Washington DC Veterans Health Administration Washington, DC
Introduction: Sleeve gastrectomy is the most common bariatric surgery performed in the US and leads to significant weight loss and improvement in metabolic syndrome. Based on manufacture’s recommendations, accuracy of vibration controlled transient elastography (VCTE) with ECHOSENS Fibroscan results are uncertain in patients with body mass index (BMI) greater than 30 kg/m^2. However, we routinely utilize Fibroscan to identify liver fibrosis stage prior to sleeve gastrectomy. We evaluated the accuracy of Fibroscan results in individuals with obesity compared to the gold standard liver biopsy performed at time of sleeve gastrectomy.
Methods: This is a retrospective study of 90 patients who underwent sleeve gastrectomy between January 1, 2018- September 19, 2021 at a Veterans Affairs medical center. Liver biopsy at the time of surgery is standard practice at our center. Patients with known alcohol use, without a Fibroscan prior or without a liver biopsy at the time of surgery were excluded. 28 patients had both liver biopsy and pre-operative Fibroscan. Summary statistics were used to determine the prevalence of NAFLD at time of surgery and sensitivity and specificity for Fibroscan testing compared to liver biopsy.
Results: 34% of patients had abnormal ALT and 21% had abnormal AST prior to bariatric surgery. There was no evidence of liver synthetic dysfunction with normal INR, bilirubin and albumin. Pre-operative median liver stiffness measurement was 5.2 kPa. Fibroscan results showed 93% of patients with no to mild fibrosis (stage F0-F1) and 7% with F2, and no patients had F3 or F4 fibrosis preoperatively. 90% of patients had no evidence of fibrosis or mild fibrosis (stage 0-1) and 10% of patients had stage 2 (moderate) fibrosis on liver biopsy. There were 2 patients (6%) with liver stiffness consistent with F1 and liver biopsy showing F2 fibrosis. Fibroscan results had a negative predictive value of 92%.
Discussion: There is a high prevalence of fatty liver disease without fibrosis in the veteran patients undergoing sleeve gastrectomy. Although the utility of Fibroscan to determine fibrosis in BMI above 30 is uncertain, fibrosis staging is nearly 94% accurate in our patient population with high negative predictive value. Non-invasive testing utilizing Fibroscan predicted the lack of advanced fibrosis and may be useful for risk stratification prior to bariatric surgery.
