Right ventricular function in adults with repaired tetralogy of Fallot assessed with cardiovascular magnetic resonance imaging: detrimental role of right ventricular outflow aneurysms or akinesia and adverse right-to-left ventricular interaction

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.

Right-Left Ventricular Interdependence in Repaired Tetralogy of Fallot Patients With Right Ventricular Heart Failure

BACKGROUND

Patients with repaired tetralogy of Fallot (rTOF) continue to face a heightened risk of deteriorating cardiac function, and quantitative techniques of cardiac MRI-derived cardiac structure and function provide an opportunity to explore the causes and mechanisms of cardiac deterioration.

PURPOSE

To explore right-left ventricular interdependence in rTOF patients before and after the onset of right ventricular (RV) heart failure.

STUDY TYPE

Retrospective.

POPULATION

One hundred eighteen rTOF patients (21.85 [16.74, 29.20] years, 58 females) and 34 controls (23.5 [21, 26.5] years, 17 females) that underwent cardiac MRI were analyzed, with rTOF patients being further subdivided into those with preserved RV function (N = 54) and those that experienced RV heart failure (N = 64).

FIELD STRENGTH/SEQUENCE

3.0 T/balanced steady-state free precession sequence.

ASSESSMENT

RV, left ventricular (LV), and septal strain; RV and LV volume.

STATISTICAL TESTS

Chi-squared tests or Fisher's exact test, One-way ANOVAs with Bonferroni's post hoc test, Pearson/Spearman correlation, and multivariate backward linear regression analysis. A two-tailed P < 0.05 was deemed as the significance threshold.

RESULTS

The MRI-derived RV, LV, and septal strain decreased sequentially in controls, patients with preserved RV function, and patients with RV heart failure, with a good intra-observer (0.909-0.964) and inter-observer (0.879-0.937) agreement. Correlations between LV and RV strain were found to change sequentially with RV function and were the closest in rTOF patients with RV heart failure (r = -0.270 to 0.506). Correlations between RV volume and septal strain was variable in controls (r = 0.483 to -0.604), patients with preserved RV function (r = -0.034 to -0.295), and patients with RV heart failure (r = -0.026 to 0.500). Multivariate analyses revealed that the RV longitudinal strain was independently correlated with LV strain in three directions in rTOF patients with RV heart failure (Radial -0.70 [-1.33, -0.06]; Circumferential 0.44 [0.17, 0.72]; Longitudinal 0.54 [0.26, 0.81]).

DATA CONCLUSION

In rTOF patients, the coupling between RV volume and septal strain was broken during RV function compensation, and the adverse effect of RV on LV deformation was highest in patients with RV heart failure.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 5.

Repaired Tetralogy of Fallot: Have We Understood the Right Timing of PVR?

Despite many advances in surgical repair during the past few decades, the majority of tetralogy of Fallot patients continue to experience residual hemodynamic and electrophysiological abnormalities. The actual issue, which has yet to be solved, is understanding how this disease evolves in each individual patient and, as a result, who is truly at risk of sudden death, as well as the proper timing of pulmonary valve replacement (PVR). Our responsibility should be to select the most appropriate time for each patient, going above and beyond imaging criteria used up to now to make such a clinically crucial decision. Despite several studies on timing, indications, procedures, and outcomes of PVR, there is still much uncertainty about whether PVR reduces arrhythmia burden or improves survival in these patients and how to appropriately manage this population. This review summarizes the most recent research on the evolution of repaired tetralogy of Fallot (from adolescence onwards) and risk factor variables that may favor or delay PVR.

Surgically repaired tetralogy of Fallot in the 7th decade: a late presentation of severe pulmonic regurgitation

BACKGROUND

Surgically repaired tetralogy of Fallot (TOF) is a congenital heart disease with a cumulative survival rate of 72% in the 4th decade of life in longitudinal single-cohort studies. Debate surrounds conservative versus surgical management in adults with TOF once pulmonary regurgitation occurs.

CASE PRESENTATION

A 73-year-old male with surgically corrected TOF presented with heart failure symptoms. He underwent ToF repair with a classic right Blalock-Taussig shunt at 2 years of age with transannular patching at 18 years of age. Echocardiography revealed elevated right ventricular systolic pressures, severe right ventricular dilatation, and pulmonary regurgitation. Our patient's new-onset right-sided heart failure was managed medically with diuresis. He received a new pulmonic valve via percutaneous approach on a later planned hospitalization with resolution of symptoms and improved tricuspid regurgitation.

CONCLUSION

It is a class I recommendation for pulmonic valve intervention once greater than moderate PR occurs; however, medical optimization should take place first. Following adequate RV load optimization, our patient underwent successful transcatheter pulmonic valve implantation with resolution of symptoms and cessation of diuretic.

Impact of right ventriculotomy on cardiac function after pulmonary valve sparing repair of tetralogy of Fallot and double outlet right ventricle with pulmonary stenosis

OBJECTIVES

Pulmonary valve-sparing repair of tetralogy of Fallot and double outlet right ventricle with pulmonary stenosis has the advantage of reduced incidence of late pulmonary valve regurgitation and better-preserved cardiac function. However, a right ventriculotomy is sometimes necessary in order to adequately relieve subvalvular pulmonary stenosis. We aimed to compare postoperative cardiac function and patients' symptoms between pulmonary valve-sparing repair with and without right ventriculotomy.

MATERIALS AND METHODS

We retrospectively collected data from electronic medical records of Ramathibodi Hospital from 1st January 2013 to 31st October 2023. Patients diagnosed with tetralogy of Fallot and double outlet right ventricle with pulmonary stenosis who underwent pulmonary valve-sparing repair were included. Patients who underwent other types of repairs and whose medical record data were significantly missing were excluded. Demographic data, operative, and postoperative details were collected and reviewed.

RESULTS

There were 49 patients included in our study with 10 patients undergoing pulmonary valve-sparing repair with and the other 39 without right ventriculotomy. Before-discharge echocardiographic parameters were generally similar between both groups (tricuspid annular plane systolic excursion = 0.9 versus 0.89 cm, P = 0.737; pressure gradient across pulmonary valve across pulmonary valve = 24 versus 19 mmHg, P = 0.275; left ventricular end-systolic volume index = 17.84 versus 19.19 ml/m2, P = 0.437; left ventricular end-diastolic volume index = 63.79 versus 61.13 ml/m2, P = 0.436). Patients' symptoms were also not statistically different. There was no early and late death up to the end date of our study.

CONCLUSIONS

Right ventriculotomy in pulmonary valve-sparing repair did not result in worse postoperative cardiac function and symptoms. This suggested that the previously thought-to-be hazardous incision could be strongly considered if mandated.

Right Ventricular and Outflow Tract Functional Characteristics After Repair of Tetralogy of Fallot with Major Aortopulmonary Collaterals

This study describes right ventricle (RV) characteristics and right ventricle to pulmonary artery (RV-PA) conduit function pre- and post-repair in patients with tetraology of Fallot with major aortopulmonary collaterals (TOF/MAPCAs). We reviewed patients who underwent single-stage, complete unifocalization, and repair of TOF/MAPCAs between 2006 and 2019 with available pre- and early postoperative echocardiograms. For a subset of patients, 6-12 month follow-up echocardiogram was available. RV and left ventricle (LV) characteristics and RV-PA conduit function were reviewed. Wilcoxon signed rank test and McNemar's test were used. 170 patients were reviewed, 46 had follow-up echocardiograms. Tricuspid valve annular plane systolic excursion (TAPSE) Z-scores were reduced from pre- (Z-score 0.01) to post-repair (Z-score -4.5, p < 0.001), improved but remained abnormal at follow-up (Z-score -4.0, p < 0.001). RV fractional area change (FAC) and LV ejection fraction were not significantly different before and after surgery. Conduit regurgitation was moderate or greater in 11% at discharge, increased to 65% at follow-up. RV-PA conduit failure (severe pulmonary stenosis or severe pulmonary regurgitation) was noted in 61, and 63% had dilated RV (diastolic RV area Z-score > 2) at follow-up. RV dilation correlated with the severe conduit regurgitation (p = 0.018). Longitudinal RV function was reduced after complete repair of TOF/MAPCAs, with decreased TAPSE and preserved FAC and LV ejection fraction. TAPSE improved but did not normalize at follow-up. Severe RV-PA conduit dysfunction was observed prior to discharge in 11% of patients and in 61% at follow-up. RV dilation was common at follow-up, especially in the presence of severe conduit regurgitation.

Predictive value of Cardiac Magnetic Resonance: new and old parameters in the natural history of repaired Tetralogy of Fallot

BACKGROUND

Patients with repaired Tetralogy of Fallot (rTOF) often develop pulmonary regurgitation (PR) and right ventricle (RV) dysfunction, experiencing increased mortality and morbidity rates in adulthood. Pulmonary valve replacement (PVR) timing to address PR is controversial. Cardiac Magnetic Resonance (CMR) is the gold standard for morpho-functional evaluation of complex cardiopathies. This study aims to identify CMR parameters predictive of adverse outcomes to help defining the best therapeutic management of rTOF patients.

METHODS

130 rTOF patients who underwent CMR (2006-2019) were enrolled in this retrospective single-center study. CMR, clinical, ECG and exercise data were analyzed. Univariate and multivariate analyses identified clinical and CMR parameters predictive of adverse outcomes both individually (e.g., death, arrhythmias, heart failure (HF), pharmacological therapy, QRS ≥ 160ms) and as composite outcome.

RESULTS

Univariate analysis confirmed RV volumes and RV ejection fraction corrected for PR as adverse outcome predictors and identified interesting correlations: pulmonary artery bifurcation geometry and abnormal interventricular septum (IVS) motion with arrhythmias (p < .001; p = .037), HF (p = .049; p = .005), composite outcome (p = .039; p = .009); right atrium (RA) dimensions with the composite outcome and the outcomes individually (p < .001). The best predictive models by multivariate analysis included sex (male), RV and RA dilation for QRS ≥ 160ms, time form repair to CMR, age at TOF repair and IVS fibrosis for pharmacological therapy.

CONCLUSIONS

Besides RV volumes, new adverse prognostic factors could guide rTOF therapeutic management: pulmonary arteries morphology, abnormal IVS motion, RV dysfunction, RA dilation. Perspective multicentric evaluation is needed to specify their effective role.

Tricuspid valve annular tilt for assessment of pre- and post-intervention right ventricular volume in patients undergoing transcatheter pulmonary valve replacement

INTRODUCTION

Transcatheter pulmonary valve replacement serves as a successful alternative to surgical replacement of a right ventricle to pulmonary artery conduit. Guidelines for recommending transcatheter pulmonary valve replacement depend on MRI right ventricular volumes, which have been correlated to the echocardiographic measure of right ventricular annular tilt. We aim to assess whether right ventricular annular tilt can be a clinically useful alternative tool in the acute and long-term periods after transcatheter pulmonary valve replacement to assess right ventricular health.

METHODS

We reviewed 70 patients who underwent transcatheter pulmonary valve replacement at a single institution. Echocardiographic measurements were obtained prior to transcatheter pulmonary valve replacement, immediately after transcatheter pulmonary valve replacement, and within 6 months to 1 year after transcatheter pulmonary valve replacement. Right ventricular annular tilt measures the angle of the tricuspid valve plane relative to the mitral valve plane at end-diastole in the apical four-chamber view. Right ventricular fractional area change, right ventricular systolic strain, tissue Doppler velocity, and tricuspid annular plane systolic excursion Z-scores were obtained using published methods.

RESULTS

Right ventricular annular tilt decreased significantly immediately after transcatheter pulmonary valve replacement (p = 0.0004), and this reduction in right ventricular volume persisted at the mid-term follow-up (p < 0.0001). Fractional area change did not change significantly after transcatheter pulmonary valve replacement while right ventricular global strain improved at mid-term follow-up despite no significant difference immediately after transcatheter pulmonary valve replacement.

CONCLUSIONS

Right ventricular annular tilt decreases both immediately after transcatheter pulmonary valve replacement and at mid-term follow-up. Right ventricular strain also improved after transcatheter pulmonary valve replacement, corresponding to the improved volume load. Right ventricular annular tilt can be considered as an additional echocardiographic factor to assess right ventricular volume and remodeling after transcatheter pulmonary valve replacement.

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.

Application of Speckle Tracking Echocardiography for Evaluating Ventricular Function after Transcatheter Pulmonary Valve Replacement

Pulmonary regurgitation usually leads to right heart dilatation and eventually right heart dysfunction, which is associated with a poor prognosis. Transcatheter pulmonary valve replacement is a developing treatment for pulmonary valve dysfunction that can take the place of traditional surgery and make up for the shortcomings of a large injury. Echocardiography plays a significant role in assessing ventricular function; however, conventional echocardiographic parameters have several limitations. Speckle tracking echocardiography has been regarded as a more accurate tool for quantifying cardiac function than conventional echocardiography. Therefore, the aim of this review was to summarize the application of speckle tracking echocardiography for evaluating right and left ventricular functions in patients after transcatheter pulmonary valve replacement.

The Right Heart in Congenital Heart Disease

PURPOSE OF REVIEW

To analyze the pathophysiologic importance of the right heart in different types of congenital heart disease (CHD), summarize current diagnostic modalities, and discuss treatment options.

RECENT FINDINGS

The right ventricle (RV) plays a key role in disease progression and prognosis, either as the subpulmonary or as the systemic ventricle. Volume and/or pressure overload as well as intrinsic myocardial disease are the main factors for RV remodeling. Echocardiography and cardiac magnetic resonance imaging are important noninvasive modalities for assessing anatomy, size, and function of the right heart. Timely repair of related lesions is essential for preventing RV dysfunction. Few inconclusive data exist on conventional pharmacotherapy in CHD-related RV dysfunction. Cardiac resynchronization therapy and ventricular assist devices are an option in patients with advanced systemic RV failure. Right heart disease is highly related with adverse clinical outcomes in CHD. Research should focus on early identification of patients at risk and development of medical and interventional treatments that improve RV function.

Essentials of Imaging the Repaired Tetralogy of Fallot Patient

Tetralogy of Fallot is one of the commoner forms of congenital heart disease (CHD) with an incidence estimated at around 1 in 3000 live births. Its prevalence is roughly 5%-10% of all forms of CHD. Although it is a cyanotic disorder at presentation, early surgical repair has led to survival to adulthood in the overwhelming majority of cases. However-as with most repaired CHD-such patients are fixed, not cured, and will inevitably come to the attention of the imaging specialist. This article attempts to describe and summarize the main forms of repaired tetralogy that may be encountered in tertiary hospital imaging practice. The anatomy of different forms of tetralogy is reviewed, and relevant pathophysiology is discussed. Reference is made to 22q11 syndrome, which is often missed or not considered by even specialist congenital physicians, and the alerting features of this condition are reviewed. The benefits and challenges of computed tomography and magnetic resonance imaging in the congenital population are covered, and there is discussion regarding the various approaches to imaging available using these techniques.

Abnormal developmental trajectory and vulnerability to cardiac arrhythmias in tetralogy of Fallot with DiGeorge syndrome

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease. Ventricular dysfunction and cardiac arrhythmias are well-documented complications in patients with repaired TOF. Whether intrinsic abnormalities exist in TOF cardiomyocytes is unknown. We establish human induced pluripotent stem cells (hiPSCs) from TOF patients with and without DiGeorge (DG) syndrome, the latter being the most commonly associated syndromal association of TOF. TOF-DG hiPSC-derived cardiomyocytes (hiPSC-CMs) show impaired ventricular specification, downregulated cardiac gene expression and upregulated neural gene expression. Transcriptomic profiling of the in vitro cardiac progenitors reveals early bifurcation, as marked by ectopic RGS13 expression, in the trajectory of TOF-DG-hiPSC cardiac differentiation. Functional assessments further reveal increased arrhythmogenicity in TOF-DG-hiPSC-CMs. These findings are found only in the TOF-DG but not TOF-with no DG (ND) patient-derived hiPSC-CMs and cardiac progenitors (CPs), which have implications on the worse clinical outcomes of TOF-DG patients.

The prognostic role of right ventricular dysfunction in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) primarily affects the left ventricle (LV) sparing the right ventricle (RV) in vast majority of cases. However, several studies employing CMR have revealed that myocardial hypertrophy may also involve the RV. To assess RV size and function in a large prospectively cohort of HCM patients and to evaluate whether these parameters in association with other MR findings can predict cardiac events. Two participating centers prospectively included patients with known or suspected HCM between 2011 and 2017. CMR studies were performed with three different scanners. Outcome measures were a composite of ventricular arrhythmias, hospitalization for HF and cardiac death. Of 607 consecutive patients with known or suspected HCM, 315 had complete follow-up information (mean 65 ± 20 months). Among them, 115 patients developed major cardiac events (MACE) during follow-up. At CMR evaluation, patients with events had higher left atrium (LA) diameter (41.5 ± 8 mm vs. 37.17 ± 7.6 mm, p < 0.0001), LV mass (156.7 vs. 144 g, p = 0.005) and myocardial LGE (4.3% vs. 1.9%, p = 0.001). Similarly, patients with events had lower RV stroke volume index (42.7 vs. 47.0, p = 0.0003) and higher prevalence of both RV hypertrophy (16.4% vs. 4.7%, p = 0.0005) and reduced RV ejection fraction (12.2% vs. 4.4%, p = 0.006). In the multivariate analysis, LA diameter and RV stroke volume index were the strongest predictors of events (p < 0.001 and p = 0.0006, respectively). Anatomic and functional RV anomalies detected and characterized with CMR may have may have a major role in predicting the prognosis of HCM patients.

Surgical and transcatheter pulmonary valve replacement in patients with repaired tetralogy of Fallot: cardiac magnetic resonance imaging characteristics and morphology of right ventricular outflow tract

BACKGROUND

Pulmonary valve replacement is recommended in patients with repaired tetralogy of Fallot based on cardiac magnetic resonance imaging (MRI) criteria. This procedure is performed by surgical or transcatheter approaches.

OBJECTIVE

We aimed to investigate the differences in preprocedural MRI characteristics (volume, function, strain) and morphology of the right ventricular outflow tract and branch pulmonary arteries in patients for whom surgical or transcatheter pulmonary valve replacement was planned.

MATERIALS AND METHODS

Cardiac MRI of 166 patients with tetralogy of Fallot were analyzed. Of these, 36 patients for whom pulmonary valve replacement was planned were included. Magnetic resonance imaging characteristics, right ventricular outflow tract morphology, branch pulmonary artery flow distribution and diameter were compared between surgical and transcatheter groups. Spearman correlation and Kruskal-Wallis tests were performed.

RESULTS

Circumferential and radial MRI strain for the right ventricle were lower in the surgical group (P=0.045 and P=0.046, respectively). The diameter of the left pulmonary artery was significantly lower (P=0.021) and branch pulmonary artery flow and diameter ratio were higher (P=0.044 and P = 0.002, respectively) in the transcatheter group. There was a significant correlation between right ventricular outflow tract morphology and right ventricular end-diastolic volume index and global circumferential and radial MRI strain (P=0.046, P=0.046 and P= 0.049, respectively).

CONCLUSION

Preprocedural MRI strain, right-to-left pulmonary artery flow, diameter ratio and morphological features of the right ventricular outflow tract were significantly different between the two groups. A transcatheter approach may be recommended for patients with branch pulmonary artery stenosis, since both pulmonary valve replacement and branch pulmonary artery stenting can be performed in the same session.

Effect of pulmonary regurgitation on cardiac functions based on a human bi-ventricle model

BACKGROUND AND OBJECTIVE

Assessing the severity of pulmonary regurgitation (PR) and identifying optimal clinically relevant indicators for its treatment is crucial, yet standards for quantifying PR remain unclear in clinical practice. Computational modelling of the heart is in the process of providing valuable insights and information for cardiovascular physiology research. However, the advancements of finite element computational models have not been widely applied to simulate cardiac outputs in patients with PR. Furthermore, a computational model that incorporates both the left ventricle (LV) and right ventricle (RV) can be valuable in assessing the relationship between left and right ventricular morphometry and septal motion in PR patients. To enhance our understanding of the effect of PR on cardiac functions and mechanical behaviour, we developed a human bi-ventricle model to simulate five cases with varying degrees of PR severity.

METHODS

This bi-ventricle model was built using a patient-specific geometry and a widely used myofibre architecture. The myocardial material properties were described by a hyperelastic passive constitutive law and a modified time-varying elastance active tension model. To simulate realistic cardiac functions and the dysfunction of the pulmonary valve in PR disease cases, open-loop lumped parameter models representing systemic and pulmonary circulatory systems were designed.

RESULTS

In the baseline case, pressures in the aorta and main pulmonary artery and ejection fractions of both the LV and RV were within normal physiological ranges reported in the literature. The end-diastolic volume (EDV) of the RV under varying degrees of PR was comparable to the reported cardiac magnetic resonance imaging data. Moreover, RV dilation and interventricular septum motion from the baseline to the PR cases were clearly observed through the long-axis and short-axis views of the bi-ventricle geometry. The RV EDV in the severe PR case increased by 50.3% compared to the baseline case, while the LV EDV decreased by 18.1%. The motion of the interventricular septum was consistent with the literature. Furthermore, ejection fractions of both the LV and RV decreased as PR became severe, with LV ejection fraction decreasing from 60.5% at baseline to 56.3% in the severe case and RV ejection fraction decreasing from 51.8% to 46.8%. Additionally, the average myofibre stress of the RV wall at end-diastole significantly increased due to PR, from 2.7±12.1 kPa at baseline to 10.9±26.5 kPa in the severe case. The average myofibre stress of the LV wall at end-diastole increased from 3.7±18.1 kPa to 4.3±20.3 kPa.

CONCLUSIONS

This study established a foundation for the computational modelling of PR. The simulated results showed that severe PR leads to reduced cardiac outputs in both the LV and RV, clearly observable septum motion, and a significant increase in the average myofibre stress in the RV wall. These findings demonstrate the potential of the model for further exploration of PR.

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.

Incremental prognostic value of myocardial strain over ventricular volume in patients with repaired tetralogy of Fallot

OBJECTIVES

The relative incremental predictive value of myocardial deformation over ventricular volume for future adverse events in patients with repaired tetralogy of Fallot (rTOF) remains unknown. We aimed to determine the incremental prognostic value of myocardial deformation over ventricular volume to predict adverse events in patients with rToF.

METHODS

We retrospectively included patients with rTOF who completed cardiac magnetic resonance (CMR) and follow-up in our hospital from January 2014 to October 2020, and stratified according to the presence or absence of adverse events during follow-up. The strain parameters of the right ventricular (RV) and left ventricular (LV) were obtained from CMR-derived feature tracking. Multivariable Cox proportional hazard models and net reclassification improvement analysis were used to analyze the prognostic information of biventricular strain and volume parameters in rTOF patients.

RESULTS

Among 98 patients with rTOF, 54 (55.1%) experienced primary and/or secondary events during a median follow-up period of 27.0 months. Univariable analysis indicated that RV volume and strain were significantly associated with both primary events and all adverse events (all p < .01). Multivariable Cox regression and net reclassification improvement analyses achieved incremental global χ² (all p < .001), C index (all p < .001), and overall correct reclassification by sequentially adding CMR-derived RV volume, RV strain and LV strain parameters to preexisting clinical factors in adverse events model analyses.

CONCLUSIONS

RV and LV myocardial deformation provided incremental prognostic information and significant improvement for risk stratification over RV size and clinical variables and therefore can be combined to further enhance prognostication.

KEY POINTS

• RV volume and strain were significantly associated with both primary events and all adverse events, whereas LV volume and strain were associated with primary events. • Ventricular myocardial deformation is a strong predictor of adverse outcomes of patients with repaired tetralogy of Fallot, providing increased prognostic information and significantly improved risk stratification over ventricular size.

Computed tomography in tetralogy of Fallot: pre- and postoperative imaging evaluation

Tetralogy of Fallot (TOF) is the most common cause of cyanotic congenital heart disease (CHD) and the most frequent complex CHD encountered in adulthood. Although children with TOF share four characteristic features (subaortic ventricular septal defect, overriding aorta, right ventricular hypertrophy, pulmonary stenosis), the clinical spectrum and course are in fact greatly heterogeneous. Echocardiography remains the mainstay for diagnosis, presurgical planning and postoperative follow-up. However, with continued technological advances, CT now plays an increasing role in TOF evaluation and management, helping to minimize routine invasive catheter angiography. Preoperatively, CT is uniquely suited to assess associated pulmonary arterial, aortic and coronary anomalies as well as extra-cardiovascular structures and is particularly helpful for delineating complex anatomy in the TOF subtypes of absent pulmonary valve and pulmonary atresia with major aortopulmonary collaterals. Postoperatively, CT is useful for identifying surgical complications and for long-term monitoring including volumetry quantification, especially in children for whom MRI is contraindicated or limited by implanted devices such as pacemakers and stents. In this article, we review key clinical features and considerations in the pre- and postoperative TOF patient and the burgeoning role of CT for facilitating accurate diagnosis and personalized intervention.

Statistical shape modeling reveals the link between right ventricular shape, hemodynamic force, and myocardial function in patients with repaired tetralogy of Fallot

Patients with repaired tetralogy of Fallot (rTOF) can develop chronic pulmonary insufficiency (PI) with right ventricular (RV) dilation, progressive RV dysfunction, and decreased exercise capacity. Pulmonary valve replacement (PVR) can help reduce the amount of PI and RV dilation; however, optimal timing remains controversial; a better understanding of rTOF pathophysiology is of fundamental importance to inform clinical management of patients with rTOF and optimal timing of PVR. In this study, we hypothesize a tight interplay between RV shape, intracardiac biomechanics, and ventricular function in patients with rTOF. To explore this hypothesis and derive quantitative measures, we combined statistical shape modeling with physics-based analysis of in vivo 4D flow data in 36 patients with rTOF. Our study demonstrated for the first time a correlation between regional RV shape variations, hemodynamic forces (HDF), and clinical dysfunction in patients with rTOF. The main findings of this work include 1) general increase in RV size, due to both volume overload and physiological growth, correlated with decrease in strain magnitude in the respective directions, and with increased QRS; 2) regional PI-induced remodeling accounted for ∼10% of the shape variability of the population, and was associated with increased diastolic HDF along the diaphragm-to-right ventricular outflow tract (RVOT) direction, resulting in a net RV deformation along the same direction and decreased tricuspid annular plane systolic excursion (TAPSE); and 3) three shape modes independently correlated with systolic HDF and exercise capacity. Identification of patients based on the shape variations described in this study could help identify those at risk for irreversible dysfunction and guide optimal timing of PVR.NEW & NOTEWORTHY We combine statistical shape modeling with physics-based analysis of 4D flow data to elucidate the interplay between RV shape, hemodynamic forces, and clinical dysfunction in repaired tetralogy of Fallot. We are the first to show that ventricular remodeling is related to hemodynamic force magnitude and direction, global and regional functional parameters, and exercise intolerance. Identification of patients based on the shape variations described in this study could help identify those at risk for irreversible dysfunction.

Le Cœur en Sabot: shape associations with adverse events in repaired tetralogy of Fallot

BACKGROUND

Maladaptive remodelling mechanisms occur in patients with repaired tetralogy of Fallot (rToF) resulting in a cycle of metabolic and structural changes. Biventricular shape analysis may indicate mechanisms associated with adverse events independent of pulmonary regurgitant volume index (PRVI). We aimed to determine novel remodelling patterns associated with adverse events in patients with rToF using shape and function analysis.

METHODS

Biventricular shape and function were studied in 192 patients with rToF (median time from TOF repair to baseline evaluation 13.5 years). Linear discriminant analysis (LDA) and principal component analysis (PCA) were used to identify shape differences between patients with and without adverse events. Adverse events included death, arrhythmias, and cardiac arrest with median follow-up of 10 years.

RESULTS

LDA and PCA showed that shape characteristics pertaining to adverse events included a more circular left ventricle (LV) (decreased eccentricity), dilated (increased sphericity) LV base, increased right ventricular (RV) apical sphericity, and decreased RV basal sphericity. Multivariate LDA showed that the optimal discriminative model included only RV apical ejection fraction and one PCA mode associated with a more circular and dilated LV base (AUC = 0.77). PRVI did not add value, and shape changes associated with increased PRVI were not predictive of adverse outcomes.

CONCLUSION

Pathological remodelling patterns in patients with rToF are significantly associated with adverse events, independent of PRVI. Mechanisms related to incident events include LV basal dilation with a reduced RV apical ejection fraction.

Weakly supervised attention model for RV strain classification from volumetric CTPA scans

BACKGROUND AND OBJECTIVE

Evaluation of the right ventricle (RV) is a key component of the clinical assessment of many cardiovascular and pulmonary disorders. In this work, we focus on RV strain classification from patients who were diagnosed with pulmonary embolism (PE) in computed tomography pulmonary angiography (CTPA) scans. PE is a life-threatening condition, often without warning signs or symptoms. Early diagnosis and accurate risk stratification are critical for decreasing mortality rates. High-risk PE relies on the presence of RV dysfunction resulting from acute pressure overload. PE severity classification and specifically, high-risk PE diagnosis are crucial for appropriate therapy. CTPA is the golden standard in the diagnostic workup of suspected PE. Therefore, it can link between diagnosis and risk stratification strategies.

METHODS

We retrieved data of consecutive patients who underwent CTPA and were diagnosed with PE and extracted a single binary label of "RV strain biomarker" from the CTPA scan report. This label was used as a weak label for classification. Our solution applies a 3D DenseNet network architecture, further improved by integrating residual attention blocks into the network's layers.

RESULTS

This model achieved an area under the receiver operating characteristic curve (AUC) of 0.88 for classifying RV strain. For Youden's index, the model showed a sensitivity of 87% and specificity of 83.7%. Our solution outperforms state-of-the-art 3D CNN networks. The proposed design allows for a fully automated network that can be trained easily in an end-to-end manner without requiring computationally intensive and time-consuming preprocessing or strenuous labeling of the data.

CONCLUSIONS

This current solution demonstrates that a small dataset of readily available unmarked CTPAs can be used for effective RV strain classification. To our knowledge, this is the first work that attempts to solve the problem of RV strain classification from CTPA scans and this is the first work where medical images are used in such an architecture. Our generalized self-attention blocks can be incorporated into various existing classification architectures making this a general methodology that can be applied to 3D medical datasets.

Prevalence and Prognostic Implications of Left Ventricular Systolic Dysfunction in Adults With Congenital Heart Disease

BACKGROUND

Although the prevalence and prognostic implications of left ventricular systolic dysfunction (LVSD), and the effect of cardiac therapies on LVSD are well described in patients with acquired heart disease, such data are sparse in adults with congenital heart disease (CHD).

OBJECTIVES

The purpose of this study was to determine the prevalence, risk factors, and prognostic implications of LVSD, and the effect of cardiac therapies (guideline-directed medical therapy [GDMT] and cardiac resynchronization therapy [CRT]) on LVSD in adults with CHD.

METHODS

This was a retrospective study of adults with CHD with systemic LV (2003-2019). LVSD was defined as left ventricular ejection fraction (LVEF) <52%/<54% (men/women). Cardiovascular event was defined as heart failure hospitalization, heart transplant, and cardiovascular death.

RESULTS

Of 4,358 patients, 554 (12%) had LVSD, and the prevalence of LVSD was higher in right-sided lesions compared with left-sided lesions (15% vs 10%; P < 0.001). Cardiovascular events occurred in 312 (7%) patients. LVEF was independently associated with cardiovascular events (HR: 0.95; 95% CI: 0.93-0.97; P = 0.009). Of 544 patients with LVSD, 311 received GDMT and 48 patients received CRT. LVEF increased by 6% (95% CI: 2%-10%) and 11% (95% CI: 8%-14%), and N-terminal pro-hormone brain natriuretic peptide decreased by 151 pg/mL (95% CI: 62-289 pg/mL) and 201 pg/mL (95% CI: 119-321 pg/mL) in patients who received GDMT and CRT, respectively.

CONCLUSIONS

LVSD was present in 12% of adults with CHD, was more common in patients with right-sided lesions, and was associated with cardiovascular events. GDMT and CRT were associated with improvement in LVEF. These results provide a foundation for clinical trials to rigorously test the benefits of these therapies in CHD patients.

Impact of Right Ventricular Pressure Load After Repair of Tetralogy of Fallot

Background Right ventricular outflow tract (RVOT) stenosis after repair of tetralogy of Fallot has been linked with favorable right ventricular remodeling but adverse outcomes. The aim of our study was to assess the hemodynamic impact and prognostic relevance of right ventricular pressure load in this population. Methods and Results A total of 296 patients with repaired tetralogy of Fallot (mean age, 17.8±7.9 years) were included in a prospective cardiovascular magnetic resonance multicenter study. Myocardial strain was quantified by feature tracking technique at study entry. Follow-up, including the need for pulmonary valve replacement, was assessed. The combined end point consisted of ventricular tachycardia and cardiac death. A higher echocardiographic RVOT peak gradient was significantly associated with smaller right ventricular volumes and less pulmonary regurgitation, but lower biventricular longitudinal strain. During a follow-up of 10.1 (0.1-12.9) years, the primary end point was reached in 19 of 296 patients (cardiac death, n=6; sustained ventricular tachycardia, n=2; and nonsustained ventricular tachycardia, n=11). A higher RVOT gradient was associated with the combined outcome (hazard ratio [HR], 1.03; 95% CI, 1.00-1.06; P=0.026), and a cutoff gradient of ≥25 mm Hg was predictive for cardiovascular events (HR, 3.69; 95% CI, 1.47-9.27; P=0.005). In patients with pulmonary regurgitation ≥25%, a mild residual RVOT gradient (15-30 mm Hg) was not associated with a lower risk for pulmonary valve replacement. Conclusions Higher RVOT gradients were associated with less pulmonary regurgitation and smaller right ventricular dimensions but were related to reduced biventricular strain and emerged as univariate predictors of adverse events. Mild residual pressure gradients did not protect from pulmonary valve replacement. These results may have implications for the indication for RVOT reintervention in this population.

Usefulness of a New Transthoracic Echocardiography Score to Assess Right Ventricular Volumes in Patients with Repaired Tetralogy of Fallot

Quantification of right ventricular (RV) volumes is essential in the follow-up of patients with a repaired tetralogy of Fallot (TOF). Cardiac magnetic resonance imaging (MRI) is the gold standard for RV assessment. However, given its cost and availability, the systematic use of MRI for serial longitudinal follow-up is limited. Herein, we examined the utility of a new two-dimensional (2D) transthoracic echocardiography (TTE) score (the RVDi score), which includes a compilation of 2D RV dimensions indexed to the body surface area, for predicting MRI-derived RV end-diastolic volume (RVEDV) in patients with a repaired TOF. Using our congenital heart clinic database, we retrospectively included 29 adult patients with a repaired TOF between February 2015 and July 2019. The 2D TTE RVDi score was compared with the MRI-derived RVEDV. Sensitivity and specificity values for predicting an RVEDVi > 150 ml/m² were calculated. The TTE RVDi score was highly correlated (r = 0.944) with MRI RVEDVi. A cut-off RVDi score set at 120 mm/m² predicted an RVEDVi > 150 ml/m² with a sensitivity of 83% and specificity of 94%. Use of a simple echocardiographic score based on indexed RV dimensions from 2D standard TTE imaging may complement the assessment of RV volumes in TOF patients.

The Interplay between Myocardial Fibrosis, Strain Imaging and Collagen Biomarkers in Adults with Repaired Tetralogy of Fallot

Background: We sought to assess the interplay between right ventricle (RV) fibrosis, biventricular dysfunction based on global longitudinal strain (GLS) analysis, and biomarkers such as Galectin-3 (Gal-3), procollagen type III (PCIII), and NTproBNP. Methods: We studied 35 adult patients with rToF. All patients underwent a cardiac magnetic resonance (CMR) scan including feature tracking for deformation imaging. Blood biomarkers were measured. Results: LGE RV was detected in all patients, mainly at surgical sites. Patients with the highest RV LGE scoring had greater RV dilatation and dysfunction whereas left ventricular (LV) function was preserved. LV GLS correlated with RV total fibrosis score (p = 0.007). A LV GLS value of −15.9% predicted LGE RV score > 8 (AUC 0.754 (p = 0.02)). Neither RV GLS nor biomarker levels were correlated with the extent of RV fibrosis. A cut-off value for NTproBNP of 145.25 pg/mL predicted LGE RV score > 8 points (AUC 0.729, (p = 0.03)). A cut-off value for Gal-3 of 7.42 ng/mL predicted PR Fraction > 20% [AUC 0.704, (p = 0.05)]. Conclusions: A significant extent of RV fibrosis was mainly detected at surgical sites of RV, affecting RV performance. CMR-FT reveals subtle LV dysfunction in rToF patients, due to decreased performance of the fibrotic RV. Impaired LV function and elevated NTproBNP in rToF reflect a dysfunctional fibrotic RV.

Concomitant pulmonary valve replacement with intracardiac repair for adult tetralogy of Fallot

Objectives :

Adult patients undergoing tetralogy of Fallot (TOF) repair have a higher risk of mortality compared to pediatric patients. Pulmonary regurgitation (PR) further predisposes these patients to heart failure, arrhythmias, and sudden death. Pulmonary valve replacement (PVR) may improve the symptoms in these patients but, fails to reverse the other deleterious effects. Aim of our study was to evaluate the effect of concomitant PVR with TOF repair on right ventricular (RV) parameters, cardiopulmonary exercise capacity, and bioprosthetic valve durability at mid-term.

Materials and Methods:

Between January 2013 and August 2018, 37 adolescents and adults with TOF who had hypoplastic pulmonary annulus underwent concomitant TOF repair with PVR at our institute. We retrospectively collected the data from the hospital records including follow-up.

Results :

Mean age of the patients was 18.48 ± 7.53 years. Bioprosthetic valve size ranged from 19 mm to 25 mm. There was no early or late mortality. No patient had developed significant perioperative complications. At a mean follow-up of 53.3 ± 16.4 months, there was no significant change in mean QRS duration, RV function, RV end-systolic and end-diastolic dimensions, RV myocardial performance index, and functional status (including NYHA class and 6-min walk test) compared to at-discharge values. Four patients developed prosthetic valve degeneration with mild PR and without significant increase in gradient.

Conclusion :

Concomitant PVR with TOF repair in adult provides excellent mid-term outcome, with a minimal rate of pulmonary valve degeneration. It not only eases the early postoperative course but also preserves the RV function as well as functional status at mid-term.

Right-left ventricular shape variations in tetralogy of Fallot: associations with pulmonary regurgitation

BACKGROUND

Relationships between right ventricular (RV) and left ventricular (LV) shape and function may be useful in determining optimal timing for pulmonary valve replacement in patients with repaired tetralogy of Fallot (rTOF). However, these are multivariate and difficult to quantify. We aimed to quantify variations in biventricular shape associated with pulmonary regurgitant volume (PRV) in rTOF using a biventricular atlas.

METHODS

In this cross-sectional retrospective study, a biventricular shape model was customized to cardiovascular magnetic resonance (CMR) images from 88 rTOF patients (median age 16, inter-quartile range 11.8-24.3 years). Morphometric scores quantifying biventricular shape at end-diastole and end-systole were computed using principal component analysis. Multivariate linear regression was used to quantify biventricular shape associations with PRV, corrected for age, sex, height, and weight. Regional associations were confirmed by univariate correlations with distances and angles computed from the models, as well as global systolic strains computed from changes in arc length from end-diastole to end-systole.

RESULTS

PRV was significantly associated with 5 biventricular morphometric scores, independent of covariates, and accounted for 12.3% of total shape variation (p < 0.05). Increasing PRV was associated with RV dilation and basal bulging, in conjunction with decreased LV septal-lateral dimension (LV flattening) and systolic septal motion towards the RV (all p < 0.05). Increased global RV radial, longitudinal, circumferential and LV radial systolic strains were significantly associated with increased PRV (all p < 0.05).

CONCLUSION

A biventricular atlas of rTOF patients quantified multivariate relationships between left-right ventricular morphometry and wall motion with pulmonary regurgitation. Regional RV dilation, LV reduction, LV septal-lateral flattening and increased RV strain were all associated with increased pulmonary regurgitant volume. Morphometric scores provide simple metrics linking mechanisms for structural and functional alteration with important clinical indices.

Applicability and Durability of Valve-Sparing Tetralogy of Fallot Repair

BACKGROUND

Although valve-sparing repair remains ideal for patients with tetralogy of Fallot, the durability of valve-sparing repair and which patients may have been better served with a transannular patch remain unclear.

METHODS

Retrospective review was performed of tetralogy of Fallot operations at our institution from January 2008 to December 2018. Standard demographic data were collected, including echocardiographic parameters, operative details, and clinical outcomes. Statistical analysis was performed comparing the transannular patch and valve-sparing repair groups.

RESULTS

Sixty-seven patients underwent tetralogy of Fallot repair with a median age of 4.5 (3.2-6.0) months and weight of 5.8 (5.2, 6.7) kg. Seventeen (25%) patients underwent transannular patch repair and 50 (75%) patients underwent valve-sparing repair. There was no difference in age or weight between patients who underwent a transannular patch repair and those who underwent a valve-sparing repair. At last follow-up (median 42 months), there was a trend of a higher peak pulmonary valve/right ventricular outflow tract gradient (P = .06) in the valve-sparing group, but no difference in the pulmonary valve annulus z-scores. Additionally, the pulmonary valve z-scores in the valve-sparing group decreased from -2.3 ± 1.0 on predischarge echocardiogram of to -1.2 ± 1.6 on last follow-up, with the peak gradient on predischarge 23 (0-37) mm Hg remaining stable on last follow-up at 18 (0-29) mm Hg. There was one reoperation: pulmonary valve replacement six years after a transannular patch.

CONCLUSIONS

Obtaining a postrepair pulmonary valve z-score of -2 yields satisfactory, stable valve-sparing repair with pulmonary valve growth, acceptable gradients, minimal regurgitation, and high freedom from reintervention during follow-up.

QRS Duration During Follow-Up of Tetralogy of Fallot: How Valuable is it? Analysis of ECG Changes in Relation to Pulmonary Valve Implantation

Long-term results after tetralogy of Fallot (TOF) repair are determined by the extent of right ventricular remodeling to chronic pulmonary regurgitation entailing progressive RV dysfunction and a risk of developing ventricular arrhythmia. Pulmonary valve replacement (PVR) can alleviate this burden. As a predictor of ventricular arrhythmia, QRS duration remains a strong parameter in this decision. We performed a retrospective analysis of all PVR patients between 2005 and 2018, studying the time evolution of electrocardiographic parameters before and after PVR through linear mixed model analysis. 42 TOF patients underwent PVR. The median timespan between primary repair and PVR was 18 years (IQR 13-30). The indication for PVR was primarily based on the association of exercise intolerance (67%) and significant RV dilation on cMRI (median RVEDVi 161 ml/m² IQR 133-181). Median QRS length was 155 ms (IQR 138-164), 4 (10%) patients had a QRS > 180 ms. QRS duration increased significantly before PVR, but barely showed regression after PVR. Changes of QRS duration after PVR were independent of RV dilation. In conclusion, when the decision for PVR in TOF patients is primarily based on RV volume and/or function threshold, QRS duration > 180 ms is rarely observed. In contrast with the significant increase of QRS duration before PVR, QRS length regression appears to be independent of the extent of RV dilation or QRS > 160 ms. Considering that the decision for PVR is based on mechanical RV characteristics, the utility of serial follow-up of QRS duration in contemporary operated TOF patients becomes questionable in absence of clinical arguments for ventricular arrhythmia.

Assessment of regional and global right ventricular systolic function in children with repaired tetralogy of Fallot

BACKGROUND

Echo assessment of right ventricular function is difficult due to its complex geometry and regional differences in wall motion. In patients with repaired tetralogy of Fallot, cardiac MRI is the gold standard for assessment of right ventricular function. There is scant data regarding the correlation of echo measures of right ventricular function with cardiac MRI right ventricular function in the paediatric population.

METHODS

Echocardiographic measures of regional and global right ventricular function were reviewed in 56 patients with repaired tetralogy of Fallot and 27 patients with structurally normal hearts. These measures were compared to global right ventricular ejection fraction by cardiac MRI.

RESULTS

Despite having the same right ventricular ejection fraction by cardiac MRI as normal controls, patients with repaired tetralogy of Fallot had significantly worse global and regional echocardiographic measures of right ventricular function. Right ventricular fractional area change and fractional shortening of the right ventricular outflow tract correlated best with global right ventricular function by MRI. Incorporation of these measures into a regression model allowed accurate prediction of global right ventricular function by cardiac MRI.

CONCLUSION

Children with repaired tetralogy of Fallot have abnormal regional and global right ventricular function compared to patients with normal hearts. Despite the presence of patch material, the right ventricular outflow tract significantly contributes to global right ventricular function by cardiac MRI. When incorporated into a model that includes regional and global echocardiographic measures of right ventricular function, right ventricular outflow tract fractional shortening helps predict global right ventricular function by MRI.

Outcomes of pulmonary valve replacement using a bioprosthetic valve and polytetrafluoroethylene bicuspid valve for pulmonary valve regurgitation after intracardiac repair of tetralogy of Fallot

BACKGROUND

Excellent results have been reported regarding pulmonary valve replacement (PVR) for pulmonary valve regurgitation (PR) after intracardiac repair (ICR) in patients with tetralogy of Fallot (TOF). However, there are apparently no reports comparing the following procedures: PVR using a bioprosthetic valve and PVR using a polytetrafluoroethylene (PTFE) bicuspid valve. Herein, we retrospectively analyzed the outcomes of PVR for PR after ICR of TOF in our institution and assessed which of the two PVR procedures was better.

METHODS

From June 2008 to December 2017, we performed PVR for PR after ICR of TOF in 34 patients. Patients with the right ventricle to the pulmonary artery conduits were excluded. Preoperative and postoperative cardiac magnetic resonance imagings (cMRIs) were performed in all patients. The patients were divided into the bioprosthetic valve group (BV group, n = 17) and the PTFE bicuspid valve group (PTFE group, n = 17).

RESULTS

There were no significant differences in the preoperative cMRI data and perioperative factors between the two groups. There were no deaths in either group. Postoperative cMRI showed that the PR fraction and the right ventricular end-diastolic volume index (RVEDVI)/left ventricular end-diastolic volume index ratio were significantly improved in both groups. However, RVEDVI was significantly improved only in the BV group. Re-PVR was required in four patients in the PTFE group.

CONCLUSION

PVR using a bioprosthetic valve was more effective for PR treatment after ICR of TOF than PVR using a PTFE bicuspid valve.

Finding the Optimal Timing for Repair of Standard Tetralogy of Fallot: Analysis of Cardiac Magnetic Resonance and Echocardiography Parameters Related to Intermediate Term Outcomes in a Pediatric Population

INTRODUCTION

Right ventricular (RV) dilatation is the determining prognostic factor in the long-term follow up of patients with repaired Tetralogy of Fallot (TOF). The objective of this study is to analyze whether the results vary depending on the timing of the complete repair and on the surgical technique applied.

MATERIAL-METHODS

This is a retrospective longitudinal study in which patients with standard TOF were divided into 3 groups depending on their age at surgical repair: group 1 = Early repair (n = 12,1-8 months), group 2 = Late repair (n = 26, > 8 months), and group 3 = Late repair with previous palliative surgery (n = 17, > 8 months). Clinical, echocardiographic and cardiac magnetic resonance (CMR) data from patients that had received complete reparative surgery in our institution from January 2000 to March 2014 were analyzed and compared.

RESULTS

55 patients with echocardiogram and CMR studies (13.39 ± 3.59 years) were reviewed. All patients had at least moderate pulmonary regurgitation (PR). We observed a positive correlation between PR and right ventricular end-diastolic volume (r² = 0.418; p = 0,004). Group 3 had more severe right ventricular dilatation than patients in groups 1 and 2 (p = 0.001). No differences in right ventricular end-diastolic volume, PR, and pulmonary trunk dimensions were observed between groups 1 and 2. Patients in group 3 had a longer hospital stay.

CONCLUSIONS

Although all patients from our cohort had significant PR, age at surgery was not related to RV or pulmonary trunk dilatation. Previous palliative surgery was associated with more severe right ventricular dilatation and longer hospital stays. No differences were observed between early and late repair groups. Our study suggests that postponing TOF repair to a late stage does not improve the degree of PR or long-term morbidity from RV dilatation. Palliative surgery should be avoided if possible.

Left Ventricular Torsion Obtained Using Equilibrated Warping in Patients with Repaired Tetralogy of Fallot

Patients after surgical repair of Tetralogy of Fallot (rTOF) may suffer a decrease in left ventricular (LV) function. The aim of our study is to evaluate a novel method of assessing LV torsion in patients with rTOF, as an early indicator of systolic LV dysfunction. Motion tracking based on image registration regularized by the equilibrium gap principle, known as equilibrated warping, was employed to assess LV torsion. Seventy-six cases of rTOF and ten normal controls were included. The group of controls was assessed for reproducibility using both equilibrated warping and standard clinical tissue tracking software (CVI42, version 5.10.1, Calgary, Canada). Patients were dichotomized into two groups: normal vs. loss of torsion. Torsion by equilibrated warping was successfully obtained in 68 of 76 (89%) patients and 9 of 10 (90%) controls. For equilibrated warping, the intra- and interobserver coefficients of variation were 0.095 and 0.117, respectively, compared to 0.260 and 0.831 for tissue tracking by standard clinical software. The intra- and inter-observer intraclass correlation coefficients for equilibrated warping were 0.862 and 0.831, respectively, compared to 0.992 and 0.648 for tissue tracking. Loss of torsion was noted in 32 of the 68 (47%) patients with rTOF. There was no difference in LV or RV volumes or ejection fraction between these groups. The assessment of LV torsion by equilibrated warping is feasible and shows good reliability. Loss of torsion is common in patients with rTOF and its robust assessment might contribute into uncovering heart failure in an earlier stage.

Impaired right and left ventricular function and relaxation induced by pulmonary regurgitation are not reversed by tardive antifibrosis treatment

Pulmonary regurgitation (PR) after repair of tetralogy of Fallot (rTOF) is associated with progressive right (RV) and left (LV) ventricular dysfunction and fibrosis. However, angiotensin II receptor blockade therapy has shown mixed and often disappointing results. The aim of this study was to serially assess changes in biventricular remodeling, dysfunction, and interactions in a rat model of isolated severe PR and to study the effects of angiotensin II receptor blockade. PR was induced in Sprague-Dawley rats by leaflet laceration. Shams (n = 6) were compared with PR (n = 5) and PR + losartan treatment (n = 6). In the treatment group, oral losartan (50 mg·kg^-1·day^-1) was started 6 wk after PR induction and continued for 6 wk until the terminal experiment. In all groups, serial echocardiography was performed every 2 wk until the terminal experiment where biventricular myocardium was harvested and analyzed for fibrosis. PR and PR + losartan rats experienced early progressive RV dilatation by 2 wk which then stabilized. RV systolic dysfunction occurred from 4 wk after insult and gradually progressed. In PR rats, RV dilatation caused diastolic LV compression and impaired relaxation. PR rats developed increased RV fibrosis compared with shams. Although losartan decreased RV fibrosis, RV dilatation and dysfunction were not improved. This suggests that RV dilatation is an early consequence of PR and affects LV relaxation. RV dysfunction may progress independent of further remodeling. Reduced RV fibrosis was not associated with improved RV function and may not be a viable therapeutic target in rTOF with predominant RV volume loading.NEW & NOTEWORTHY The time-course of RV dilatation and the mechanisms of biventricular dysfunction caused by PR have not been well characterized and the effect of losartan in volume-overloaded RV remains controversial. Our findings suggest that severe PR induces early onset of RV dilatation and dysfunction with little progression after the first 4 wk. The RV dilatation distorts LV geometry with associated impaired LV relaxation. Losartan reduced RV fibrosis but did not reverse RV dilatation and dysfunction.

Impact of pulmonary valve replacement on left ventricular rotational mechanics in repaired tetralogy of Fallot

BACKGROUND

In repaired tetralogy of Fallot (rTOF), abnormal left ventricular (LV) rotational mechanics are associated with adverse clinical outcomes. We performed a comprehensive analysis of LV rotational mechanics in rTOF patients using cardiac magnetic resonance (CMR) prior to and following surgical pulmonary valve replacement (PVR).

METHODS

In this single center retrospective study, we identified rTOF patients who (1) had both a CMR ≤ 1 year before PVR and ≤ 5 years after PVR, (2) had no other intervening procedure between CMRs, (3) had a body surface area > 1.0 m2 at CMR, and (4) had images suitable for feature tracking analysis. These subjects were matched to healthy age- and sex-matched control subjects. CMR feature tracking analysis was performed on a ventricular short-axis stack of balanced steady-state free precession images. Measurements included LV basal and apical rotation, twist, torsion, peak systolic rates of rotation and torsion, and timing of events. Associations with LV torsion were assessed.

RESULTS

A total of 60 rTOF patients (23.6 ± 7.9 years, 52% male) and 30 healthy control subjects (20.8 ± 3.1 years, 50% male) were included. Compared with healthy controls, rTOF patients had lower apical and basal rotation, twist, torsion, and systolic rotation rates, and these parameters peaked earlier in systole. The only parameters that were correlated with LV torsion were right ventricular (RV) end-systolic volume (r = - 0.28, p = 0.029) and RV ejection fraction (r = 0.26, p = 0.044). At a median of 1.0 year (IQR 0.5-1.7) following PVR, there was no significant change in LV rotational parameters versus pre-PVR despite reductions in RV volumes, RV mass, pulmonary regurgitation, and RV outflow tract obstruction.

CONCLUSION

In this comprehensive study of CMR-derived LV rotational mechanics in rTOF patients, rotation, twist, and torsion were diminished compared to controls and did not improve at a median of 1 year after PVR despite favorable RV remodeling.

Four-dimensional flow cardiovascular magnetic resonance in tetralogy of Fallot: a systematic review

BACKGROUND

Patients with repaired Tetralogy of Fallot (rTOF) often develop cardiovascular dysfunction and require regular imaging to evaluate deterioration and time interventions such as pulmonary valve replacement. Four-dimensional flow cardiovascular magnetic resonance (4D flow CMR) enables detailed assessment of flow characteristics in all chambers and great vessels. We performed a systematic review of intra-cardiac 4D flow applications in rTOF patients, to examine clinical utility and highlight optimal methods for evaluating rTOF patients.

METHODS

A comprehensive literature search was undertaken in March 2020 on Google Scholar and Scopus. A modified version of the Critical Appraisal Skills Programme (CASP) tool was used to assess and score the applicability of each study. Important clinical outcomes were assessed including similarities and differences.

RESULTS

Of the 635 articles identified, 26 studies met eligibility for systematic review. None of these were below 59% applicability on the modified CASP score. Studies could be broadly classified into four groups: (i) pilot studies, (ii) development of new acquisition methods, (iii) validation and (vi) identification of novel flow features. Quantitative comparison with other modalities included 2D phase contrast CMR (13 studies) and echocardiography (4 studies). The 4D flow study applications included stroke volume (18/26;69%), regurgitant fraction (16/26;62%), relative branch pulmonary artery flow(4/26;15%), systolic peak velocity (9/26;35%), systemic/pulmonary total flow ratio (6/26;23%), end diastolic and end systolic volume (5/26;19%), kinetic energy (5/26;19%) and vorticity (2/26;8%).

CONCLUSIONS

4D flow CMR shows potential in rTOF assessment, particularly in retrospective valve tracking for flow evaluation, velocity profiling, intra-cardiac kinetic energy quantification, and vortex visualization. Protocols should be targeted to pathology. Prospective, randomized, multi-centered studies are required to validate these new characteristics and establish their clinical use.

Heart failure in adult congenital heart disease: tetralogy of Fallot

The number of rTOF patients who survive into adulthood is steadily rising, with currently more than 90% reaching the third decade of life. However, rTOF patients are not cured, but rather have a lifelong increased risk for cardiac and non-cardiac complications. Heart failure is recognized as a significant complication. Its occurrence is strongly associated with adverse outcome. Unfortunately, conventional concepts of heart failure may not be directly applicable in this patient group. This article presents a review of the current knowledge on HF in rTOF patients, including incidence and prevalence, the most common mechanisms of heart failure, i.e., valvular pathologies, shunt lesions, left atrial hypertension, primary left heart and right heart failure, arrhythmias, and coronary artery disease. In addition, we will review information regarding extracardiac complications, risk factors for the development of heart failure, clinical impact and prognosis, and assessment possibilities, particularly of the right ventricle, as well as management strategies. We explore potential future concepts that may stimulate further research into this field.

Value of pulmonary annulus index in predicting transannular patch in tetralogy of Fallot repair

OBJECTIVE

It is very important to accurately assess the transannular patch (TAP) in the surgical treatment of tetralogy of Fallot (TOF). The pulmonary annulus index (PAI; the actual pulmonary annulus diameter divided by the expected pulmonary annulus diameter), GA ratio (the ratio of pulmonary annulus and aortic annulus), PAAI (the ratio of pulmonary annulus cross-section and aortic annulus cross-section), and pulmonary annulus Z score (PA Z score) were compared. This study aimed to analyze and explore the application value of PAI in predicting the need for TAP in children undergoing TOF repair.

METHODS

In total, 130 patients who were diagnosed with TOF and underwent TOF repair in Beijing Anzhen Hospital affiliated to Capital Medical University from December 2018 to December 2019 were retrospectively studied. In total, 112 cases were included in this study and 18 cases were excluded, of which 16 cases were aged above 18 years and 2 cases suffered from Down syndrome. They were divided into TAP group and no TAP group; the values of the pulmonary annulus and aortic annulus were measured. GA ratio, PAI, PAAI, the pulmonary annulus Z score, and main pulmonary artery (MPA) Z score were calculated to perform statistical analysis.

RESULTS

A total of 112 patients were included in the study, aged 4-177 months, with an average of 22.87 ± 30.21 months; 66 males and 46 females; weighing 5.3-29 kg, with an average of 9.94 ± 4.08 kg; three cases died, one case died of sepsis caused by pulmonary infection, one case died of low cardiac output syndrome, and one case died of multiple organ failure. In total, 62 cases (55.8%) did not undergo TAP and 50 cases (44.2%) underwent TAP. The pulmonary annulus Z score, main pulmonary artery Z score, and PAI in the TAP group were smaller than those in the no TAP group (p < .05). Receiver operating curve (ROC) analysis showed that when the cut-off value of pulmonary annulus was -1.98, the area under the curve (AUC) was 0.88, the sensitivity was 80%, and the specificity was 71%; when the cut-off value of PAI was 0.53, AUC was 0.85, the sensitivity was 75%, and the specificity was 80%; when the cut-off value of GA ratio was 0.55, AUC was 0.85, the sensitivity was 76%, and the specificity was 80%. The area under the PAAI curve was 0.85, the sensitivity was 76%, and the specificity was 79%. When the pulmonary valve Z score, PAI, GA ratio, PAAI, and MPA Z score were all greater than the dividing value, TAP was avoided in more than 90% of children with TOF. When the pulmonary valve Z score, PAI, GA ratio, PAAI, and the main pulmonary artery Z score were all below the dividing value, more than 90% of children with TOF needed TAP.

CONCLUSION

The predictive effect of PAI as a simple and effective predictor of TAP in TOF radical operation is the same as that of pulmonary annulus Z score, and combining it with the main pulmonary artery Z score was the most accurate method of prediction.

Wharton's Jelly-Mesenchymal Stem Cell-Engineered Conduit for Pediatric Translation in Heart Defect

The materials available for the right ventricular outflow tract (RVOT) reconstruction in patients with tetralogy of fallot (TOF)/pulmonary atresia come with the severe limitation of long-term degeneration and lack of growth potential, causing right ventricular dysfunction, aneurysm formation, and arrhythmias, thus necessitating several high-risk reoperations throughout patients' lives. In this study, we evaluated the capacity of mesenchymal stem cells (MSCs) derived from the Wharton's Jelly (WJ-MSCs), the gelatinous inner portion of the umbilical cord, to grow and recellularize an extracellular matrix (ECM) graft in our optimized xeno-free, good manufacturing practice-compliant culture system. WJ-MSCs were phenotypically and functionally characterized by flow cytometry and multilineage differentiation capacity, respectively. The typical MSC immunophenotype and functional characteristics were retained in our xeno-free culture system, as well as the capacity to grow and engraft onto a naturally occurring scaffold. WJ-MSCs, from both human and swine source, showed excellent capacity to recellularize ECM graft producing a living cell-seeded construct. In addition, we have provided an in vivo proof of concept of feasibility of the cellularized conduit, engineered with swine WJ-MSCs, to be used in a novel porcine model of main pulmonary artery reconstruction, where it showed good integration within the host tissue. Our study indicates that the addition of WJ-MSCs to the ECM scaffold can upgrade the material, converting it into a living tissue, with the potential to grow, repair, and remodel the RVOT. These results could potentially represent a paradigm shift in pediatric cardiac intervention toward new modalities for effective and personalized surgical restoration of pulmonary artery and RVOT function in TOF/pulmonary atresia patients. Impact Statement The materials available for pulmonary artery reconstruction in pediatric patients with Congenital Heart Defect come with the limitation of long-term degeneration and lack of growth, thus necessitating several reoperations. Here, we describe a novel approach combining perinatal stem cells and naturally occurring scaffold to create a living tissue engineered conduit that showed good growth potential in a pulmonary artery reconstruction porcine model. We envision this approach is of great interest and relevance in tissue engineering field applied to cardiovascular regenerative medicine, as it may open up new avenues for correction of congenital cardiac defects, with remarkable medical and social benefits.

Predictors of right ventricular function and size in patients with hypertrophic cardiomyopathy

We investigated factors associated with right ventricular (RV) function and size in hypertrophic cardiomyopathy (HCM) patients. Two hundred fifty-three consecutive HCM patients and 20 healthy volunteers underwent cardiac magnetic resonance examination. In addition to measuring RV function (ejection fraction—RVEF) and size (end-diastolic volume—RVEDV), each image was inspected for the presence of RV and left ventricular (LV) hypertrophy, and the maximal wall thickness of the left and right ventricles was recorded. HCM patients had higher RVEF and lower RVEDV than healthy volunteers and similar RV mass. The mean RV wall thickness was higher in HCM patients than in controls. LV late gadolinium enhancement (LGE) was present in 89.7% of patients, and RV LGE was present in 3.1% of patients (p < 0.0001). Univariate and multivariable analyses revealed that LVEF, peak LV outflow tract gradient, LV LGE, maximal LV wall thickness, and tricuspid regurgitation (TR) volume by magnetic resonance imaging were positive predictors of RVEF. In addition to TR volume, the only independent predictor of RVEF < 45% was LVEF (odds ratio = 0.80, 95% confidence interval 0.67–0.95). Multivariable analysis revealed that LVEDV and TR volume were positive predictors of RVEDV, whereas negative predictors were RVEF, maximal RV wall thickness, LV LGE, and age. Neither estimated systolic pulmonary artery pressure nor TR grade by echocardiography proved to be predictors of RVEF. There were no differences in either the maximal RV wall thickness or the maximal left ventricular (LV) wall thickness in patients stratified according to NYHA functional class (p = 0.93 and p = 0.15, respectively). There were no differences in mean RV wall thickness in patients categorised based on the number of clinical risk factors for sudden cardiac death (SCD), i.e., non-sustained ventricular tachycardia, family history of SCD, or unexplained syncope (p = 0.79). On the other hand, there was a weak positive association between RV hypertrophy and the estimated probability of SCD at 5 years (rho = 0.16, p = 0.01). RV systolic dysfunction measured as decreased RVEF was uncommon in HCM and was associated with poor LV systolic function. LV also had a significant impact on RV size.

The impact of pulmonary regurgitation on right ventricular size and function in patients with repaired tetralogy of Fallot and additional haemodynamic abnormalities

Purpose

Right ventricular (RV) outflow tract obstruction (RVOTO) was demonstrated to be protective against RV dilatation in patients with repaired tetralogy of Fallot and chronic pulmonary regurgitation (PR). We hypothesised that the presence of additional haemodynamic abnormalities (more than mild tricuspid regurgitation, residual ventricular septal defect) reduces this protective association. Accordingly, we aimed to assess the impact of PR on RV size and function in this population.

Material and methods

Consecutive patients with additional haemodynamic abnormalities after tetralogy of Fallot (TOF) repair, who had undergone cardiovascular magnetic resonance, were included.

Results

Out of 90 patients studied, 18 individuals (mean age 32.5 ± 10.7 years, 72.2% males) met the inclusion criteria. There were no differences in RV volumes and ejection fraction between patients with and without RVOTO. Neither PR fraction (PRF) nor PR volume (PRV) correlated with RV end-diastolic volume (r = 0.36; p = 0.15 and r = 0.37; p = 0.14, respectively, for PRF and PRV) or RV end-systolic volume (r = 0.2; p = 0.42 and r = 0.19; p = 0.45, respectively, for PRF and PRV). Similarly, no significant correlations were observed between PRF or PRV and RV ejection fraction (r = –0.04; p = 0.87 and r = –0.03; p = 0.9, respectively).

Conclusions

Additional haemodynamic abnormalities are associated with the abolition of the protective effect of RVOTO on RV size. There was no significant relationship between measures of PR and RV volumes in patients after TOF repair with concomitant haemodynamic abnormalities. These abnormalities acted as confounding factors in the assessment of the impact of pulmonary regurgitation on RV size and function.

Relationship between right and left ventricular diastolic dysfunction assessed by 2-dimensional speckle-tracking echocardiography in adults with repaired tetralogy of Fallot

Several studies have reported a correlation between right ventricular (RV) and left ventricular (LV) systolic dysfunction in adults with repaired tetralogy of Fallot (TOF). However, data are lacking regarding the relationship between RV and LV diastolic dysfunction assessed by 2-dimensional speckle-tracking echocardiography. We studied 69 adults with repaired TOF (mean age 34 years, 61% male) who had been regularly followed up and had routinely undergone echocardiography. In addition to conventional echocardiography, global longitudinal strain (GLS) and early diastolic strain rate (SRe) of both ventricles were assessed using 2-dimensional speckle-tracking echocardiography. Results were compared with 30 age- and sex-matched controls. RV and LV GLS were decreased in TOF patients compared with controls (− 18.4 ± 3.3% vs. −23.5 ± 4.2%, p < 0.001 and − 16.0 ± 3.8% vs. −20.0 ± 3.0%, p < 0.001, respectively). RV and LV SRe were also decreased in TOF patients compared with controls (1.22 ± 0.34 sec^− 1 vs. 1.47 ± 0.41 sec^− 1, p = 0.003 and 1.29 ± 0.42 sec^− 1 vs. 1.63 ± 0.42 sec^− 1, p < 0.001, respectively). A correlation between RV and LV SRe was found in TOF patients (r = 0.43, p < 0.001) as well as between RV and LV GLS (r = 0.45, p < 0.001). Two-dimensional speckle-tracking echocardiography reveals subclinical RV and LV diastolic dysfunction in adults with repaired TOF. A correlation is observed between RV and LV diastolic dysfunction as well as between RV and LV systolic dysfunction.

Sex differences in patients with repaired tetralogy of Fallot support a tailored approach for males and females: a cardiac magnetic resonance study

Purpose Substantial differences between sexes exist with respect to cardiovascular diseases, including congenital heart disease. Nevertheless, clinical decisions in the long-term follow-up of patients with repaired tetralogy of Fallot (rTOF) are currently based on unisex thresholds for cardiac magnetic resonance (CMR) measurements. This study aimed to assess whether sex differences exist in cardiac adaptation to hemodynamic loading conditions in patients with rTOF. Methods and Results This cross-sectional, two-center, combined pediatric and adult cohort included 320 rTOF patients (163 males, 51%) who underwent routine CMR. Despite similar age (median and interquartile range [m + IQR] 23.4 [15.2-34.4] years), surgical history, and hemodynamic loading, males with rTOF demonstrated higher biventricular CMR-derived volumes and masses, indexed for body surface area, compared to females (e.g. m + IQR right ventricular (RV) end-diastolic volume: males 123 [100-151] mL/m2, females 114 [94-131] mL/m2, P = 0.007). Sex-specific Z-scores of biventricular volumes and masses were similar for males and females. RV volumes and masses correlated with hemodynamic loading, but these relations did not differ between sexes. Biventricular ejection fraction (EF) appeared to be lower in male patients, compared to female patients (e.g. m + IQR RVEF: males 48 [43-54]%, females 52 [46-57]%, P < 0.001). Conclusion Indexed ventricular volumes and masses are higher in males with rTOF, compared to females, similar to the healthy population. RV hypertrophy and dilatation correlated to loading conditions similarly for both sexes. However, under comparable loading conditions, males demonstrated more severe functional impairment. These results indicate that sex-differences should no longer be ignored in treatment strategies, including timing of pulmonary valve replacement.

Outflow tract geometries are associated with adverse outcome indicators in repaired tetralogy of Fallot

OBJECTIVES

A wide variety of right ventricular outflow tract (RVOT) and pulmonary artery (PA) geometries has been reported in patients with repaired tetralogy of Fallot (rTOF). We aimed to investigate the associations between RVOT/PA geometries and outcome indicators in a large rTOF cohort receiving non-conduit repair.

METHODS

Three-dimensional magnetic resonance angiographic images of 206 patients with rTOF who had a pulmonary regurgitation (PR) fraction ≥20% were reviewed. Patients' RVOT geometry was quantitatively classified into 4 distinct shapes (tubular, hourglass, pyramid, and inverted trapezoid). Bilateral PA size discrepancy was defined as the diameter of the smaller side being less than 70% of that of the bigger side.

RESULTS

Based on lateral projection of the 3-dimensional images, patients with an inverted trapezoid-shaped RVOT had the smallest RV end-diastolic volume index (EDVi) (108.7 ± 24.3 mL/m²) and pulmonary valve annulus diameter, and shortest QRS duration, whereas those with a pyramid-shaped RVOT had the largest RV EDVi (161.0 ± 44.6 mL/m²) and pulmonary valve annulus diameter. Similar trends of differences were also observed if such classifications were based on the frontal projections. Multivariable analysis revealed that RVOT shapes, subvalvular diameter, PR fraction, QRS duration, and the presence of bilateral PA size discrepancy were independent determinants of RV EDVi. Furthermore, having bilateral PA size discrepancy (25.2%) was independently associated with lower peak oxygen consumption (P = .041).

CONCLUSIONS

Distinct RVOT morphologies and branch PA size discrepancy are associated with variations in RV remodeling and exercise capacity in patients with rTOF. These findings may aid decision-making regarding reintervention for PR and branch PA size discrepancy.