3-Dimensional Versus 2-Dimensional STE for Right Ventricular Myocardial Fibrosis in Patients With End-Stage Heart Failure

Background: Longitudinal strain of the right ventricular (RV) free wall (RVFWLS) assessed by 2-dimensional (2D) speckle-tracking echocardiography (STE) has been recently demonstrated to correlate with the extent of RV myocardial fibrosis (MF). However, the value of 3-dimensional (3D) STE-derived strain parameters in predicting RV MF has not been investigated in patients with end-stage heart failure (HF).

Objectives: This study aimed to determine which RV strain parameter assessed by 2D-STE and 3D-STE was the most reliable parameter for predicting RV MF in patients with end-stage HF against histological confirmation of MF.

Methods: A total of 105 consecutive patients with end-stage HF undergoing heart transplantation were enrolled in our study. The conventional RV function parameters, 2D-RVFWLS, and 3D-RVFWLS were obtained in these patients. The degree of MF was quantified by Masson trichrome staining in RV myocardial samples. The study population was divided into 3 groups according to the degree of MF on histology.

Results: Patients with severe MF had lower 3D-RVFWLS, 2D-RVFWLS, and conventional parameters of RV function compared with those with mild and moderate MF. RV MF strongly correlated with 3D-RVFWLS (r = -0.72; p < 0.001), modestly with 2D-RVFWLS (r = -0.53; p < 0.001), and weakly with conventional RV function parameters (r = -0.21 to -0.49; p < 0.01). 3D-RVFWLS correlated best with the degree of MF (r = -0.72 vs. -0.21 to -0.53; p < 0.05) compared with 2D-RVFWLS and conventional RV function parameters. 3D-RVFWLS had the highest accuracy for detecting severe MF (area under the receiver-operating characteristic curve: 0.90 vs. 0.24-0.80; p < 0.05) compared with 2D-RVFWLS and conventional RV parameters. The model with 3D-RVFWLS (R² = 0.63; p < 0.001) was better in predicting the degree of RV MF than that with 2D-RVFWLS (R² = 0.54; p < 0.001).

Conclusions: 3D-RVFWLS may be the most robust echocardiographic measure for predicting the extent of RV MF in patients with end-stage HF.