Introduction MII-pH catheter studies measure both acid and non-acid reflux and are considered by some to be the gold standard in the diagnosis of GORD. Wireless pH capsule (Bravo) may increase the diagnostic yield of standard 24 hr catheter-based studies by overcoming the limitation of day-to-day reflux variability. This study aims to assess the additional diagnostic yield of extended Bravo recordings (up to 96 hours) in patients with normal 24 hr MII-pH results.
Methods A total of 44 patients with typical GORD symptoms but negative 24 hr MII-pH studies off proton pump inhibitor(PPI) were referred for Bravo capsule studies. Bravo studies were performed beyond 48 hrs (up to 96 hrs). Bravo analysis was conducted using the ‘Worst Day Analysis’ (WDA) and ‘Average Day Analysis’ (ADA). Reference values for MII-pH and Bravo equivalent were adopted from internationally established studies (Table 1). Subgroup analyses were made on cohorts whose MII-pH showed normal AET with (A) normal number of total reflux events (TRE), (B) normal number of non-acid reflux (NAR) events and (C) increased number of NAR events. Statistical analysis was performed using SPSS V20.
Results Our study group (male = 14, female =30) successfully completed Bravo studies up to 96 hours in 77.3% and beyond 48 hours in 97.7%. Using the WDA and ADA respectively, Bravo (AET cut-off >4.2%) captured an additional 59.1% and 43.2% of patients with increased AET (p < 0.001) in cases with normal AET on MII-pH. In MII-pH subgroups (A), (B) and (C), Bravo WDA was able to reveal an additional positive AET of 61.8%(p < 0.001), 60.9%(p < 0.001) and 50.0%(p = 0.016) respectively compared to MII-pH. Inclusion of symptom reflux association in Bravo cases with increased AET also showed additional diagnostic yield over MII-pH ranging from 42.9–47.7% (p ≤ 0.031) across all subgroups.
Conclusion Extended Bravo studies (>48hours) diagnosed GORD in more than half of cases with an initial normal MII-pH. Half of those with increased NAR events on MII-pH showed positive acid reflux on prolonged Bravo. This additional yield can alter diagnosis from functional heartburn/hypersensitive oesophagus to GORD in difficult cases and influence management.
Disclosure of Interest None Declared