Effect of Drinking Warm Water on Esophageal Preparation Before Peroral Endoscopic Myotomy in Patients With Achalasia

BACKGROUND/AIMS: Food retention, which is a characteristic observed in patients with achalasia, can interfere with peroral endoscopic myotomy (POEM). However, there is no established guideline for esophageal preparation for POEM. A previous study has shown that drinking warm water may reduce the lower esophageal sphincter pressure in patients with achalasia. This study aims to evaluate the possibility of proper preparation of POEM by instructing the patient to drink warm water. METHODS: The warm water preparation was performed in 29 patients with achalasia who underwent POEM. The patients drank 1 L of warm water (60oC) the night before POEM. We evaluated the esophageal clearness and determined the preparation quality. Twenty-nine patients were prospectively recruited and compared to control group. The control cohort comprised achalasia patients whose endoscopic image was available from the achalasia database of our institution. A 12 propensity score-matched control cohort was established from the database of achalasia subjects (n = 155) to compare the outcome of the preparation. RESULTS: In the warm water preparation group, only 1 patient (3.4%) had some solid retention, but it did not interfere with the POEM procedure. The grade of clearness (P = 0.016) and quality of preparation (P < 0.001) were significantly better in the warm water preparation group than in the matched control group. There was no any adverse event at all related to warm water preparation protocol. CONCLUSIONS: Drinking warm water dramatically reduces esophageal food retention and significantly improves the quality of esophageal preparation. This simple protocol is quite useful, safe, and cost-effective in the preparation of achalasia patients for POEM.