Esophageal distensibility was significantly limited in patients with eosinophilic esophagitis, compared with healthy controls, reported Monika A. Kwiatek, Ph.D., and colleagues in the January issue of Gastroenterology.
The finding, which represents "the first quantification of reduced esophageal distensibility in EoE," could make distensibility "a useful objective measure to characterize disease severity ... [given that] solid food dysphagia and food impaction are likely dependent on the opening aperture of the esophagus," wrote the researchers (Gastroenterology 2011 January [doi:10.1053/j.gastro.2010.09.037]).
Dr. Kwiatek of the division of gastroenterology at Northwestern University, Chicago, looked at 33 patients with EoE, including 22 males and 11 females (age range, 19-67 years). Patients were from the gastroenterology clinic at Northwestern Memorial Faculty Foundation, and had current endoscopic biopsies with histopathology confirming EoE (that is, 15 or more eosinophils per high-powered field).
These patients were compared with a volunteer group of 15 healthy controls (6 males and 9 females, aged 21-68 years) who had no gastrointestinal symptoms and were not currently using gastrointestinal medications.
Esophageal volume was measured with a functional luminal imaging probe, known as the EndoFLIP, which uses impedance planimetry to determine multiple, adjacent, cross-sectional areas (CSAs) in the esophagus, according to the authors. The compliant, cylindrical bag is filled with a "specially formulated conductive solution" once it is inside the esophagus, which allows communication between electrodes inside the bag. The device is also capable of measuring intrabag pressure during distension, they added.
All subjects underwent esophagogastroduodenoscopy to evaluate for EoE and to help place the EndoFLIP across the esophagogastric junction (EGJ).
Dr. Kwiatek found that when the EndoFLIP bag was placed at the EGJ and inflated to 20 mL, controls had a median CSA of 15 mm2. That was significantly greater than EoE patients’ median CSA of 13 mm2 (P less than 0.05).
The difference was even greater when the EndoFLIP was further inflated to 30 mL. In this stage, controls had a median CSA of 22 mm2, whereas EoE patients registered a median of just 14 mm2 (P less than 0.05).
A similar – although not statistically significant – trend was seen when the EndoFLIP was used to measure pressure. With the bag inflated to 20 mL, control subjects had a median pressure of 19 mm Hg, compared with 21 mm Hg among EoE patients.
With the bag inflated to 30 mL, the pressure difference was once again even greater, although not significant (24 mm Hg among controls vs. 29 mm Hg among EoE patients).
The measures amounted to a "distensibility index" that was significantly lower among EoE patients, compared with controls, at both the 20-mL level (controls, 0.9 mm2/Hg vs. EoE patients, 0.5 mm2/Hg; P = .03) and the 30-mL threshold (controls, 0.8 mm2/Hg vs. EoE patients, 0.5 mm2/Hg; P = .01).
The authors also sought to determine whether esophageal distensibility was correlated with the degree of eosinophilic infiltration, or any other patient factors.
They found that none of the following factors were significantly related: mucosal eosinophil count, patient age and sex, and current gastrointestinal treatment at the time of the study.
The process of testing distensibility was well tolerated, according to the researchers. There were no cases of bleeding or mucosal tearing related to the subsequent esophageal biopsy.
"We hypothesize that measuring esophageal distensibility may be an important adjunct to the clinical management of EoE that potentially provides a more objective measure from which to guide medical and dilation therapy," concluded the authors.
"However, future studies done before and after therapy are required to determine whether reduced distensibility is responsive to treatment focused on reducing inflammation and fibrosis, and whether these changes are associated with improvement in patient reported symptom severity reported outcomes," they added.
The authors disclosed that the EndoFLIP equipment used in this study was provided by Crospon Ltd., maker of the device. One of the authors also disclosed serving on the advisory board for Crospon.