The Impact of Magnetic Sphincter Augmentation (MSA) on Esophagogastric Junction (EGJ) and Esophageal Body Physiology and Manometric Characteristics.

OBJECTIVE

To evaluate the impact of MSA on lower esophageal sphincter (LES) and esophageal body using high resolution impedance manometry.

BACKGROUND

MSA is an effective treatment in patients with gastroesophageal reflux disease, but there is limited data on its impact on esophageal functional physiology.

METHODS

Patients who underwent MSA were approached 1-year after surgery for objective foregut testing consists of upper endoscopy, esophagram, high resolution impedance manometry, and esophageal pH-monitoring. Postoperative data were then compared to the preoperative measurements.

RESULTS

A total of 100 patients were included in this study. At a mean follow up of 14.9(10.1) months, 72% had normalization of esophageal acid exposure. MSA resulted in an increase in mean LES resting pressure [29.3(12.9) vs 25(12.3), P < 0.001]. This was also true for LES overall length [2.9(0.6) vs 2.6(0.6), P = 0.02] and intra-abdominal length [1.2(0.7) vs 0.8(0.8), P < 0.001]. Outflow resistance at the EGJ increased after MSA as demonstrated by elevation in intrabolus pressure (19.6 vs 13.5 mmHg, P < 0.001) and integrated relaxation pressure (13.5 vs 7.2, P < 0.001). MSA was also associated with an increase in distal esophageal body contraction amplitude [103.8(45.4) vs 94.1(39.1), P = 0.015] and distal contractile integral [2647.1(2064.4) vs 2099.7(1656.1), P < 0.001]. The percent peristalsis and incomplete bolus clearance remained unchanged ( P = 0.47 and 0.08, respectively).

CONCLUSIONS

MSA results in improvement in the LES manometric characteristics. Although the device results in an increased outflow resistance at the EGJ, the compensatory increase in the force of esophageal contraction will result in unaltered esophageal peristaltic progression and bolus clearance.