Ambulatory arterial stiffness index in children after kidney transplantation

Given the increase in CV morbidity after RTx and the scarcity of CV events in pediatrics, surrogate markers should be assessed to characterize CV damage in this population. AASI is a marker of arterial stiffness in adults, predicting cardio- and cerebrovascular morbidity. Our aim was to assess the determinants of AASI in RTx children (n = 54, 15.5 ± 3.5 yr) and to examine its relationship to central PWV. AASI was calculated from 24 h ABPM. PWV was determined by applanation tonometry, body composition by multifrequency bioimpedance measurement. The dipping state, volume overload, and time on dialysis were the main predictors of AASI (p < 0.05). Children with established HT (n = 34) had increased AASI, extracellular body water, and BNP (p < 0.05). In contrast to AASI, PWV did not differ between HT and normotensive RTx patient groups. There was no correlation between AASI and PWV. PWV was increased in children who spent more than one yr on dialysis prior to RTx. In conclusion, increased AASI in HT RTx children better characterizes the actual volume- and pressure-dependent arterial rigidity rather than long-term morphological changes in large arteries as reflected by PWV.