RESUMEN
Objective To study the role of esophagogastric junction contractile index (EGJ-CI) in evaluating the function of anti-reflux barrier,and in differentiating patients with gastroesophageal reflux disease (GERD) from those with functional heartburn (FH).Methods A total of 115 patients presenting heartburn were enrolled in the study from January 2012 to June 2015.All subjects had completed Gerd-Q questionnaire and undergone gastroscopy,24-hour pH-impedance monitoring and esophageal high-resolution manometry.GERD patients were divided into as reflux esophagitis,acid-nonerosive reflux disease (NERD) and weakly acid-NERD groups.Patients with normal esophageal mucosa,normal acid exposure and negative proton pump inhibitor test were enrolled in FH group.EGJ-CI (mmHg · cm) as well as EGJ rest pressure and 4s integrated relaxation pressure (IRP 4s) were measured.Results Among the 115 patients,18 were reflux esophagitis [(49.0 ± 18.9) years,M ∶ F =10 ∶ 8],25 were acid-NERD [(48.7 ± 14.4) years,M∶F=13∶ 12],37 were weakly acid-NERD [(52.0 ±14.8) years,M∶F=15∶22] and 35 were FH [(53.6 ± 14.8),M∶ F =8∶27].No differences of Gerd-Q scores were noticed between the four groups.(1) Negative correlations were demonstrated between EGJ-CI and esophageal acid exposure time (r =-0.283,P =0.002),EGJ-CI and acid reflux events (r =-0.233,P =0.012),EGJ-CI and weakly acid reflux events (r =-0.213,P =0.022),EGJ-CI and non-acid reflux events (r =-0.200,P =0.032).(2)The value of EGJ-CI was significantly higher in FH patients than in the three subgroups of GERD(all P ＜ 0.01).EGJ rest pressure of FH group was higher than that of acid-NERD (P ＜ 0.01).IRP 4s in acid-NERD group was lower than that of FH and weakly acid-NERD (P ＜ 0.05).(3) The area under curve (AUC) of EGJ-CI was higher than that of EGJ-CIT,EGJ rest pressure or IRP 4s (0.686 vs 0.678,0.641 and 0.578).The cut-off value of EGJ-CI to differentiate GERD from FH was 9.74 mmHg · cm with sensitivity 82.86％ and specificity 51.52％.Conclusions The EGJ-CI values are negatively correlated with esophageal acid exposure time,weakly acid reflux events and non-acid reflux events.Thus it might be used as a metric to reflect the anti-reflux function of EGJ.According to the cut-off value of EGJ-CI 9.74 mmHg · cm,patients with GERD can be sensitively differentiated from patients with FH.