S488 The Diagnostic Capability of FLIP Compared to Barium Esophagram for Esophageal Pathologies

Abstract

Introduction: In disorders of LES dysfunction, HRM and TBE have long been the standard of care for diagnosis by LES pressure and fluid retention/capsule arrest. But the Functional Lumen Impedance Planimetry (FLIP), able to measure distensibility (DI) and detect peristalsis, has shown to be a useful adjunct test for such pathologies in practice and many industry funded studies. Specifically these studies found high agreement of normality between FLIP and TBE, as well as established the normal range for DI values. Our novel independent study aimed to confirm the diagnostic role of FLIP by evaluating the agreement between FLIP and TBE diagnoses and evaluate the pathologic range of DI. Methods: Retrospective review of pre-intervention dysphagia patients with documented outcomes from the above procedures was performed. Retention, arrest, and diagnosis data was collected from TBE reports. Maximum volume DI and diagnosis data was collected from FLIP reports. Results: Full FLIP testing showed 100% diagnostic sensitivity for LES pathologies, but only 39.58% specificity, an agreement of 54.21% with TBE diagnoses (k=0.24). Using DI< 2.8 as a determinant of abnormality, FLIP showed a sensitivity and specificity of 0.58 and 0.5 with no individual pathology showing significantly improved detection. Using DI< 2.0 as the cutoff for normality showed a sensitivity and specificity of 0.48 and 0.69 and an agreement of only 64.4% (k=0.158) (Table). Conclusion: We found that FLIP testing during dysphagia workup showed excellent, 100% detection of LES pathologies EGJOO, achalasia and absent contractile response, when used as an adjunct test to TBE and HRM. Though when investigating the individual component metrics that make up the clinical diagnosis, neither cutoff value of 2.8 nor 2.0 for DI was acceptably sensitive or specific to make accurate diagnoses compared to barium study. These findings differ from previous studies which established a DI of 2.8 as a diagnostic value for esophageal pathologies and showed agreement of 0.78 between TBE and FLIP. Our findings support that FLIP is well suited for a role requiring high sensitivity such as intraoperative repair screening or adjunct testing, as opposed to a stand-alone diagnostic test as previous industry funded studies suggested. Further investigation will aim to determine which metrics from FLIP testing used in standard diagnosis are the most sensitive and specific. From this, it could be determined what pathologic physiology is reliably detectable by FLIP in clinical practice. Table 1. - Sensitivities and specificities of FLIP metrics compared to TBE FLIP Metric Sensitivity Specificity Agreement k Full Assessment 1 0.396 0.54 0.24 DI< 2.8 0.58 0.5 0.54 0.081 DI< 2 .0 0.48 0.69 0.64 0.158