[Valsalva leak point-pressure (LPP) and maximal urethral closure pressure (MUCP) in women with stress urinary incontinence (SUI)].

One-hundred and twenty-two women with USI have been evaluated with clinical examination and urodynamics and divided in two groups: only in 74 patients with urinary loss during the Valsalva manoeuvre, LPP was compared to MUCP by linear regression analysis and its ability (cut-off = 60 cmH2O) to predict a MUCP < or = 20 cmH2O was tested. Weak correlations were observed between MUCP and LPP (r = 0.56). Fifty-two patients presented a LPP < or = 60 cmH2O, in 6 of them MUCP was < or = 20 cmH2O; none with LPP > 60 cmH2O showed a MUCP < or = 20 cmH2O. Median MUCP and intravesical pressures at the instant of leakage of patients with LPP < or = 60 cmH2O were significantly different from those of patients with LPP > 60 cmH2O (p < 0.01). The specificity and positive predictive value of LPP < or = 60 cmH2O for the detection of a "low pressure urethra" were respectively 32% and 11.5%, while sensibility and negative predictive value were 100%. LPP can not be regarded as a specific test for urethral sphincteric deficits. For its sensibility, it can be an useful screening tool for patients at high risk of type III urinary incontinence.