Anorectal manometry with simulated evacuation (SE) has limited applicability in predicting balloon expulsion (BE) test results. The newly developed high-resolution anorectal manometry (HRAM) technique can yield spatiotemporal plots with three-dimensional pressurization. We aimed to define new parameters based on three-dimensional integrated pressurized volume (IPV) for predicting the BE test results in asymptomatic normal individuals.Methods
Fifty-four asymptomatic healthy individuals were prospectively enrolled. BE tests were performed using 50 mL of water, and a requirement of more than 1 min was considered as delayed BE. HRAM profiles were converted into ASCII files and analyzed using a MATLAB program. A three-dimensional IPV was plotted after transforming the data to a cubic spline interpolation followed by resampling the manometry position at 0.1-cm intervals.Key Results
Eight of the 54 (15%) individuals demonstrated delayed BE. Conventional manometric profiles did not differ significantly between cases of early and delayed BE. Receiver-operator characteristic curve analysis revealed that the ratio of the IPVs of the upper 1 cm to the lower 4 cm of the anorectal canal with balloon distension was more predictable of the BE results (area under curve, 0.73: 95% confidence interval, 0.53–0.92; p = 0.04) than the other IPVs or their ratios.Conclusions & Inferences
The newly developed IPV methods could predict delayed BE tests during SE better than the conventional parameters defined on the basis of linear waves. Well-designed prospective trials on a large number of subjects are warranted to validate the clinical application of this novel parameter.Conclusions & Inferences
In this study, for the first time, we aimed to define new parameters based on three-dimensional IPV for predicting BE test results in asymptomatic normal individuals using HRAM. During SE, the newly developed IPV methods indicated a better ability to predict delayed BE tests as compared to conventionally used parameters that are based on linear waves.