PP‐3 THE UTILITY OF INTEGRATED RELAXATION PRESSURE TO PREDICT ACHALASIA IN CHILDREN
Authors: Ciecierega T. , Crawford C.V. , Zarnegar R. , Tipnis N.A. 
Published: September 2015

Background:Esophageal High Resolution Manometry (eHRM) is a widely available technique to evaluate dysphagia symptoms in children. In adults, the 4 second integrated relaxation pressure (IRP4 s) has been used to characterize lower esophageal sphincter function and esophageal obstruction. To date, no study has evaluated the utility of the IRP to predict achalasia in children. Aims: To determine the utility of the IRP4 s to predict achalasia in a cohort of children with achalasia.Methods:Following IRB approval, records at New York Presbyterian Hospital‐Weill Cornell Medical College were reviewed for pediatric patients undergoing eHRM. Manometric studies were performed using the Manoscan Eso System (Given Imaging, USA) and solid‐state catheters. Children with greater than 80% normal peristalsis and complete esophageal emptying based on barium fluoroscopy, impedance or other clinical criteria were considered control subjects. Children with greater than 20% abnormal peristalsis and evidence of esophageal obstruction by fluoroscopic, impedance or clinical criteria were considered achalasia subjects. Categorical data was evaluated using chi‐squared tests. Continuous variables were compared using the Student's t‐test. Receiver operator curve (ROC) analysis was used to determine the best IRP4 s cut‐point to predict achalasia.Results:16 children (9 M) were identified as controls and 12 children (8 M) identified as having achalasia. All achalasia subtypes were identified in the cohort: type 1 (n = 3), 2 (5) and 3 (1). Control children were older than achalasia children (13.9 ± 3.6y vs. 9.92 ± 5.0y, p = 0.021), but there was no difference in gender distribution. Mean esophageal length (22.7 ± 2.7 cm vs 20.6 ± 4.6 cm, p = 0.14) and basal LES pressure (23.6 ± 11.7mmHg vs 23.0 ± 12.9mmHg, p = 0.91) were similar between groups. However, the IRP4 s was significantly greater in the achalasia group vs. controls (17.9 ± 8.9 mmHg vs 7.0 ± 3.6mmHg, p = 0.0002). ROC analysis predicted an optimal IRP4 s cut‐point of 12.3mmHg, (empiric AUC = 0.844, sens = 75%, spec = 93.8%, accuracy = 85.7%, PPV = 90%, NPV = 83.3%, LR(+) = 12, LR(‐) = 0.27). Based on this cut‐point, 3 false negative results occurred in children with achalasia type 2 based on morphologic appearance of eHRM and esophageal obstruction on fluoroscopy. The single false positive case had normal fluoroscopy and 100% peristalsis eHRM morphology.Discussion:This study suggests that an IRP4 s greater than 12.3mmHg is predictive of achalasia in children, particularly when used in conjunction with other clinical signs such as esophageal obstruction on barium fluoroscopy and abnormal peristalsis on eHRM. This finding is limited to studies performed using the Manoscan Eso platform and solid‐state eHRM catheters, as adult studies suggest variation in absolute pressure measurements occur among motility platforms and catheter types. While this study reports on a large cohort of children with achalasia, this study may be limited due to its overall small sample size and difference in age ranges between groups.Conclusions:IRP4 s is a useful eHRM measure to aid in the identification of children with achalasia. Multi‐center studies will provide additional support for the use of the eHRM measurements best suited to categorize esophageal outlet obstruction in children.