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Journal Club

Cerebrovascular

The POST trial: initial post-market experience of the Penumbra system: revascularization of large vessel occlusion in acute ischemic stroke in the United States and Europe

Journal of NeuroInterventional Surgery | 2018

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

10.1136/jnis.2010.002600.rep

PMID

N/A

PICO

Population

One hundred fifty-seven consecutive on-label patients with acute ischemic stroke and large-vessel occlusion treated with the Penumbra system at seven international centers after approval.

Intervention

Mechanical thrombectomy with the Penumbra system, with adjunctive intravenous and or intra-arterial rtPA at operator discretion.

Comparator

Historical comparison with the Penumbra Pivotal trial and within-cohort comparison of successfully revascularized versus unrevascularized vessels.

Outcomes

TIMI 2-3 revascularization, modified Rankin Scale score of 2 or less at 90 days, procedural serious adverse events, symptomatic intracerebral hemorrhage, and death.

Design

Type

Retrospective multicenter post-market case review with historical comparison

Randomized

No

Multicenter

Yes

Blinded

N/A

Follow-up

90 days

Primary endpoint

Target-vessel revascularization to TIMI 2 or 3, good functional outcome at 90 days, and procedural serious adverse events.

Secondary endpoints

  • Symptomatic intracerebral hemorrhage within 24 hours
  • All-cause death at 90 days
  • Outcomes stratified by successful versus failed revascularization

Practice impact

What this means

The POST trial was a retrospective, seven-center, real-world check on the early Penumbra thrombectomy experience. Revascularization was high at 87%, serious procedural events were uncommon at 5.7%, and 41% of patients reached mRS 2 or less at 90 days, which looked better than the historical Pivotal trial. The catch is that this was not a randomized comparison, so it is a useful reassurance study, not a definitive practice-changing trial.

Bottom line

This early post-market series suggests that the Penumbra system can reproduce high recanalization with acceptable safety in routine on-label practice, but the retrospective historical comparison is not strong enough by itself to change stroke thrombectomy protocols.

Strength of evidence

low

Recommendation

do not change

Why it matters

  • Revascularization remained high at 87%, with 41% achieving functional independence and 20% mortality at 90 days.
  • Patients with successful revascularization had materially better outcomes than those with failed revascularization.
  • Confidence is limited because the comparison was retrospective, nonrandomized, and not adjudicated by a core laboratory.

What would change my mind

  • A prospective multicenter study with contemporaneous controls and core-laboratory TIMI adjudication showing the same functional advantage.
  • Evidence that patient-selection factors such as infarct-core or penumbra imaging do not explain the better outcomes seen in POST.

Critical appraisal

How strong is the paper?

Methods critique

Risk of bias

This was a retrospective post-market review benchmarked against a separate historical pivotal cohort, so selection bias and noncontemporaneous comparison are major limitations.

Confounding

Case mix, workflow, and adjunctive lytic use could vary across seven centers and versus the Pivotal trial, and there was no randomization or core-laboratory adjudication.

Missing data

The report does not describe losses to 90-day follow-up or missing functional assessments, so completeness of retrospective outcome capture cannot be judged from the paper.

Multiplicity

Multiple endpoints and subgroup comparisons were analyzed with Fisher exact testing without a reported correction for multiple comparisons.

Notes

  • Investigators enrolled the first 157 on-label patients treated after approval to reduce selection bias, and off-label cases were excluded.
  • Perfusion or core-penumbra imaging was not routinely available across sites, limiting adjustment for baseline infarct biology.

Stats check

NNT

N/A

Effect sizes

  • TIMI 2-3 revascularization was achieved in 87% of POST patients versus 82% in the Pivotal trial.
  • Good 90-day outcome, defined as mRS 2 or less, occurred in 41% of POST patients versus 25% in the Pivotal trial (p<0.05).
  • Among POST patients, open vessels after treatment were associated with lower 90-day mortality and better function than closed vessels: death 16% versus 50% and mRS 2 or less 45% versus 13% (p<0.01).

Absolute effects

  • Nine procedural serious adverse events occurred in 157 patients, for a rate of 5.7%.
  • All-cause mortality at 90 days was 20% in POST (32 of 157) versus 33% in the Pivotal trial.
  • Symptomatic intracerebral hemorrhage occurred in 6.4% of POST patients versus 11% in the Pivotal trial.

Concerns

  • The headline improvements are based on comparison with a historical cohort rather than a concurrent control group.
  • TIMI scoring was performed locally without a core laboratory, which can introduce measurement variability.
  • The study could not identify why functional outcomes were better than in the Pivotal trial, and the authors call for prospective confirmation.

External validity

Who it applies to

Centers using the Penumbra system for on-label large intracranial vessel occlusion in acute ischemic stroke.

Who it does not

Off-label thrombectomy cases or patients whose selection depends on advanced core-penumbra imaging not captured in this report.

Generalizability notes

  • The study spans seven centers in the United States and Europe, which improves transportability compared with a single-center report.
  • Because procedures were done according to local standard of care, the series reflects pragmatic post-market use.
  • Target-vessel distribution differed somewhat from the Pivotal trial, with more vertebrobasilar occlusions in POST.

Evidence trace

Source trace and metadata

Citations (13)

claim_id

methods_critique.risk_of_bias

locator

p. 1; p. 2; p. 4

claim_id

methods_critique.confounding

locator

p. 2 Table 3; p. 3 Table 6; p. 4

claim_id

methods_critique.missing_data

locator

p. 2; p. 4

claim_id

methods_critique.multiplicity

locator

p. 2; p. 3 Table 5; p. 3 Table 6

claim_id

methods_critique.notes

locator

p. 2; p. 4

claim_id

stats_check.effect_sizes

locator

p. 2 Table 4; p. 3 Table 5

claim_id

stats_check.absolute_effects

locator

p. 2 Table 4; p. 3

claim_id

stats_check.nnt

locator

p. 2 Table 4; p. 4

claim_id

stats_check.concerns

locator

p. 4

claim_id

practice_impact.bottom_line

locator

p. 3; p. 4

claim_id

practice_impact.strength_of_evidence

locator

p. 4

claim_id

practice_impact.recommendation

locator

p. 3; p. 4

claim_id

practice_impact.rationale

locator

p. 2 Table 4; p. 3 Table 5; p. 4

Metadata

Generated at

2026-03-08T20:55:00Z

Version

manual-pdf-repair-v1