279. NOVEL REFLUX MICROASPIRATION SCINTIGRAPHY ALLOWS EFFECTIVE PATIENT SELECTION FOR ANTIREFLUX SURGERY IN PROXIMAL REFLUX EVENTS

Abstract Background and Aims There is currently no reference standard test for the detection of the extra-esophageal manifestations of gastroesophageal reflux disease (GORD). The current suite of diagnostic tests principally assess reflux events in the oesophagus have problematic accuracy issues in the pharynx. A new scintigraphic technique has been developed and validated against 24-hour oesophageal monitoring with pH, impedance. It allows direct visualization of refluxate in the laryngopharynx and lungs. This was utilised to evaluate patients having laparoscopic fundoplication for severe proximal reflux resistant to maximal medical therapy. Scanning may allow succesful patient selection for antireflux surgery. Methodology Following Institutional Ethics approval, 50 patients were assessed by scintigraphy before and after laparoscopic fundoplication (LF) at a single nuclear medicine facility. Standardised Reflux Symptom Indices (RSI) were obtained from each patient before and after surgery. Patients were scanned after oral 99m technetium Fyton administration with early dynamic images and delayed SPECT/CT images of the head, neck and lungs. Background corrected time-activity curves were generated for the pharynx and upper oesophagus from which frequency of reflux was estimated by counting events with activities greater than 2 standard deviations above fitted values. Frequencies, Spearman correlation and the student’s t test were utilised for analysis. Results The study population (35F, 15M) had a mean age of 63.9 years (Range 21-86). All patients underwent LF. Mean BMI was 26.8 with 67% being over-weight or obese. All patients had proximal reflux events in the early dynamic study. SPECT/ CT showed LPR events in 45/50 and pulmonary micro-aspiration (PMA) in 45/50 pre-operatively and in 36/50 and 20/50 post-operatively. The RSI, cough and throat clearing indices showed a significant fall post-operatively (p< 0.001). The frequency of scintigraphic pharyngeal reflux events was reduced from a mean of 4.5 in 30 minutes to 2.9 (t=9.1, p=0.004). Conclusion The novel scintigraphic test detects oesophageal and extra-oesophageal reflux events and permits direct visualization of refluxate in the head and neck structures and lungs. Scintigraphy correlates well with symptoms of reflux in the oesophagus and extra-esophageal structures such as the laryngopharynx (chronic cough and throat clearing) and the response to LF albeit partial. PMA was significantly reduced.