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ICSS

Long-term outcomes after stenting versus endarterectomy for treatment of symptomatic carotid stenosis: the International Carotid Stenting Study (ICSS) randomised trial

Year of Publication: 2015

Authors: Leo H Bonati, Joanna Dobson, Roland L Featherstone, ..., for the International Carotid Stenting Study investigators

Journal: The Lancet

Citation: Lancet 2015; 385: 529-38

Link: https://www.thelancet.com/action/showPdf...%2814%2961184-3

PDF: https://www.thelancet.com/action/showPdf...%2814%2961184-3

Clinical Question

What are the long-term outcomes of carotid artery stenting versus endarterectomy for treatment of symptomatic carotid stenosis?

Bottom Line

Stenting and endarterectomy have similar long-term functional outcomes and risk of fatal or disabling stroke in patients with symptomatic carotid stenosis up to 10 years after treatment.

        Major Points
        Primary endpoint of fatal or disabling stroke showed no significant difference between stenting and endarterectomy (6.4% vs 6.5% at 5 years, HR 1.06, p=0.77)
Stenting associated with higher risk of any stroke (15.2% vs 9.4% at 5 years, HR 1.71, p<0.001), mainly non-disabling strokes
Functional outcomes measured by modified Rankin scale were similar between treatment groups at 1 year, 5 years, and final follow-up
No significant difference in all-cause mortality between groups
Severe carotid restenosis rates were similar between groups (10.8% vs 8.6% at 5 years)

      

Design

Study Type: Randomized controlled trial

Randomization: 1

Blinding: Independent endpoint committee unaware of treatment assignment; patients and investigators not masked

Enrollment Period: May 2001 to October 2008

Follow-up Duration: Median 4.2 years (maximum 10 years)

Centers: 50

Countries: Europe, Australia, New Zealand, Canada

Sample Size: 1713

Analysis: Intention-to-treat and per-protocol analysis. Kaplan-Meier estimates, Cox proportional hazards models

Inclusion Criteria

Age >40 years
Symptomatic atherosclerotic carotid stenosis causing ≥50% reduction in carotid artery lumen diameter
Deemed equally suited for both treatments

Exclusion Criteria

Major stroke or previous treatment with carotid stenting or endarterectomy
Contraindications to stenting or surgery
Stenosis caused by non-atherosclerotic disease
Life expectancy <2 years
Scheduled for major surgery within 1 month

Baseline Characteristics

Characteristic	Control	Active
Age (years)	70 (9)	70 (9)
Male sex	606 (71%)	601 (70%)
Treated hypertension	596 (70%)	587 (69%)
Systolic blood pressure (mm Hg)	146 (24)	147 (24)
Cardiac failure	47 (5%)	23 (3%)
Previous myocardial infarction	156 (18%)	151 (18%)
Type 2 diabetes	147 (17%)	134 (16%)
Current smoker	198 (23%)	205 (24%)
Degree of symptomatic carotid stenosis 70-99%	781 (91%)	761 (89%)
Most recent ipsilateral event - Ischaemic hemispheric stroke	376 (44%)	393 (46%)
Modified Rankin score 0-2 at randomisation	744 (87%)	756 (89%)

Arms

Field	Stenting	Control
Intervention	Carotid artery stenting with cerebral protection devices chosen at discretion of interventionist, CE marked and approved by steering committee	Standard or eversion endarterectomy under local or general anaesthesia, with or without shunts and patches
Duration	Single procedure with long-term follow-up	Single procedure with long-term follow-up

Outcomes

Outcome	Type	Control	Intervention	HR / OR / RR	P-value
Fatal or disabling stroke in any territory after randomisation	Primary	49 events, 6.5% cumulative 5-year risk	52 events, 6.4% cumulative 5-year risk	1.06	0.77
Any stroke	Secondary	72 events, 9.4% cumulative 5-year risk	119 events, 15.2% cumulative 5-year risk	1.71	<0.001
All-cause death	Secondary	129 events, 17.2% cumulative 5-year risk	153 events, 17.4% cumulative 5-year risk	1.17	0.19
Procedural stroke or procedural death or ipsilateral stroke during follow-up	Secondary	57 events, 7.2% cumulative 5-year risk	95 events, 11.8% cumulative 5-year risk	1.72	<0.01
Non-disabling stroke	Adverse	27 events	73 events

Subgroup Analysis

No significant effects of patient baseline characteristics on comparison of stenting and endarterectomy. Age was independent predictor of stroke risk in stenting patients.

Criticisms

Carotid stenting was relatively new procedure when ICSS started, limiting experience
Unable to account for causes of functional decline over time other than endpoint events
Modified Rankin scale not precise measure of independence level
Trial not powered to detect variations in treatment effects between subgroups
Cannot rule out subtle differences in functional outcome not captured by modified Rankin scale

Funding

Medical Research Council, Stroke Association, Sanofi-Synthélabo, European Union

Based on: ICSS (The Lancet, 2015)