ARTERY BLOOD-PRESSURE OSCILLATION AFTER ACTIVE STANDING UP - AN INDICATOR OF SYMPATHETIC FUNCTION IN DIABETIC-PATIENTS

Dynamic artery blood pressure (Finapres) response to active standing u p, normally consisting of initial rise, fall and recovery above the ba seline (overshoot), was compared with the early steady-state artery bl ood pressure level to measure sympathetic vasomotor function in health y subjects (n=23, age 35+/-9 years; mean+/-SD) and in type I diabetic patients without autonomic neuropathy (AN) (group 1: n=18, 38+/-13 yea rs), with AN but no cardiovascular drugs (group 2a: n=7, 44+/-11 years ) and with both AN and cardiovascular drugs (group 2b: n=10, 47+/-7 ye ars). Systolic and diastolic overshoot were similar in the control (15 +/-13/15+/-11 mmHg) and group 1 subjects. Systolic overshoot disappear ed in 57% of patients in group 2a (-1+/-9 mmHg; P<0.03), whereas arter y blood pressure still overshot in diastole (8+/-7 mmHg; NS). Systolic overshoot disappeared in all patients in group 2b (-22+/-22 mmHg; P<0 .0006) and diastolic overshoot disappeared in 60% of these patients (- 6+/-16 mmHg; P=0.0006). Systolic early steady-state level was not lowe r in group 2a than in group 1 (NS), but it was impaired in group 2b (P <0.006), in which six diabetic patients had a pathological response be yond the age-related reference values. There was a strong association between the overshoot and steady-state levels (P for chi(2)<0.001, n=5 8). Overshoot of the control subjects and patients in group 2b correla ted to their respective steady-state blood pressure levels (r greater than or equal to 0.76; P less than or equal to 0.001). In conclusion, baroreceptor reflex-dependent overshoot of the artery blood pressure a fter active standing up diminishes with the development of AN and it i s associated with the early steady-state level of the artery blood pre ssure.