Right ventricular area strain from 3-dimensional echocardiography: Mechanistic insight of right ventricular dysfunction in pediatric pulmonary hypertension

Transcatheter Ductus Arteriosus Stenting for Acute Pediatric Pulmonary Arterial Hypertension is Associated with Improved Right Ventricular Echocardiography Strain

BACKGROUND

Interventional therapies for severe pulmonary arterial hypertension (PAH) can provide right ventricular (RV) decompression and preserve cardiac output. Transcatheter stent placement in a residual ductus arteriosus (PDA) is one potentially effective option in critically ill infants and young children with PAH. We sought to assess recovery of RV function by echocardiographic strain in infants and young children following PDA stenting for acute PAH.

METHODS

Retrospective review of patients < 2 years old who underwent PDA stenting for acute PAH. Clinical data were abstracted from the electronic medical record. RV strain (both total and free wall components) was assessed from echocardiographic images at baseline and 3, 6, and 12 months post-intervention, as well as at last echocardiogram.

RESULTS

Nine patients underwent attempted ductal stenting for PAH. The median age at intervention was 38 days and median weight 3.7 kg. One-third (3of 9) of patients had PAH associated with a congenital diaphragmatic hernia. PDA stents were successfully deployed in eight patients. Mean RV total strain was - 14.9 ± 5.6% at baseline and improved to - 23.8 ± 2.2% at 6 months post-procedure (p < 0.001). Mean free wall RV strain was - 19.5 ± 5.4% at baseline and improved to - 27.7 ± 4.1% at 6 months (p = 0.002). Five patients survived to discharge, and four patients survived 1 year post-discharge.

CONCLUSION

PDA stenting for severe, acute PAH can improve RV function as assessed by strain echocardiography. The quantitative improvement is more prominent in the first 6 months post-procedure and stabilizes thereafter.

[Research progress of right ventricular strain imaging evaluation technology in pulmonary arterial hypertension]

Pulmonary arterial hypertension (PAH) has a subtle onset, rapid progression, and high mortality rate. Imaging evaluation is an important diagnostic and follow-up method for PAH patients. Right ventricular (RV) strain evaluation can identify early changes in RV function and predict the prognosis. Currently, various methods such as tissue Doppler imaging, velocity vector imaging, speckle tracking imaging, and cardiac magnetic resonance imaging can be used to evaluate RV strain in PAH patients. This article aims to summarize the research progress of RV strain imaging evaluation technology in PAH patients, in order to provide a basis for clinical diagnosis and follow-up of PAH patients.

Guidelines for Performing a Comprehensive Pediatric Transthoracic Echocardiogram: Recommendations From the American Society of Echocardiography

Echocardiography is a fundamental component of pediatric cardiology, and appropriate indications have been established for its use in the setting of suspected, congenital, or acquired heart disease in children. Since the publication of guidelines for pediatric transthoracic echocardiography in 2006 and 2010, advances in knowledge and technology have expanded the scope of practice beyond the use of traditional modalities such as two-dimensional, M-mode, and Doppler echocardiography to evaluate the cardiac segmental structures and their function. Adjunct modalities such as contrast, three-dimensional, and speckle-tracking echocardiography are now used routinely at many pediatric centers. Guidelines and recommendations for the use of traditional and newer adjunct modalities in children are described in detail in this document. In addition, suggested protocols related to standard operations, infection control, sedation, and quality assurance and improvement are included to provide an organizational structure for centers performing pediatric transthoracic echocardiograms.

Added value of 3D echocardiography in the diagnosis and prognostication of patients with right ventricular dysfunction

Recent inroads into percutaneous-based options for the treatment of tricuspid valve disease has brought to light how little we know about the behavior of the right ventricle in both health and disease and how incomplete our assessment of right ventricular (RV) physiology and function is using current non-invasive technology, in particular echocardiography. The purpose of this review is to provide an overview of what three-dimensional echocardiography (3DE) can offer currently to enhance RV evaluation and what the future may hold if we continue to improve the 3D evaluation of the right heart.

Three-Dimensional, Right Ventricular Surface Strain Computation From Three-Dimensional Echocardiographic Images From Patients With Pediatric Pulmonary Hypertension

Right Ventricular (RV) dysfunction is routinely assessed with echocardiographic-derived global longitudinal strain (GLS). GLS is measured from a two-dimensional echo image and is increasingly accepted as a means for assessing RV function. However, any two-dimensional (2D) analysis cannot visualize the asymmetrical deformation of the RV nor visualize strain over the entire RV surface. We believe three-dimensional surface (3DS) strain, obtained from 3D echo will better evaluate myocardial mechanics. Components of 3DS strain (longitudinal, LS; circumferential, CS; longitudinal-circumferential shear, ɣCL; principal strains PSMax and PSMin; max shear, ɣMax; and principal angle θMax) were computed from RV surface meshes obtained with 3D echo from 50 children with associated pulmonary arterial hypertension (PAH), 43 children with idiopathic PAH, and 50 healthy children by computing strains from a discretized displacement field. All 3DS freewall (FW) normal strain (LS, CS, PSMax, and PSMin) showed significant decline at end-systole in PH groups (p < 0.0001 for all), as did FW-ɣMax (p = 0.0012). FW-θMax also changed in disease (p < 0.0001). Limits of agreement analysis suggest that 3DS LS, PSMax, and PSMin are related to GLS. 3DS strains showed significant heterogeneity over the 3D surface of the RV. Components of 3DS strain agree with existing clinical strain measures, well classify normal -versus- PAH subjects, and suggest that strains change direction on the myocardial surface due to disease. This last finding is similar to that of myocardial fiber realignment in disease, but further work is needed to establish true associations.

Right ventricular contraction patterns in healthy children using three-dimensional echocardiography

Background

The right ventricle (RV) has complex geometry and function, with motion along three separate axes-longitudinal, radial, and anteroposterior. Quantitative assessment of RV function by two-dimension echocardiography (2DE) has been limited as a consequence of this complexity, whereas newer three dimensional (3D) analysis offers the potential for more comprehensive assessment of the contributors to RV function. The aims of this study were to quantify the longitudinal, radial and anteroposterior components of global RV function using 3D echocardiography in a cohort of healthy children and to examine maturational changes in these parameters.

Methods

Three-dimensional contours of the RV were generated from a cohort of healthy pediatric patients with structurally normal hearts at two centers. Traditional 2D and 3D echo characteristics were recorded. Using offline analysis of 3D datasets, RV motion was decomposed into three components, and ejection fractions (EF) were calculated (longitudinal-LEF; radial-REF; and anteroposterior-AEF). The individual decomposed EF values were indexed against the global RVEF. Strain values were calculated as well.

Results

Data from 166 subjects were included in the analysis; median age was 13.5 years (range 0 to 17.4 years). Overall, AEF was greater than REF and LEF (29.2 ± 6.2% vs. 25.1 ± 7.2% and 25.7 ± 6.0%, respectively; p < 0.001). This remained true when indexed to overall EF (49.8 ± 8.7% vs. 43.3 ± 11.6% and 44.4 ± 10%, respectively; p < 0.001). Age-related differences were present for global RVEF, REF, and all components of RV strain.

Conclusions

In healthy children, anteroposterior shortening is the dominant component of RV contraction. Evaluation of 3D parameters of the RV in children is feasible and enhances the overall understanding of RV function, which may allow improvements in recognition of dysfunction and assessment of treatment effects in the future.

Comprehensive ultrasound imaging of right ventricular remodeling under surgically induced pressure overload in mice

This study reports a new methodology for right heart imaging by ultrasound in mice under right ventricular (RV) pressure overload. Pulmonary artery constriction (PAC) or sham surgeries were performed on C57BL/6 male mice at 8 wk of age. Ultrasound imaging was conducted at 2, 4, and 8 wk postsurgery using both classical and advanced ultrasound imaging modalities including electrocardiogram (ECG)-based kilohertz visualization, anatomical M-mode, and strain imaging. Based on pulsed Doppler, the PAC group demonstrated dramatically enhanced pressure gradient in the main pulmonary artery (MPA) as compared with the sham group. By the application of advanced imaging modalities in novel short-axis views of the ventricles, the PAC group demonstrated increased thickness of RV free wall, enlarged RV chamber, and reduced RV fractional shortening compared with the sham group. The PAC group also showed prolonged RV contraction, asynchronous interplay between RV and left ventricle (LV), and passive leftward motion of the interventricular septum (IVS) at early diastole. Consequently, the PAC group exhibited prolongation of LV isovolumic relaxation time, without change in LV wall thickness or systolic function. Significant correlations were found between the maximal pressure gradient in MPA measured by Doppler and the RV systolic pressure by catheterization, as well as the morphological and functional parameters of RV by ultrasound.NEW & NOTEWORTHY The established protocol overcomes the challenges in right heart imaging in mice, thoroughly elucidating the changes of RV, the dynamics of IVS, and the impact on LV and provides new insights into the pathophysiological mechanism of RV remodeling.

Echocardiographic Assessment of Right Ventricular Function in Paediatric Heart Disease: A Practical Clinical Approach

As the right ventricle (RV) plays an integral role in different paediatric heart diseases, the accurate assessment of RV size and function is essential in the diagnosis, management, and prognostication of congenital and acquired cardiac lesions. Yet, echocardiographic evaluation of the RV is challenging because of its complex and variable morphology, its different physiology compared with the left ventricle, and its capability to adapt to different loading conditions associated with congenital and acquired heart diseases within certain ranges. Reliable echocardiographic detection of RV systolic and diastolic dysfunction remains challenging while important for patient management. This review provides an updated, practical approach to assessing RV function in structurally normal hearts and in children with common congenital heart defects and in those with pulmonary hypertension. We also review the impact of tricuspid valve function on RV functional parameters. There is no single functional RV parameter that uniquely describes RV function; instead a combination of different parameters is recommended in clinical practice. Qualitative and quantitative analysis of RV function will be reviewed including more recent techniques such as speckle tracking and 3D echocardiography.

Association of Three-Dimensional Mesh-Derived Right Ventricular Strain with Short-Term Outcomes in Patients Undergoing Cardiac Surgery

BACKGROUND

Three-dimensional (3D) right ventricular (RV) strain analysis is not routinely performed perioperatively. Although 3D RV strain adds incrementally to outcome prediction in various cardiac diseases, its role in the perioperative setting is not sufficiently understood. The aim of this study was to investigate the association between 3D RV strain measured on RV meshes created from 3D transesophageal echocardiographic data and short-term outcomes among patients undergoing cardiac surgery.

METHODS

A total of 496 patients undergoing cardiac surgery who underwent intraoperative 3D transesophageal echocardiography (under general anesthesia, before sternotomy) were retrospectively selected, and RV meshes were generated using commercially available speckle-tracking software. Custom-made software automatically quantified longitudinal and circumferential RV strains on the mesh surfaces. Echocardiographic and clinical parameters were entered into logistic regression models to determine their associations with the primary (in-hospital death or need for extracorporeal life support) and secondary (postoperative ventilation > 48 hours) end points.

RESULTS

Mesh-derived RV strain analysis was feasible in 94% of patients and revealed distinct regional patterns with basal-apical gradients for both longitudinal and circumferential strain. Thirty-seven patients (7.6%) reached the primary end point, and 118 patients (23.8%) reached the secondary end point. In a multivariable logistic regression model, serum lactate (P < .01), an emergency indication for surgery (P < .01), tricuspid regurgitation (P < .001), and mesh-derived RV global longitudinal strain (RV-GLS; P < .01) were independently associated with the primary end point, while established measures of RV function (3D RV ejection fraction, fractional area change, tricuspid annular plane systolic excursion) and left ventricular (LV) function (3D-derived LV ejection fraction and LV-GLS) were not independently associated. Hematocrit (P < .01), serum lactate (P < .001), pulmonary hypertension (P = .04), tricuspid regurgitation (P < .01), emergency procedures (P = .02), LV-GLS (P = .02), and RV-GLS (P < .001) were associated with the secondary end point.

CONCLUSIONS

RV-GLS measured on RV meshes derived from 3D transesophageal echocardiography was independently associated with short-term outcomes in patients undergoing cardiac surgery and might be helpful for identifying patients at risk for adverse postoperative events.

Right Ventricular Function and Its Coupling With Pulmonary Circulation in Precapillary Pulmonary Hypertension: A Three-Dimensional Echocardiographic Study

Objective: To assess right ventricular (RV) function and RV-pulmonary arterial (PA) coupling by three-dimensions echocardiography and investigate the ability of RV-PA coupling to predict adverse clinical outcomes in patients with precapillary pulmonary hypertension (PH). Methods: We retrospectively collected a longitudinal cohort of 203 consecutive precapillary PH patients. RV volume, RV ejection fraction (RVEF), and RV longitudinal strain (RVLS) were quantitatively determined offline by 3D echocardiography. RV-PA coupling parameters including the RVEF/PA systolic pressure (PASP) ratio, pulmonary arterial compliance (PAC), and total pulmonary resistance (TPR) were recorded. Results: Over a median follow-up period of 20.9 months (interquartile range, 0.1-67.4 months), 87 (42.9%) of 203 patients experienced adverse clinical outcomes. With increasing World Health Organization functional class (WHO-FC), significant trends were observed in increasing RV volume, decreasing RVEF, and worsening RVLS. RV arterial coupling (RVAC) and PAC were lower and TPR was higher for WHO-FC III+IV than WHO-FC I or II. The RVEF/PASP ratio showed a significant correlation with RVLS. RVAC had a stronger correlation with the RVEF/PASP ratio than other indices. Multivariate Cox proportional-hazard analysis identified a lower 3D RVEF and worse RVLS as strong predictors of adverse clinical events. RVAC, TPR, and PAC had varying degrees of predictive value, with optimal cutoff values of 0.74, 11.64, and 1.18, respectively. Conclusions: Precapillary-PH with RV-PA uncoupling as expressed by a RVEF/PASP ratio <0.44 was associated with adverse clinical outcomes. PAC decreased and TPR increased with increasing WHO-FC, with TPR showing better independent predictive value.