Tricuspid Anatomic Regurgitant Orifice Area by Cardiac Computed Tomography: Novel Outcome Insights

Anatomic regurgitant orifice area (AROA) can be measured by 4-dimensional (4D)-computed tomography angiography (CTA) to define tricuspid regurgitation (TR) severity, but its association with outcomes has not been established.

This study aims to assess the independent prognostic value of TR quantification by 4D-CTA AROA measurement.

Comprehensive clinical, echocardiographic and 4D-CTA data were collected from patients with clinically significant TR evaluated at 4 Allina Health centers between 2019 and 2023 for TR intervention. The outcome of interest was all-cause mortality under medical management after diagnosis.

AROA measurement was obtained in 174 patients (median age 83 years [Q1-Q3: 77- 97 years], left ventricular ejection fraction 58% [Q1-Q3: 51%-60%], right ventricular [RV] ejection fraction 46% [Q1-Q3: 41%-51%] and tricuspid AROA 0.74 cm² [Q1-Q3: 0.55-1.42 cm²]). During a median follow-up of 2.3 years [Q1-Q3: 1.1-3.2 years], 49 (28%) patients died under medical management with 3-year survival rate of 55% [Q1-Q3: 45%-67%]. Spline curve analysis showed that AROA 1.1 cm² was the threshold associated with increased mortality within the cohort. Patients with AROA ≥1.1 cm² had higher TRI-SCOREs, larger tricuspid annulus dimension, tricuspid maximum coaptation gap, RV and right atrial volumes (all P < 0.001). Despite similar RV ejection fraction, patients with AROA ≥1.1 cm² had worse RV function denoted by lower RV free-wall longitudinal strain (P < 0.001) compared to those with AROA <1.1 cm². In multivariable analysis, AROA ≥1.1 cm² remained independently associated with excess mortality (adjusted HR 2.23 [95% CI: 1.02-4.85]; P = 0.040) and worse 3-year survival under medical management (68% [Q1-Q3: 56%-82%] vs 36% [Q1-Q3: 28%-52%]; P = 0.013).

This first outcome study of patients with clinically significant TR examined by 4D-CTA shows that higher AROA measurement strongly associates with worse right heart remodeling and independently associates with excess mortality. Therefore, 4D-CTA, beyond anatomical assessment, provides prognostically relevant assessment of TR severity. Thus, AROA measurement should be considered in patients with TR evaluated by 4D-CTA.