The Neurosurgery Signal — Signal, Not Noise

Rapid review note

Journal Club is a rapid, AI-assisted appraisal layer. It highlights study design, effect estimates, and practice relevance, but it is still a briefing, not a replacement for the paper.

For education only. Not medical advice.

Paper snapshot

Rapid study overview

Open paper

DOI

10.1001/jama.2011.1610

PMID

22068990

PICO

Population

Patients with recently symptomatic atherosclerotic internal carotid artery occlusion (AICAO) and hemodynamic cerebral ischemia identified by PET OEF >1.130

Intervention

EC-IC bypass surgery (superficial temporal artery to middle cerebral artery anastomosis) plus best medical therapy

Comparator

Best medical therapy alone (antithrombotic therapy and risk factor intervention)

Outcomes

Primary: composite of all stroke/death within 30 days of surgery (or randomization) plus ipsilateral ischemic stroke within 2 years

Design

Type

Parallel-group randomized clinical trial

Randomized

Yes

Multicenter

Yes

Blinded

Open-label with blinded adjudication

Follow-up

2 years with 99% completion

Primary endpoint

Composite of all stroke/death within 30 days of surgery (or randomization) plus ipsilateral ischemic stroke within 2 years

Secondary endpoints

All stroke
Disabling stroke
Fatal stroke
Death
NIHSS
modified Barthel Index
Rankin Scale
SS-QoL

Practice impact

What this means

COSS randomized 195 patients with symptomatic carotid occlusion and PET-confirmed hemodynamic ischemia to EC-IC bypass plus medical therapy vs medical therapy alone. The trial was stopped early for futility with no difference in the primary composite endpoint (21.0% vs 22.7% at 2 years). Bypass surgery carried a significant 30-day stroke risk (14.4% vs 2.0%). This provides high-quality evidence against routine EC-IC bypass for this population.

Bottom line

EC-IC bypass does not reduce 2-year stroke risk in carefully selected patients with hemodynamic ischemia from carotid occlusion

Strength of evidence

high

Recommendation

do not change

Why it matters

Randomized trial with 195 patients showed no benefit (21.0% vs 22.7% primary endpoint)
Higher perioperative stroke risk (14.4% at 30 days)
Consistent with previous EC-IC bypass trial negative results

What would change my mind

New trial showing benefit with different patient selection (e.g., different imaging criteria)
Long-term follow-up showing late benefit beyond 2 years
Subgroup analysis identifying responders missed in this trial

Critical appraisal

How strong is the paper?

Methods critique

Risk of bias

Low risk: multicenter randomized design with blinded adjudication of outcomes, 99% follow-up completion

Confounding

Minimal: randomization with stratification for clinical site and contralateral carotid stenosis

Missing data

Minimal: only 1% lost to follow-up, intention-to-treat analysis

Multiplicity

Appropriate: primary endpoint clearly defined, trial stopped early for futility based on pre-specified criteria

Notes

Early termination for futility at interim analysis
Surgical certification required for neurosurgeons

Stats check

NNT

Not applicable: no benefit demonstrated

Effect sizes

Primary endpoint difference 1.7% (95% CI -10.4% to 13.8%)
30-day ipsilateral stroke difference 12.4% (95% CI 4.9% to 19.9%)

Absolute effects

2-year primary event rate: surgical 21.0% (20/97), nonsurgical 22.7% (20/98)
30-day ipsilateral stroke: surgical 14.4% (14/97), nonsurgical 2.0% (2/98)

Concerns

Early termination reduces precision of estimates
Higher 30-day stroke risk in surgical group

External validity

Who it applies to

Patients with symptomatic carotid occlusion and PET-confirmed hemodynamic ischemia (OEF >1.130) within 120 days of symptoms

Who it does not

Patients without PET-confirmed hemodynamic compromise, asymptomatic occlusions, or non-atherosclerotic occlusions

Generalizability notes

Requires specialized PET imaging not widely available
49 US/Canada centers mostly academic

Evidence trace

Source trace and metadata

Citations (3)

claim_id

methods_critique.risk_of_bias

locator

p. 2 Methods

quote

Parallel group, randomized, open-label, blinded-adjudication clinical treatment trial

claim_id

stats_check.effect_sizes

locator

p. 1 Results

quote

Two-year rates for the primary endpoint were 21.0% (95% CI, 12.8% to 29.2%; 20 events) for the surgical group and 22.7% (95% CI, 13.9% to 31.6%; 20 events) for the nonsurgical group (P = .78, Z test), a difference of 1.7% (95% CI, -10.4%...

claim_id

practice_impact.bottom_line

locator

p. 1 Conclusions

quote

EC-IC bypass surgery plus medical therapy compared with medical therapy alone did not reduce the risk of recurrent ipsilateral ischemic stroke at 2 years

Metadata

Generated at

2026-03-06T13:41:29.251Z

Version

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