Significance of strictly defined idiopathic tricuspid regurgitation

Moderate to severe tricuspid regurgitation (TR) is known to cause right ventricular (RV) failure and death. Although TR is traditionally classified as primary or secondary, recently, a new class of TR called idiopathic TR has been proposed, with varying definitions among different studies.

The data were retrospectively collected for the period of January to June 2018 for 8711 patients from the patient cohort of the National Cheng Kung University Hospital echocardiography laboratory. A total of 670 patients (7.7%) with moderate-to-severe TR were included. Idiopathic TR was diagnosed strictly using a new systematic approach.

The distribution of significant TR included 74 (11.0%) primary TR cases, 48 (7.2%) with pacemaker-related TR, 267 (39.9%) with left heart disease, 24 (3.6%) with congenital heart disease, 6 (0.9%) with RV myopathy, 105 (15.7%) with pulmonary hypertension, and 146 (21.8%) with idiopathic TR. The mean age in primary and idiopathic TR groups was older ( p = 0.004), with lower estimated pulmonary pressure ( p < 0.001), higher RV fraction area change (FAC, p < 0.001), and tricuspid annulus systolic velocity (S', p = 0.004) compared with functional TR group. Multivariate analysis showed that idiopathic TR ( p = 0.002) and primary TR ( p = 0.008) had better RV FAC than functional TR.

Idiopathic TR was associated with better RV function than the other secondary TRs. Thus, idiopathic TR should be strictly defined and regarded as a distinct type of TR.