Multichannel Intraluminal Impedance and pH (MII-pH) in Functional Heartburn (FH)

Abstract

Purpose: Patients with heartburn and regurgatation but normal endoscopy and 24hour pH have FH. Causes of FH are uncertain but include a false negative pH study, sensitivity to minute amounts of acid, non acid and gas reflux. 24 hour MII-pH allows examination of each of these potential causes. AIMS 1.Determine potential causes of FH symptoms. 2.Determine the clinical usefulness of MII-pH testing in these patients. Methods: 29 consecutive FH patients age 48 years (29–71 yrs), 22 F, off PPIs for 2 weeks underwent 24hour MII-pH, noting heartburn and regurgation.The catheter dectected pH 5cm above the LES and impedance at 6 sites throughout the esophagus.The following parameters were studied: Acid reflux (pH<4), Minor acid reflux (ph drop >1 log unit but pH remains >4), Non acid reflux (pH change of <1 log unit with pH>4), Type of reflux (liquid, gas or mixed). Symptoms occurring within 180sec of a reflux event were considered related to the reflux. The Symptoms Index (SI) was caculated if 4 or more symptoms occurred during a study and considered + if 50% or more. All studies were hand read. Results: 1) 8 patients (28%) had a + SI and therefore FH. 2) 4 patients (14%) had a + 24 hour pH test despite an initial negative study and had GERD. 3) 5 patients (17%) had a -SI and therefore no evidence of FH as defined. 4)12 patients (41%) had < 4 symptoms during the exam. Liquid, gas and mixed reflux were equally divided amongest the 98 total reflux episodes in the 8 FH patients. The table shows causes of reflux, SI of acid reflux and SI of all reflux in the 8 FH patients.Table: Patients with FHConclusions: 1) Minor acid/non acid reflux is a frequent cause of symptoms in FH (50/98 episodes). 2) 28% (8 of 29) had FH (+SI). 5 of these 8 (62.5%) would have had -SI without MII-ph testing and would have been missed. 3) 24 hour MII-pH was useful in determining whether FH was or wasn't present in almost half of all patients (48%) (+SI based on total reflux, -SI and original false −24hour pH). 4) 41% of patients had too few symptoms during the exam to properly catogorize. 5) Liquid, gas and mixed reflux were equally symptomatic in these FH patients.