Detrusor Contraction Duration May Predict Response to ·–Blocker Therapy for Lower Urinary Tract Symptoms

Abstract

Objectives: Baseline pressure/flow parameters have not correlated well with response to medical therapy for lower urinary tract symptoms (LUTS). This open–label, nonrandomized retrospective study was designed to evaluate whether the urodynamic parameter duration (in seconds) of the detrusor contraction (DCD) correlates better with α–blocker response than previously described urodynamic parameters. Methods: 93 men (mean age 62.6±8.5) with LUTS underwent urodynamic evaluation prior to initiating therapy with doxazosin titrated to 8 mg and followed for 6 months. Parameters of evaluation included the AUA symptom score (AUASx), peak urinary flow rate (Q_max), maximal detrusor pressure (P_max), detrusor pressure at maximal flow (P_det) and DCD. The correlation and predictive value of therapeutic response and baseline urodynamic parameters were assessed. Results: 85 patients were evaluable at 6 months. For the entire group, AUASx decreased from 15.1±6.9 to 9.7±5.1 (–36%) and Q_max increased from 9.3±3.7 to 11.9±5.7 ml/s (+28%). Baseline P_max was 74.8±19.6 cm H₂O, P_det was 61.6±18.9 cm H₂O and DCD was 107.6±28.6 s. There was weak correlation between either baseline P_max or P_det and therapeutic response (defined as a decrease in AUASx of 40% and an increase in Q_max of 30%). Utilizing a baseline DCD of 90 s or more, there was a significant correlation to therapeutic response (r = 0.48, p = 0.002). Conclusions: These preliminary data suggest that DCD may be a useful urodynamic parameter to predict and optimize therapy with a–blockade. The potential utility and cost–effectiveness of DCD remains to be determined.