Herein, we report the case of a 67-year-old woman who was admitted to our hospital because of dyspnoea and oedema of the lower extremities. Transthoracic echocardiography revealed severe tricuspid and
mitral regurgitation, and the leaflets of the tricuspid valve were found to be rigid and almost immobile. The plasma concentrations of
serotonin and
chromogranin A were elevated, and hence, suspicion for
carcinoid heart disease was raised. In addition to the diagnostic workup and medical and surgical treatment, we analysed levels of novel cardiovascular
biomarkers throughout the entire follow-up by means of
enzyme-linked
immunosorbent assay. A
dopa positron emission tomography (
DOPA-PET) was conducted and showed a
neoplasm in the terminal ileum. Tricuspid valve replacement, mitral valve repair, and a closure of the
patent foramen ovale (PFO) were conducted. Two months later,
hemicolectomy and liver segment resection were performed. The tumour was resected, and the diagnosis of a neuroendocrine tumour (NET) was confirmed. Throughout the follow-up, we observed a decrease in the plasma levels of novel
biomarkers [e.g.
interleukin-8 (IL-8), soluble suppression of tumorigenicity-2 (sST2), and heart-type
fatty acid-binding protein (
H-FABP)] over the follow-up period. In our case,
carcinoid heart disease resulted in a severe
tricuspid regurgitation as commonly seen in these patients. Moreover, a pre-existent
mitral regurgitation was likely aggravated by fibrotic remodelling, because a PFO has led to a right-to-left shunt and might have caused left heart involvement. As
IL-8 was associated with adverse outcomes in patients with NETs, and sST2 and
H-FABP were associated with adverse outcomes in patients with
heart failure previously, these
biomarkers could aid in the risk stratification of patients with NET.