The Calculation and Comparison of the Detrusor Contractility Parameter (vCE) and Watts Factor

AIMS: To test the significance of association between a validated index of detrusor contractility, vCE , the Watts Factor, and the Detrusor Contractility Parameter, t20-80 ; and to test whether t20-80 depends on outflow tract resistance as indicated by Bladder Outlet Obstruction Index (BOOI). METHODS: Thirty-seven pressure-flow traces from 20 male and 17 female patients were analyzed and forms of the Watts Factor, t20-80 and BOOI were compared with vCE . RESULTS: The Detrusor Contractility Parameter, t20-80 , is significantly associated with vCE for both women and men without a high degree of bladder outlet obstruction. The Watts Factor only had a significant association with vCE at the point of maximum flow in women. CONCLUSIONS: The Detrusor Contractility Parameter (DCP) (t20-80 ), can be measured easily from the pressure flow curves of a urodynamic test. The Watts Factor at maximum urine flow, WFQmax , can be readily calculated, but is only applicable to women. In both women and men without a high degree of bladder outlet obstruction, DCP is better associated with true detrusor contractility than any Watts Factor analysis.