OAGB to Sleeve Conversion

A one-anastomosis gastric bypass (OAGB) works well for many people, yet some develop problems with the bypass itself that are best solved by returning to a simpler stomach operation.

Converting OAGB to a sleeve gastrectomy undoes the intestinal bypass and restores normal food flow through the duodenum, while keeping a restrictive stomach operation. The pouch is reconnected to the bypassed stomach, and the combined stomach is then shaped into a sleeve. It is chosen mainly when the bypass itself is causing problems: malnutrition, refractory marginal ulcers, post-bariatric hypoglycemia, or a need for normal endoscopic access to the duodenum and bile ducts.

With over 25 years in bariatric surgery and more than 9,000 bariatric operations, including complex revisions for patients who travel from across the country, Dr. de la Cruz-Muñoz tailors each OAGB-to-sleeve conversion to your anatomy, symptoms and nutritional status.

Why OAGB Sometimes Needs Revision

OAGB, also known as mini gastric bypass, pairs a long, narrow stomach pouch with a single loop of small intestine connected roughly 150–200 cm downstream. It is widely performed and effective, but the loop design is linked to three recognized long-term problems: bile reflux into the pouch and esophagus, nutritional deficiency when the bypassed (biliopancreatic) limb is too long for a given patient's total bowel length, and weight regain in some patients. When the bypass itself is the problem, a sleeve conversion removes it.

Converting to a sleeve gastrectomy involves several steps:

• The gastrojejunostomy is taken down and the intestinal loop is restored to continuity.
• The pouch is joined to the remnant stomach (a gastro-gastrostomy), or the remnant is resected so the stomach is reconstructed as a single sleeve.
• The stomach is calibrated over a bougie to sleeve dimensions, and any hiatal hernia is repaired.

Food again passes the pylorus and duodenum, so iron, calcium, B12 and protein absorption return toward normal. The sleeve continues to limit portion size.

Before the intestine is reconnected, the full length of the small bowel is measured, since total bowel length differs widely from person to person and shapes how safe and effective the restored anatomy will be.

How a Sleeve Conversion Compares With Other OAGB Revisions

• Bile or acid reflux: usually conversion to Roux-en-Y gastric bypass or a targeted bile reflux revision, since a sleeve can worsen acid reflux
• Malnutrition: conversion to sleeve gastrectomy (this page), which restores normal absorption, or alternatively a limb-length revision or a Roux-en-Y conversion with a shorter limb
• Weight regain or persistent diabetes: a more powerful operation such as conversion to SADI-S or conversion to duodenal switch, or limb lengthening, rather than a sleeve
• Ulcers or hypoglycemia: conversion to sleeve is a strong option, as are pouch revision or Roux-en-Y conversion

Because problems after OAGB often overlap, your plan accounts for every issue, not just the main one.

• Restores normal absorption and corrects malnutrition
• Removes the gastrojejunostomy, eliminating marginal ulcer recurrence there
• Often resolves post-bypass hypoglycemia
• Restores normal endoscopic access to the duodenum and bile ducts
• Keeps a restrictive bariatric operation to help limit regain

• Malnutrition or deficiencies not correctable with supplements
• Recurrent or non-healing marginal ulcers
• Severe hypoglycemia after OAGB
• Chronic diarrhea or intolerance related to the bypass

Because a sleeve can worsen acid reflux, patients with significant reflux or bile reflux are usually better served by conversion to Roux-en-Y gastric bypass. Some weight regain should be expected.

Smokers need to quit before a sleeve conversion, and any nutritional deficits are corrected first. If you live out of town, much of the evaluation can be done by telehealth.

1. Laparoscopic or robotic access under general anesthesia
2. Takedown of the gastrojejunostomy and restoration of intestinal continuity
3. Reconnection or resection of the remnant stomach
4. Sleeve calibration and staple line reinforcement as needed
5. Hiatal hernia repair, leak testing and closure

OAGB-to-sleeve conversions are usually done through small incisions and generally take two to four hours, depending on scar tissue and how complex the reconstruction is.

• Leak along the new staple lines or connections, bleeding, infection, blood clots, and anesthesia risk, each somewhat higher in a revision than in a first operation
• Nutritional deficiencies, which should become less likely once absorption is restored but still depend on the final anatomy and call for lifelong supplements and labs
• Weight change in either direction, depending on the revision

• Hospital stay: usually one to two nights.
• Diet: over roughly four to six weeks, progress from clear liquids to protein shakes, then pureed and soft foods, and finally regular textures.
• Activity: walk on the day of surgery, return to desk work in about two weeks, and avoid heavy lifting for four to six weeks.
• Supplements and labs: take a bariatric multivitamin, calcium, vitamin D, B12 and iron as directed, and check nutrition labs at 3, 6 and 12 months, then once a year.
• Travel: out-of-town patients should plan to stay in Miami for approximately one week.

Most patients see nutrition and ulcer problems resolve after conversion. Weight usually stabilizes, with some regain in many patients. Ongoing dietitian support helps keep it in check. Reflux should be monitored, and medication or further treatment can be added if it develops.

To find out whether conversion to a sleeve gastrectomy is right for you, call 305-692-0392.

What the Research Shows

• A series of 10 patients revised for severe protein-energy malnutrition after OAGB found original bypassed limbs of 170–250 cm among those reversed to normal anatomy; the others had the limb shortened to 65–120 cm or were converted to Roux-en-Y bypass (Abu-Abeid et al., Nutrients, 2022).
• For comparison, a multicenter series of 23 OAGB-to-Roux-en-Y conversions was driven by bile reflux (61%), gastrogastric fistula (17%), severe malnutrition (13%) and leak (9%); by two years no patient reported bile reflux or had persistent malnutrition, and complications occurred in 22% with one reoperation (Antonopulos et al., Obesity Surgery, 2022).
• The ASMBS literature review on marginal ulcers notes that conversion to sleeve or reversal is reserved for the most difficult cases because of higher complication and nutritional-support rates (Vosburg et al., Surgery for Obesity and Related Diseases, 2024).

More in OAGB Revisions

Related procedures: OAGB to SADI Conversion, OAGB to Duodenal Switch Conversion, One-Anastomosis Gastric Bypass, OAGB to Gastric Bypass Conversion, OAGB Revision for Bile Reflux, OAGB Limb Length Revision. Related primary operations: Sleeve Gastrectomy. For an overview of all options, see Revisional Bariatric Surgery.

Related conditions after OAGB: Malnutrition After Bariatric Surgery, Marginal Ulcer, Bile Reflux, Weight Regain.

Dr. Nestor de la Cruz-Muñoz is a nationally recognized bariatric and metabolic surgeon with extensive experience in complex revisional surgery. He applies that expertise with the goal of a safe OAGB takedown, precise sleeve reconstruction, and durable long-term outcomes.

Undoing a mini gastric bypass and rebuilding a sleeve requires a surgeon comfortable with every type of bariatric anatomy. Dr. de la Cruz-Muñoz has more than 9,000 bariatric operations behind him across over 25 years of practice, a volume few surgeons reach.

Research and Publications

Dr. de la Cruz-Muñoz's published and presented work on this topic includes:

• Haidar Ahmad H, de la Cruz-Muñoz N. Revisional surgery outcomes. Poster presentation, ObesityWeek, 2013.
• Invited lecture: “Reversals and Elongations.” 3rd Annual International Symposium on Magnetic Gastrointestinal & Colon Surgery, Montreal, 2025.

When weight regain is part of the picture, further weight loss varies from patient to patient. If the sleeve conversion is done for malnutrition, ulcers or hypoglycemia without regain, weight may change very little.

Conversion to sleeve may improve dumping, stabilize glucose levels, and eliminate bile exposure. Metabolic improvements vary based on baseline anatomy and goals.

Because a sleeve is purely restrictive, lasting success relies on protein-forward meals, resistance training, avoiding slider foods, maintaining muscle, and consistent metabolic follow-up.

Sleeve gastrectomy may improve bile reflux but may worsen acid reflux in some patients. Patients with severe GERD may benefit more from conversion to gastric bypass. Hiatal hernia repair is performed when needed.

Future revision options include conversion to gastric bypass for reflux, conversion to SADI-S or DS for metabolic failure, or endoscopic revision depending on anatomy and goals.

Lean mass is worth protecting during weight change after sleeve conversion. Patients prioritize protein, do resistance training, keep hydrated, and have their body composition monitored.

Most insurers cover revisional surgery when medical necessity is documented, including bile reflux, marginal ulcer, or complications from OAGB.

The work-up before restoring a sleeve may include laboratory tests, imaging, endoscopy, a visit with our dietitian, a psychological evaluation, and review of your medications.

Eating resumes step by step: clear liquids, full liquids, purees, soft foods, then regular textures. Even with absorption restored, protein goals and vitamin supplements remain essential.

Walking starts right after the sleeve conversion. Keep activity light through the second week; most patients can begin resistance exercise at about four to six weeks.

If hypoglycemia is the reason for conversion, glucose logs or continuous glucose monitor data from home are very helpful to send in advance. International patients typically stay in Miami for approximately one week, with diet and glucose follow-up handled by telehealth.