What Is the Incidence of Acidic and Nonacidic Gastroesophageal Reflux (GER) in Lung Transplant Recipients (LTR)?

Abstract

Purpose: Bronchiolitis obliterans syndrome (BOS) is the most significant cause of mortality in LTR. GER may be a contributing factor in BOS. We evaluated our LTR population to determine the prevalence of acid and nonacid GER and to determine if there is an association between GER, bronchiolitis obliterans syndrome (BOS), and the known BOS risk factor of acute rejection. Methods: Given concerns that GER may cause airway damage after transplant, all living recipients who underwent lung transplant at our institution have been offered pH analysis. These studies were performed off medication and with either standard pHmetry (Sandhill Scientific, Highlands Ranch, CO), or more recently, with impedance technology (Sandhill Scientific, Highlands Ranch, CO). Studies were performed using standard techniques. Each patient's medical record was then reviewed to collect demographic data, confirmed episodes of acute rejection, and pulmonary function data. Patients with prior antireflux surgery were excluded from data analysis. The data were analyzed using SAS software (Cary, NC). Results: To date, 40 patients have had pH studies, and 37 met study criteria. Median age = 41 yrs, 49% were male, and 70% (N = 26) had a primary diagnosis of cystic fibrosis (CF). Nineteen of the 37 (51%) had an abnormal pH study (% time with pH < 4 of > 4.2%). Acid exposure in the CF subgroup was significantly increased compared to the rest of the study population. Among CF patients, 16 of the 26 (62%) had an abnormal pH study. There was no significant association between acid reflux and acute rejection or BOS (N = 37). However, the CF subgroup (N = 26) showed that elevated acid exposures were significantly associated with a history of acute rejection (P= 0.0315). The association between BOS and GER in the CF subgroup also trended toward significance (P= 0.192). Fifteen of the 37 patients completed an impedance study. The median total reflux was 40 events and 2/15 patients had significantly abnormal total reflux (≥73 events). One of these 2 patients had normal acid exposures. Conclusion: GER is highly prevalent among recipients of lung transplant. In CF patients, there was an association between GER and acute rejection. GER may be injurious to the transplanted lung secondary to reduced pulmonary mucociliary clearance, a diminished cough reflex, and immunosuppressive therapy, thus predisposing to chronic graft rejection.