Single-blinded randomized controlled trial comparing the effect of underwater versus carbon dioxide insufflation during peroral endoscopic myotomy on post-procedural pain (U-POEM trial).

Evaluate for achalasia any patient with dysphagia to solids and liquids, regurgitation, or chest pain, and specifically consider it in patients presumed to have GERD who do not respond to acid suppression (strong recommendation, very low quality). Diagnose with high-resolution manometry using esophageal pressure topography rather than conventional line tracings (strong, high). Subtype by Chicago Classification (I, II, III), this is a conditional recommendation (low quality): subtyping may inform prognosis and treatment choice, with type II having the most favorable outcomes and type III requiring a longer/tailored myotomy; ACG does not make subtyping mandatory for diagnosis. Always perform upper endoscopy in suspected achalasia to exclude pseudoachalasia from an obstructing mass; use cross-sectional imaging and/or endoscopic ultrasound in difficult cases (ACG states this as narrative guidance, not a numbered recommendation, and specifies no biopsy protocol). FLIP is described as complementary, useful in patients who cannot tolerate manometry and as an arbiter in difficult cases where manometry fails to diagnose achalasia despite high clinical suspicion, not as a required confirmatory test. TREATMENT: pneumatic dilation is superior to medical therapy for symptom relief and esophageal emptying (strong, very low). PD and laparoscopic Heller myotomy are both effective and equivalent short- and long-term for patients who are candidates for definitive therapy (strong, high). POEM and LHM give comparable symptomatic improvement (strong, moderate). POEM and PD give comparable symptomatic improvement in type I or II (conditional, low). For type III, tailored POEM or LHM is recommended as a more efficacious disruptive LES therapy than PD (strong, moderate), ACG does NOT single out POEM over LHM for type III. When surgical myotomy is performed, add fundoplication: myotomy with fundoplication is superior to myotomy alone for controlling distal esophageal acid exposure (strong, moderate), using either Dor or Toupet (conditional, moderate). Botulinum toxin injection is first-line therapy for patients unfit for definitive therapy (strong, moderate), and prior botulinum toxin does not significantly compromise subsequent myotomy performance or outcomes (strong, low). POEM carries a higher incidence of GERD than LHM with fundoplication or PD (strong, moderate). Do not place stents for long-term dysphagia (strong, low). Reserve esophagectomy for surgically fit patients with megaesophagus who have failed other interventions (strong, low), and consider Heller myotomy before esophagectomy in patients who failed PD and POEM when the anatomy is conducive and there is evidence of incomplete myotomy (strong, very low). FOLLOW-UP: use timed barium esophagram as the first-line test to evaluate continued or recurrent symptoms after definitive therapy (strong, very low); the Eckardt score alone or HRM alone should not be used to define treatment failure. Do not obtain routine gastrografin esophagram after dilation, reserve it for clinical suspicion of perforation (strong, low). RETREATMENT: PD is appropriate and safe after failed surgical myotomy or POEM (strong, moderate), and POEM is safe in patients who previously underwent PD or LHM (strong, low). SURVEILLANCE: ACG recommends AGAINST routine endoscopic surveillance for esophageal carcinoma in patients with achalasia (strong, low), although risk is elevated (~1 cancer per 300 patient-years), absolute numbers are low, an estimated >400 endoscopies would be needed to detect one cancer, and surveillance has not demonstrated improved survival.