Silent Brain Infarction in Patients with Rheumatic Mitral Stenosis

Silent brain infarction (SBI) frequency is increased in patients with carotid stenosis and atrial fibrillation (AF), but its relation with rheumatic mitral stenosis (MS) (another major embolic source) is uncertain. The aim of this study is to investigate SBI incidence in patients with MS. Silent brain infarction is defined as asymptomatic infarction detected on computerized tomography (CT) in patients without a history of stroke. Transthoracic echocardiographically (TTE) diagnosed 53 patients (44 F, 9M; mean age 38±7 years) with MS were enrolled in the study. Mitral valve calcification, left atrium (LA) diameter and presence of mitral regurgitation were recorded. Besides TTE, electrocardiographic recording for rhythm analysis, detailed neurologic examination and cerebral CT were also performed. SBI-detected patients on CT underwent carotid artery Doppler examination to exclude carotid artery lesions. History of hypertension and diabetes mellitus, presence of carotid murmur, presence of LA thrombus, left ventricular systolic dysfunction and other valve diseases on TTE, were the exclusion criteria.
RESULTS
Silent brain infarction incidence was 24.5% in patients with MS. The incidence was significantly higher in patients with LA diameter >4 cm or with atrial fibrillation (p<0.05). If AF was associated to enlarged LA, SBI incidence was markedly higher than the ones with sinus rhythm and small LA (p<0.01). When moderate to severe mitral regurgitation was associated to MS, SBI incidence was lower (p<0.05). Although SBI incidence was higher in patients with mitral valve area <1.5cm2, it was not significant (p>0.05). No significant relation was found between calcific and noncalcific valves for SBI (p>0.05).
CONCLUSION
SBI was detected in one-quarter of MS patients. Association of LA enlargement and AF increase SBI incidence, whereas association of moderate to severe mitral regurgitation decreases SBI incidence.