381. MULTICENTER PAN-CANADIAN EXPERIENCE OF PER ORAL ENDOSCOPIC MYOTOMY (POEM) FOR THE TREATMENT OF ACHALASIA: A RETROSPECTIVE STUDY

Abstract Background Per oral endoscopic myotomy (POEM) has emerged as a modality for the surgical treatment of achalasia using a minimally invasive approach with similar clinical efficacy to laparoscopic Heller myotomy. Japanese, European, American and International clinical practice guidelines now cite POEM as a first line treatment for achalasia. In Canada, single-centre experiences with POEM have shown promising results. This study aims to capture the pan-Canadian national experience with POEM for the treatment of achalasia across multiple institutions. Methods This was a retrospective study of patients who underwent POEM for achalasia across four Canadian institutions (St. Joseph's Healthcare Hamilton, Kingston Health Sciences Centre, Surrey Memorial Hospital and Montreal Sacred Heart Hospital) between 2012 to 2022. Pre-operative, procedural and post-operative data was collected. Our primary outcome was the proportion of patients with normal Eckhardt score (≤ 3) at 4 weeks. Secondary outcomes included procedure related adverse events, length of stay in hospital, post-procedure lower esophageal sphincter pressures, post-procedure gastroesophageal reflux disease (GERD) and response rate at further timepoints. Outcomes are reported as either proportions (%) or medians (IQR). Results POEM was attempted in 369 patients with a success rate of 99%. The median duration of surgery was 64 (47 – 89) minutes and length of stay was ≤1 day in 88% of patients. Peri-operative complications occurred in 11% of patients, all of which were Clavien-Dindo Grade ≤III. The post-operative response rate (Eckhardt score ≤3) was 100%, 98% and 95% at 1, 6 and 12 months, respectively. Additional interventions for achalasia following POEM were required in 6% of patients. High DeMeester scores, endoscopic esophagitis and symptomatic GERD were reported in 36%, 43% and 44%, respectively. 93% of GERD was treated with PPI therapy. Conclusions POEM is safe and feasible in Canadian institutions with efficacy in keeping with current international literature.