CRITERIA FOR OBJECTIVE DEFINITION OF TRANSIENT LOWER ESOPHAGEAL SPHINCTER RELAXATION

We developed and evaluated objective manometric criteria that define t ransient lower esophageal sphincter (LES) relaxation. In 23 normal sub jects and 9 patients with gastroesophageal reflux disease, systematic analysis of swallow-induced LES relaxation showed that dry swallows pr eceded LES relaxation by a median of 1.4 s. The relaxation rate was al ways >1 mmHg/s, the relaxation nadir always occurred within 7 s, and t he duration of relaxation was <9 s. During concurrent esophageal manom etry and pH monitoring, 104 reflux episodes associated with a LES pres sure fall that was not related to swallowing were identified and the p ressure falls classified as transient LES relaxations or not by visual recognition. LES pressure was always less than or equal to 2 mmHg at time of reflux, and relaxation was significantly longer than for swall ow-induced LES relaxation. Of 88 pressure falls classified visually as transient LES relaxations, 90% reached nadir pressure within 7 s at a rate of > 1 mmHg/s. Sixteen pressure falls were classified as a gradu al downward drift in LES pressure, which in 15 cases was <1 mmHg/s. Ba sed on the analysis, transient LES relaxation can be defined by 1) abs ence of swallowing for 4 s before to 2 s after the onset of LES relaxa tion, 2) relaxation rate of less than or equal to 1 mmHg/s, 3) time fr om onset to complete relaxation of less than or equal to(1)0 s, and 4) nadir pressure of less than or equal to 2 mmHg. Excluding multiple sw allows, LES pressure falls that fulfill the last three criteria but ha ve a duration of > 10 s can also be classified as transient LES relaxa tions irrespective of the timing of LES relaxation to swallowing.