Pyloric EndoFLIP Parameters Before and After Pyloric Botulinum Toxin Injection and Dilation Are Comparable in Adult and Pediatric Patients With Gastroparesis

Introduction: Pyloric therapies of gastroparesis including botulinum toxin injection (BTx) and balloon dilation are proposed to relieve gastric outflow impairment in both adult and pediatric patients. Impedance planimetry with EndoFLIP (Functional Lumen Imaging Probe) measures pyloric diameter (DM) and distensibility (DI) in adults with gastroparesis and may help identify responders to pyloric therapy. However, pyloric EndoFLIP findings in pediatric patients are less established. We hypothesized (i) adult and pediatric gastroparesis cases have similar baseline pyloric DM and DI and (ii) adult and pediatric patients show similar DM and DI increases after combined pyloric BTx and balloon dilation. Methods: EndoFLIP tests of pyloric DM and DI before and immediately after pyloric BTx (100 units) and balloon dilation (15-22 mm) were performed in 15 gastroparesis cases including 6 adult (age 19.5+0.8 yr) and 9 pediatric (age 13.6+3.2 yr) cases. Analyses for 50 mL EndoFLIP inflations compared DM and DI at baseline and after pyloric therapy in adults vs. children. Results: Pre-procedure gastric emptying was similar in adult vs. pediatric cases (19.8±19.3% vs. 25.8±8.6% 4-hr gastric retention, P=0.44). Baseline pyloric DM was higher in adults vs. children (16.3±1.3 vs. 14.8±1.2 mm, P=0.04) but baseline DI was similar in both groups (5.6±1.1 vs. 5.2±1.3 mm2/mmHg, P=0.60). DM (17.1±2.1 vs. 16.1±0.9 mm, P=0.23) and DI (6.4±1.5 vs. 6.3±1.3 mm2/mmHg, P=0.93) after pyloric therapy were not different in adults vs. children. Pyloric DM increased significantly after BTx and dilation in pediatric cases by 1.3+1.2 mm (P=0.01) while DI increased by 1.1+1.3 mm2/mmHg (P=0.03). Increases in DM (0.8+1.4 mm, P=0.22) and DI (0.8+1.0 mm2/mmHg, P=0.10) in adults did not reach significance. However, pyloric DM increased in 5/6 (83%) adult vs. 7/9 (78%) pediatric cases and DI increased in 5/6 (83%) adult vs. 8/9 (89%) pediatric cases (both P=1.00). Conclusion: Compared to adults, EndoFLIP testing in pediatric gastroparesis revealed somewhat lower baseline pyloric diameters but more significant increases in diameter and distensibility after combined pyloric botulinum toxin and dilation therapy. These differences were modest and may reflect small sample sizes. Our findings show comparable degrees of pyloric dysfunction in adults and children with gastroparesis and support further study to investigate the value of EndoFLIP tests to predict responses to pyloric therapy in pediatric cases.