FACTORS AFFECTING PREOPERATIVE DISTENSIBILITY INDEX ON IMPEDANCE PLANIMETRY
Teagan E. Marshall*, Hala Al Asadi, Niloufar Salehi, Yeon Lee, Abhinay Tumati, Brendan M. Finnerty, Thomas J. Fahey, SriHari Mahadev, Rasa Zarnegar
Surgery, Weill Cornell Medicine, New York, NY
Introduction: Impedance planimetry is gaining popularity as a method of quantifying changes in the distensibility index (DI) of the gastroesophageal junction during anti-reflux surgery. Studies have shown that patients with gastroesophageal reflux disease (GERD) have higher baseline DI compared to controls. However, these measurements may differ depending on patient and procedural variables. In this study, we sought to further quantify changes in DI with increasing impedance planimetry balloon-fill volumes (BV) in patients with GERD and to identify patient factors contributing to preoperative DI.
Methods: A retrospective review of a prospectively maintained anti-reflux surgery database was conducted between 2021-2022, including patients who underwent hiatal hernia repair and fundoplication with preoperative impedance planimetry.
Results: 61 patients underwent anti-reflux surgery with impedance planimetry at multiple BVs. A subset of 10 patients underwent measurements with increasing BV by 5mL increments, ranging from 10mL to 50mL, with the remaining patient measurements obtained sequentially at 30, 40, and 50mL. All measurements were obtained post-induction in the supine position prior to abdominal insufflation. In patients undergoing 5mL incremental increases in BV, DI significantly increased with increasing volume ranging from a median DI of 2.0 (IQR 1.63-2.36) at 10mL BV to 3.62 (IQR 2.35-6.05) at 50mL BV (p=0.03). In the cohort of patients evaluated at 30, 40 and 50mL of BV, there was a plateau effect with no significant difference in median DIs of 2.69 (IQR 1.63-4.50), 2.81 (IQR 1.84-4.60), and 2.88 (IQR 2.06-4.66) (p=0.64). To further investigate factors contributing to preoperative DI, univariate analysis was performed examining patient factors including age, sex, BMI, manometric results, symptom profiles, and barium swallow findings while controlling for balloon-fill volume. The presence of atypical GERD symptoms was associated with lower DI (β=-1.30 p=0.038), while the presence of hiatal hernia on barium swallow was predictive of increased DI (β=1.11 p=0.028). Age, sex, BMI, and manometry findings were not associated with changes in DI.
Conclusion: While preoperative distensibility index does appear to increase with balloon-fill volumes ranging from 10mL to 50mL, values measured at the BVs used in clinical practice (30, 40, and 50mL) do not significantly differ from one another. Factors found to contribute to preoperative DI included the presence of hiatal hernia on barium swallow and the presence of atypical GERD symptoms. Further research is needed to correlate patient factors with DI, allowing for improved interpretation of results and application in clinical practice.
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