title: Clinical and echocardiographic measures governing thromboembolism destination in atrial fibrillation.
abstract: Although infrequent, embolic occlusion to non-cerebral arteries may result in limb loss, organ failure, and death. The aim of this study was to define clinical and echocardiographic characteristics determining thromboembolism destination in non-valvular atrial fibrillation. An inception cohort of individuals (n=72) were identified with incident peripheral embolism in the setting of non-valvular atrial fibrillation (1995-2005). A randomly selected group of atrial fibrillation related stroke patients (n=100) were identified for comparison. Arteries of the extremities were the most common site of embolism (85%); lower extremity involvement was twice as common compared with the upper extremity. Clinical features distinguishing peripheral embolism from stroke included age>75, heart failure and hypertension. Severe left ventricular dysfunction, spontaneous echo contrast and left atrial thrombus were 2-3 fold more common in peripheral embolism patients. Mean CHADS-2 scores were low and comparable for both groups. By multivariate analysis, age>5 years (hazard ratio [HR] 2.3, 95% confidence interval [CI] 1.3-3.9; p=0.05) was predictive of peripheral embolism. After adjustment for age>75 years, severe left atrial enlargement (HR 1.8, 95% CI 0.99-3.1; p=0.055) and CHADS score (HR 1.2, 95% CI 0.99-1.6; p=0.06) were of borderline significance. In conclusion, several clinical and echocardiographic measures distinguish the clinical presentation of thromboembolism in non-valvular atrial fibrillation. Small emboli are destined to lodge in the cerebral circulation as a result of hydrodynamic, anatomic, and physical factors. Advanced age, atrial enlargement and other co-morbidities may increase the propensity for the formation of larger thrombi which may bypass the carotid orifice merely as a function of size.
authors.affiliation: Division of Cardiovascular Medicine, Department of Health Sciences Research, Mayo Clinic and Foundation for Education and Research, 200 First Street S.W., Rochester, MN 55905, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: McBane
authors.forename: David O
authors.initials: DO
authors.lastname: Hodge
authors.forename: Waldemar E
authors.initials: WE
authors.lastname: Wysokinski
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging / Q000209:etiology* / Q000628:therapy; D001281:Atrial Fibrillation / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy; D017548:Echocardiography, Transesophageal; D005121:Extremities / Q000098:blood supply*; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging; D006333:Heart Failure / Q000150:complications / Q000000981:diagnostic imaging; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000000981:diagnostic imaging; D008297:Male; D018570:Risk Assessment; D012307:Risk Factors; D020521:Stroke / Q000000981:diagnostic imaging / Q000209:etiology* / Q000628:therapy; D013923:Thromboembolism / Q000150:complications* / Q000000981:diagnostic imaging / Q000209:etiology / Q000628:therapy