Upper esophageal sphincter metrics on high-resolution manometry differentiate etiologies of esophagogastric junction outflow obstruction

Background: Upper esophageal sphincter (UES) metrics on high-resolution manometry (HRM), particularly nadir UES residual pressure (UES-RP), are abnormal in achalasia and may help characterize the underlying mechanism or predict management outcome in esophagogastric junction outflow obstruction (EGJOO). Methods: A database of consecutive patients undergoing esophageal HRM from 2008 to 2013 yielded 134 patients (59.8 ± 1.4 years, 68% F) with EGJOO. Final clinical diagnoses and treatment response were extracted from chart review. Esophageal body, UES, and lower esophageal sphincter (LES) metrics were compared between EGJOO and asymptomatic healthy controls (n = 16, 27.7 ± 0.7 years, 56% F). Logistic regression evaluated differences between HRM metrics amongst etiologies of EGJOO grouped into motor versus mechanical disorders. Key results: Distal contractile integral, distal latency, and nadir UES-RP were significantly different between EGJOO subgroups (P ≤ 0.01 for each comparison), but only nadir UES-RP remained independently predictive of subgroups (adjusted odds ratio 1.15, 95% confidence intervals 1.05-1.27, P < 0.01). Nadir UES-RP was highest in achalasia variants, and lowest in mechanical EGJOO and controls (P < 0.001). Of 19 patients who underwent LES myotomy, durable benefit was reported by 68.4% over mean 3.6 years of follow-up. Significantly higher nadir UES-RP was noted with symptom relief (3.4 vs −0.7 mm Hg with symptom recurrence, 95% confidence intervals of difference = 1.35-6.83). A threshold UES-RP of ≥2.0 mm Hg yielded a sensitivity of 84.6% and specificity of 83.3% in predicting symptom resolution following myotomy. Conclusions and inferences: Nadir UES-RP offers clues to differentiation of subtypes within EGJOO and may predict symptom outcome from myotomy.