Mitigation of Variability among 3D Echocardiography-Derived Regional Strain Values Acquired by Multiple Ultrasound Systems by Vendor Independent Analysis

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.

Regional Left Ventricular Myocardial Dysfunction After Cardiac Surgery Characterized by 3-Dimensional Strain

BACKGROUND

Three-dimensional (3D) strain is an echocardiographic modality that can characterize left ventricular (LV) function with greater accuracy than ejection fraction. While decreases in global strain have been used to predict outcomes after cardiac surgery, changes in regional 3D longitudinal, circumferential, radial, and area strain have not been well described. The primary aim of this study was to define differential patterns in regional LV dysfunction after cardiac surgery using 3D speckle tracking strain imaging. Our secondary aim was to investigate whether changes in regional strain can predict postoperative outcomes, including length of intensive care unit stay and 1-year event-free survival.

METHODS

In this prospective clinical study, demographic, operative, echocardiographic, and clinical outcome data were collected on 182 patients undergoing aortic valve replacement, mitral valve repair or replacement, coronary artery bypass graft, and combined cardiac surgery. Three-dimensional transthoracic echocardiograms were performed preoperatively and on the second to fourth postoperative day. Blinded analysis was performed for LV regional longitudinal, circumferential, radial, and area strain in the 17-segment model.

RESULTS

Regional 3D longitudinal, circumferential, radial, and area strains were associated with differential patterns of myocardial dysfunction, depending on the surgical procedure performed and strain measure. Patients undergoing mitral valve repair or replacement had reduced function in the majority of myocardial segments, followed by coronary artery bypass graft, while patients undergoing aortic valve replacement had reduced function localized only to apical segments. After all types of cardiac surgery, segmental function in apical segments was reduced to a greater extent as compared to basal segments. Greater decrements in regional function were seen in circumferential and area strain, while smaller decrements were observed in longitudinal strain in all surgical patients. Both preoperative regional strain and change in regional strain preoperatively to postoperatively were correlated with reduced 1-year event-free survival, while postoperative strain was not predictive of outcomes. Only preoperative strain values were predictive of intensive care unit length of stay.

CONCLUSIONS

Changes in regional myocardial function, measured by 3D strain, varied by surgical procedure and strain type. Differences in regional LV function, from presurgery to postsurgery, were associated with worsened 1-year event-free survival. These findings suggest that postoperative changes in myocardial function are heterogeneous in nature, depending on the surgical procedure, and that these changes may have long-term impacts on outcome. Therefore, 3D regional strain may be used to identify patients at risk for worsened postoperative outcomes, allowing early interventions to mitigate risk.

Evaluation of left and right ventricular myocardial function after lung resection using speckle tracking echocardiography

The impact of major lung resections on myocardial function has not been well-investigated. We aimed to identify this impact through the use of speckle tracking echocardiography (STE) to evaluate the right and left ventricular myocardial function in patients who underwent lung resections.Thirty patients who had lung resections were recruited for this study. Ten patients who underwent pneumonectomies were matched by age and sex, with 20 patients who underwent lobectomies. STE was performed on both right and left ventricle (RV and LV). Strain values of pre and postlung resections were compared in both the pneumonectomy group and the lobectomy group. Comparison between the pneumonectomy group and the lobectomy group was also studied.Left ventricular ejection fraction remained normal (>55%), but significantly decreased after lung resection in both the pneumonectomy group and the lobectomy group. An accelerated heart rate was observed in both groups after lung resection, with the pneumonectomy group demonstrating extra rapid heart rate (P < 0.05). Strain values in the RV and LV decreased in both groups after lung resection, with the pneumonectomy group exhibiting a further decrease in longitudinal strain in LV and RV when compared with the lobectomy group (P < 0.05).Right and left ventricular dysfunction can occur after lung resection regardless of pneumonectomy or lobectomy, and lobectomy may have a less significant impact on myocardial functions. This study demonstrated that STE is able to detect acute cardiac dysfunction after lung resection.