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Risks of Gastric Bypass Surgery: Anastomotic Leaking

If you are severely obese and have had trouble losing weight, your healthcare provider tor may recommend weight loss surgery. Weight loss surgery is also known as bariatric surgery. It is an effective way to lose weight and reduce the risk for weight-related problems. These include heart disease, diabetes, high blood pressure, stroke, sleep apnea, and arthritis.

One type of weight loss surgery is the gastric bypass. As with any surgery, gastric bypass carries some risks. Complications of surgery include infection, blood clots, and internal bleeding. Another risk is an anastomosis. This is a new connection created in your intestines and stomach during the bypass surgery that will not fully heal and will leak. Leaking of digestive juices and partially digested food through an anastomosis is one of the most serious complications after gastric bypass surgery. 

Gastric bypass overview

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Gastric bypass is one common type of weight-loss surgery. During bypass surgery, the top of the stomach is changed into a small gastric pouch. A loop of your small intestine is cut, and one end of the loop is brought up and is connected to the gastric pouch. This connection is one anastomosis. The other end of the small intestine loop is reconnected to the small intestine, further down. This is another anastomosis. 

Food is then redirected to an area farther down in your digestive system. It bypasses the stomach. Because food will now bypass your stomach, your body does not absorb as many calories. You will feel full much faster after eating.  

Your healthcare provider may suggest this surgery if you have a body mass index (BMI) of 40 or higher or if you have a BMI of 35 or higher along with serious weight-related, health problems. A BMI of more than 40 typically means that you are at least 100 pounds overweight.

Symptoms of anastomotic leaking

Anastomotic leaks happen in 1.5% to 6% of bypass procedures, depending on the type of surgery. A leak may happen up to several weeks later. Most develop within 3 days after surgery. Symptoms of an anastomotic leak include:

  • Rapid heart rate

  • Fever

  • Stomach pain

  • Drainage from a surgical wound

  • Nausea and vomiting

  • Pain in the left shoulder area

  • Low blood pressure

  • Decreased urine output

The more obese you are, the more at risk you are for an anastomotic leak. Other risk factors include being male, having other medical problems besides obesity, and having a history of previous abdominal surgery.

Diagnosis and treatment of anastomotic leaking

A diagnostic test used to look for anastomotic leaking is an upper GI or a CT scan. Both involve swallowing some liquid contrast dye and then taking X-rays to see if the dye is leaking through the anastomosis. Even if you have a negative exam but still have symptoms, your healthcare provider may recommend an emergency operation to look for a leak. 

The medical team treating an anastomotic leak will likely take these steps:

  • Give you antibiotics through an intravenous line (IV). 

  • Drain any infection caused by the leak, repair the leak, or make a new anastomosis by operating again.

  • Use an upper endoscopy to place a temporary stent across the leaking area, from the inside of the gastric pouch or the small intestine. 

  • Stop all oral feedings. You may be fed through a tube that goes directly into your intestine until the leak has healed.

Risks of anastomotic leaking         

A leaking anastomosis may cause bleeding and infection until it is treated. These leaks are serious and can be life-threatening. Long-term complications may include ulcers, scarring, and narrowing of the anastomosis (where the intestine is connected to the gastric pouch), known as a stricture. A drainage tract through the skin called a fistula may also develop. A fistula could develop between the gastric pouch and the bypassed stomach. Pneumonia is another dangerous complication, because digestive juices can spill into the lungs. 

If you are considering gastric bypass surgery for obesity, discuss the procedure carefully with your healthcare provider. The overall risk of serious complications should be weighed against the risk of continued obesity. Remember that gastric bypass surgery works best when combined with long-term, healthy lifestyle choices. These involve good nutritional eating habits and regular exercise. 

Medical Reviewers:

  • Meilahn, John, MD
  • Sather, Rita, RN