Divided gastric bypass surgery and vertical banded gastroplexy are major operations. Just like any other surgical procedure, it is important for you to understand their risks. Potential risks are the same as for any clinically severe obese patient undergoing any other major abdominal operation. The level of risk depends upon the degree of obesity and other conditions such as diabetes, heart and/or lung disease.

Obesity and these other conditions can increase complications of both the surgery and anesthesia. Possible complications include respiratory problems, infection, cardiac complications, leaks where intestine and stomach are sutured together, and blood clots in the deep veins of the legs. Rarely, death can result from heart attack or a blood clot to the lung, resulting from the body’s response to surgery. Gastric bypass is NOT cosmetic surgery. This procedure is performed only to try to prevent major illness or premature death from the complications of clinically severe obesity.

• Respiratory complications are a potential risk immediately after surgery. If a patient has another condition involving the respiratory tract, a pulmonary evaluation with a lung specialist before surgery may be recommended. During the operation, special forms of anesthesia may be necessary to minimize effect on the lungs. Using an incentive spirometer every 1 to 2 hours after surgery will promote deep breathing and coughing to prevent lung complications. If you are able, you will be helped to sit up in a chair several hours after you wake up from surgery, which will also help your lungs.
• A leak or rupture where the intestine is joined to the stomach is serious and may require an immediate return to the operating room to be corrected. On the morning after surgery, you may have an x-ray test called a gastrograffin swallow, to make sure there is no leak. If a leak is detected, re-operation is required and additional drains are inserted. You will be given a feeding tube for nutritional formula to be passed into your intestinal tract below the leak, to allow the site to heal. In some cases, the radiologist in x-ray may place a drain to eliminate the need for this surgery.
• Constipation. After surgery, you may be constipated. Remember that you will be eating less, and you will have fewer bowel movements. Many people report having a bowel movement every two to three days. You will get instructions about drinking more fluids, taking a stool softener, doing exercises, and adding fiber to your diet to help prevent constipation.
• Blood clotting in the leg veins and clots migrating to the lungs are a possibility and could be serious. The larger a person is, the more likely it will happen. Low dose injections of heparin, a blood thinner, are used to prevent clots from forming during times of maximum risk. Also, inflatable boots, elastic stockings and frequent walking after surgery help to decrease the risk of blood clots.
• Bleeding during or after the surgery is a complication. Doctors pay close attention to controlling bleeding throughout the operation, with special efforts paid to the spleen and other places where bleeding is more common. If bleeding occurs, blood transfusion, re-operation, and potentially removal of the spleen may be required.

Other potential complications may occur months or even years following gastric bypass surgery.