Risk factors and predictive model for gas-related adverse events following peroral endoscopic myotomy

Gas-related adverse events (GRAEs) are common after peroral endoscopic myotomy (POEM). Although air insufflation is a recognized risk factor, determinants of GRAEs in the era of carbon dioxide insufflation remain unclear. We aimed to identify independent risk factors after excluding air-insufflation cases and to develop and validate a clinically applicable prediction model.

We retrospectively analyzed 3965 consecutive patients who underwent POEM between 2011 and 2024 at a tertiary referral center. GRAEs were defined as pneumoperitoneum, pneumothorax, pneumomediastinum, or subcutaneous emphysema requiring intervention. Patients were randomly allocated to training (80%) and validation (20%) cohorts. Independent predictors were identified using multivariable logistic regression in the training cohort. Model performance was evaluated in the validation cohort using discrimination (AUC) and calibration.

GRAEs occurred in 298 patients (7.5%). Multivariable analysis identified mucosal edema (OR 1.97; 95% CI 1.33-2.89), tunnel length ≥ 13 cm (OR 2.75; 95% CI 1.95-3.94), selective myotomy (OR 11.81; 95% CI 8.63-16.18), and mucosal injury (OR 2.52; 95% CI 1.74-3.62) as independent predictors (all P ≤ 0.001). Patients were stratified into low- (< 2 factors) and high-risk (≥ 2 factors) groups with significantly different GRAE rates. The model demonstrated good discrimination (AUC 0.763; 95% CI 0.732-0.794) and satisfactory calibration.

We developed and internally validated a practical risk prediction model for GRAEs after POEM in the carbon dioxide era. This model may facilitate risk stratification and individualized perioperative management.