Clinical utility of anal sphincter relaxation integral in water-perfused and solid-state high-resolution anorectal manometry.

BACKGROUND/PURPOSE: We investigated the diagnostic performance of the anal sphincter relaxation integral (ASRI) for infants with Hirschsprung's disease (HD). METHODS: We performed water-perfused high-resolution anorectal manometry (HRAM) in 18 infants (9 with HD), and solid-state HRAM in another 18 infants (4 with HD). We calculated the ASRI during the rectoanal inhibitory reflex (RAIR) maneuver at pressure cutoffs of <10 mmHg (ASRI 10) and <15 mmHg (ASRI 15). We investigated the diagnostic performance of the ASRI for HD in infants undergoing water-perfused and solid-state HRAM. RESULTS: HD infants who underwent either water-perfused or solid-state HRAM had significantly lower ASRI 10 and ASRI 15 values, compared with non-HD infants (P < 0.05 and P < 0.05, respectively). Using the water-perfused HRAM system, ASRI 10 and ASRI 15 values of <7 and <29 mmHg s.cm, respectively, exhibited good diagnostic performance for HD (88.89% and 88.89%, respectively). Receiver operating characteristic curve analysis indicated that ASRI 10 and ASRI 15 values of <5.5 and <20 mmHg s.cm, respectively, were optimal for the diagnosis of HD infants when using the solid-state HRAM system, with high diagnostic accuracies of 83.33% and 83.33%, respectively. CONCLUSION: ASRI may assist the diagnosis of HD infants using either water-perfused or solid-state HRAM. These systems require different catheter-specific ASRI cutoffs for the prediction of HD.