Introduction: G-POEM is a promising therapy in patients with GP. Functional lumen imaging probe (FLIP) is used to measure pylorus distensibility. However, current FLIP balloon is not designed for the pylorus, and it measures distensibility in a non-isobaric fashion. It is difficult to determine which pylorus characteristics are altered by G-POEM.

Aim: To determine the changes of pyloric diameter and compliance after G-POEM in patients with GP.

Methods: Single center prospective cohort study was conducted. Pylorus FLIP was performed in patients with GP before and 6 months after G-POEM. EndoFLIP® catheter (Medtronic) was inserted to mid-duodenum and withdrawn to straddle pylorus with about 75% of FLIP balloon in the antrum (to avoid bending catheter in duodenum C-loop). Narrowest diameter, cross-sectional area (CSA) and pressure (P) were measured at 30, 35, 40, 45 and 50-mL balloon distensions. Two additional measurements were taken at 50-mL distension by advancing the catheter to straddle pylorus at middle and proximal end of balloon to construct the distensibility curve (Yim et al. J Neurogastroenterol 2022). Distensibility plateau (DP) was determined by pre-defined criteria. Minimal distension P (MDP) was defined as the first P >5mmHg compared to P from 30-mL balloon distension. Diameter at MDP (a marker for resting pylorus opening) was determined. Pylorus compliance (stiffness) was determined from the slope of distensibility curve between the MDP and DP. Paired t-tests were used.

Results: 73 patients (mean age 48 yrs, 90% females, 49% idiopathic) with GP completed pylorus FLIP before and 6 months after G-POEM. An example of distensibility curves from a patient before and 6-month after G-POEM is shown in Figure 1. Overall results are shown in Table 1. Pylorus diameter significantly improved at all balloon stepwise distensions. DI improved at the 40, 45, and 50 mL distensions only. By constructing distensibility curves, we found that diameter at MDP significant increased after G-POEM. Pylorus compliance also significantly increased (less stiff) after G-POEM. However, DP was obtained in only 21% of the FLIP procedures performed. Pylorus resting diameter and compliance improved in 49 (67%) and 39 (53%) patients after G-POEM, respectively, but only 24 (33%) patients had improvement for both. 64 (88%) patients had improvement of resting pylorus diameter and/or compliance, but 9 (12%) patients did not.

Conclusions: Overall, pylorus diameter (at rest and with distension) and compliance significantly improved on our cohort of 73 patients with GP at 6 months after G-POEM. 88% of patients had improvement of resting pylorus opening and/or compliance, but only 33% had improvement of both. Further studies are needed to determine optimal G-POEM techniques to improve pylorus distension profile and to correlate these findings with clinical outcomes.

Brandon Yim

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