Pan-Esophageal Pressurization in Achalasia: Is 30 mmHg the Best Discriminator for Predicting Good Treatment Outcome?

Background: Achalasia is classically defined by absent peristalsis and impaired EGJ relaxation. Recent data from esophageal pressure topography (EPT) studies suggest that additional features defining esophageal pressurization patterns may define clinically relevant subtypes. In particular, pan-esophageal pressurization (PEP) >30 mmHg has been shown to be a predictor of good treatment outcome. However, the 30 mmHg threshold for defining PEP was arbitrary and there is concern that this threshold value may be too high. The aim of this study was to evaluate the relationship between PEP values 30 mmHg). Impaired EGJ relaxation was defined as an Integrated Relaxation Pressure (IRP) >15 mmHg relative to gastric pressure. The level of PEP, spanning from the UES to the EGJ, was measured with the isobaric contour tool (ManoViewTM) as the pressure (relative to atmospheric) first showing a 1cm break. The average of the two highest PEP measurements was used to classify patients into two groups for comparison: A) ≤ 15 mmHg and B) >15 mmHg but ≤ 30 mmHg. Treatment outcome after therapy was determined by chart review. Failure of therapy was defined as continued symptoms prompting further intervention, continued weight loss, or related hospitalization. Results: Of the 3600 patients, 33 patients (20M/13F, mean age 54) were found to have an abnormal IRP and no evidence of contractile activity or PEP > 30 mmHg in at least 2 swallows. The mean PEP in this group was 14.1 (± 6.5) mmHg. Patients with PEP 15 mmHg, approaching statistical significance with a p value of 0.076. A comparison between the two groups of PEP is presented in the table. Conclusion: Pan-esophageal pressurization measurements are an important predictor of outcome in Type I achalasia. Although statistical significance was not achieved, our data confirm a trend towards better outcome in the group with higher values of PEP. We hypothesize that the ability of the esophagus to pressurize to a level above 15 mmHg likely provides sufficient driving pressure for flow across the EGJ after achalasia therapy. Thus, the threshold PEP for defining Type II achalasia may be lower than the previously described threshold of 30 mmHg. Results Table