Beneficial effects of residual right ventricular outflow tract obstruction on right ventricular volume and function in patients after repair of tetralogy of Fallot

Residual pulmonary stenosis and right ventricular contractility in repaired tetralogy of Fallot

OBJECTIVES

The impact of residual pulmonary stenosis (rPS) or right ventricular (RV) outflow tract obstruction on prognosis after surgical pulmonary valve insertion) in repaired tetralogy of Fallot patients with pulmonary regurgitation (PR) remains controversial. rPS assessment is partially dependent on RV contractility. We investigated the impact of rPS according to RV ejection fraction (RVEF).

METHODS

In this multicentre, retrospective study, 117 repaired tetralogy of Fallot patients who underwent surgical pulmonary valve insertion for more than moderate PR between 2003 and 2021 were examined. Regarding rPS, the threshold for PR with rPS (PSR) and PR was 25 mmHg. For RVEF, the threshold for preserved RVEF (pEF) and reduced RVEF (rEF) was 40%. The patients were divided into 4 groups: patients with PR and pEF (PR-pEF) (n = 48), those with PR and rEF (PR-rEF) (n = 44), those with PSR and pEF (PSR-pEF) (n = 16), and those with PSR and rEF (PSR-rEF) (n = 9). Clinical parameters, postoperative adverse event rates and their associations were studied.

RESULTS

The 5-year freedom from adverse cardiovascular events was the highest in the PSR-pEF and the lowest in the PSR-rEF groups. The PSR-rEF group had the highest RV end-diastolic pressure (RVEDP) (12 ± 2.2 mmHg) (P = 0.006). From multivariable analysis, RVEDP was associated with postoperative adverse events (P = 0.016). RVEDP > 8 mmHg was associated with a lower freedom from adverse events.

CONCLUSIONS

The freedom from adverse events was the lowest in the PSR-rEF group, with the highest RVEDP, suggesting RV systolic and diastolic dysfunction. Reduced RVEF may mask the intrinsic degree of residual stenosis, delay surgical pulmonary valve insertion timing and increase adverse events.

Myocardial, Valvular and Vascular Abnormalities in Repaired Tetralogy of Fallot

Tetralogy of Fallot is the most common heart defect associated with cyanosis characterized by the co-occurrence of pulmonary stenosis, right ventricular hypertrophy, and ventricular septal defect with over-riding of the aorta. The present review purposed to summarize myocardial, valvular and vascular abnormalities, which were described in a series of patients following repair of tetralogy of Fallot. It was also aimed to describe potential differences in these parameter using different surgical strategies.

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.

The value of myocardial strain imaging in the evaluation of patients with repaired Tetralogy of Fallot: a review of the literature

Tetralogy of Fallot (ToF) is considered to be the most common, complex, cyanotic congenital heart disease (CHD) representing 7-10% of all congenital heart defects, whereas the patients with ToF are the most frequently operated in their early infancy or childhood. Cardiac magnetic resonance (CMR) consists a valuable imaging technique for the diagnosis and serial follow-up of CHD patients. Furthermore, in recent years, advanced echocardiography imaging techniques have come to the fore, aiming to achieve a complete and more accurate evaluation of cardiac function using speckle tracking imaging modalities. We conducted a review of the literature in order to assess the myocardial deformation of patients with repaired ToF (rToF) using echocardiographic and CMR parameters. Patients with rToF have impaired myocardial strain parameters, that are well standardized either with the use of speckle tracking echocardiography or with the use of CMR imaging. Subclinical left ventricular dysfunction (low GLS) and myocardial dyssynchrony are commonly identified in rToF patients. Impaired left atrium (LA) and right atrium (RA) mechanics are, also, a common finding in this study population, but the studies using atrial strain are a lot fewer than those with LV and RV strain. No studies using myocardial work were identified in the literature, as far as rToF patients are concerned, which makes it an ideal field for further investigation.

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.

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

Background

Pulmonary arterial end‐diastolic forward flow (EDFF) following repaired tetralogy of Fallot has been thought to represent right ventricular (RV) restrictive physiology, but is not fully understood. This systematic review and meta‐analysis sought to clarify its physiological and clinical correlates, and to define a framework for understanding EDFF and RV restrictive physiology.

Methods and Results

PubMed/MEDLINE, Embase, Scopus, and reference lists of relevant articles were searched for observational studies published before March 2021. Random‐effects meta‐analysis was performed to identify factors associated with EDFF. Forty‐two individual studies published between 1995 and 2021, including a total of 2651 participants (1132 with EDFF; 1519 with no EDFF), met eligibility criteria. The pooled estimated prevalence of EDFF among patients with repaired tetralogy of Fallot was 46.5% (95% CI, 41.6%–51.3%). Among patients with EDFF, the use of a transannular patch was significantly more common, and their stay in the intensive care unit was longer. EDFF was associated with greater RV indexed volumes and mass, as well as smaller E‐wave velocity at the tricuspid valve. Finally, pulmonary regurgitation fraction was greater in patients with EDFF, and moderate to severe pulmonary regurgitation was more common in this population.

Conclusions

EDFF is associated with dilated, hypertrophied RVs and longstanding pulmonary regurgitation. Although several studies have defined RV restrictive physiology as the presence of EDFF, our study found no clear indicators of poor RV compliance in patients with EDFF, suggesting that EDFF may have multiple causes and might not be the precise equivalent of RV restrictive physiology.

Clinical Application of Individualized Pulmonary Bi-Orifice for the Reconstruction of Right Ventricular Outflow Tract in Tetralogy of Fallot

Objective: The study aims to establish a new method in the Tetralogy of Fallot (ToF) called the pulmonary valve bi-orifice method (pulmonary annular sparing with an individualized autologous pericardial patch; thus, two orifices are formed at the level of the pulmonary valve annulus) to reconstruct the right ventricular outflow tract (RVOT).

Methods: A retrospective analysis of 128 TOF patients from October 2009 to June 2018 with severe pulmonary valve dysplasia who underwent transvalvular annular patch (TAP) procedure (control group) or an individualized pulmonary valve bi-orifice procedure (observation group) were studied. The RVOT for each patient in the observation group was individually reconstructed per the patient's weight and the size of the autologous pulmonary valve using the bi-orifice method; however, increasing the cross-sectional area of the pulmonary valve annulus without destroying its integrity. The result was then compared to the control group, where TAP procedures were applied to evaluate the short to mid-term outcome(s). An in vitro simulation test was used to verify the anti-regurgitation mechanism of the new method.

Results: The in vitro simulation test indicated that the anti-regurgitation mechanism was completed by the pericardial patch and the autologous pulmonary valve movement toward each other. Thus, for clinical applications, patients in both groups were compared. The results showed no significant differences in cardiopulmonary bypass and aortic cross-clamp time, mechanical ventilation, and ICU and post-operative residence between the two groups.

During the follow-up period (3- to 12-years), 14 patients in the observation group had mild regurgitation after surgery (22.2%), while 10 patients had moderate pulmonary regurgitation (15.8%) with no right ventricular (RV) dilation. On the other hand, 22 patients (39.6%) had moderate to severe regurgitation in the control group, while left pulmonary artery stenosis occurred in one patient. In the control group, six patients (9.2%) with severe RV dilation were reoperated.

Conclusion: Individualized pulmonary valve bi-orifice procedure is a safe and excellent method for reconstructing RVOT in ToF.

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.

Outcomes of pulmonary valve leaflet augmentation for transannular repair of tetralogy of Fallot

OBJECTIVE

To evaluate the midterm results of pulmonary valve leaflet augmentation in transannular repair of tetralogy of Fallot (TOF).

METHODS

From 2007 to 2019, 131 patients underwent a transannular repair with pulmonary leaflet augmentation for TOF (n = 120) and double outlet right ventricle with pulmonary stenosis (n = 11). Patch material was expanded polytetrafluoroethylene (n = 76), glutaraldehyde-treated autologous pericardium (n = 47) and bovine pericardium (n = 8).

RESULTS

Median age at repair was 8.9 months (interquartile range, 5.4-14.8). There was no operative mortality. Median follow-up was 6.25 years (interquartile range, 2.77-7.75). Freedom from severe pulmonary regurgitation (PR) was 85% (95% confidence interval [CI], 77%-90%) and 76% (95% CI, 66%-83%) at 1 and 5 years, respectively. Freedom from moderate or greater PR was 69% (95% CI, 60%-76%) and 30% (95% CI, 21%-39%) at 5 and 10 years, respectively. Three patients required pulmonary valve replacement for PR. Nine patients required pulmonary balloon valvuloplasty. Freedom from intervention for pulmonary valve stenosis was 98% (95% CI, 93%-99%) and 94% (95% CI, 87%-97%) at 1 and 5 years, respectively. One patient with severe PR had an indexed right ventricular volume >160 mL/m². Use of expanded polytetrafluoroethylene resulted in a greater freedom from moderate or greater PR (log-rank test P < .001; Cox regression hazard ratio, 0.40; 95% CI, 0.25-0.63; P < .001).

CONCLUSIONS

At midterm follow-up of transannular repair with pulmonary valve leaflet augmentation, severe PR occurs in less than 50% of patients. The expanded polytetrafluoroethylene patch performs better than pericardium.

Comparison of different pulmonary valve reconstruction techniques during transannular repair of tetralogy of fallot

BACKGROUND

Transannular patch, which results in pulmonary insufficiency (PI), is usually required during repair of tetralogy of fallot (TOF). In this study, we compared three types of pulmonary valve reconstruction techniques during transannular repair of TOF.

METHODS

Between February 2014 and January 2018, 50 patients with TOF underwent primary repair with transannular patch. These patients were divided into three groups. In Group 1, (n = 15), a single gluteraldehyde-treated autologous pericardial patch (standard method) was reconstructed as monocusp. In Group 2, (n = 16) Nunn's bileaflet pulmonary valve reconstruction technique was used with pericardial patch. In Group 3, (n = 19), Nunn's bileaflet technique was performed with expanded polytetrafluoroethylene membrane. The outcomes of the patients and early and midterm competency of the pulmonary valves were analyzed.

RESULTS

These techniques were significantly effective in early postoperative period. Freedom from moderate to severe PI were 73.3%; 100% and 89.4%, respectively. Mortality, duration of intensive care unit and hospital stay were similar between the groups. The mean follow-up period was 17.5 ± 13.0 (3-57) months. Freedom from moderate to severe PI decreased to 40%; 81.2% and 73.7%, respectively at the end of the follow-up period. Presence of moderate to severe PI was significantly higher in Group 1 (p = .018 between Groups 1 and 2, p = .048 between Groups 1 and 3).

CONCLUSION

All three pulmonary valve reconstruction techniques provided competent pulmonary valves. Nunn's bileaflet technique had better outcome at midterm. It has a potential to delay right ventricular dysfunction at long-term.

Biventricular myocardial adaptation in patients with repaired tetralogy of Fallot: Mechanistic insights from magnetic resonance imaging tissue phase mapping

BACKGROUND

The myocardial adaptive mechanism in patients with repaired tetralogy of Fallot (rTOF) is less understood. We aimed to investigate biventricular myocardial adaptive remodeling in rTOF patients.

METHODS

We recruited 32 rTOF patients and 38 age- and sex-matched normal controls. The pulmonary stenosis of rTOF patients was measured using catheterized pressure gradient between right ventricle (RV) and pulmonary artery (PGRVPA). rTOF patients with PGRVPA < 15 mmHg and ≥15 mmHg were classified as low pulmonary stenosis (rTOFlow, n = 19) and high pulmonary stenosis (rTOFhigh, n = 13) subgroups, respectively. Magnetic resonance imaging tissue phase mapping was employed to evaluate the voxelwise biventricular myocardial motion in longitudinal (Vz), radial (Vr), and circumferential (Vφ) directions.

RESULTS

The rTOFlow subgroup presented higher pulmonary regurgitation fraction than rTOFhigh subgroup (p < 0.001). Compared with the normal group, only rTOFlow subgroup presented a decreased RV ejection fraction (RVEF) (p < 0.05). The rTOFlow subgroup showed decreased systolic and diastolic Vz in RV and LV, whereas rTOFhigh subgroup showed such change only in RV. In rTOFlow subgroup, RVEF significantly correlated with RV systolic Vr (r = 0.56, p < 0.05), whereas LVEF correlated with LV systolic Vz (r = 0.51, p = 0.02). Prolonged QRS correlated with RV systolic Vr (r = -0.58, p < 0.01) and LV diastolic Vr (r = 0.81, p < 0.001). No such correlations occurred in rTOFhigh subgroup.

CONCLUSIONS

The avoidance of unfavorable functional interaction in RV and LV in rTOFhigh subgroup suggested that adequate pulmonary stenosis (PGRVPA ≥ 15 mmHg in this sereis) has a protective effect against pulmonary regurgitation.

Bidirectional Glenn for residual outflow obstruction in Tetralogy of Fallot

BACKGROUND

Residual right ventricular outflow obstruction during Tetralogy of Fallot repair necessitates peri-operative revision often requiring trans-annular patch with its negative sequels. Bidirectional Glenn shunt in this setting reduces trans-pulmonary gradient to avoid revision.

METHODS

Bidirectional Glenn shunt was added during Tetralogy repair in patients with significant residual obstruction. A total of 53 patients between January, 2011 and June, 2018 were included. Final follow-up was conducted in July, 2018.

RESULTS

Mean age at operation was 5.63±3.1 years. Right to left ventricular pressure ratio reduced significantly (0.91±0.09 versus 0.68±0.05; p&lt;0.001) after bidirectional Glenn, avoiding revision in all cases. Glenn pressures at ICU admission decreased significantly by the time of ICU discharge (16.7±3.02 versus 13.5±2.19; p&lt;0.001). Pleural drainage ≥ 7 days was seen in 14 (26.4%) patients. No side effects related to bidirectional Glenn-like facial swelling or veno-venous collaterals were noted. Mortality was 3.7%. Discharge echocardiography showed a mean trans-pulmonary gradient of 32.11±5.62 mmHg that decreased significantly to 25.64±5 (p&lt;0.001) at the time of follow-up. Pulmonary insufficiency was none to mild in 45 (88.2%) and moderate in 6 (11.8%). Mean follow-up was 36.12±25.15 months (range 0.5-90). There was no interim intervention or death. At follow-up, all the patients were in NYHA functional class 1 with no increase in severity of pulmonary insufficiency.

CONCLUSION

Supplementary bidirectional Glenn shunt significantly reduced residual right ventricular outflow obstruction during Tetralogy of Fallot repair avoiding revision with satisfactory early and mid-term results.

Cardiac Ventricular Contractile Responses to Chronically Increased Afterload Secondary to Right Ventricular Outflow Obstruction in Patients With Tetralogy of Fallot

We examined the adaptive mechanism of the pulmonary ventricle (PV) in response to increased afterload secondary to pulmonary stenosis in tetralogy of Fallot (TOF, n = 47) and congenitally corrected transposition of the great arteries (cCTGA, n = 18), where the PV is morphologically different. We also elucidated the effects of such adaptation on systemic ventricular (SV) function. PV contractility, assessed by dp/dt_max, showed significant positive correlations with PV pressure (r = 0.82, p <0.01 for TOF and r = 0.78, p <0.01 for cCTGA) and pulmonary-to-systemic ventricular pressure ratio (r = 0.70, p <0.01 for TOF and r = 0.76, p <0.01 for cCTGA) in patients with both TOF and cCTGA. Notably, the slopes of these correlations were significantly higher in cCTGA than in TOF (p <0.01), suggesting enhanced contractile responses in cCTGA. Moreover, SV dp/dt_max showed significant positive correlations with PV dp/dt_max in patients with both TOF and cCTGA (r = 0.67, p <0.01 and r = 0.61, p <0.01, respectively), indicating positive ventricular-ventricular interaction. In this relationship, the slopes of correlations were significantly higher in TOF than in cCTGA (p = 0.024). These results, indicating different behaviors of PV contractile physiology and its interaction with the SV, may have important therapeutic implications when considering medical, catheter, and surgical interventions for pulmonary stenosis in these diseases. The results may also offer the potential for a new approach for improvement of prognosis, especially in cCTGA.

Clinical Predictors of Right Ventricular Myocardial Fibrosis in Patients With Repaired Tetralogy of Fallot

BACKGROUND

This study aimed to identify the clinical predictors of the degree of right ventricular (RV) myocardial fibrosis in patients with repaired tetralogy of Fallot (TOF) with special focus on the RV pressure load.

METHODS AND RESULTS

From April 2004 to March 2017, 30 patients with repaired TOF underwent pulmonary valve replacement and concomitant RV myocardial biopsy. The stroke volume ratio (RV stroke volume/left ventricular stroke volume), RV end-diastolic volume index, and right-to-left ventricular systolic pressure ratio were evaluated with respect to their prognostic value for the degree of RV myocardial fibrosis. Significant positive linear correlations were detected between the stroke volume ratio and the degree of RV myocardial fibrosis (P=0.003, r=0.52). Patients with a right-to-left ventricular systolic pressure ratio >0.45 showed a significantly greater degree of RV myocardial fibrosis under an equivalent stroke volume ratio.

CONCLUSIONS

Under conditions of RV volume overload, a right-to-left ventricular systolic pressure ratio >0.45 was a predisposing factor for progression of RV myocardial fibrosis in patients with repaired TOF.

Assessment of Diffuse Ventricular Myocardial Fibrosis Using Native T1 in Children With Repaired Tetralogy of Fallot

BACKGROUND

Myocardial fibrosis is linked with adverse clinical outcomes in adults after tetralogy of Fallot repair (rTOF). Native T1 times (T1) by cardiac magnetic resonance have been shown to be a surrogate marker of diffuse myocardial fibrosis. The objective was to quantify native T1 in children post-rTOF and to evaluate their relationship with surgical, imaging, and clinical factors.

METHODS AND RESULTS

A retrospective cross-sectional study was performed. Midventricular native T1 were obtained in 100 children post-rTOF using a modified look-locker inversion recovery cardiac magnetic resonance sequence and compared with 35 pediatric controls. rTOF patients, aged 13.0±2.9 years, had higher indexed right ventricular (RV) end-diastolic (range 85-326 mL/m², mean 148 mL/m²) volumes, and lower RV and left ventricular (LV) ejection fractions compared with controls. RV, but not LV, T1 were higher in patients than in controls (1031±74 versus 954±32 ms, P<0.001) and female patients had higher RV T1 compared with males (1051±79 versus 1017±68 ms, P=0.02). LV T1 correlated with RV T1 (r=0.45, P<0.001), cardiopulmonary bypass (r=0.30, P=0.007), and aortic cross-clamp times (r=0.32, P=0.004). RV T1 correlated inversely with RV outflow tract gradient (r=-0.28, P=0.02). Longer aortic cross-clamp times were independently associated with LV and RV T1 on multivariable analysis. There was no association between exercise intolerance, arrhythmia, and native T1 or LV extracellular volume.

CONCLUSIONS

Children after rTOF do not have elevated LV native T1 or LV extracellular volume, but show evidence of increased RV native T1 suggestive of diffuse RV fibrosis, for which volume loading seems to be a risk factor. Surgical bypass and cross-clamp times are associated with fibrotic remodeling over a decade later.

Tetralogy of Fallot and Its Variants

OBJECTIVES

The objectives of this review are to discuss the anatomy, pathophysiology, surgical repair, and perioperative management strategies for tetralogy of Fallot and its variants.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSIONS

Significant refinements have been made in the repair strategy for tetralogy of Fallot, based on improved understanding of postrepair physiology. Important considerations for timing and technique of surgery and perioperative management have been presented, and continued evolution is expected. Expanded use of the pulmonary valve reconstruction technique outlined herein, whatever the age of repair, may improve long-term outcome.

Aiming to Preserve Pulmonary Valve Function in Tetralogy of Fallot Repair: Comparing a New Approach to Traditional Management

Pulmonary valve (PV) incompetence following transannular patch (TAP) repair of tetralogy of Fallot (TOF) results in long-term morbidity and mortality. Valve-sparing repairs have recently gained recognition; however, they may be associated with residual pulmonary stenosis (PS) in patients with small PV z scores. We sought to determine whether a repair that increases the PV annulus and augments the valve leaflet with a biomaterial would result in annular growth and in longer duration of valve competence compared with TAP. Eighty patients (median age 136 days, range 4-350) who underwent surgical repair of TOF between 2010 and 2014 were included in the study. Patients were divided into three groups based on the PV intervention: balloon dilation/valvotomy (n = 29), valve-sparing transannular repair (VSTAR) (n = 19) and TAP (n = 32). Intraoperative, early postoperative and midterm follow-up echocardiographic data (median 19 months, range 1-59) were obtained. The primary outcomes were the presence and severity of pulmonary regurgitation and/or PS. Compared with TAP, VSTAR patients demonstrated significantly less severe PR with 100 % freedom of severe PR immediately post-op (vs. 0 % in TAP), 60 % at 6 months and 20 % at 20 months. There were no differences in PS between VSTAR and TAP at follow-up. A subgroup analysis of the VSTAR group was performed. PV z scores were calculated and fit to a random effects model. Patient data fit the model closely, predicting a reproducible increase in valve annulus size over time. With better short-term and comparable midterm results, VSTAR may be appropriate for TOF repair in patients with small PV that would conventionally require a TAP.

Differential Effect of the Ratio of Right Ventricular Volume to Left Ventricular Volume in Children with Repaired Tetralogy of Fallot

We aimed to compare the diagnostic value of indexed right ventricular end-diastolic volume (RVEDVi) and the ratio of right ventricle volume to left ventricle volume (RV/LV ratio) in prediction of the severity of pulmonary regurgitation (PR) expressed as the PR fraction (PRF) after surgery of tetralogy of Fallot (TOF). Forty-one patients with repaired TOF were included in the study. RVEDVi, LVEDVi, RV/LV ratio, PRF and ejection fraction were measured with magnetic resonance imaging. A PRF of more than 20% was considered significant. The predictive capability of two markers (RVEDVi and RV/LV ratio) for significant PR was compared using multivariate linear regression analysis and receiver operating characteristic (ROC) analysis. Both the RV/LV ratio and RVEDVi showed a correlation with PRF (r = 0.526/0.321, p = 0.001/0.041) in the correlation analysis, but in multivariate regression analysis the only independent predictor of PRF was the RV/LV ratio (F = 14.890, p = 0.001). ROC analysis revealed that a better discrimination of significant PR (>20%) from slight types (=20%) PR can be reached with the RV/LV ratio than RVEDVi (AUC = 0.805/0.709, p = 0.01). The RV/LV ratio was better than RVEDVi at differentiating mild from moderate PR (p = 0.006 vs. p = 0.153), and proved superior over RVEDVi in predicting PR based on the PRF criterion.

Current status of right ventricular outflow tract reconstruction: complete translation of a review article originally published in Kyobu Geka 2014;67:65-77

Right ventricular outflow tract (RVOT) reconstruction is becoming more prevalent as the number of adult patients who require repeated surgery long after definitive repair of congenital heart defects during childhood has increased. Early primary repair and annulus-preserving surgery have been the two current strategies of RVOT reconstruction from the viewpoint of timing and indications for surgical intervention; however, the long-term outcomes of both procedures remain unknown. Although various materials have been used for pulmonary valve replacement during RVOT reconstruction, deficient durability due primarily to immunological rejection frequently arises, particularly when implanted into young patients. A multicenter study in Japan showed that the clinical outcomes of expanded polytetrafluoroethylene (ePTFE) valved patches/conduits that we developed and manufactured comprised an excellent alternative material for RVOT reconstruction. Such enhanced outcomes might have partly been attributable to the biocompatibility and low antigenicity of ePTFE, and also to the fluid dynamic properties arising from the structural characteristics of a bulging sinus and a fan-shaped valve. However, numerous issues concerning RVOT reconstruction, such as indications for and the timing of definitive repair, as well as the choice of materials for pulmonary valve replacement, must be resolved to achieve better patient prognoses and quality of life. This review describes recent surgical strategies and outstanding issues associated with RVOT reconstruction.

Factors associated with right ventricular dilatation and dysfunction in patients with chronic pulmonary regurgitation after repair of tetralogy of Fallot: analysis of magnetic resonance imaging data from 218 patients

OBJECTIVE

The aim of the present study was to identify the factors associated with right ventricular (RV) dilatation and dysfunction in patients with chronic pulmonary regurgitation (PR) after repair of tetralogy of Fallot.

METHODS

From April 2002 to June 2013, 218 patients with repaired tetralogy of Fallot underwent magnetic resonance imaging; 165 (76%) underwent transannular repair and 36 (17%) underwent nontransannular repair. Linear regression analyses were used to identify the predictors for RV end-diastolic volume index (EDVI), end-systolic volume index (ESVI), and ejection fraction.

RESULTS

On univariable analysis, male sex, ventricular septal defect (VSD) closure through the right ventricle, larger pulmonary artery index, and greater PR fraction were associated with greater RV volume indexes. Multivariable analyses identified male sex (β = 17.55, P < .001 for RV EDVI; β = 14.08, P = .001 for RV ESVI), VSD closure through RV (β = 8.49, P = .048 for RV ESVI), longer interval since repair (β = 1.29, P = .014 for RV EDVI), and greater PR fraction (β = 1.92, P < .001 for RV EDVI; β = 1.38, P < .001 for RV ESVI) as independent predictors for greater RV volume indexes. On univariable analysis, male sex, VSD closure through the right ventricle, and greater PR fraction were associated with a lower RV ejection fraction. Multivariable analysis identified male sex (β = -3.10, P = .018), VSD closure through the right ventricle (β = -3.05, P = .020), and greater PR fraction (β = -0.27, P < .001) as independent predictors for a lower RV ejection fraction.

CONCLUSIONS

Male sex, VSD closure through the right ventricle, longer interval since repair, and greater PR fraction were independent predictors of RV dilatation after tetralogy of Fallot repair. Male sex, VSD closure through the right ventricle, and greater PR fraction were also independent predictors of RV dysfunction.

Early and 1-year outcome and predictors of adverse outcome following monocusp pulmonary valve reconstruction for patients with tetralogy of Fallot: A prospective observational study

Background and Objectives:

Repair of tetralogy of Fallot (TOF) with monocusp pulmonary valve reconstruction prevents pulmonary regurgitation (PR) for a variable period. Since postoperative outcome is governed by PR and right ventricular function, we sought to assess the severity of pulmonary regurgitation and right ventricular outflow (RVOT) gradient in the immediate postoperative period and at 1 year and attempted to identify the anatomical substrates responsible for adverse outcomes.

Methods:

The study included 30 patients. Transthoracic echocardiography was performed before surgery, within 5 days of surgery, and 1 year later. Presence and severity of PR, RVOT gradient, and residual branch pulmonary stenosis were assessed. Right ventricular and monocusp valve functions were studied.

Results:

Median age was 36.5 months (3-444 months). There were no deaths. Pulmonary regurgitation was mild in 18, moderate in 10, and severe in 2 patients immediately following surgery. At 1 year, 10 patients had severe PR and one had significant RVOT gradient. None of the variables like age, presence of supravalvar pulmonary branch stenosis, main pulmonary artery diameter, or mobility of monocusp valve was found to have any significant association with the progression of PR. McGoon index <1.5 showed a trend toward more PR, while patients with more residual RVOT gradient had lesser regurgitation.

Conclusions:

Repair of TOF with monocusp pulmonary valve reduces immediate postoperative PR. At 1 year, the monocusp valve underwent loss of function in a significant proportion and PR also progressed. This study could not identify any predictors of progression of PR, though patients with McGoon index <1.5 tended to have more PR while those with more outflow gradient had lesser PR.

Ventricular geometric characteristics and functional benefit of mild right ventricular outflow tract obstruction in patients with significant pulmonary regurgitation after repair of tetralogy of Fallot

BACKGROUND

Right ventricular (RV) outflow tract obstruction (RVOTO) might protect the RV from adverse remodeling caused by significant pulmonary regurgitation (PR) in patients with repaired tetralogy of Fallot (rTOF), but the underlying mechanisms and influences on exercise tolerance remain unclear. This study sought to investigate the impacts from mild RVOTO on ventricular remodeling and exercise capacity in rTOF.

METHODS

Eighty-five rTOF patients with a PR fraction ≥20% were assessed with cardiac magnetic resonance, cardiopulmonary exercise test, and echocardiography. Patients with a peak RVOT pressure gradient 20-50 mmHg were considered to have mild RVOTO (n = 29), while those with a gradient <20 mmHg had isolated PR (n = 56).

RESULTS

Comparing to patients with isolated PR, patients with combined PR and mild RVOTO had smaller RV and RVOT dimension, better RV and left ventricular (LV) ejection fraction (EF), and superior exercise capacity. PR severity and RV mass/volume ratio were similar between these 2 groups. LVEF coupled with RVEF only in patients with isolated PR. In multivariate analysis, smaller RVOT dimension was independently related to smaller RV dimension (P < .001) and higher RVEF (P = .005). Furthermore, mild RVOTO was independently associated with higher peak oxygen consumption (P = .014) and oxygen uptake efficiency slope (P = .005).

CONCLUSIONS

Patients with combined PR and mild RVOTO had better RV remodeling and exercise capacity compared to those with isolated PR. Our findings confirm the benefits from mild residual RVOTO support a policy of conservative RVOTO relief at repair.

Effect of right ventricular outflow tract obstruction on right ventricular volumes and exercise capacity in patients with repaired tetralogy of fallot

Patients with tetralogy of Fallot and combined right ventricular outflow tract obstruction (RVOTO) and pulmonary regurgitation (PR) have a less dilated right ventricular (RV) and better RV function compared with patients without RVOTO. It is not known whether RVOTO is associated with improved exercise capacity. We compared cardiac magnetic resonance imaging, echocardiography, and exercise tests in 12 patients with RVOTO (Doppler peak RVOT gradient ≥30 mm Hg) and 30 patients without RVOTO. RV end-systolic and end-diastolic volumes were smaller in patients with RVOTO compared with patients without RVOTO (50 ± 16 vs 64 ± 18 ml/m(2) and 117 ± 24 vs 135 ± 28 ml/m(2), respectively) and patients with RVOTO had a higher RV mass (52 ± 14 vs 42 ± 11 ml/m(2)), p <0.05. RV ejection fraction was marginally significantly different between both groups (58 ± 8% vs 53 ± 7%), p = 0.051. Degree of PR, left ventricular volumes, and function did not differ significantly between both groups. Peak oxygen uptake in patients with RVOTO was significantly lower (25 ± 3 vs 32 ± 8 ml/kg/min) than in patients without RVOTO, as was the percentage of predicted peak oxygen uptake (63 ± 7% vs 79 ± 14%), p <0.001. Multivariate analysis showed that the peak RVOT gradient was the only independent predictor of exercise capacity. In conclusion, exercise capacity is lower in patients with RVOTO compared with those without RVOTO despite a less dilated RV and comparable degree of PR. Therefore, exercise capacity may be of importance and should additionally be taken in consideration to RV volumes and function in patients with tetralogy of Fallot and PR.

Native Pulmonary Valve Restoration After Remote Tetralogy of Fallot Repair

Methods to repair tetralogy of Fallot have evolved from large ventriculotomy, large transannular patch placement techniques to smaller, transatrial approaches with valve-sparing strategies in select patients. Despite these advances, there continue to be patients in whom transannular patch is inevitable, and the management of the resulting pulmonary insufficiency that develops from this has been the source of considerable discussion. Techniques aimed at restoring pulmonary valve competence utilizing the remaining valve leaflets after transannular patch placement have recently been proposed for very select patient populations. We review the technical aspects of the operation including removal of the transannular patch and bicuspidization of a formerly tricuspid pulmonary valve, which results in a competent, nonstenotic valve. This report confirms the feasibility of these operative details and highlights the importance of planning before initial repair of tetralogy of Fallot as a way to prepare for a future valve restoration procedure and therefore avoid prosthetic valve placement.