Surgical Correction of Carcinoid Heart Disease Improves Liver Function and 5-Hydroxyindoleacetic Acid Levels

INTRODUCTION: Carcinoid heart disease (CHD) is a consequence of neuroendocrine tumors releasing 5-hydroxytryptamine (5-HT) into the systemic circulation, affecting right heart valves, causing fibrosis, and eventually right heart failure. The aim of this study was to determine the effect of valve-replacement on kidney function, liver function, and 5-hydroxyindoleacetic acid (5-HIAA) levels. METHODS: A Retrospective study of 17 patients with CHD who had undergone heart-valve replacement surgery between 2010 and 2019, from the Queen Elizabeth Hospital Birmingham. 5-HIAA levels, liver, and kidney function were measured in addition to hepatic inferior vena cava (IVC) diameter and its relationship to carcinoid symptoms. RESULTS: Eleven patients were male and six were female. At time of surgery, average age was 66.6 ± 8.1 years and average BMI was 25.8 ± 5.5 Kg/cm(2). Three out of 17 patients had one valve replaced, 13/17 had two replaced (tricuspid and pulmonary), and 1/17 had three replaced (tricuspid, pulmonary and aortic). There was a 31% average decline in 5-HIAA [799.8 (343.6–1078.0) to 555.3 (275.8–817.9), p = 0.011], a 35% decline in bilirubin [20 (16–29) to 13 (10–19), p = < 0.001], and a 15% reduction in the short and long axes of the IVC after valve-replacement surgery [20.0 (18.0–25.0) and 36.5 (29.0–39.8) to 17.0 (14.5–19.3) and 31.0 (26.5–34.3) respectively, p = < 0.001 and 0.002 respectively]. CONCLUSION: Valve replacement surgery improves 5-HIAA levels alongside improved liver function and hepatic IVC diameter. These findings are consistent with resolution of congestive hepatopathy, and therefore enhanced clearance of 5-HIAA. This suggests that valve-replacement surgery can indirectly have beneficial outcomes on hepatic function and is also associated with a drop in the circulating levels of tumor derived serotonin.