This is the current release of the guideline.

Definitions of the strength of the recommendations (A, B, C, U) and classification of the evidence (Class I through Class IV) are provided at the end of the "Major Recommendations" field.

Practice Recommendations

For patients who have had a cryptogenic stroke and have a patent foramen ovale (PFO), the evidence indicates that the risk of subsequent stroke or death is no different from other cryptogenic stroke patients without PFO when treated medically with antiplatelet agents or anticoagulants. Therefore, in persons with a cryptogenic stroke receiving such therapy, neurologists should communicate to patients and their families that presence of PFO does not confer an increased risk for subsequent stroke compared to other cryptogenic stroke patients without atrial abnormalities (Level A). However, it is possible that the combination of PFO and atrial septal aneurysm (ASA) confers an increased risk of subsequent stroke in medically treated patients who are less than 55 years of age. Therefore, in younger stroke patients, studies that can identify PFO or atrial septal aneurysm (ASA) may be considered for prognostic purposes (Level C).

Among patients with a cryptogenic stroke and atrial septal abnormalities, there is insufficient evidence to determine the superiority of aspirin or warfarin for prevention of recurrent stroke or death (Level U), but the risks of minor bleeding are possibly greater with warfarin (Level C). There is insufficient evidence regarding the effectiveness of either surgical or percutaneous closure of PFO (Level U).

Definitions:

Rating of Recommendations

A = Established as effective, ineffective, or harmful for the given condition in the specified population.

B = Probably effective, ineffective, or harmful for the given condition in the specified population.

C = Possibly effective, ineffective, or harmful for the given condition in the specified population.

U = Data inadequate or conflicting. Given current knowledge, treatment (test, predictor) is unproven.

Translation of Evidence to Recommendation

Level A rating requires at least two consistent Class I studies*.

Level B rating requires at least one Class I study or two consistent Class II studies.

Level C rating requires at least one Class II study or two consistent class III studies.

Level U rating for studies not meeting criteria for class I– class III.

*Note: In exceptional cases, one convincing Class I study may suffice for an "A" recommendation if 1) all criteria met, 2) magnitude of effect >5, and 3) narrow confidence intervals (lower limit >2).

Rating of Therapeutic Article

Class I: Prospective, randomized, controlled clinical trial (RCT) with masked outcome assessment, in a representative population. The following are required:

1. Primary outcome(s) is/are clearly defined.
2. Exclusion/inclusion criteria are clearly defined.
3. Adequate accounting for dropouts and crossovers with numbers sufficiently low to have minimal potential for bias.
4. Relevant baseline characteristics are presented and substantially equivalent among treatment groups or there is appropriate statistical adjustment for differences.

Class II: Prospective matched group cohort study in a representative population with masked outcome assessment that meets a–d above OR an RCT in a representative population that lacks one criteria a–d.

Class III: All other controlled trials (including well-defined natural history controls or patients serving as own controls) in a representative population, where outcome is independently assessed, or independently derived by objective outcome measurement.

Class IV: Evidence from uncontrolled studies, case series, case reports, or expert opinion.

Note: Objective outcome measurement – an outcome measure that is unlikely to be affected by an observer's (patient, treating physician, investigator) expectation or bias (e.g., blood tests, administrative outcome data).

Rating of Prognostic Article

Class I: Evidence provided by a prospective study of a broad spectrum of persons who may be at risk for developing the outcome (e.g., target disease, work status). The study measures the predictive ability using an independent gold standard for case definition. The predictor is measured in an evaluation that is masked to clinical presentation and the outcome is measured in an evaluation that is masked to the presence of the predictor.

Class II: Evidence provided by a prospective study of a narrow spectrum of persons at risk for having the condition, or by a retrospective study of a broad spectrum of persons with the condition compared to a broad spectrum of controls. The study measures the prognostic accuracy of the risk factor using an acceptable independent gold standard for case definition. The risk factor is measured in an evaluation that is masked to the outcome.

Class III: Evidence provided by a retrospective study where either the persons with the condition or the controls are of a narrow spectrum. The study measures the predictive ability using an acceptable independent gold standard for case definition. The risk factor is measured in an evaluation that is masked to the outcome.

Class IV: Any design where the predictor is not applied in a masked evaluation OR evidence provided by expert opinion or case series without controls.

None provided

The type of supporting evidence is identified and graded for each recommendation (see "Major Recommendations").

Not applicable: The guideline was not adapted from another source.

2004 Apr 13

American Academy of Neurology - Medical Specialty Society

American Academy of Neurology (AAN)

Quality Standards Subcommittee of the American Academy of Neurology

AAN Quality Standards Subcommittee Members: Gary Franklin, MD, MPH (co-chair); Gary Gronseth, MD (co-chair); Charles Argoff, MD; Christopher Bever, Jr., MD; Jody Corey-Bloom, MD, PhD; John England, MD; Gary Friday, MD; Michael Glantz, MD; Deborah Hirtz, MD; Donald Iverson, MD; David Thurman, MD; Samuel Weibe, MD; William Weiner, MD; Stephen Ashwal, MD (ex-officio); Jacqueline French, MD (ex-officio); Catherine Zahn, MD (ex-officio)

Not stated

This is the current release of the guideline.

None available

This NGC summary was completed by ECRI on August 17, 2004. The information was verified by the guideline developer on September 9, 2004. This summary was updated by ECRI on March 6, 2007 following the U.S. Food and Drug Administration (FDA) advisory on Coumadin (warfarin sodium). This summary was updated by ECRI Institute on September 7, 2007 following the revised U.S. Food and Drug Administration (FDA) advisory on Coumadin (warfarin).

This NGC summary is based on the original guideline, which is copyrighted by the American Academy of Neurology.