You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Non-neurogenic Voiding Dysfunction I1 Apr 2018PD50-06 A NOVEL MATHEMATICAL FORMULA FOR CALCULATING FLOW RESISTIVE FORCES INDEX, A NEW ESTIMATOR OF BLADDER OUTLET RESISTANCE ENHANCING THE DIAGNOSTIC PERFORMANCE (DISCRIMINATIVE ABILITY) OF UROFLOWMETRY TESTING Evangelos Spyropoulos Evangelos SpyropoulosEvangelos Spyropoulos More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2018.02.2334AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES To improve the diagnostic performance of uroflowmetry for assessment of outflow obstruction, we developed a mathematical formula calculating Flow Resistive Forces Index (QRF), a novel measure of urethral resistance during voiding and examined its clinical applicability compared to the traditional standard indicator Qmax. METHODS Based on the assumption of urine volume momentum changes during voiding, the concept of diphasic uroflow pattern (acceleration/deceleration) and relying on the Urethral Resistance Factor (URA) equation, we developed a mathematical formula to calculate QRF, representing the dependent variable of the equation which contains five key uroflow parameters: voided volume, voiding time, Qmax, Qave, time to peak flow. We then evaluated clinical QRF applicability, by assessing it's diagnostic performance compared to Qmax in a cohort of 84 patients (61 males-23 females) complaining of voiding dysfunction symptoms. All were subjected to uroflowmetry followed by pressure-flow study (PFS) and subsequently divided into two groups (obstructed, unobstructed), according to established PFS criteria (LinPURR, AGN, URA). Data were processed using linear correlation, logistic regression and ROC curve analysis (SPSS-22, MedCalc - p<0,05). RESULTS Outflow obstruction was diagnosed in 31(50,82%) men and 6(26,09%) women (p=0,042). Pearson correlation showed QRF to be significantly associated with AGN (p=0,001/0,003), URA (p=0,0001/0,002) and LinPURR (p<0,0001/<0,0001) in men/women respectively while, Qmax was significantly related to AGN (p=0,003) in women. On binary logistic regression analysis, QRF score (22,476 -p<0,0001) was significantly higher vs Qmax (0,287-p=0,592) in men/women (11,172-p=0,001 vs 0,942-p=0,332 respectively). On ROC curve analysis, AUC of QRF was significantly higher in men and women vs Qmax (0,865 vs 0,502 [p=0,0001] and 0,926 vs 0,613 [p=0,009] respectively) while, Youden index was 0,643 (optimal cutoff point: <2,8 [sensitivity: 87,1%-specificity: 73,3%]) in males and 0,823 (>3,4 [sensitivity: 100% - specificity: 82,35%]) in females. CONCLUSIONS Our mathematical equation,based on key uroflowmetry parameters, derives a novel index (QRF) that highly accurately predicts outflow obstruction, significantly outperforming Qmax, the most widely currently used urinary blockage estimator. We anticipate that after proper clinical validation, it might become a valuable complement to uroflowmetry. © 2018FiguresReferencesRelatedDetails Volume 199Issue 4SApril 2018Page: e972 Advertisement Copyright & Permissions© 2018MetricsAuthor Information Evangelos Spyropoulos More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...