Bladder outlet obstruction shows distinct urodynamic patterns

By Joanna Lyford, Senior medwireNews Reporter

Chinese researchers have identified a number of distinct urodynamic patterns among older men with non-neurogenic lower urinary tract symptoms (LUTS) and bladder outlet obstruction (BOO).

Writing in Urology, Lei Yin (Changzheng Hospital, Second Military Medical University) and colleagues say that the seven urodynamic patterns they describe “can be used to optimize the diagnosis and treatment of these patients.”

Yin’s team retrospectively analysed urodynamic study data on 1984 men aged 45 years and above with symptoms suggestive of BOO. The patients were primarily categorised according to detrusor function, and then further subdivided according to degree of BOO and detrusor compliance. This system yielded seven urodynamic study patterns, which the team labelled A to G.

Pattern A (8.0% of the cohort) was typified by equivocal or mild BOO with sphincter synergia with or without idiopathic detrusor overactivity. Pattern B (3.0%) was equivocal/mild BOO with idiopathic sphincter overactivity. Pattern C (53.3%), the most common, was classic BOO with idiopathic sphincter synergia.

Pattern D (14.0%) was classic BOO with idiopathic sphincter overactivity. Pattern E (6.0%) was classic BOO with detrusor low compliance. Pattern F (4.7%) was BOO with both detrusor underactivity and low compliance. Finally, pattern G (11.0%) was equivocal BOO with detrusor underactivity and normal compliance.

Certain parameters, such as detrusor pressure at maximal flow rate (PdetQmax), the A-G number (PdetQmax–2Qmax) and postvoid residual urine volume, were significantly higher in patients with patterns C, D or E than in those with patterns A or B.

Furthermore, the functional profile length of the urethra was significantly longer in patients with patterns C or D than in others.

Treatment also differed by urodynamic profile. Patients with patterns C, D and E typically underwent transurethral resection of the prostate whereas those with patterns F and G received 4–6 weeks of catheterisation and pharmacological therapy aimed at promoting recovery of the detrusor contraction. Meanwhile, patients with patterns A and B received pharmacological therapy in the first instance followed by surgery if needed.

Yin et al conclude that comprehensive urodynamic study should be reserved for men with severe voiding symptoms, men who are catheterised and have potentially severed detrusor and those with a large postvoid residual urine volume.

“For most male patients, about 73.3% in this group, clinical judgment of their detrusor as intact, was the dominant demand”, they remark.

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