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N19 Autonomic nervous system activity in patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia estimated by heart rate variability

      Introduction and Objectives

      Aging induces autonomic nervous system (ANS) dysfunction with increased sympathetic drive. Benign Prostatic Hyperplasia (BPH) is responsible for lower urinary tract symptoms (LUTS). The probably cause of BPH and LUTS is due to the overly active sympathetic NS. The aim of our study was to estimate the ANS activity in BPH patients with LUTS using frequency domain analysis parameters of heart rate variability (HRV). Additionally, the relationship of ANS activity to the subjective measures of LUTS, and the objective measures of BPH, as well as the biochemical and biometrical variables, were investigated.

      Material and Methods

      The study was performed on 30 men with LUTS secondary to BPH. The cohort of patients was asked to complete IPSS and quality of life questionnaires. We performed biometrical measurements (waist, hip circumference and waist-to-hip circumference ratio, body mass index, body area surface), biochemical measurements (serum catecholamine levels) and urological estimations (measurements of the prostate and transition zone of gland, uroflowmetry with post void residual volume evaluation). Additionally, a serum sample was obtained for Prostate Specific Antigen – PSA (total, free, free/total ratio) and PSA derivatives (PSA density, PSA density of transition zone) analysis. ANS activity was assessed by HRV measurements in resting conditions, after simulation with deep breathing (DB test) and by the tilt up test (TUT). In the HRV recording, frequency domain analysis parameters were calculated according to fast Fourier transformation (FFT) and the correlation for ANS activity parameters vs. BPH variables were analyzed.

      Results

      All participants presented moderate LUTS with Qave. = 7.4 ml/sec. and PVR = 48±45 ml. Normalized values of LF and HF were 60.86±18.96 [%] and 39.14±18.96 [%], respectively. LF/HF ratio and its normalized value were 2.97±3.04 [1] and 1.57±1.40 [1], respectively. In response to DB, significant increases of LF, LFnu, LF/HF, LF/HFnu and total power of HRV spectrum and a decrease of HFnu were observed. The E/I ratio was 1.12±0.08. During the TUT, VLF, LFnu, LF/HF, and LF/HFnu were increased, while HFnu decreased. The 30/15 ratio was 0.98±0.05. The observed strong correlations are as follows between:
      • 1.
        prostate enlargement and HFnu and LFnu power;
      • 2.
        total PSA level and LFnu, HF, HFnu;
      • 3.
        free/total PSA ratio and LF/HFnu;
      • 4.
        PSA density of the transition zone and HF;
      • 5.
        plasma noradrenalin level and HF;
      • 6.
        age and LFnu, HFnu, LF/HF and LF/HFnu;
      • 7.
        plasma adrenaline level and prostate enlargement: prostate length and transition zone height.

      Conclusions

      These results demonstrate the sympathetic overactivity of ANS at rest in patients with BPH and LUTS. It is also suggested that in the pathophysiology of BPH, the heighten activity of the sympathetic ANS, and parasympathetic drive are important.