Bravo capsule induction of esophageal hypercontractility and chest pain

Abstract

The Bravo catheter-free pH monitoring system uses a capsule attached to the esophageal mucosa to detect acid exposure. Placement of the Bravo capsule is associated with intermittent chest pain in 50% of normal volunteers. The authors hypothesized that chest pain in this setting may be attributable to hypertensive esophageal contractions induced by the Bravo capsule. The study population consisted of 40 consecutive patients with reflux symptoms who had stationary esophageal manometry within 1 h after Bravo capsule placement. The control group consisted of 40 patients with symptomatic gastroesophageal reflux disease (GERD) from a population of patients with foregut symptoms who were computer matched to the study group for age, sex, lower esophageal sphincter (LES) pressure, LES length, and 24-h pH composite score. The patients in the control group had manometry before Bravo capsule placement. The occurrence of chest pain was assessed before and during the monitoring period by interview and review of the patient's diary. Mean contraction amplitudes in the distal third of the esophagus after 10 wet swallows were averaged. The prevalence of patients with esophageal contraction amplitudes in the distal third that exceeded the 95th percentile of normal (180 mmHg) and the mean amplitude of distal third esophageal contractions in the study and control populations were compared. In the study group, the incidence of chest pain among the patients with hypercontractility of the esophagus was compared with the incidence among those without hypercontractility. The mean contraction amplitude was higher in the study group (144.7 vs 105.5 mmHg; p = 0.002). The number of patients with a mean distal esophageal contraction amplitude exceeding the 95th percentile of normal also was significantly higher in the study group (13/40 vs 5/40; p = 0.03). A total of 10 patients experienced new onset of chest pain with the Bravo capsule in place, and 6 patients experienced hypertensive esophageal contractions. The intraesophageal Bravo capsule can cause hypertensive esophageal contractions, which may lead to chest pain.