Hepatic Effects of Gastric Bypass Surgery

Before or on the day of surgery liver function will be determined using the DDG-2001 Analyzer. This monitor is able to detect the concentration of a dye called indocyanine green dye (ICG) when present in the blood stream. A dose of 0.5 mg/kg of ICG will be injected into an IV in the arm. Over approximately fifteen minutes the DDG-2001 Analyzer will determine how quickly the liver removes the dye ICG from the blood stream. This value represents how well the liver is functioning. Blood samples are drawn before injection of ICG to measure liver function using standard liver function tests. This same routine for injecting ICG and obtaining blood for routine liver function tests will happen one more time, after surgery, once the subject has lost a significant amount of the original weight (60% of excess weight). This amount of weight loss typically occurs between 12 to 18 months after gastric bypass surgery. This second ICG measurement will occur during an outpatient follow-up visit to CCF. A biopsy will be taken from the liver during surgery. A second biopsy taken after the 60% weight loss will be compared to determine the effect of this surgery on the liver.