End-Diastolic Forward Flow and Restrictive Physiology in Repaired Tetralogy of Fallot: A Systematic Review and Meta-Analysis

Echocardiographic assessment of Right Ventricular Diastolic Function in Children and Adults: Present State and Future Directions

Diastolic function plays an important but often overlooked role in overall ventricular performance and is comprised of sequence of events which together result in adequate filling at low filling pressures. From a physiologic point of view there are two distinct, yet related periods that drive diastole: active relaxation and late filling. Much of the literature on diastolic function is based on the left ventricle however there are significant differences in morphology, physiology and adaptation between ventricles. Echocardiographic assessment of RV diastolic function is challenging due to our imperfect understanding in RV physiology, suboptimal imaging tools and the use of models that have been built using the left ventricle. Conventional assessment includes IVC size, RA volume and the use of Doppler to quantify tissue and blood velocity (TV E/A, e', a', E/e', IVRT, hepatic vein and pulmonary artery). In adults, TV E/A used in combination with e', IVC size, may be used to classify diastolic impairment however in children this is dependent to a greater degree on age and pathology. Right atrial and ventricular strain suffers from fewer limitations and may show incremental benefit however remains understudied, particularly in children. Novel methods made possible with ultrafast ultrasound provide a means to non-invasively assess intraventricular pressure differences as a measure of active relaxation, and shear wave velocity to directly assess myocardial stiffness, however these remain in pre-clinical stages. This review discusses right ventricular diastolic physiology, the current state and limitations of echocardiographic evaluation and explores promising new methods for its assessment.

Residual Pulmonary Valve Disease Following Repair of Tetralogy of Fallot-Is Stenosis Better Than Regurgitation?

BackgroundResidual pulmonary valve disease (PVD) including pulmonary stenosis (PS), pulmonary regurgitation (PR), or both remains a known complication following repair of Tetralogy of Fallot (TOF). We sought to clarify prevalence, progression, and prognostic impact of residual PVD.MethodsWe identified consecutive patients who underwent repair of TOF at our institution between January 2004 and July 2023. Based on echocardiographic measurements following repair, residual PVD was defined: nonsevere PVD (PS < 25 mm Hg; PR Collapse

Key Words

• annulus-sparing repair
• pulmonary valve
• tetralogy of Fallot
• transannular patch

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Affiliation(s)

Maria von Stumm Department of Congenital and Pediatric Heart Surgery, German Heart Center Munich, Technical University of Munich, School of Medicine, Munich, Germany Division of Congenital and Paediatric Heart Surgery, University Hospital of Munich, Ludwig-Maximilians-Universität, Munich, Germany European Kids Heart Centre, Munich, Germany
Gregory Heger Department of Congenital and Pediatric Heart Surgery, German Heart Center Munich, Technical University of Munich, School of Medicine, Munich, Germany European Kids Heart Centre, Munich, Germany
Julia Danner Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, Technical University of Munich, School of Medicine & Health, Munich, Germany
Zahra Alalawi Department of Congenital and Pediatric Heart Surgery, German Heart Center Munich, Technical University of Munich, School of Medicine, Munich, Germany Division of Congenital and Paediatric Heart Surgery, University Hospital of Munich, Ludwig-Maximilians-Universität, Munich, Germany European Kids Heart Centre, Munich, Germany
Cordula Wolf Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, Technical University of Munich, School of Medicine & Health, Munich, Germany DZHK (German Centre for Cardiovascular Research), Munich, Germany
Katarzyna Gendera Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, Technical University of Munich, School of Medicine & Health, Munich, Germany
Stanimir Georgiev Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, Technical University of Munich, School of Medicine & Health, Munich, Germany
Peter Ewert Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, Technical University of Munich, School of Medicine & Health, Munich, Germany
Jürgen Hörer Department of Congenital and Pediatric Heart Surgery, German Heart Center Munich, Technical University of Munich, School of Medicine, Munich, Germany Division of Congenital and Paediatric Heart Surgery, University Hospital of Munich, Ludwig-Maximilians-Universität, Munich, Germany European Kids Heart Centre, Munich, Germany
Julie Cleuziou Department of Congenital and Pediatric Heart Surgery, German Heart Center Munich, Technical University of Munich, School of Medicine, Munich, Germany Division of Congenital and Paediatric Heart Surgery, University Hospital of Munich, Ludwig-Maximilians-Universität, Munich, Germany European Kids Heart Centre, Munich, Germany

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Retrospective Evaluation of End-Diastolic Forward Flow and Restrictive Physiology in One Hundred and Sixty-Four Dogs with Pulmonary Stenosis

The study of the function of the right ventricle (RV) is a topic of great interest in the scientific community, and some studies have evaluated parameters of the right ventricular systolic function and have correlated them to various RV pathologies and possible clinical findings. Less information was obtained on the right ventricular diastolic function. In veterinary medicine, the characteristics of the restrictive RV and the presence of end-diastolic forward flow (EDFF) in patients with pulmonary stenosis have not yet been described. This type of flow is an antegrade flow that is observed with the Doppler study of the pulmonary artery and occurs at the end of the diastolic phase. Pulmonary valve stenosis (PVS) is one of the most common congenital heart diseases in dogs. The echocardiographic parameter that is mainly taken as a reference for evaluating the severity of the disease is the peak gradient of the pulmonary antegrade flow. For our retrospective study, we consider a total of 164 dogs with PVS divided into 149 dogs with type A and 15 type B, seen at a reference veterinary clinic from 2020 to 2024. All these dogs underwent echocardiographic examinations to observe the morphological characteristics of the PVS and consider the presence or absence of restrictive RV with EDFF. An independent sample t-test analysis revealed that the severity of PVS is greater in dogs with EDFF, both in the group of patients with type A stenosis and in patients with type B stenosis. This study suggests that RV restrictive physiology is common in dogs with severe PVS.

Right Ventricular Remodeling in Complex Congenital Heart Disease

In congenital heart diseases (CHDs) of moderate to great complexity involving the right ventricle (RV), the morphologic RV can be exposed to significant stressors across the lifespan, either in a biventricular circulation in a subpulmonary or subaortic position or as part of a univentricular circulation. These include pressure and/or volume overload, hypoxia, ischemia, and periprocedural surgical stress, leading to remodeling, maladaptation, dilation, hypertrophy, and dysfunction. In this review we examine the macroscopic remodeling of the RV in various forms of CHD and explore remodeling trajectories, along with the effects of surgeries and residual lesion repair, in tetralogy of Fallot, Ebstein anomaly, congenitally corrected transposition of the great arteries, transposition of the great arteries with atrial switch surgery, and single ventricle palliated by Fontan. In addition, the role of metabolism, genetic markers, and imaging criteria of RV remodeling are explored. Finally, the optimal timing for addressing residual lesions in CHD through surgery or percutaneous interventions is discussed, along with advanced heart failure management strategies and medical therapy aimed at preventing further RV dilation and/or systolic deterioration or promoting reverse remodeling.

Accuracy of Intraoperative Transesophageal Echocardiographic Doppler Parameters in Assessing the Right Ventricular Diastolic Function After Repair of Tetralogy of Fallot in Pediatric Patients

BACKGROUND

This study aimed to assess the accuracy of tricuspid spectral Doppler (E/A) and tissue Doppler parameters (E/E') to diagnose right ventricular diastolic dysfunction (RVDD) in comparison to American Society of Echocardiography (ASE criteria) in pediatric tetralogy of Fallot (TOF) patients after surgical repair.

METHODS

This prospective, observational study was done at a tertiary care hospital involving 40 pediatric TOF patients aged less than 2 years who underwent complete intracardiac repair with cardiopulmonary bypass (CPB). Echocardiographic observations were made using a pediatric transesophageal echocardiography probe after surgical repair in the post-CPB period. The ASE-described parameters (late diastolic forward flow in the main pulmonary artery, right atrial dilatation, inferior vena cava dilatation, and hepatic venous flow reversal) were acquired to diagnose the RVDD. The tricuspid Doppler parameters (E/A and E/E') were measured, and its predictive ability to diagnose RVDD was analyzed and compared with the ASE criteria.

RESULTS

Based on the ASE criteria, 13 patients (32.5%) were diagnosed to have RVDD. We found that an E/E' ratio of ≥ 6.26 and an E/A ratio of >1.34 can be taken as the cutoff for diagnosing the RVDD. Based on the tricuspid Doppler parameters (E/A > 1.34 and E/E' >6.26), 17 patients (42.5%) were diagnosed to have RVDD, which was comparable to that of the diagnosis by ASE criteria (P > 0.05).

CONCLUSION

The results suggested that the use of tricuspid Doppler parameters can be equally accurate and reproducible to the current ASE-described echocardiographic parameters for diagnosing RVDD after surgical repair of TOF.

Right Ventricular Restrictive Physiology Is Associated With Right Ventricular Direct Flow From 4D Flow CMR

Background

Right ventricular restrictive physiology (RVRP) is a common occurrence in repaired tetralogy of Fallot (rTOF). The relationship of RVRP with biventricular blood flow components and kinetic energy (KE) from 4-dimensional (4D) flow cardiovascular magnetic resonance (CMR) is unclear.

Objectives

The purpose of this study was to investigate the association of 4D flow CMR parameters with RVRP in rTOF patients.

Methods

A total of 103 rTOF patients and 62 age and sex-matched healthy control subjects were prospectively recruited. All participants underwent CMR (cine, 2-dimensional phase-contrast, and 4D flow sequences), and cardiopulmonary exercise test in adult populations. RVRP was identified from pulmonary artery flow curve using 2-dimensional phase-contrast images. Biventricular flow components (direct flow, retained inflow, delayed ejection flow, and residual volume) and KE parameters normalized to end-diastolic volume (KEiEDV) were analyzed encompassing global, peak systolic, average systolic, average diastolic, peak E-wave, and peak A-wave.

Results

Compared with control subjects, rTOF patients had significantly lower RV direct flow and higher RV residual volume (both P < 0.001). All RV KEiEDV parameters, except peak A-wave, were higher in rTOF patients. In rTOF patients, 70 of 103 (68%) had RVRP, with increasing RV direct flow (27% vs 20%; P = 0.002) and RV peak E-wave KEiEDV (28.4 vs 20.7μJ/mL; P = 0.015) and decreasing RV residual volume (37% vs 42%; P = 0.039) than rTOF without RVRP. Exercise capacity was impaired in rTOF, although comparable between RVRP subgroups. Multivariable analysis revealed RV direct flow was an independent predictor of RVRP (OR: 1.158; 95% CI: 1.074-1.249; P < 0.001).

Conclusions

RVRP is associated with dilated RV, higher pulmonary regurgitation, and higher RV direct flow. (Integrated Computational modeling of Right Heart Mechanics and Blood Flow Dynamics in Congenital Heart Disease; NCT03217240).

Assessment of right ventricular diastolic function in pediatric patients with repaired tetralogy of Fallot by cardiovascular magnetic resonance and echocardiography

OBJECTIVES

Cardiovascular magnetic resonance (CMR) imaging is routinely performed for assessing right ventricular (RV) systolic but not diastolic function. We aimed to investigate CMR-based assessment of RV diastolic function in pediatric patients with repaired tetralogy of Fallot (rTOF), compared to transthoracic echocardiography (TTE) measurements.

METHODS

A total of 130 consecutive pediatric patients with rTOF who underwent clinically indicated CMR and same-day TTE were included. Forty-three controls were recruited. Phase-contrast images were used to measure trans-tricuspid valve flow velocities during early (E) and late diastolic (A) phases (measured in cm/s). Feature tracking of the tricuspid annulus was performed to derive early (e') and late diastolic (a') myocardial velocities (measured in cm/s). RV diastolic function was evaluated by E/A ratio, E/e' ratio, and E-wave deceleration time (measured in milliseconds). Regression analyses were utilized to identify potential variables associated with RV diastolic dysfunction (DD). The performance of CMR-derived parameters in diagnosing RV DD was assessed using receiver-operating characteristic analyses.

RESULTS

Good agreement was found between CMR and TTE measurements (ICC 0.70-0.89). Patients with RV DD (n = 67) showed significantly different CMR-derived parameters including E and e' velocities, and E/A and E/e' ratio, compared to patients without DD (n = 63) (all p < 0.05). CMR-derived E and e' velocities and E/e' ratio were independent predictors of RV DD. E/e' of 5.8 demonstrated the highest discrimination of RV DD (AUC 0.76, sensitivity 70%, specificity 86%).

CONCLUSIONS

CMR-derived parameters showed good agreement with TTE parameters in determining RV DD. CMR-derived E/e' was proved to be the most effective in identifying RV DD.

CLINICAL RELEVANCE STATEMENT

This study demonstrated the feasibility and efficacy of CMR in assessing diastolic function in pediatric patients. RV DD was presented in over half of patients according to current TTE guidelines, highlighting the need for assessing RV diastolic function during follow-up.

KEY POINTS

• Routinely acquired cine and phase-contrast cardiovascular magnetic resonance (CMR) images yielded right ventricular (RV) diastolic parameters which demonstrated good agreement with transthoracic echocardiography (TTE) measurements. • There was a high prevalence of RV diastolic function impairment in pediatric patients with repaired tetralogy of Fallot (rTOF). • CMR is a reliable complementary modality of TTE for RV diastolic function evaluation.

Adverse remodelling in tetralogy of Fallot: From risk factors to imaging analysis and future perspectives

Although contemporary outcomes of initial surgical repair of tetralogy of Fallot (TOF) are excellent, the survival of adult patients remains significantly lower than that of the normal population due to the high incidence of heart failure, ventricular arrhythmias, and sudden cardiac death. The underlying mechanisms are only partially understood but involve an adverse biventricular response, so-called remodelling, to key stressors such as right ventricular (RV) pressure-and/or volume-overload, myocardial fibrosis, and electro-mechanical dyssynchrony. In this review, we explore risk factors and mechanisms of biventricular remodelling, from histological to electro-mechanical aspects, and the role of imaging in their assessment. We discuss unsolved challenges and future directions to better understand and treat the long-term sequelae of this complex congenital heart disease.

Significance of End-Diastolic Forward Flow in Patients With Repaired Tetralogy of Fallot - Its Interaction With the Left Ventricular Property and End Organ Damage

BACKGROUND

Although right ventricular (RV) enlargement may affect RV diastolic dysfunction assessed by end-diastolic forward flow (EDFF) in patients with repaired tetralogy of Fallot (TOF), EDFF may also be modified by left ventricular (LV) hemodynamics. We hypothesized that EDFF is affected by LV hemodynamics, not limited to RV diastolic stiffening.

METHODS AND RESULTS

Among 145 consecutive patients with repaired TOF who underwent catheterization, hemodynamic properties in 47 with consistent EDFF and 75 without EDFF were analyzed. Compared with patients without EDFF, those with EDFF had a large RV volume with a high regurgitant fraction. Although cardiac index and central venous pressure (CVP) were similar, contrast injection augmented CVP and LV end-diastolic pressure (EDP) in patients with vs. those without EDFF, suggesting compromised diastolic reserve. In patients with EDFF, the velocity-time integral (VTI) of EDFF was positively correlated with LVEDP and systemic vascular resistance, in addition to RV EDP. EDFF-VTI was correlated with hepatic venous wedge pressure and markers of hepatic dysfunction. Subanalysis of the older (≥6 years) half of the study cohort revealed that EDFF was associated with bi-atrial enlargement independent of RV volume, highlighting the pronounced role of EDFF on the diastolic property in the aged cohort.

CONCLUSIONS

EDFF-VTI in patients with repaired TOF reflects RV diastolic dysfunction, affected by the left heart system. EDFF-VTI indicates blood stagnation, which may be attributed to end-organ damage.

Multimodality Imaging Assessment of Tetralogy of Fallot: From Diagnosis to Long-Term Follow-Up

Tetralogy of Fallot (TOF) is the most common complex congenital heart disease with long-term survivors, demanding serial monitoring of the possible complications that can be encountered from the diagnosis to long-term follow-up. Cardiovascular imaging is key in the diagnosis and serial assessment of TOF patients, guiding patients' management and providing prognostic information. Thorough knowledge of the pathophysiology and expected sequalae in TOF, as well as the advantages and limitations of different non-invasive imaging modalities that can be used for diagnosis and follow-up, is the key to ensuring optimal management of patients with TOF. The aim of this manuscript is to provide a comprehensive overview of the role of each modality and common protocols used in clinical practice in the assessment of TOF patients.

The right ventricle in tetralogy of Fallot: adaptation to sequential loading

Right ventricular dysfunction is a major determinant of outcome in patients with complex congenital heart disease, as in tetralogy of Fallot. In these patients, right ventricular dysfunction emerges after initial pressure overload and hypoxemia, which is followed by chronic volume overload due to pulmonary regurgitation after corrective surgery. Myocardial adaptation and the transition to right ventricular failure remain poorly understood. Combining insights from clinical and experimental physiology and myocardial (tissue) data has identified a disease phenotype with important distinctions from other types of heart failure. This phenotype of the right ventricle in tetralogy of Fallot can be described as a syndrome of dysfunctional characteristics affecting both contraction and filling. These characteristics are the end result of several adaptation pathways of the cardiomyocytes, myocardial vasculature and extracellular matrix. As long as the long-term outcome of surgical correction of tetralogy of Fallot remains suboptimal, other treatment strategies need to be explored. Novel insights in failure of adaptation and the role of cardiomyocyte proliferation might provide targets for treatment of the (dysfunctional) right ventricle under stress.

Association of cardiovascular magnetic resonance diastolic indices with arrhythmia in repaired Tetralogy of Fallot

BACKGROUND

Patients with repaired Tetralogy of Fallot (rTOF) experience a high burden of long-term morbidity, particularly arrhythmias. Cardiovascular magnetic resonance (CMR) is routinely used to assess ventricular characteristics but the relationship between CMR diastolic function and arrhythmia has not been evaluated. We hypothesized in rTOF, left ventricular (LV) diastolic dysfunction on CMR would correlate with arrhythmias and mortality.

METHODS

Adolescents and adults with rTOF who underwent CMR were compared to healthy controls (n = 58). Standard ventricular parameters were assessed and manual planimetry was performed to generate filling curves and indices of diastolic function. Chart review was performed to collect outcomes. Univariate and multivariable logistic regression was performed to identify outcome associations.

RESULTS

One-hundred sixty-seven subjects with rTOF (mean age 32 years) and 58 healthy control subjects underwent CMR. Patients with rTOF had decreased LV volumes and increased right ventricular (RV) volumes, lower RV ejection fraction (RVEF), lower peak ejection rate (PER), peak filling rate (PFR) and PFR indexed to end-diastolic volume (PFR/EDV) compared to healthy controls. Eighty-three subjects with rTOF had arrhythmia (63 atrial, 47 ventricular) and 11 died. Left atrial (LA) volumes, time to peak filling rate (tPFR), and PFR/EDV were associated with arrhythmia on univariate analysis. PER/EDV was associated with ventricular (Odds ratio, OR 0.43 [0.24-0.80], p = 0.007) and total arrhythmia (OR 0.56 [0.37-0.92], p = 0.021) burden. A multivariable predictive model including diastolic covariates showed improved prediction for arrhythmia compared to clinical and conventional CMR measures (area under curve (AUC) 0.749 v. 0.685 for overall arrhythmia). PFR/EDV was decreased and tPFR was increased in rTOF subjects with mortality as compared to those without mortality.

CONCLUSIONS

Subjects with rTOF have abnormal LV diastolic function compared to healthy controls. Indices of LV diastolic function were associated with arrhythmia and mortality. CMR diastolic indices may be helpful in risk stratification for arrhythmia.

End-diastolic forward flow in repaired tetralogy of Fallot: Mid-term outcomes from a single center

Background

Pulmonary arterial end-diastolic forward flow (EDFF) following repaired tetralogy of Fallot (rTOF) is recognized as right ventricular (RV) restrictive physiology, which is closely related to poor prognosis. This study sought to review mid-term experience and investigate the risk factors of EDFF in the rTOF patients.

Methods

From September 2016 to January 2019, 100 patients (age < 18 years old) who underwent complete tetralogy of Fallot (TOF) repair were enrolled and were divided into EDFF group (n = 52) and non-EDFF group (n = 48) based on the presence of postoperative EDFF. Elastic net analysis was performed for variable selection. Univariate and multivariate logistic analyses were used to analyze the correlation between risk factors and EDFF.

Results

End-diastolic forward flow group had lower systolic blood pressure (P = 0.037), diastolic blood pressure (P = 0.027), and higher vasoactive-inotrope score within 24 h after surgery (P = 0.022) than non-EDFF group. Transannular patch (TAP) was an independent predictor of postoperative EDFF [P = 0.029, OR: 2.585 (1.102∼6.061)]. Patients were followed up for a median of 2.6 years [interquartile range (IQR) 1.6] after the first TOF repair. During follow-up, the prevalence of the EDFF was lower in those with pulmonary valve (PV) reconstructions than that in those undergoing patch enlargement without PV reconstructions in the primary TOF repair (P < 0.001).

Conclusion

End-diastolic forward flow was associated with TAP. Patients with EDFF might have a transient hemodynamic instability in the early postoperative period. PV reconstructions in the TOF repair might reduce the incidence of EDFF in the mid-term follow-up.