# Therapeutic potential of gastro-gastric fistulas created via lumen-apposing metal stents for nutritional deficiencies after roux-en-y gastric bypass

## TL;DR

Creating temporary gastro-gastric fistulas using metal stents in gastric bypass patients improves nutritional deficiencies without affecting weight or metabolic benefits.

## Contribution

Demonstrates that temporary reversal of gastric bypass using LAMS can address nutritional deficiencies.

## Key findings

- Significant improvements in hemoglobin, vitamin B12, iron, albumin, and magnesium levels were observed.
- No significant changes in weight, BMI, or metabolic markers like glucose and lipids were found.
- Non-significant trends in folate and ferritin levels suggest potential for further improvement.

## Abstract

Roux-en-Y gastric bypass (RYGB) is an effective long-term weight loss operation with improvements in metabolic diseases. Nutritional deficiencies, however, are highly prevalent despite supplementation, largely due to exclusion of the proximal small bowel. In RYGB patients who require pancreaticobiliary access, the EUS-directed transgastric ERCP (EDGE) procedure provides a stable gastro-gastric (GG) fistula using a lumen-apposing metal stent (LAMS). The metabolic and nutritional effects of temporary food diversion remain unknown.

We conducted a review of 60 consecutive RYGB patients from two tertiary centers who underwent EDGE. Nutritional and metabolic parameters were assessed before LAMS placement and after removal.

Mean age was 63.2 ± 11.05 years; 23% were male. Significant improvements were observed in serum hemoglobin (mean difference (MD) 1.1 g/dL;
P
= 0.004), vitamin B12 levels (MD 204.4 pg/mL;
P
= 0.021), iron (MD 57.9 mcg/dL;
P
= 0.017), albumin (MD 0.4 g/dL;
P
= 0.013), and magnesium levels (MD 0.24 mg/dL;
P
= 0.016). In addition, serum folate (MD 2.2 μg/mL;
P
= 0.873), and ferritin levels (MD 315.5 μg/mL;
P
= 0.335), showed improvement trends, but these did not reach statistical significance. No significant changes were observed in total body weight, body mass index, serum glucose, hemoglobin A1c, serum triglycerides, low-density lipoprotein, or high-density lipoprotein (
P
> 0.05 for all).

Temporary partial-reversal of RYGB using a LAMS improves key nutritional parameters without compromising metabolic benefits of RYGB. These findings may support a therapeutic role for iatrogenic GG fistulas as a minimally invasive option for RYGB patients with refractory nutritional deficiencies.