Autonomic dysfunction and ambulatory blood pressure in renal transplant recipients

Abnormal circadian blood pressure (BP) rhythm (nondipping) and autonomic dysfunction are both common in end-stage renal disease (ESRD). It is not known whether these abnormalities are related or if they are associated with greater left ventricular hypertrophy.

Nineteen renal transplantation (RT) recipients, aged 22-67 years, who were transplanted at least 12 months (1-29 years) previously, were studied with 24-hr ambulatory blood pressure monitoring (ABPM). Autonomic function was tested by automated analysis of heart rate variations and echocardiography was used to estimate left ventricular mass index (LVMI).

Thirteen patients (68%) were nondippers. Although seven (37%) patients had significant parasympathetic dysfunction, this was not related to dipper status. Neither abnormality showed a tendency to diminish with time after RT. Systolic hypertension, diagnosed by ABPM, occurred in 5% of patients during the awake period and in 52% during sleep, whereas diastolic hypertension occurred in 47% when awake and in 63% when asleep. Awake systolic BP was the strongest predictor of LVMI (r=0.7, P<0.001), and was considerably better than systolic BPs recorded at the clinic (r=0.48, P<0.05).

Nondipping is common after RT but is not related to the degree of autonomic dysfunction. These findings suggest that autonomic dysfunction is not a major contributor to nondipping in ESRD. In RT patients, ABPM is a more sensitive measure of hypertension and a stronger predictor of LVMI than clinic BP.