Localizing the contractile deceleration point (CDP) in patients with abnormal esophageal pressure topography

Background The contractile deceleration point (CDP) is an important landmark for interpreting esophageal pressure topography (EPT) plots. Previous analysis in normal subjects confirmed that the CDP could be localized using an algorithm that found the time during peristalsis at which a maximal length of the distal esophagus was contracting concurrently (tML method). This study aimed to test the tML method for localizing CDP in patients with abnormal motility. Methods High-resolution manometry studies of 75 patients with normal and disordered peristalsis were analyzed. Two experts, JEP and YX, used the original tangent-intersection method to score CDP coordinates for the first two swallows of each study. Alternative computerized algorithms tested against the expert were: (i) the tML method, (ii & iii) the intercept between the leading edge of the 30-mmHg isobaric contour and a line 2.0cm (or 10% of esophageal length) proximal to the esophagogastric junction (EGJ) at rest, or (iv) the 'tML-3cm' method, which added the stipulation that the CDP be within 3cm of the EGJ. Key Results All tested algorithms were highly correlated with the expert. However, the tMl-3cm method was better in the sense that it eliminated outliers (>1s discrepancy with the expert) that occurred with the other methods usually attributable to weak distal peristalsis. Conclusions & Inferences Optimal automated CDP localization was achieved in both normal and a spectrum of abnormal motility using the tML method with the added stipulation that the CDP be restricted to within the distal 3cm of the EGJ at rest.