Preliminary Characterization of Proximal Versus Distal Esophageal Function in Healthy, Asymptomatic Adults

The reference standard for the assessment of esophageal motility and sphincter function is high-resolution esophageal manometry (HRM). Diagnostic values for HRM are determined by the Chicago Classification (CC v4.0), which is based almost entirely on distal esophageal function without measures to address the proximal esophageal segment. Therefore, we sought to determine normal HRM values for proximal esophageal function when obtained in the standard HRM positions (supine and upright).

Healthy, asymptomatic adults (≥ 18 years) were recruited. All participants completed a standard protocol. CC v4.0 measurements, along with a proximal contractile integral (PCI) (millimeters mercury-seconds-centimeters[mmHg-s-cm]), temporal measures of proximal and distal contractility (seconds), and lengths of proximal and distal esophagus (centimeters), were performed. Summary statistics, tests of normality, and paired two-sided t-tests were performed.

HRM data from 30 participants were included. Mean supine PCI was 423.9 mmHg-s-cm with a mean contraction time of 3.2 s and a mean length of 5.5 cm. The mean upright PCI was 183.9 mmHg-s-cm with a mean contraction time of 2.2 s, and a mean length of 4.5 cm. All proximal values were significantly different comparing the two positions (PCI p < 0.0001; time p < 0.0001; length p < 0.0001). All distal measurements fell within the ranges of normal, and all measures for contractile integral, contraction time, and contraction length were statistically significantly different (p < 0.0001 for all) comparing proximal versus distal measurements.

These preliminary data represent our first attempt to quantify normal proximal esophageal function using HRM measurements of contractile vigor, contraction length, and time.