The value of high-resolution manometry in the assessment of the resting characteristics of the lower esophageal sphincter.

INTRODUCTION: High-resolution manometry (HRM) is faster and easier to perform than conventional water perfused manometry. There is general acceptance of its usefulness in evaluating upper esophageal sphincter and esophageal body. There has been less emphasis on the use of HRM to evaluate the lower esophageal sphincter (LES) resting pressure and length, both factors important in LES barrier function. The aim of this study was to compare the resting characteristics of the LES determined by HRM and conventional manometry in the same patients.
METHODS: We performed both HRM and conventional manometry including a slow motorized pull-through technique in 55 patients with foregut symptoms. The characteristics of the LES analyzed were: resting pressure, total length, and abdominal length. Four available modes of HRM analysis were used to assess resting characteristics of the LES: spatiotemporal mode using both abrupt color change and isobaric contour, line tracing, and pressure profile. The values obtained from these four HRM modes were then compared to the conventional manometry measurements.
RESULTS: High-resolution manometry and conventional manometry did not differ in their measurement of LES resting pressure. LES overall and abdominal length were consistently overestimated by HRM. A variability up to 4 cm in overall length was observed and was greatest in patients with hiatal hernia (1.8 vs. 0.9 cm, p = 0.027).
CONCLUSION: The current construction of the catheter and software analysis used in high-resolution manometry do not allow precise measurement of LES length. Errors in the identification of the upper border of the sphincter may compromise accurate positioning of a pH probe.