# Mechanistic and clinical outcomes of a surgical innovation aimed at minimizing GERD associated with vertical sleeve gastrectomy (INNOVATE-VSG)

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA-IRVINE · 2024 · $314,827

## Abstract

PROJECT SUMMARY
Conventional vertical sleeve gastrectomy (cVSG) accounts for approximately 60% of all bariatric surgery
procedures. Its popularity is attributable to procedural simplicity, low complications, durable weight loss and
significant improvement of obesity-related comorbidities. However, numerous studies have found that the
cVSG is associated with new-onset gastroesophageal reflux disease (GERD) and persistence or worsening of
pre-existing GERD. Chronic GERD is associated with increased risk for Barrett’s esophagus and esophageal
cancer. Hence, it is imperative to develop strategies to minimize GERD associated with the cVSG. The
pathophysiology cVSG-associated GERD is attributable to its surgical technique. First, the patients evaluated
for bariatric surgery are often found to have a defective antireflux barrier (ARB) and hiatal hernia, which
increase the risk of GERD. Second, the cVSG removes the entire gastric fundus resulting in 1) higher
intragastric pressure which is conducive to reflux, 2) disrupts gastric sling fibers leading to altered lower
esophageal sphincter function, and 3) disrupts the gastric cardia leading to loss of the gastroesophageal flap
valve (GEFV). The current project will test a modified VSG (mVSG) which will preserve the gastric sling fibers,
anchor the cardia to the distal esophagus, and recreate the GEFV. INNOVATE-VSG is a randomized single-
blind clinical trial with a 12-month follow-up. A total of 40 subjects with BMI 30-50 kg/m2 and GERD, meeting
eligibility for bariatric surgery, will be randomly assigned in 1:1 ratio to the conventional VSG (cVSG) or the
mVSG at two academic sites. Aim 1. to determine whether mVSG, in comparison to cVSG, will be associated
with lower acid exposure time (AET, measured by the Bravo pH test) at 12 months. Aim 2. To elucidate the
mechanistic basis for Aim 1, we will perform following tests, before and at 12 months post-surgery: 1) High
resolution esophageal manometry (HREM) to determine the LES and intragastric pressure. We expect higher
LES pressure and lower intragastric pressure in patients with mVSG vs cVSG. 2) EndoFLIP testing to examine
changes in compliance of the LES. We expect lower LES compliance in patients with mVSG vs cVSG. 3)
Measure the length of the gastroesophageal flap valve (GEFV) on the retroflex view during endoscopic exam.
We expect that GEFV will be present after mVSG vs absent after cVSG. Aim 3. Examine the impact of GERD
on quality of life (QoL) with two validated rating scales – GERD-HRQL and SF-36. We hypothesize mVSG
patients will have superior QoL compared to cVSG patients at 12 months. Additionally, we examine for the
presence of sling fibers in the resected stomach specimens. We expect to see sling fibers to be present in the
cVSG specimens but not in the mVSG specimens. We believe that the mVSG will lead to improvement of pre-
existing GERD along with improved quality of life for patients with obesity. The study findings have the
potential to ...

## Key facts

- **NIH application ID:** 11050836
- **Project number:** 1R01DK138047-01A1
- **Recipient organization:** UNIVERSITY OF CALIFORNIA-IRVINE
- **Principal Investigator:** RAVINDER K. MITTAL
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $314,827
- **Award type:** 1
- **Project period:** 2024-09-20 → 2027-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11050836

## Citation

> US National Institutes of Health, RePORTER application 11050836, Mechanistic and clinical outcomes of a surgical innovation aimed at minimizing GERD associated with vertical sleeve gastrectomy (INNOVATE-VSG) (1R01DK138047-01A1). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/11050836. Licensed CC0.

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