Tricuspid regurgitation (TR) has gained attention in recent years due to its prognostic significance and the emergence of transcatheter interventional treatments. However, not all TR is not a homogenous condition, and classification of TR has been proposed distinguishing atrial from ventricular TR.

We sought to define patients with TR into atrial vs. ventricular forms as defined by Schlotter et al. and assess markers of right ventricular function between the two groups and compare prognosis.

The study analyzed 138 patients with severe or more functional TR and divided them into either atrial or ventricular TR. Atrial TR was defined, as proposed by Schlotter et al., by the following parameters: tenting height ≤10mm, RV midventricular diameter ≤38mm, LVEF ≥50%.

According to the definition, 58 patients (42%) had atrial TR, including 57% of women, 73% of patients had atrial fibrillation. The groups were comparable in terms of gender, age, and comorbidities. Significant differences were found between atrial and non-atrial TR in TR Vmax (P=0.0411), systolic and mean pulmonary artery pressure (respectively, P=0.0232 and P=0.0238), right atrial surface area (P=0.0397), tricuspid annular dimension (P=0.0016), LVEF (P<0.0001), TAPSE (P=0.069), right ventricle fractional area change (P=0.0345). However, TAPSE/systolic PAP ratio, right atrial strain, and RV free wall strain were not significantly different between the groups. Patients with atrial TR appeared to have better survival (Fig. 1), but this was not statistically significant in the 5-year Log-Rank test (P=0.1983). A post-hoc survival analysis excluding the grade 5 TR cases did not show a significant difference based on atrial status of the TR (P=0.243).

The results of this study support that the classification of TR based on atrial and non-atrial parameters is possible. Mortality was high in this cohort and compared to the findings of Schlotter et al., no significant survival difference was observed between the groups. Our patients had a higher proportion of torrential TR but even when this group was excluded there still was no significant difference in terms of survival. The utility of this grouping system needs to be explored in predicting response to treatment and prognosis in a prospective study powered appropriately.