Can the upper esophageal sphincter contractile integral help classify achalasia?

The use of high-resolution manometry (HRM) in achalasia patients has revealed abnormal findings concerning upper esophageal sphincter (UES) function. The introduction of the UES contractile integral (UES-CI), as with the distal contractile integral (DCI), may complement the interpretation of the manometric study of achalasia subtypes, defined by the Chicago Classification v3.0.

Patients were classified into achalasia subtypes based on HRM. UES length (cm), UES resting pressure (mmHg), and UES residual pressure (mmHg) were recorded. UES-CI (mmHg·sec·cm) was calculated in a manner similar to that used for the DCI measurement at rest (landmark CI), corrected for respiration, and its relation to achalasia subtypes was evaluated.

Twenty-four achalasia patients with mean age 55.29 years were included. Of these, 16.6% (n=4) were diagnosed with achalasia type I, 58.3% (n=14) with type II, and 25% (n=6) with type III. The landmark UES-CI, mean UES-CI, UES-CI corrected for respiration, and UES resting pressure were found to be significantly higher among patients with achalasia type II compared to the other types (1768.9 vs. 677.1, P=0.03; 1827.1 vs. 3555.1, P=0.036; 174.2 vs. 72.8, P=0.027; and 108.1 vs. 55.8, P=0.009, respectively).

We introduce the CI index as a tool for the manometric evaluation of the UES in achalasia. UES resting pressure, landmark UES-CI and mean UES-CI were significantly higher in achalasia patients with panesophageal pressurization compared to types I and III. This finding may reflect a protective reaction against the risk of aspiration in this group, but further studying and clinical correlation is required.