IMPEDANCE-PH MONITORING AND SYMPTOMANALYSIS IN NON-CARDIAC CHEST PAIN PATIENTS ON AND OFF THERAPY

Background and aim: The aetiology of non-cardiac chest-pain (NCCP) is unknown, but previous studies demonstrated that both visceral hyperalgesia to esophageal distension or even chemostimulation with acid are frequently involved. However, the role of weakly acidic reflux in provoking NCCP is poorly known. To assess the role of weakly acidic reflux in a large group of NCCP patients studied using impedance-pH. Material and methods: Consecutive patients complaining of NCCP underwent impedance-pH monitoring while on or off-PPI therapy (discontinued PPI >14 days prior to testing). Forty-eight healthy volunteers (27F; mean age 42yrs) served as controls. During impedance-pH tracings analysis we measured distal esophageal acid exposure time, characteristics of reflux episodes (acid/weakly acidic) and symptom-reflux association using both symptom association probability (SAP + if = 95%) and symptom index (SI + if = 50%). Symptom association was considered positive in case of SAP + and/or SI +. Results: Out of 307 NCCP patients (167F/140M, mean age 49), 266 (86%) experienced NCCP during the impedance-pH monitoring and were included in the study. Among the 198 off-PPI (111F/87M, mean age 47), a positive SAP/SI was found in 77 (39%) for acid reflux only, 31 (16%) for both acid and weakly acidic reflux and 26 (13%) for weakly acidic reflux only. Sixty-four patients (32%) patients had no reflux-symptom association. In the group of patients on-PPI (N=68; 36F/32M, mean age 50), 13 (19%) had a positive SAP for acid reflux only, 22 (32%) for weakly acidic reflux only and 5 (7%) for both acid and weakly acidic reflux. Twenty-eight (41%) patients had no reflux-symptom association. Identifying patients with symptomatic weakly acidic reflux reduces the number of patients with unexplained chest pain from 91 (46%) to 64 (32%) and from 51 (75%) to 28 (41%) among patients off-PPI and on-PPI, respectively (p<0.01). Conclusions: Monitoring for weakly acidic reflux in NCCP patients increases our ability to identify patients in whom symptoms are associated with reflux, mainly in patients on-PPI therapy. Our data support the use of ambulatory impedance-pH monitoring in a diagnostic algorithm for patients with unexplained chest pain. The impact of this improved diagnostic value on NCCP management remains to be investigated by outcome studies.