CHAMGAP
APPROVEDReviewed and approved by the Chamgap Editorial Team (2026-08-07). The draft was written by AI, the existence of all 3 cited sources was verified at the original page, and the verdict passed blind grading and adversarial audit. Methodology v0.7.
Verdict No. 2341 · Search date 2026-08-07 · Methodology v0.7

PFO closure,
does it really help with Reduction of recurrent stroke after a carefully evaluated cryptogenic ischemic stroke?

30-Second Summary
A
Evidence Grade A · 86 · Safety caution
Closure reduces recurrence in selected younger cryptogenic-stroke patients, but atrial arrhythmia and procedural harm must be considered
Atrial fibrillation or flutter occurred in 6.6% versus 0.4% in REDUCE, and new atrial fibrillation in 4.6% versus 0.9% in CLOSE. Device and procedural serious events require specialist selection and follow-up.
What the
research shows
The grade is A. In patients no older than 60 with a carefully evaluated cryptogenic ischemic stroke, REDUCE and CLOSE found fewer recurrent strokes with closure plus antiplatelet therapy than with antiplatelet therapy alone. Rates were 1.4% versus 5.4% over a median 3.2 years in REDUCE and 0 of 238 versus 14 of 235 over a mean 5.3 years in CLOSE. Atrial arrhythmia and procedural complications prevent extrapolation to every person with a PFO.
What the
ads claim
Finding a PFO does not by itself establish an indication for closure. Promotion should disclose the age limit, complete cryptogenic-stroke workup, high-risk anatomy, background antithrombotic treatment, atrial arrhythmia, and procedural risk.
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Useful facts when choosing a product

  • REDUCE used Gore HELEX or CARDIOFORM devices, and both groups received antiplatelet therapy.
  • CLOSE required a large right-to-left shunt or atrial septal aneurysm in patients aged 16 to 60 and allowed 11 approved devices.
  • Name-by-name comparison of all article authors found no shared author. REDUCE was Gore funded and CLOSE was funded by the French Ministry of Health.
  • Verdict 1908 is D with 30 points for migraine, a different indication from prevention of recurrent cryptogenic stroke.
Gap Measurement · Verdict 2341 · A 86
What advertising claims
What independent, higher-quality research supports
△ GAP
01

What the research actually shows

REDUCE randomized 664 patients aged 18 to 59 with a recent cryptogenic ischemic stroke and PFO to closure plus antiplatelet therapy, 441, or antiplatelet therapy alone, 223; 82% had a moderate or large shunt. Serious device-related events occurred in 1.4% and serious procedure-related events in 2.5%. CLOSE ended enrollment with 663 participants, short of its target of 900; the closure comparison was 238 versus 235. The reason enrollment ended was not verified in the original article reviewed here. Procedural complications occurred in 14 of 238 closure patients (5.9%). DEFENSE-PFO randomized 120 high-risk PFO patients at two South Korean centers and received a research grant from the Cardiovascular Research Foundation, Seoul. It provided smaller, directionally consistent Korean evidence.

02

Why this is classified as A (86)

REDUCE and CLOSE measured recurrent stroke in comparable selected populations against antiplatelet therapy and found effects in the same direction. Their author teams did not overlap and their funding sources differed. One pivotal trial was manufacturer funded and one publicly funded, but replicated large hard-outcome evidence without a counted avoidable design defect supports A with 86 points.

Counterpoint. Absolute benefit accrued over years, whereas atrial arrhythmia and procedural harm can occur early. The result cannot be directly extended beyond age 60, to a small shunt alone, or to patients with another plausible stroke cause.

Rejudgment record. Cross-check applied — Direct comparison of REDUCE and CLOSE eligibility, hard outcomes, complete named author lists, distinct funding sources, and absolute harm rates

Scoring profile behind this grade
EndpointHHard endpoint - actual events such as death
ReplicationR2Independently replicated across trials
IndependenceI1Mixed funding sources
Effect sizeE+Meets the clinically important threshold

The scoring table and the verdict agree (A).

Sub-claim grades by effect

This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.

Effect (sub-claim)GradeBasis
Reduction of recurrent stroke in selected patients no older than 60AREDUCE and CLOSE replicated lower absolute event rates.
Prophylactic closure for every person with a PFO?People without a qualifying stroke or with another plausible cause were outside these trials.
Reduction of migraine attacksDThe separate migraine indication in verdict 1908 is D with 30 points and cannot be upgraded by stroke evidence.

Cross-check — Codex and Claude

This verdict was drafted by Codex through literature review and source-existence checks, cross-checked through blind grading and adversarial audit, and settled by reapplying the methodology boundary rules. Cases with split grades were resolved through rejudgment.
03

Evidence Table

StudyDesignSampleFundingEndpointResultWeight
Study 1Multinational randomized open-label trial with blinded endpoint adjudication223Sponsored by W. L. Gore and Associates, which collaborated in design and analysisCoprimary clinical ischemic stroke and new brain infarction; median 3.2 yearsClinical ischemic stroke in 6/441 (1.4%) versus 12/223 (5.4%), HR 0.23 (95% CI 0.09 to 0.62)Pivotal manufacturer-funded hard-outcome trial
Study 2Multicenter randomized open-label trial with blinded endpoint adjudication235French Ministry of Health Hospital Clinical Research ProgramFatal or nonfatal stroke; mean 5.3 years0/238 versus 14/235; new atrial fibrillation 4.6% versus 0.9%; procedural complications 14/238 (5.9%)Independent publicly funded replication trial
Study 3Investigator-initiated randomized trial at two South Korean centers120Research grant from the Cardiovascular Research Foundation, SeoulTwo-year composite of stroke, vascular death, or major bleedingNo primary events with closure versus six with medical therapySmall directionally consistent Korean evidence
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Receipt — 3 References

All 3 cited sources were verified for existence at the original page (as of 2026-08-07).

Søndergaard L, Kasner SE, Rhodes JF, Andersen G, Iversen HK, Nielsen-Kudsk JE, Settergren M, Sjöstrand C, Roine RO, Hildick-Smith D, Spence JD, Thomassen L; Gore REDUCE Clinical Study Investigators. Patent Foramen Ovale Closure or Antiplatelet Therapy for Cryptogenic Stroke. N Engl J Med. 2017;377:1033-1042. PMID: 28902580. DOI: 10.1056/NEJMoa1707404.
checked
Mas JL, Derumeaux G, Guillon B, et al.; CLOSE Investigators. Patent Foramen Ovale Closure or Anticoagulation vs Antiplatelets after Stroke. N Engl J Med. 2017;377:1011-1021. PMID: 28902593. DOI: 10.1056/NEJMoa1705915.
checked
Lee PH, Song JK, Kim JS, et al. Cryptogenic Stroke and High-Risk Patent Foramen Ovale: The DEFENSE-PFO Trial. J Am Coll Cardiol. 2018;71:2335-2342. PMID: 29544871. DOI: 10.1016/j.jacc.2018.02.046.
checked
Draft and rewrite: Codex (AI) · Verification: Codex blind grading and adversarial audit · Final adjudication: Claude
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-08-07 · Corrections: none

Cite this verdict

PFO closure x prevention of recurrent cryptogenic stroke Evidence Grade A card
[Chamgap] PFO closure x prevention of recurrent cryptogenic stroke — Evidence Grade A·86. 3 cited sources checked. Source: https://chamgap.com/en/verdicts/heart/pfo-closure-cryptogenic-stroke-recurrence/ · CC BY 4.0

CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.

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