Comparison of functional lumen imaging probe and high-resolution manometry to assess response after peroral endoscopic myotomy

Background and Aims: Outcomes after peroral endoscopic myotomy (POEM) are assessed clinically by the Eckardt score (ES) or objectively by high-resolution manometry (HRM) and functional lumen imaging probe (FLIP). This study compared HRM and FLIP to evaluate clinical response after POEM. Methods: This was a single tertiary center retrospective study of consecutive patients who underwent POEM for treatment-naive achalasia and with >= 6 months of follow-up. Baseline and follow-up testing in all patients included ES, HRM, and FLIP of the esophagogastric junction (EGJ). A normal post-POEM (or normalized) EGJ distensibility index (EGJ-DI) >2.8 mm(2)/mm Hg, maximum EGJ diameter (MxEGJD) >= 14 mm, and integrated relaxation pressure (IRP) <15 mm Hg were compared with a clinical response, defined as ES <= 3. Results: Eighty-seven patients (58% men, mean age 51 +/- 17 years) were included. Overall clinical response by ES, IRP, MxEGJD, and EGJ-DI were 97.7%, 86.2%, 75.9%, and 92.0%, respectively. The sensitivity of a normal IRP (87.1% [95% confidence interval {CI}, 78.0-93.4]) was similar to the sensitivity of a normal MxEGJD (75.3% [95% CI, 64.7-84.0], P = .053) and normal EGJ-DI (91.8% [95% CI, 83.8%-96.6%], P = .39) after POEM to predict clinical response. However, the sensitivity of a normal post-POEM EGJ-DI was superior to a normal post-POEM MxEGJD (P = .001) to predict clinical response. There was no difference in the area under the curve of a normal MxEGJD or EGJ-DI to predict a normal IRP (P = .956) after POEM. Conclusions: Normal FLIP metrics >= 6 months after POEM for achalasia show good to excellent sensitivity but are equivalent to a normalized IRP by HRM to predict clinical response by ESs. FLIP may be used as an alternative to HRM to assess lower esophageal sphincter response to POEM in these patients.