The Significance of the Influence of Aging and Infravesical Obstruction Caused by Benign Prostatic Enlargement on Detrusor Impairment

Objective: to analyze the influence of aging and infravesical obstruction on cystometric characteristics of patients with lower urinary tract symptoms (LUTS) and proven benign prostatic enlargement (BPE). Methodology: A retrospective analysis was performed of basic characteristics of randomly chosen 213 patients with LUTS caused by BPE and urodynamic findings made in period 2005-2009 at the Urology Department of the Sarajevo University Clinical Center. The patients were divided into groups based on their age ( 60 years/46 patients, 60-69 years /95 pat., and 70 years /72 pat.), and the degree of bladder compliance loss ( 20 ml/cmH2O-76 patients, 20-40 ml/cmH2O-57 pat., and 40 ml/cmH2O-80 pat.). All patients had International Prostate Symptom Score (IPS-S) completed, prostate volume measured transabdominally, free uroflowmetry, as well as complete urodynamic study (UDS) findings – cystometry and pressure/flow studies (PFS). The PFS data were plotted on L-PURR, URA and ICS nomogram, bladder contractility index (BCI) and obstruction coefficient (OCO) were calculated for each patient. Results: There was no statistically significant difference of IPS-S, prostate volume and postvoid residual urine among the age groups. Qmax (ml/sec.) declines significantly with age (mean 11.9 vs. 10.3 vs. 7.9, ANOVA p 0.001), along with statistically significant decrease of cystometric capacity (mean 331ml vs. 293 ml vs. 264 ml, p=0.001), bladder compliance (BC-ml/cmH2O) (mean 35.3 vs. 31 vs. 26.5, p=0.013), with increased incidence of detrusor overactivity (DO) (21.7% vs. 32.6% vs. 45.8%, chi2 test for trend p=0.006), followed by a higher incidence of obstruction (URA≥29 cmH2O) (37% patients vs. 61% patients vs. 72.2% patients Chi2 for trend=13.8; p=0.0002), along with noticeable reduction of BCI (117 vs. 121 vs. 106; p=0.02). Patients with severe BC damage ( 20 ml/cmH2O) showed a difference with respect to the degree of obstruction and age, along with decreased cystometric capacity and higher incidence of DO, while the difference in IPP-S was insignificant. OCO with cut-off point of 1 showed significant difference with regard to age (66.3 vs. 66.6 years, T test, p=0.015), prostate volume (45 cc vs. 51.8 cc, p=0.007) and incidence of DO (26% vs. 43.4%, p=0.02). Conclusion: the degree of bladder compliance loss and incidence of obstruction increase with age, as reflected in decreased bladder capacity, decreased urine voided volume and increased incidence of DO, along with noticeably impaired detrusor contractility