Echocardiographic Follow-Up of Treated Patients With Carcinoid Syndrome

Carcinoid heart disease is a rare disease, and its prevalence is uncertain. The aim of the present prospective study was to assess the prevalence of carcinoid heart disease using annual echocardiographic follow-up. We studied 80 consecutive patients presenting with histologically proven digestive endocrine tumor and carcinoid syndrome. All patients underwent annual conventional transthoracic echocardiographic studies and measurement of biologic carcinoid markers. Right- and left-sided carcinoid heart disease and the score of the severity of carcinoid heart disease were systematically assessed. At baseline, the prevalence of right- and left-sided carcinoid heart disease was 33% and 8%, respectively. At the end of follow-up, the corresponding prevalence was 53% and 21%. The correlations were strong between urinary 5-hydroxyindoleacetic acid (5-HIAA) and the right-sided carcinoid heart disease score (r = 0.75, p <0.0001), between urinary 5-HIAA and the left-sided carcinoid heart disease score (r = 0.83, p = 0.001), and between urinary 5-HIAA and the overall carcinoid heart disease score (r = 0.84, p <0.0001). All patients with ≥3 years of carcinoid syndrome and increased level of urinary 5-HIAA presented with echocardiographic evidence of valve disease on routine monitoring. In conclusion, the prevalence of carcinoid heart disease remained high and increased during follow-up. Carcinoid heart disease progresses over time, highlighting the need for echocardiographic follow-up once carcinoid syndrome has been diagnosed.