Use of impedance planimetry (325 catheter with 8-cm balloon) improves per-oral endoscopic myotomy outcomes in achalasia patients: a systematic review and a meta-analysis

Summary Achalasia is a motility condition defined by failure of relaxation of the lower esophageal sphincter and loss of peristalsis in the distal esophagus. Per-oral endoscopic myotomy (POEM) is a technique to reduce lower esophageal sphincter pressure. We performed a systematic review and meta-analysis to assess the association between POEM and the clinical outcomes. We performed a systematic review and a meta-analysis (CRD420251052240). Literature search was done on PubMed and Embase (up to 8 June 2025). Original studies involving achalasia patients who underwent esophageal POEM with impedance planimetry using 8-cm balloon at 30 or 40 mL filling volumes with 325 catheter only (not the 322-N catheter) were included. The outcomes of interest were the clinical response groups (responders’ Eckardt score [ES] < 3 and non-responders’ ES > 3), reflux esophagitis, cross-sectional area (CSA), distensibility index (DI), and diameter. Nineteen studies with 1215 patients were included. The responders (ES < 3) showed a statistically significantly greater increase in DI due to POEM (post-op minus pre-op) (mean difference [MD] = 1.92 mm2/mmHg [0.32, 3.53], P = 0.02) as well as a higher postoperative DI (MD = 1.87 mm2/mmHg [0.04, 3.70], P = 0.05) (40 mL). Reflux esophagitis group had statistically significantly higher CSA and diameter values (CSA MD = 15.68 mm2 [6.91, 24.24], P = 0.0005) (diameter MD = 0.96 mm [0.58, 1.33], P < 0.00001) but no statistically significant difference for DI as compared to the non-reflux esophagitis group (DI MD = 0.19 mm2/mmHg [−0.51, 0.89], P = 0.59). In achalasia patients undergoing esophageal POEM, a greater interval increase in the DI as well as a higher post-procedural DI absolute value predicts a favorable clinical response. Higher postoperative CSA and diameter were linked to reflux esophagitis.