837 PERORAL ENDOSCOPIC MYOTOMY (POEM): ANTERIOR VERSUS POSTERIOR APPROACH, A RANDOMIZED SINGLE-BLINDED CLINICAL TRIAL

Abstract

POEM has been adopted worldwide for the treatment of achalasia. Practice patterns vary and the optimal technique (anterior vs posterior) to myotomy is not known. The primary objective is to compare the rate of clinical success (Eckardt sore < 3) of anterior and posterior approaches at 12 months post POEM. Secondary objectives included comparison of dysphagia score, reduction in IRP on HRM, rate/severity of adverse events (AEs, ASGE lexicon), post-operative pain (VAS), procedure times, technical difficulty (Likert scale), length of hospital stay, analgesic use during hospitalization, and GERD parameters (DeMeester score, GerdQ questionnaire, PPI use), and QOL (SF-36). Consecutive adult patients with achalasia presenting for POEM at 6 centers (3 Asia, 2 Europe and 1 US) were randomly allocated with a 1:1 ratio using the block randomization method. A total of 150 patients was needed to show non-inferiority of the posterior approach with a power of 80% and two-sided α of 0.05. POEM was performed in standard fashion with anterior approach being at 1-2 o’clock position and posterior approach at the 5-6 o’clock. A total of 150 patients (70 female, mean age 51yr) with achalasia (19 type I, 107 type II, 24 type III) were randomized to either anterior (n=73) or posterior (n=77) POEM. All baseline characteristics of patients in both groups were equivalent (table 1). Technical success was achieved in 71 (97.3%) patients in the anterior group vs 77 (100%) patients in the posterior group (p=0.23). The mean length of submucosal tunnel and myotomy were similar between the two groups (13.8cm vs 14.4cm, p=0.23; 10.6cm vs 11.2cm, p=0.24, respectively). The median procedure time (59min vs 67min, p=0.57), mean degree of procedure difficulty (1.9 vs 1.9, p=0.76), and mean degree of post-operative pain (4.4 vs 3.9, p=0.51) were also similar. Rate of AEs (none severe) was not different between both groups (11% anterior vs 9% posterior, p=0.70). At 12 months, rate of clinical success was equivalent between the anterior and posterior groups (91% vs 89%, p=0.67) (table 2). Repeat HRM showed similar decrease in IRP in both groups (17.2 vs 16.7, p=0.83). IRP normalization occurred in 74% of patients who had anterior POEM and in 75% of patients who had posterior POEM (p=0.91). Rate of abnormal esophageal acid exposure (DeMeester score >14.72) was similar between the 2 groups (49% vs 42%, p=0.67). At one-year follow-up, mean GerdQ score was 7.1 in the anterior group as compared to 7.1 in the posterior group (p=0.99) (table 2). QOL improved after POEM in all SF-36 scales in both groups. Improvement in social functioning was higher in the posterior group (p= 0.02). Anterior and posterior approaches to POEM are equally highly effective and safe for the treatment of achalasia (NCT03228758).View Large Image Figure ViewerDownload Hi-res image Download (PPT)