The Effect of Peroral Endoscopic Myotomy in Achalasia Patients with Prior Endoscopic Intervention: A Systematic Review and Meta-Analysis

Background: Peroral endoscopic myotomy (POEM) has been reported to be effective in achalasia patients with prior failed endoscopic intervention (PFI). We performed this meta-analysis to compare and summarize the clinical outcome of POEM in patients with or without prior endoscopic intervention. Method: We searched relevant studies published up to March 2020. Meta-analysis for technical success, clinical success, Eckardt score, lower esophageal sphincter (LES) pressure, clinical reflux, and adverse event were conducted based on a random-effects model. Results: Eight studies enrolling 1,797 patients who underwent POEM were enrolled, including 1,128 naive achalasia patients and 669 patients with PFI. In the PFI group, the pooled estimated rate of technical success was 97.7% (95% confidence interval [CI], 95.8-98.8%), the pooled clinical success rate was 91.0% (95% CI, 88.0-93.4%), and the pooled adverse events rate was 23.5% (95% CI, 10.6-44.1%). The Eckardt score significantly decreased by 5.95 points (95% CI, 5.50-6.40, p < 0.00001) and the LES pressure significantly reduced by 19.74 mm Hg (95% CI, 14.10-25.39, p < 0.00001) in the PFI group. There were no difference in the technical success, clinical success, and adverse events rate between the treatment-naive group and PFI group, with a risk ratio of 1.0 (95% CI, 0.99-1.01, p = 0.89), 1.02 (95% CI, 0.98-1.06, p = 0.36), and 0.88 (95% CI, 0.67-1.16, p = 0.38), respectively. Conclusions: POEM is an effective and safe treatment for achalasia patients with prior endoscopic intervention. Randomized clinical trials are needed to further verify the efficiency and safety of the POEM in those patients.