A more accurate method to evaluate outcomes of treatment for achalasia is described in the May issue of Clinical Gastroenterology and Hepatology. The method identifies patients with good outcomes with higher levels of sensitivity (same specificity) than timed-barium esophagrams or impedance-manometry bolus transit assessments alone.
Achalasia is an esophageal motor disorder characterized by impaired deglutitive lower esophageal sphincter relaxation and absent peristalsis. Symptoms include esophageal dysphagia, chest pain, and regurgitation. Reducing symptoms is an essential objective and often the primary outcome measure for gauging treatment response.
Esophageal retention is typically evaluated by timed-barium esophagram in patients treated for achalasia. Esophageal bolus clearance can also be evaluated using high-resolution impedance manometry. However, neither of these measures is consistently associated with patient-reported effects on symptoms.
Dustin A. Carlson performed a prospective study of 70 patients with achalasia to evaluate the associations of conventional and new high-resolution impedance manometry metrics, esophagrams, and patient-reported outcomes (PROs) after treatment for achalasia.
In this study, patients were treated by pneumatic dilation or myotomy and then assessed using timed-barium esophagrams and high-resolution impedance manometry. PROs were determined from Eckardt scores and a brief esophageal dysphagia questionnaire.
In analyzing data from high-resolution impedance manometry, Carlson et al used an improved quantitative evaluation, based on the esophageal impedance integral (EII) ratio (see figure). A greater EII ratio indicates a greater degree of bolus retention.
After treatment, the patients’ median timed-barium esophagram column height was 3.2 cm, and the EII ratio was 0.36.
Nineteen patients (27%) had complete bolus transit and the remaining 51 (73%) had incomplete bolus transit. The average timed-barium esophagram column height was 0 cm among patients with complete bolus transit and 4 cm among patients with incomplete bolus transit.
When the authors plotted the timed-barium esophagram column height with the EII ratio or bolus transit, they observed complementary effects of timed-barium esophagram column height and HRIM evaluation in association with PRO. In the authors’ analysis, 23 of 25 patients (92%) with a low timed-barium esophagram column height and a low EII ratio had a good PRO, whereas 14 of 17 patients (82%) with a high timed-barium esophagram column height and high EII ratio had a poor PRO.
Carlson et al conclude that the EII ratio has a significant association with achalasia symptoms. The EII ratio alone associates with PROs to a similar extent as timed-barium esophagram column height. However, the combination of timed-barium esophagram column height and the EII ratio has a stronger association with PRO than either factor alone.
The authors explain that although timed-barium esophagram and the EII ratio each assess esophageal retention, the timed-barium esophagram assesses retention of a larger volume over time whereas the EII ratio indicates the amount of esophageal retention associated with small-volume swallows. The timed-barium esophagram also provides important anatomic information.
Limitations of the study included the use of the Eckardt score, which is a nonvalidated but commonly used PRO. The authors attempted to offset this limitation by also including a validated dysphagia chest pain PRO, the brief esophageal dysphagia questionnaire.
Calculation of the EII ratio requires high-resolution impedance manometry and customized software, so it is quite technical and not widely available, limiting the generalization of these findings to general practice. However, integration of this metric into commercially available high-resolution impedance manometry analysis software could expand its clinical use and aid in evaluation of patients with achalasia.