Interactions between prostate volume, filling cystometric estimated parameters, and data from, pressure-flow studies in 565 men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia

The aim of this study was to establish the characteristics and to investiga te the interactions between prostate volume, degree of obstruction, bladder contractility, the prevalence of residual volume, bladder compliance, blad der capacities, and the prevalence of instability in a large, well-defined group of men with lower urinary tract symptoms (LUTS) suggestive of benign prostatic hyperplasia (BPH). The 565 consecutive men included in this study met the criteria of the International Consensus Committee on BPH and voide d more than 150 mL during uroflowmetry. Their residual urine volume and pro state size were estimated, and filling cystometry and pressure-flow studies were performed. Fifty-three percent of the men appeared to have obstructio n. We found a positive correlation between prostate volume and Schafer's ob struction grade, except that mean prostate volume decreased at Schafer's gr ades 5 and 6. Significant negative correlations existed between Schafer's g rade and cystometric bladder capacity and effective capacity. Bladder outle t obstruction results in incomplete emptying. Of all men, 26% had a signifi cant residual volume (> 20% of cystometric capacity). Thirty-nine percent d id not have residual volume. Of the 565 men, 46% had an unstable bladder. I n particular, patients with an unstable bladder in the sitting and lying po sitions have a significantly higher Schafer's grade and contractility grade and a significantly lower cystometric and effective bladder capacity compa red with patients without instability. Patients with a residual volume or i nstability were significantly older. We conclude that in men with LUTS sugg estive of BPH, abnormalities of bladder and bladder outlet function vary gr eatly and have complex mutual interactions. (C) 2001 Wiley-Liss, Inc.