Prevalence and predictive factors for clinical outcomes of isolated functional tricuspid regurgitation

Background: A substantial number of patients have functional tricuspid regurgitation (TR). Isolated functional TR has been undertreated and may be a next target for transcatheter intervention. However, the prevalence, patient characteristics, and predictive factors for prognosis remain unclear. Methods: From patients in our echocardiographic database (N = 64,242), we extracted those with severe TR and examined prognosis according to etiologies of TR. Thereafter, we focused on two types of isolated functional TR; progressive TR after left-sided valve surgery (postoperative TR) and TR associated with annular dilatation (atrial TR). Composite adverse events were defined as all-cause death or hospitalization for heart failure (HF). Results: Of 1001 patients with severe TR (median age, 77 years; female, 58 %), 71 (7 %) patients were classified as postoperative TR, and 149 (15 %) as atrial TR. During the follow-up period (median, 1.6 years), 30 composite adverse events were observed (postoperative TR, n = 14; atrial TR, n = 16). Composite adverse events were less frequent in these two types of functional TR than TR of other etiologies. Multivariate analysis adjusted for age and sex showed that a history of hospitalization for HF, history of cardiac surgery >2 times, loop diuretics, estimated glomerular filtration rate, blood urea nitrogen, hemoglobin, platelet level, left ventricular ejection fraction, and right ventricular dimension were associated with clinical adverse events (p < 0.05), while B-type natriuretic peptide level was not. Conclusions: A considerable number of patients had isolated functional TR. Extracardiac factors such as renal function, hemoglobin and platelet are important in determining clinical outcomes.