Arterial blood pressure oscillation after active standing up in kidney transplant recipients

Dynamic arterial blood pressure (FINAPRES) response to active standing up, normally consisting of initial rise, fall and recovery above the baseline (overshoot), was compared with the early steady-state arterial blood pressure level to measure sympathetic vasomotor function in healthy subjects [group 1: n=50, 10 female subjects, age 51±2.5 years; weight 78±2.3 kg; height 174±1.4 cm (mean±standard error of the mean)] and in kidney transplant recipients under basal (group 2a: n=50, age 51.7±1.7 years; weight 77±2.1 kg; height 174±1.5 cm) and under high (group 2b: same subjects as in group 2a) ciclosporine A whole blood levels. Furthermore, baroreflex sensitivity and the activity of the generating compounds of the sympathetic nervous systems (Mayer waves) were measured. Systolic and diastolic overshoot values did not differ statistically significant in the present study. In the control subjects, a systolic overshoot of 15.4±2.7 mmHg and a diastolic overshoot of 15.2±2 mmHg was detected. The systolic overshoot disappeared in 57% of group 2a (−7.1±2.7 mmHg; P<0.001) and in 50% of group 2b recipients (−8.0±2.7 mmHg; P<0.001). Systolic early steady-state level was not lower in kidney transplant recipients before ciclosporine (baseline+2 mmHg) intake, but after ciclosporine administration (baseline−3 mmHg; controls: baseline+3 mmHg; P<0.05). There was a strong association between the overshoot and steady-state levels (P for χ²<0.001, n=150). Overshoot of group 1 levels (r=0.428; P<0.01) and group 2 levels (r=0.714; P<0.001) correlated to their respective steady-state blood pressure. Furthermore, recipients had reduced baroreceptor sensitivities estimated by sequence analysis as compared to controls (10±1 ms/mmHg vs. 7.5±1.4 ms/mmHg; P<0.05). Mayer waves amplitudes of the heart rate spectrum were elevated statistically significant in renal transplant recipients (44.4±0.2 vs. 43.8±2.2 A.U.). In conclusion, baroreceptor reflex-dependent overshoot of the arterial blood pressure after active standing up is diminished in kidney transplant recipients, whereas no association to the ciclosporine A whole blood level has been detected. The reduced overshoot may be due to the diminished baroreceptor sensitivity which could be shown in renal transplant recipients.