable. 
Waiting for results of the following study
  • CANOPY (Abott)
    • asymptomatic > 60 % 
    • 3.3 % death, all stroke, 
    • >80 yr : 3.3 % death and all CVA 
      • Contrast this results to CREST. 
    • (asymptomatic > 70% stenosis)
    • (asymptomatic > 70 %)
  • SPACE 2 
    • Medical vs Procedure
    • Study abandoned due to poor recruitment 
    • Medical vs revascularization (CEA or Stenosis) 
Risk of Ipsilateral Stroke in MT vs CEA 
Major Drawback: These studies were done at a time when current aggressive medical therapy were not present, except for ACST (2010)

CEA vs CAS; CEA vs MT