# PROTECT AF

Study · id `cardio:protect-af` · Cardiovascular Atlas · release `f6f6f1b6f50379ed` (public)

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Also called: WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation

Browse, organ or system: Heart  
Browse, condition area: Stroke; Heart rhythm problems  

## In plain language

A trial that compared closing off the left atrial appendage with the WATCHMAN device against warfarin, in adults with non-valvular atrial fibrillation who were eligible for warfarin. For stroke, cardiovascular death and clots elsewhere in the body, the device group did not do worse than the warfarin group. Serious safety events, mostly linked to the procedure, were more common with the device.

## Technical summary

ClinicalTrials.gov NCT00129545, a randomized, parallel-group study with no masking, listed with phases 2 and 3, sponsored by Boston Scientific Corporation, completed 2014-05. The main report is Holmes et al. 2009;374(9689):534-42 (abstract read only; the journal is on the cited PubMed record). The abstract names Atritech as funder; the registry lists Boston Scientific Corporation as lead sponsor, and the sources do not say how the two relate. PubMed links an erratum (2009 Nov 7;374(9701):1596) that was not read. Enrollment differs by source: the registry gives 800, which includes up to three non-randomized roll-in subjects per site, and the abstract says 707 eligible patients were randomly assigned; this is a difference in what is counted, and is not reconciled further. The registry start and completion dates carry no actual-or-estimated type for the start. No structured findings are recorded here; the numbers are on the claim.

## Key facts

- Design: Multicentre, randomized, non-inferiority trial with unmasked allocation 2:1 to the device or warfarin, plus a non-randomized roll-in group (registry). Analysis by intention to treat (abstract).
- Phase: Phase 2/3
- Enrolled: 800 participants (enrolled count; WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation (PROTECT AF), snapshot `cardio:ctgov-nct00129545-2026-10-14`, retrieved 2026-10-14); 707 patients (randomized count; Percutaneous closure of the left atrial appendage versus warfarin therapy for prevention of stroke in patients with atrial fibrillation: a randomised non-inferiority trial, snapshot `cardio:pubmed-19683639-2026-10-14`, retrieved 2026-10-14)
- Started: 2005-02 (WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation (PROTECT AF), snapshot `cardio:ctgov-nct00129545-2026-10-14`, retrieved 2026-10-14)
- Primary completion: 2013-08 (actual) (WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation (PROTECT AF), snapshot `cardio:ctgov-nct00129545-2026-10-14`, retrieved 2026-10-14)
- Completion: 2014-05 (actual) (WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation (PROTECT AF), snapshot `cardio:ctgov-nct00129545-2026-10-14`, retrieved 2026-10-14)
- Results first posted: 2015-05-15 (WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation (PROTECT AF), snapshot `cardio:ctgov-nct00129545-2026-10-14`, retrieved 2026-10-14)
- Countries: United States; Czechia; Germany (WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation (PROTECT AF), snapshot `cardio:ctgov-nct00129545-2026-10-14`, retrieved 2026-10-14)
- Care setting: Not reported
- Registry status: "COMPLETED" (U.S. National Library of Medicine (ClinicalTrials.gov), snapshot `cardio:ctgov-nct00129545-2026-10-14`, retrieved 2026-10-14)

## Connected pages

- Tests the WATCHMAN device against warfarin: WATCHMAN left atrial appendage closure device (`cardio:watchman`)
- Lists atrial fibrillation as its first condition: Atrial fibrillation (AF) (`cardio:atrial-fibrillation`)
- Lead sponsor on the registry record: Boston Scientific (`cardio:boston-scientific`)
- Tests left atrial appendage closure: Left atrial appendage occlusion (`cardio:left-atrial-appendage-occlusion`)

## Provenance

Content hash: 23fbdfc7ef2187d71fb49829b5160a629fa4bf4837564168349a896fd249f9fe
Last substantive edit: 2026-10-15
Evidence last checked: 2026-10-14