Carotid atherosclerosis in renal transplant recipients

Background. Cardiovascular accidents are the major cause of morbidity and mortality in renal transplant recipients. However, there is little information concerning carotid atheroscleroric wall changes in renal transplant recipients, their relationship with cardiovascular accidents and their possible association with cardiovascular risk factors in such patients. Methods. Between April 1991 and December 1997, we prospectively assessed cardiovascular accidents in 79 renal transplant recipients who had received a transplant at our institution before January 1, 1986. Carotid morphology by B-mode ultrasonography, relevant clinical and laboratory cardiovascular risk factors, including lipid abnormalities and total homocyst(e)ine, were determined at the start of the follow-up period. Seventeen healthy subjects matched for age and sex with renal transplant recipients served as controls who volunteered for ultrasonographic examination of carotid arteries. Results. Nine patients experienced cardiovascular events during the period of follow-up. Compared with healthy, age- and sex-matched control subjects (n= 17), the frequency of carotid plaques was higher in renal transplant recipients with cardiovascular events (n=9), but not in those without such events (n=70). The frequency of cardiovascular accidents was related to the number of carotid plaques (4, 17 and 24% for no plaque, one plaque and >1 plaque respectively, P<0.04). However, by multivariate analysis, serum total cholesterol [odds ratio (OR) of 1.8 for each 1.0 mM, P < 0.07) and the presence of diabetes mellitus (OR of 28.4 for presence, P<0.01) were the only predictors of cardiovascular events in such patients, whereas the presence of carotid plaques was not. Moreover, neither serum lipoprotein (a) nor total homocyst(e)ine concentrations could be identified as risk factors. Conclusions. This prospective study shows that although a close association exists between asymptomatic carotid atherosclerosis and cardiovascular accidents in renal transplant recipients with long-term follow-up and relatively good renal function, other potentially modifiable risk factors appear to be better predictors of cardiovascular events. Consequently, the assessment of carotid atherosclerosis may not be clinically useful for the systematic identification of renal transplant recipients with an increased risk of developing cardiovascular events.