Left atrial appendage volume increased in more than half of patients with cryptogenic stroke.
BACKGROUND
Ischemic strokes without a well-defined etiology are labeled as cryptogenic, and account for 30-40% of strokes in stroke registries. The left atrial appendage (LAA) is the most typical origin for intracardiac thrombus formation when associated with atrial fibrillation. Here, we examined whether increased LAA volume detected with cardiac computed tomography (cCT) constitutes a risk factor in cryptogenic stroke patients.


METHODS
This study included 82 stroke/TIA patients (57 males; mean age, 58 years) with a diagnosis of cryptogenic stroke after extensive radiological and cardiological investigations. Cases were classified using the TOAST criteria modified by European Association of Echocardiography recommendations for defining cardiac sources of embolism. Forty age- and gender-matched control subjects without cardiovascular diseases were selected for pair-wise comparisons (21 males; mean age, 54 years). LAA volume adjusted for body surface area was measured three dimensionally by tracing the LAA borders on electrocardiogram-gated CT slices.


RESULTS
In control subjects, mean LAA volume was 3.4±1.1 mL/m(2). Mean+2SD, which was considered the upper limit for normal LAA volume was 5.6 mL/m(2). In paired Student t-test between the patient group and matched controls, LAA volume was 67% larger in cryptogenic stroke/TIA patients (5.7±2.0 mL/m(2) vs. 3.4±1.1 mL/m(2); P<0.001). Forty-five (55%) patients with cryptogenic stroke/TIA had enlarged LAA.


CONCLUSIONS
LAA is significantly enlarged in more than half of patients with cryptogenic stroke/TIA. LAA thrombosis may contribute to the pathogenesis of stroke in patients considered to have cryptogenic stroke after conventional evaluation.
Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland ; Unit of Radiology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
Mikko
M
Taina
Ritva
R
Vanninen
Marja
M
Hedman
Pekka
P
Jäkälä
Satu
S
Kärkkäinen
Tero
T
Tapiola
Petri
P
Sipola
D020517:Atrial Appendage / Q000000981:diagnostic imaging / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D015203:Reproducibility of Results; D020521:Stroke / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed