S857 Evaluation of CARS Score in Predicting Achalasia for Patients With Abnormal High Resolution Manometry (HRM) and Endoluminal Functional Lumen Imaging Probe (FLIP)

Introduction: The Contents, Anatomy, Resistance, and Stasis (CARS) score was developed to predict diagnosis of achalasia based on endoscopic features. CARS is comprised of the contents in the esophagus, dilated anatomy, resistance of the lower esophageal sphincter on passage of the scope, and stasis changes in the esophagus. Patients with abnormal esophageal manometry (HRM) often get additional testing such as endoluminal functional lumen imaging probe (FLIP) for further workup. We aimed to characterize the utility of CARS in making a diagnosis of achalasia in patients with abnormal HRM. Methods: We conducted a retrospective cohort study of patients who underwent FLIP for abnormal HRM between December 2020 and December 2024. The primary outcome was a diagnosis of achalasia after all tests. The CARS score and manometric diagnosis were compared between patients with and without a diagnosis of achalasia after all tests. Receiver operating characteristic analysis was performed to assess the performance of CARS in predicting achalasia. The association between CARS and FLIP metrics by Dallas criteria were explored. Finally, binary logistic regression analysis was performed to assess for predictors of achalasia. Results: Of the 177 patients reviewed, 104 underwent FLIP for abnormal HRM results. A total of 83 patients (68 [82%] women) with a median age of 64 years (interquartile range 22-89) were analyzed following exclusions for achalasia (11) and incomplete HRM (10). In terms of manometric diagnoses, 76 (91%) had esophagogastric junction outflow obstruction (EGJOO), 2 (2%) had hypercontractile esophagus, 2 (2%) had diffuse esophageal spasm, 2 (2%) had ineffective esophageal motility, and 1 (1%) had absent contractility. Based on FLIP, 14 (17%) were diagnosed with achalasia (13 had EGJOO and 1 had hypercontractile esophagus on HRM). CARS was significantly higher in patients diagnosed with achalasia after FLIP (median 2 [0-3] vs 0 [0-2]). CARS significantly correlated with FLIP distensibility and diameter metrics. CARS predicted achalasia with a regression coefficient (B = 1.78; 95% CI (2.49-14.1); P = < .001) after controlling for age, sex, and manometric diagnosis. On receiver operating characteristic analysis, CARS predicted achalasia amongst patients without an HRM diagnosis of achalasia with an area under the curve of 0.83. Conclusion: CARS predicted achalasia amongst patients with abnormal HRM and correlated with various metrics in FLIP. This suggests CARS can play a key role in assessment of dysphagia patients. Further study of these associations in a prospective manner is needed to verify these results.