OS 29-02 CIRCADIAN BLOOD PRESSURE PROFILE ABNORMALITIES AND AUTONOMIC DYSFUNCTION.

OBJECTIVE: To assess the autonomic regulation in patients with various circadian blood pressure profile (CBPP) anomalies that persisted despite of combined antihypertensive therapy.

DESIGN AND METHOD: We studied 114 hypertensives aged 56,8 ± 17,9 years receiving combined antihypertensive therapy divided into two groups, with adequate (n = 61) and inadequate (n = 53) CBPP. Groups were comparable in terms of age and number of drugs intake per day (2.8 ± 1.4 vs. 2.7 ± 1.3). CBPP was calculated from 3-day blood pressure monitoring data (BPLab) and reconstructed by a specialized algorithm (GS Katinas). In all patients arterial baroreflex sensitivity (BRS), forearm blood vessel vasoconstriction in response to lower body negative pressure (LBNP) and cold stress (CS), heart rate variability (HRV), blood pressure variability (BPV), Valsalva index (VI) were calculated; tilt-test (TT) and hand-grip test (HGT) were performed. Haemodynamic parameters were assessed using Finapres method (Finometer), occlusion plethysmography and ECG.

RESULTS: Patients with inadequately compared to adequately controlled systolic BP levels were characterized by lower LBNP (-0.11 ± 0.10 vs. 0.30 ± 0.20 rel. units; p < 0.05), CS (0.21 ± 0.11 vs. 0.36 ± 0.10 rel. units; p < 0.05) and LF-band HRV (536 ± 428 vs. 1124 ± 1030 ms; p < 0.01). Patients with high compared to normal BP variability had lower VI (1.49 ± 0.21 vs. 1.73 ± 0.24 rel. units; p < 0.01) and increase of systolic BP during TT (4.9 ± 10.3 vs. - 6.5 ± 10.1 mmHg). Non-dippers had lower BRS (5.1 ± 3.0 vs. 7.5 ± 4.3 ms/mmHg; p < 0.05), LBNP (0.01 ± 0.18 vs. 0.36 ± 0.25 rel. units; p < 0.01) and HRV, especially in the LF-band (480 ± 391 vs. 1720 ± 1009 ms; p < 0.001).

CONCLUSIONS: CBPP abnormalities that persisted despite of combined antihypertensive therapy are connected with the autonomic regulation disturbance and probably appear one of the causes of resistant and labile hypertension.