Acid exposure predicts pulmonary decline after lung transplant
CHICAGO — Increased acid exposure time on reflux testing before lung transplantation predicts decline in pulmonary function after transplantation, according to research presented at Digestive Disease Week.
“Acid reflux has been associated with increased morbidity and mortality after lung transplantation,” Wai-Kit Lo, MD, of Brigham and Women’s Hospital and Harvard Medical School in Boston, Mass., said during his presentation. “Our group has previously shown that objective measures of reflux on pre-transplant impedance and pH testing have been associated with poor outcomes following transplantation.”
To further study the link between reflux testing and post-lung transplant pulmonary decline, Lo and colleagues retrospectively evaluated 70 lung transplant patients who had reflux testing with 24-hour pH-impedance study without acid suppression before their transplantation (58% men; mean age, 56 years; mean follow-up, 2.2 years). Interstitial pulmonary fibrosis was the most common diagnosis (31%).
After receiving a lung transplant, 26% of patients had significantly reduced pulmonary function defined as at least a 20% reduction in forced expiratory volume in 1 second (FEV1). Fourteen patients ultimately developed bronchiolitis obliterans syndrome or persistent pulmonary decline.
Lo and colleagues found no association between decline in pulmonary function and patient demographics, cardiopulmonary function prior to transplantation, CMV mismatch, infection after transplantation, and use of acid suppressants after transplantation.
Univariate analyses showed decline in FEV1 was associated with increased acid exposure time (AET > 4.2% of time at pH < 4; HR = 3.49), and increased proximal acid reflux (> 28 episodes; HR = 3.32). Kaplan-Meier analyses confirmed these associations, and the association between pulmonary decline and increased acid exposure time remained significant on multivariate analysis controlling for possible confounders like BMI and sex (HR = 3.37; 95% CI, 1.08-10.56).
“Abnormal acid exposure on pre-transplant reflux testing was associated with significant pulmonary function decline [and] abnormal acid exposure time was associated with progressing to [bronchiolitis obliterans syndrome] or persistent clinical decline in subjects with initial decline in pulmonary function,” and patients with acid reflux and FEV1 decline are at high risk of poor transplant outcomes, Lo concluded.
Reflux testing before transplantation may help guide prognosis and management of these patients, “with implications for pulmonary function decline as reflective of allograft injury or rejection,” he and colleagues noted in their abstract. – by Adam Leitenberger
Lo WK, et al. Abstract 10. Presented at: Digestive Disease Week; May 6-9, 2017; Chicago.
Disclosures: Lo reports financial ties to Pfizer.