3D Echocardiographic and CMR Imaging for the Assessment of Right Ventricular Function and Tricuspid Regurgitation Severity.

BACKGROUND

Tricuspid regurgitation (TR) is associated with increased mortality and is often underdiagnosed due to limitations in imaging modalities. While routine 2-dimensional echocardiography (2DE) demonstrates frequent disagreement with cardiac magnetic resonance imaging (CMR) in classifying TR severity, the incremental value of 3-dimensional echocardiography (3DE) remains unknown also due to the lack of a generalizable grading scheme across imaging modalities. Therefore, this study provides an intermodality comparison of all 3 imaging modalities (2DE, 3DE, and CMR) in evaluating TR severity and proposes an adapted 5-class grading scheme for TR severity using CMR.

METHODS

A total of 144 patients with symptomatic TR were analyzed across 2 cohorts: a derivation cohort (n=91) from the University Hospital of Munich and a validation cohort (n=53) from the Heart Center Leipzig. All patients underwent multimodality imaging, including transthoracic 2DE, transesophageal 3DE, and CMR. The adapted 5-class CMR-based grading scheme was proposed and externally validated.

RESULTS

In the derivation cohort (median age 81 years, 66% female), TR severity grading by 3DE highly correlated with CMR (87% concordance within a 1-grade difference), significantly outperforming 2DE (68% concordance). While 3DE underestimated right ventricular dimensions compared with CMR (P<0.001), it provided a comparable measure of TR severity and right ventricular function. 2DE achieved the lowest accuracy rates compared with CMR (34.5%; P=0.005) with frequent overestimation of TR severity. An overestimation of TR severity by 3DE compared with CMR was significantly less frequent than with 2DE (21% versus 56%; P<0.001). Cohen κ analysis confirmed a substantial and superior agreement between 3DE and CMR compared with 2DE (κ=0.63 versus 0.41; P=0.01). The results were externally validated, showing comparable results within the derivation and validation cohorts.

CONCLUSIONS

3DE provides an accurate assessment of TR severity comparable to CMR. The proposed 5-class grading scheme for TR severity using CMR demonstrates high accuracy and external validity.