THE ROLE OF RISK-FACTORS AND TRIGGER FACTORS IN CEREBROVASCULAR EVENTS AFTER MITRAL-VALVE REPLACEMENT - IMPLICATIONS FOR ANTITHROMBOTIC MANAGEMENT

To determine the effect of risk factors and trigger factors on cerebro vascular events, 622 patients who survived mitral valve replacement be tween December 1979 and December 1992 were analyzed. Ninety-six patien ts suffered 139 nonhemorrhagic cerebrovascular events. Data were avail able on 138 events in 95 patients. There were 32 transient ischemic at tacks (TIAs), 57 reversible ischemic neurological deficits (RINDs), an d 49 strokes. Age, sex, atrial fibrillation, left atrial size, systemi c hypertension, and abnormal body mass index did not discriminate betw een patients who suffered events and those who did not. In contrast, s moking status differed significantly between patients who suffered eve nts and those who did not. Among current or recent ex-smokers, the ris k of stroke or RIND was significantly higher than in non-smokers (p < < 0.001). The odds ratio of suffering any type of event in patients wh o smoked at any time postoperatively versus those who did not smoke wa s 2.9 (95% confidence interval: 1.8 to 4.6). Of 61 patients contacted directly, 30% recalled an infective episode immediately prior to their event. A diurnal and seasonal influence on events was also detected w ith peaks in the morning and in the winter months, respectively (both p < 0.001). It is concluded that there is persuasive evidence for the involvement of several nonprosthetic factors in the incidence of cereb rovascular events after mitral valve replacement. This has implication s for patient management and for future analysis of prosthetic heart v alve series.