Detection of incomplete lower esophageal sphincter relaxation with conventional point-pressure sensors

Completeness of lower esophageal sphincter relaxation, a parameter used to establish the diagnosis of achalasia, is an important manometric determination. This study compared four analysis methods that use point-pressure measurements to determine their relative accuracy and the best threshold values for incomplete relaxation.

Analyses were performed on 153 manometric studies that employed a 21-lumen catheter with pressure recording sites spaced at 1-cm intervals. Lower sphincter relaxation was measured from most appropriate sites as the 1) lowest residual pressure within 5 s of swallowing, 2) lowest residual pressure across the entire postdeglutitive period, 3) lowest mean residual pressure over a floating 3-s interval after swallowing, and 4) mean transsphincteric esophagogastric gradient extracted from a combination of conventional and topographic manometric information. Intragastric baseline pressures were taken both from the pull-through maneuver and from concurrent intragastric recordings, and methods were compared by their receiver operating characteristics.

Best threshold values for segregating achalasia from nonachalasic controls differed across methods and depended on presence or absence of peristalsis in the comparison group. Transsphincteric gradient measurement had high sensitivity (> or = 0.94) and specificity (> or = 0.98) for achalasia irrespective of comparison group and was superior to all other methods. The 3-s mean residual pressure demonstrated greatest discriminant capabilities of the remaining conventional methods, which were modestly improved with concurrent measurement of intragastric pressure.

Analyses that average postdeglutitive pressures are superior to isolated nadir values in correctly discerning incomplete lower sphincter relaxation. The transsphincteric gradient is a novel approach for measuring sphincter relaxation, is unaffected by sphincter asymmetry and axial movement, and has the best receiver operating characteristics using point-pressure sensors.