Mazen Elsheikh, MBBCh1, Lekan Akanbi, MD2, Nishant Tripathi, MD3, Kathleen Wong, RN4, Stefanie Stephens, RN4, Laura E. Snowden, RN4, Lisbeth Selby, MD4, Bahaaeldeen Ismail, MD, MSc4; 1Ain Shams University, Cairo, Al Qahirah, Egypt; 2University of Missouri - Columbia, Lexington, KY; 3University of Kentucky College of Medcine, Lexington, KY; 4University of Kentucky, Lexington, KY
Introduction: There is a growing evidence showing increased incidence of gastroesophageal reflux disease (GERD) after lung transplantation (LT), associated with graft dysfunction. Vagal nerve manipulation has been hypothesized as an explanation but the exact mechanism is not fully understood. Advancements in high-resolution manometry (HRM) provided a more precise understanding of the underlying esophageal abnormalities in GERD, which can have therapeutic and prognostic implications. The aim of this study is to explore the GERD mechanism in the light of HRM findings in LT recipients compared to matched controls. Methods: This was a retrospective study including patients with pathologic acid reflux (defined as acid exposure time (AET) >6 % or 4-6 % with other conclusive evidence) who underwent HRM and PH testing at the University of Kentucky between 7/2012 to 10/2019. Study included 12 LT recipients and 36 controls, that were matched in 1:3 ratio for age, gender and AET. Clinical, manometric and PH parameters were compared between both groups. We then used Spearman correlation to assess their relation to AET. Results: Less patients in the LT group were symptomatic with dysphagia or heartburn (p = 0.04). Although there was no significant difference between groups regarding hiatal hernia size or esophagogastric junction (EGJ) morphology, the LT recipients had less hypotensive EGJ (mean EGJ-CI 89.2 mm Hg/cm in LT versus 33.9 mm Hg/cm in controls, p < 0.001) , (Table 1). Percentage of ineffective swallows was comparable (p = 0.4) and there was no significant difference in delayed gastric emptying either, although emptying studies were available only in a minority of patients. Inspiratory abdominal pressure measured from the HRM plots was higher in LT recipients but thoraco-abdominal pressure gradient was similar (mean 20.7 in LT, 17.9 in controls, p=0.2). AET correlated with total EGJ-contractile integral (r = -0.57, p = 0.05) and distal contractile integral (r = -0.79, p < 0.01) only in the LT group (figure 1, table 2). Discussion: Acid reflux after LT is characterized by a less hypotensive EGJ compared to controls with similar AET. Other metrics were comparable in both groups, but the strength of the association with AET differed. These results add to the understanding of reflux after LT and may help tailor an individualized treatment plan. To elaborate the findings of our exploratory study, we recommend future studies using post prandial HRM, including more LT patients with both acid and non-acid reflux.
Table 1: Clinical, PH and manometric metrics for of lung transplant and controls. LT; lung transplant recipients, AET; Acid exposure time, SAP; Symptom association probability, SI; Symptom index, DCI; Distal contractile integral, IEM; Ineffective esophageal motility, IRP; Integrated relaxation pressure, LES-PI; Lower esophageal sphincter pressure integral, EGJ-CI; Esophagogastric junction contractile integral, Total EGJ-CI; Total esophagogastric junction contractile integral, TP; Intrathoracic pressure, AP; Intra-abdominal pressure, TAPG; Thoraco-abdominal pressure gradient, EGJ; Esophagogastric junction.
Table 2: Correlation coefficients of acid exposure time and selected manometric parameters. DCI; Distal contractile integral, LES-PI; Lower esophageal sphincter pressure integral, EGJ-CI; Esophagogastric junction contractile integral, Total EGJ-CI; Total esophagogastric junction contractile integral, TAPG; Thoraco-abdominal pressure gradient.
Figure 1: Correlation between acid exposure time and the studied manometric parameters in the lung transplant and the control groups.
Disclosures: Mazen Elsheikh indicated no relevant financial relationships. Lekan Akanbi indicated no relevant financial relationships. Nishant Tripathi indicated no relevant financial relationships. Kathleen Wong indicated no relevant financial relationships. Stefanie Stephens indicated no relevant financial relationships. Laura Snowden indicated no relevant financial relationships. Lisbeth Selby indicated no relevant financial relationships. Bahaaeldeen Ismail indicated no relevant financial relationships.