MITRAL ANNULUS CALCIFICATION IS NOT AN INDEPENDENT RISK FACTOR FOR STROKE - A COHORT STUDY OF 657 PATIENTS

All studies but one in the past have shown a strong relative risk of m itral annulus calcification for stroke, but the contribution of associ ated cardiac and vascular risk factors, especially carotid atheroma ha s not been appreciated. We studied the risk of stroke in selected pati ents with mitral annular calcification, adjusting for clinical, echoca rdiographic and therapeutic factors influencing stroke risk. Of 8,160 consecutive patients with echocardiograms, 657 with and 562 without mi tral annulus calcification were followed for a mean of 2.4 years (rang e 1-6.6) to determine stroke risk by means of proportional hazards mod els with clinical, echocardiographic, and therapeutic variables that i nfluence the risk of stroke. We also determined the association of mit ral annulus calcification with subtypes of ischaemic brain lesions gen erally considered to be specific for an underlying cardioembolic cause . We therefore distinguished between territorial, small deep, and asym ptomatic (silent) brain infarcts. Fifty-one patients with mitral annul us calcification and 27 controls had a stroke in the follow-up period. Mitral annulus calcification was not significantly associated with st roke in proportional hazards models (hazard ratio 0.76, 95% confidence interval 0.42-1.36, P = 0.3), or with any of the stroke subtypes, or with the presence of silent brain infarcts after adjustments for risk factors for generalized vascular disease Hypertension and carotid athe roma, with or without stenosis, ipsilateral or contralateral to the si de of the stroke, were significantly associated with stroke in our pat ients. This study does not support the view that mitral annulus calcif ication is a risk factor for stroke. As others have found strong assoc iations between mitral annulus calcification and cardiac and vascular risk factors for stroke, the increased risk of stroke in patients with mitral annulus calcification reported may be explained by these confo unding risk factors. Therefore, in our opinion, mitral annulus calcifi cation requires treatment of cardiovascular risk factors, but generall y no specific measures such as surgery or oral anticoagulants are requ ired to lower the risk of stroke.