What is the clinical evidence from this study?

Study design: Cohort. Population: Nonvalvular atrial fibrillation (n=290). Intervention: Aspirin vs. No aspirin (prior 12-month observation period). Primary outcome: Annual incidence of new silent brain lesions on MRI (p=0.014).

January 1, 2004Open Access

Aspirin Attenuates the Incidence of Silent Brain Lesions in Patients With Nonvalvular Atrial Fibrillation

Key Result

Aspirin reduced the annual incidence of new silent brain lesions from 20.6% to 9.6% compared to an untreated observation period in patients with nonvalvular atrial fibrillation.

Study Design

Type

Cohort (n=290)

Multicenter

Yes

Structured PICO

Does aspirin reduce the incidence of silent brain lesions in patients with nonvalvular atrial fibrillation?

Population

290 adults under 80 years of age with nonvalvular atrial fibrillation or normal sinus rhythm, free of prior stroke, followed for up to 2 years to assess the incidence of silent brain lesions.

Intervention

Aspirin 330 mg oral daily administered during the second year of follow-up.

Comparator

The first year of follow-up where patients received neither antiplatelet agent nor anticoagulant (self-controlled before-after design).

Outcome

Incidence of new silent brain lesions observed by cranial MRI.surrogate

In patients with nonvalvular atrial fibrillation, aspirin treatment may be effective in preventing the occurrence of new small silent brain lesions observed on MRI.

Main Result

Absolute Event Rate: 9.6% vs 20.6%

p-value: p=0.014

Limitations

Non-randomized study design with potential treatment bias between the two observation years
Substantial selection bias in recruiting control subjects and NVAF patients
MRI instruments and magnetic field strength differed across participating institutions

Abstract

BACKGROUND: Abnormal findings, including silent cerebral infarction, are frequently observed by magnetic resonance imaging (MRI) in patients with nonvalvular atrial fibrillation (NVAF); however, the prevalence and prevention strategy for these lesions have not been extensively studied. In the present study the preventive effects of aspirin on silent ischemic lesions was investigated. METHODS AND RESULTS: Silent lesions were counted using cranial MRI performed in 78 neurologically normal adults with sinus rhythm and in 212 patients with NVAF without a history of stroke. MRIs were repeated twice in the NVAF patients at 12-month intervals. During the first year, patients received neither antiplatelet agent nor anticoagulant; in the second year, aspirin (330 mg daily) was administered. The prevalence of lesions in the initial MRI was higher in NVAF patients (86.4%) than in sinus rhythm subjects (53.8%; p<0.001). After 12 months without aspirin, new lesions were seen in 20.6% of NVAF patients. The yearly occurrence of new lesions was decreased to 9.6% during the year of treatment with aspirin (p=0.014). CONCLUSIONS: In patients with NVAF, abnormal lesions are frequently observed by MRI and aspirin treatment may be effective in preventing further small silent lesions.

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