We evaluated how positioning the Gastric Marker and eSleeve during the analysis of HRM of 98 subjects with HH might alter reported values for resting LESP. Respiratory minimum and mean LESP reported by Manoview algorithms varied significantly as a function of where and how these tools were positioned. When the Gastric Marker was moved from its subdiaphragmatic position into the HH, reported respiratory minimum and mean pressures dropped significantly. This indicates that in our patients resting pressures in the HH are greater than in the subdiaphragmatic stomach (). Here, the green hue within the HH, represents higher pressure than the more blue color below the CD. This is supported by our observation that pressure measured in the HH by the eSleeve is greater than subdiaphragmatic intragastric pressure. While we did not directly address this question, this observation suggests that the pressure gradient across the LES may be greater with a HH than when the stomach is normally positioned below the CD. In the presence of a HH, calculating resting LES pressures relative to HH pressure might be more physiologically relevant than calculating them relative to subdiaphragmatic intragastric pressure. This is because the gastric pressure adjacent to the LES is that within the HH.
Sparse data are available regarding assessment of HH with HRM.1,4-7
Crural CD function is an independent predictor of GERD and LES-CD separation is associated with GERD.5
The presence of HH may be a pivotal contributor to compromised LES function.6
In our regression analysis of 36 subjects with available pH studies, there was a trend between increased distal esophagus acid exposure and lower resting LESPs with Gastric Marker placed either below or above the CD, but these differences did not reach statistical significance in either case.
A previous report suggests that CD function may augment the barrier at the EGJ and the loss of this function is reflected by this increase in acid exposure in the distal esophagus.5
HH has been showed to alter dynamic responsiveness of LESP by spatially separating pressure components of the LES and extrinsic esophageal compression within the hernia canal8
and shape of the EGJ has been shown to correlate with grade of esophagitis.9
The severity of HH may also influence susceptibility to reflux. In a HRM comparison of type I (separation but still some overlap between LES and CD) and type II (LES and CD completely separated) HH, reflux events were twice as likely to occur with the latter EGJ spatial configuration.10
These data are corroborated by the increase in minimum and mean pressure we appreciated with the eSleeve spanning from the LES to the CD (12.2 ± 0.9 mmHg) compared to traditional measurement including the boundaries of the LES only (7.5 ± 1.1, P
Furthermore, the CD may play a role in the etiology of dysphagia in patients with HH. Subjects with HH and dysphagia have higher residual CD pressure and intrabolus pressure compared to subjects with HH and GERD.11
This suggests that HH alters pressure dynamics at the EGJ and may lead to functional obstruction. It is conceivable that not only the CD but the high pressure zone created between the LES and CD in patients with HH may create functional obstruction and dysphagia.
In summary, we demonstrated lower minimum and mean LESP in subjects with HH (≥ 2 cm) with Gastric Marker measured within the HH compared to traditional measurement below the CD. This difference may be explained by the demonstration of higher pressure within the hernia sac compared to the zone below the CD. This novel measurement technique may provide a more physiologic representation of the pressure profile across the LES in patients with HH and further investigation is necessary to validate this measurement.