Adverse events during and after per-oral endoscopic myotomy: prevention, diagnosis, and management.

Per-oral endoscopic myotomy (POEM) has surfaced as an effective endoscopic treatment modality for achalasia cardia (AC). Promising results in short- and mid-term follow-up studies have increased the use of POEM for the management of AC. POEM can be safely performed in an endoscopy suit, and major adverse events (AEs) are uncommon. AEs encountered during POEM or during the perioperative period principally include insufflation-related AEs, mucosal injuries, bleeding, pain, and aspiration pneumonia. Most insufflation-related AEs do not require an active intervention and therefore should not be considered as AEs in the true sense. When management of AEs is required, most intraoperative AEs can be managed at the same time without untoward consequences. Occurrences of AEs lessen after completion of the learning curve. However, experience alone does not ensure "zero" incidence of AEs, and early recognition remains essential. Postoperative AEs, like leaks, delayed bleeding, and delayed mucosal perforations, may pose special challenges for diagnosis and management. There is no standardized classification system for grading the severity of AEs associated with POEM, resulting in wide variation in their reported occurrences. Uniform reporting of AEs is not only crucial to comprehensively analyze the safety of POEM but also for comparison with other established treatment modalities like Heller's myotomy. GERD is an important long-term AE after POEM. Unlike the perioperative AEs, little is known regarding the intraoperative or patient-related factors that influence the occurrence of post-POEM GERD. Large prospective studies with long-term follow-up are required to determine the procedural factors associated with GERD after POEM.