A comparison of periurethral blood flow resistive indices and urethral closure pressure of incontinent women

This study correlated Doppler resistive indices (RIs) with maximum urethral closure pressures (MUCPs) in women with stress urinary incontinence. We hypothesized that urethral blood flow would be inversely correlated to urethral closure pressures. Fifty-three women underwent spectral Doppler waveform analyses of periurethral vasculature to calculate RI. Urethral morphology including pubovesicular length (PVL) with and without cough was measured. MUCPs were obtained according to International Continence Society guidelines. Physical exam and history were also obtained. Correlation coefficients were calculated for comparisons of Doppler measurements and closure pressures. Fifty patients were required to detect a difference between no correlation and a modest correlation of 0.38 with 80% power and alpha of 0.05. Significance is set at p<0.05. Measurements were reproducible between Doppler waveforms and MUCP measurements (all p=NS). RI was not correlated with age, parity, MUCP, Incontinence Impact Questionnaire-7 scores, urethral length, or urethral width (all p=NS). RI and MUCP were likewise not associated with history of diabetes, hypertension, or anterior vaginal prolapse to or beyond the hymen (all p=NS). MUCP was negatively correlated with age (r=−0.33, p=0.01) even when controlled for hormonal status (ANCOVA, p=0.003) and positively correlated with urethral/bladder neck diameter (r=27, p=0.05), PVL (r=0.30, p=0.03), and PVL with cough (r=0.36, p=0.009).