Endocrine Abstracts

Introduction: Neuroendocrine tumours of the gastrointestinal tract often cause carcinoid syndrome and in advance cases carcinoid heart disease. These tumours secrete serotonin, which can bind to heart valves and cause fibrosis and eventually valve incompetence. Most cases involve the tricuspid valve +/− pulmonary valve. Medical management comprises diuretics for fluid overload and somatostatin analogues to reduce circulating serotonin. Definitive treatment is heart-valve replacement surgery which improves exercise tolerance but has high perioperative mortality. We have previously reported that valve-replacement surgery can reduce 5-HIAA levels, reflecting a decline in tumour activity. The purpose of this study is to confirm these findings and investigate the reason for this effect. The liver is known to degrade serotonin and other tumour products; therefore, it is possible that reduction in 5HIAA is related to improvements in liver function. We investigated the role of the kidneys also.

Methods: Included in this study were all patients from the Queen Elisabeth Hospital Birmingham who had undergone heart-valve replacement surgery from 2010 to 2019 (n=40). After exclusion criteria were applied, we were left with 17 patients. We collected tumour markers, liver function data and renal function data pre- and post-surgery using electronic patient records. Data analysis was performed using SPSS.

Results: Patients with carcinoid heart disease saw a 31% drop in 5-HIAA (P = 0.011) and a 35% drop in bilirubin (P<0.001) after valve-replacement surgery. Urea and creatinine did not significantly improve (P = 0.463, 0.349 respectively).

Conclusion: Valve replacement surgery improves 5-HIAA levels alongside improved liver function. This is consistent with resolution of right heart failure induced congestive hepatopathy. The impaired renal function, a consequence of heart failure, did not improve, likely due to the additional stress that cardiac surgery and cardiac bypass places on the patient’s kidneys.