Acute and Chronic Effects of Dysfunction of Right Ventricular Outflow Tract Components on Right Ventricular Performance in a Porcine Model

Long-term outcomes of tetralogy of Fallot repair: A 30-year experience with 960 patients

OBJECTIVE

This study evaluates the long-term results of tetralogy of Fallot repair and assesses the risk factors for adverse outcomes.

METHODS

This retrospective study included 960 patients who underwent transatrial transpulmonary tetralogy of Fallot repair between 1990 and 2020.

RESULTS

A transannular patch was placed in 722 patients, and pulmonary valve preservation was achieved in 233 patients. The median age at tetralogy of Fallot repair was 9.4 (interquartile range, 6.2-14.2) months. The median follow-up duration was 10.6 (interquartile range, 5.4-16.3) years. There were 8 early deaths (0.8%) and 20 late deaths (2.1%). Genetic syndrome and pulmonary valve annulus Z score less than -3 were risk factors for mortality. The survival was 97.7% (95% confidence interval, 96.4-98.5) and 94.5% (95% confidence interval, 90.9-96.7) at 10 and 30 years, respectively. Freedom from any reoperation was 86.4% (95% confidence interval, 83.6-88.7) and 65.4% (95% confidence interval, 59.8-70.4) at 10 and 20 years, respectively. Postoperative right ventricular outflow tract peak gradient of 25 mm Hg or greater correlated with reoperation. Propensity score-matched analysis demonstrated that freedom from pulmonary valve replacement at 15 years was higher in the pulmonary valve preservation group compared with the transannular patch group (98.2% vs 78.4%, P = .004). Freedom from reoperation for right ventricular outflow tract obstruction at 15 years was lower in the pulmonary valve preservation group compared with the transannular patch group (P = .006).

CONCLUSIONS

The long-term outcomes of tetralogy of Fallot repair are excellent. A postoperative right ventricular outflow tract peak gradient less than 25 mm Hg appears to be optimal to prevent reoperation. If the pulmonary valve size is suitable, pulmonary valve preservation reduces the risk of pulmonary valve replacement, yet increases the reoperation rate for right ventricular outflow tract obstruction.

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.

Transcatheter Approaches to Palliation for Tetralogy of Fallot

To this day, controversy still exists regarding the optimal method to treat symptomatic neonates and infants with Tetralogy of Fallot (TOF). Symptomatic (severely cyanotic or ductal dependent) infants with TOF can undergo either a staged repair approach (consisting of initial palliation followed by complete repair) or primary repair. Traditionally, initial palliative procedures have been surgical, for example placement of a Blalock-Taussig-Thomas (BTT) shunt. Recent advances in technology have facilitated the introduction of catheter-based procedures as palliative techniques, for example, patent ductus arteriosus (PDA) stenting and right ventricular outflow tract (RVOT) stenting as more durable solutions than balloon pulmonary valvuloplasty (BPV). In this article, we discuss the rationale for these procedures, technical aspects of these procedures and outcomes data compared to traditional surgical procedures. Recent data have suggested that RVOT and PDA stenting procedures offer many advantages over traditional surgical palliative procedures as palliative methods in this patient population. This comes at a cost of increased reintervention burden, which may be considered part of the overall treatment strategy in smaller neonates and can be minimized with a focus on technical aspects and overall treatment strategies. Advanced surgical techniques are required at the eventual complete repair to negotiate removal of stent material and pulmonary artery reconstruction in some instances. Further adoption of catheter based palliative procedures for infants with symptomatic TOF has the potential to tip the outcomes towards favoring a staged approach, particularly in high-risk infants.

Effects of Mechanical Ventilation Versus Apnea on Bi-Ventricular Pressure-Volume Loop Recording

Respiration changes intrathoracic pressure and lung volumes in a cyclic manner, which affect cardiac function. Invasive ventricular pressure-volume (PV) loops can be recorded during ongoing mechanical ventilation or in transient apnea. No consensus exists considering ventilatory mode during PV loop recording. The objective of this study was to investigate the magnitude of any systematic difference of bi-ventricular PV loop variables recorded during mechanical ventilation versus apnea. PV loops were recorded simultaneously from the right ventricle and left ventricle in a closed chest porcine model during mechanical ventilation and in transient apnea (n=72). Variables were compared by regression analyses. Mechanical ventilation versus apnea affected regression coefficients for important PV variables including right ventricular stroke volume (1.22, 95% CI [1.08-1.36], p=0.003), right ventricular ejection fraction (0.90, 95% CI [0.81-1.00], p=0.043) and right ventricular arterial elastance (0.61, 95%CI [0.55-0.68], p<0.0001). Right ventricular pressures and volumes were parallelly shifted with Y-intercepts different from 0. Few left ventricular variables were affected, mainly first derivatives of pressure (dP/dt(max): 0.96, 95% CI [0.92-0.99], p=0.016, and dP/dt(min): 0.92, 95% CI [0.86-0.99], p=0.026), which might be due to decreased heart rate in apnea (Y-intercept -6.88, 95% CI [-12.22; -1.54], p=0.012). We conclude, that right ventricular stroke volume, ejection fraction and arterial elastance were mostly affected by apnea compared to mechanical ventilation. The results motivate future standardization of respiratory modality when measuring PV relationships.

Norepinephrine and dobutamine improve cardiac index equally by supporting opposite sides of the heart in an experimental model of chronic pulmonary hypertension

BACKGROUND

Pulmonary hypertension is a significant risk factor in patients undergoing surgery. The combined effects of general anaesthesia and positive pressure ventilation can aggravate this condition and cause increased pulmonary blood pressures, reduced systemic blood pressures and ventricular contractility. Although perioperative use of inotropic support or vasopressors is almost mandatory for these patients, preference is disputed. In this study, we investigated the effects of norepinephrine and dobutamine and their ability to improve the arterio-ventricular relationship and haemodynamics in pigs suffering from chronic pulmonary hypertension.

METHOD

Pulmonary hypertension was induced in five pigs by banding the pulmonary artery at 2-3 weeks of age. Six pigs served as controls. After 16 weeks of pulmonary artery banding, the animals were re-examined under general anaesthesia using biventricular conductance catheters and a pulmonary artery catheter. After baseline measurements, the animals were exposed to both norepinephrine and dobutamine infusions in incremental doses, with a stabilising period in between the infusions. The hypothesis of differences between norepinephrine and dobutamine with incremental doses was tested using repeated two-way ANOVA and Bonferroni multiple comparisons post-test.

RESULTS

At baseline, pulmonary artery-banded animals had increased right ventricular pressure (+ 39%, p = 0.04), lower cardiac index (- 23% p = 0.04), lower systolic blood pressure (- 13%, p = 0.02) and reduced left ventricular end-diastolic volume (- 33%, p = 0.02). When incremental doses of norepinephrine and dobutamine were administered, the right ventricular arterio-ventricular coupling was improved only by dobutamine (p < 0.05). Norepinephrine increased both left ventricular end-diastolic volume and left ventricular contractility to a greater extent (p < 0.05) in pulmonary artery-banded animals. While the cardiac index was improved equally by norepinephrine and dobutamine treatments in pulmonary artery-banded animals, norepinephrine had a significantly greater effect on mean arterial pressure (p < 0.05) and diastolic arterial pressure (p < 0.05).

CONCLUSION

While norepinephrine and dobutamine improved cardiac index equally, it was obtained in different manners. Dobutamine significantly improved the right ventricular function and the arterio-ventricular coupling. Norepinephrine increased systemic resistance, thereby improving arterial pressures and left ventricular systolic function by maintaining left ventricular end-diastolic volume.

Study of the time-relationship of the mechano-electrical interaction in an animal model of tetralogy of Fallot: implications for the risk assessment of ventricular arrhythmias

OBJECTIVES

The long-term outcome of tetralogy of Fallot (TOF) is determined by progressive right ventricular (RV) dysfunction through pulmonary regurgitation (PR) and the risk of malignant arrhythmia. Although mechano-electrical coupling in TOF is well-known, its time effect on the inducibility of arrhythmia remains ill-defined. The goal of this study was to investigate the mechano-electrical properties at different times in animals with chronic PR.

METHODS

PR was induced by a transannular patch with limited RV scarring in infant pigs. Haemodynamic assessment included biventricular pressure-volume loops after 3 (n = 8) and 6 months (n = 7) compared to controls (n = 5). The electrophysiological study included endocardial monophasic action potential registration, intraventricular conduction velocity and induction of ventricular arrhythmia by burst pacing.

RESULTS

Progressive RV dilation was achieved at 6 months (RV end-diastolic volume 143 ± 13 ml/m2-RV end-systolic volume 96 ± 7 ml/m2; P < 0.001), in association with depressed RV contractility (preload recruitable stroke work-slope: 19 ± 1 and 11 ± 3 Mw.ml-1.s-1 for control and 6 m; P < 0.001) and left ventricular contractility (preload recruitable stroke work-slope: 60 ± 13 and 40 ± 11 Mw.ml-1.s-1 for control and 6 m; P = 0.005). Concomitant to QRS prolongation, monophasic action potential90-duration and dispersion at the RV and left ventricle were increased at 6 months. Intraventricular conduction was delayed only in the RV at 6 months (1.8 ± 0.2 and 2.4 ± 0.6 m/s for group 6M and the control group; P = 0.035). Sustained ventricular arrhythmias were not inducible.

CONCLUSIONS

In animals yielding the sequelae of a contemporary operation for TOF, mechano-electrical alterations are progressive and affect predominantly the RV after midterm exposure of PR. Because ventricular arrhythmias were not inducible despite significant RV dilation, the data suggest that the haemodynamic RV deterioration effectively precedes the risk of inducing sustained arrhythmia after TOF repair and opens a window for renewed stratification of contemporary risk factors of ventricular arrhythmias in patients operated on with currently used pulmonary valve- and RV-related techniques.

Evaluation of right ventricle pulmonary artery coupling on right ventricular function in post operative tetralogy of Fallot patients underwent for pulmonary valve replacement

Background

To evaluate RV-PA coupling in post operative TOF patients with ventricular dilatation underwent for PVR and investigate the correlation between ventricular functions measuring Ea/Emax ratio using cardio magnetic resonance and the effect of surgical type at primary repair of TOF on coupling.

Method

RV-PA coupling was measured noninvasively by Ea/Emax ratio from CMRI and ECHO. From CMRI results the patients were divided in two groups, RV-PA coupling and RV-PA uncoupling. Ea/Emax ≤1 was considered for coupling patients and Ea/Emax > 1 for uncoupling patients.

Results

Ninety patients were uncoupled (Ea/Emax: 1.55 ± 0.46) and 45 were coupled (Ea/Emax: 0.81 ± 0.15). Out of 75 TAP repaired patients 60 were uncoupled RV-PV. In addition, higher pro-BNP is an important factor for uncoupled RV-PV (P = 0.001). CMR evaluation for right ventricular function between uncoupling and coupling were RVEDVi (196.65 ± 63.57 vs. 154.28 ± 50.07, P = 0.001), RVESVi (121.19 ± 51.47 vs. 83.94 ± 20.43, P = 0.001), RVSVi (67.19 ± 19.87 vs. 106.31 ± 33.44, P = 0.001), and RVEF (40.90 ± 8.73 vs. 54.63 ± 4.76, P = 0.001). The increased RVEDVi, RVESVi and RVSVi and decreased RVEF have significant correlation with Ea/Emax. Ea/Emax was also found positively correlated with RVEDVi (P = < 0.05, r = 0.35), RVESVi (P = < 0.001, r = 0.41) and negatively correlated with RVSVi (P = < 0.05, r = 0.22) and RVEF (P = < 0.05, r = 0.78).

Conclusions

Unfavorable RV-PA coupling is present in post operative TOF patients and it is affected by several factors. Our results explain a new concept of RV-PA interactions as a contributing mechanism for the observed decline in RV function.

Effect of aortic stiffness versus stenosis on ventriculo-arterial interaction in an experimental model of coarctation repair

OBJECTIVES

The aim of this study was to investigate the effect of short- versus long-segment aortic stiffness and stenosis on ventriculo-arterial interaction in a porcine model of coarctation repair.

METHODS

Short-long aortic stiffness was created by transection/suture [coarctation (CoA) suture, n = 6] and stenting (stent, n = 5) of the proximal descending aorta. Short-long aortic stenosis was achieved by wrapping a prosthetic graft around the aorta to 1/3-circumference reduction, over a segment length of 1 cm (CoA suture stenosis, n = 5) and 4.5 cm (stent stenosis, n = 6). After 3 months, aortic pressure-flow haemodynamics, aortic distensibility by intravascular ultrasound and left ventricular performance by pressure-volume loops were compared to a Sham group (n = 5) at baseline and during dobutamine administration.

RESULTS

The aortic impedance increased with 30.3 (12.6%) and 41.3 (20.9%) (P < 0.001) in CoA stenosis and stent stenosis during inotropic response. Impaired haemodynamic aortic compliance was associated with lower aortic distensibility by intravascular ultrasound, specifically in long-segment stenosis. The ventriculo-arterial coupling was disturbed in both groups with stenosis, with blunted contractile response [Sham 140.3 (19.8%), CoA suture 101.3 (14.5%), CoA suture stenosis 75.0 (8.4%), stent 115.5 (12.7%), stent stenosis 55.1 (14.6%), P < 0.001] and increased myocardial stiffness during dobutamine in the long-segment aortic stenosis group [Sham -26.0 (12.9%), CoA suture -27.5 (15.9%), CoA stenosis -9.5 (8.6%), stent -23.4 (4.8%), stent stenosis 19.9 (23.1%), P < 0.001].

CONCLUSIONS

This animal study on the sequelae of coarctation repair demonstrated that aortic stiffness had little effect on aortic pressure-flow characteristics in the absence of stenosis. However, the negative chronic effect of stenosis on aortic haemodynamics-especially a longer segment-leads to the rapid impairment of ventriculo-arterial interaction, which is accentuated by inotropy. Therefore, therapeutical management needs to focus on improving aortic remodelling after coarctation repair, preferably by minimizing residual stenosis, even at the cost of inducing aortic stiffness.

Animal models of right heart failure

Right heart failure may be the ultimate cause of death in patients with acute or chronic pulmonary hypertension (PH). As PH is often secondary to other cardiovascular diseases, the treatment goal is to target the underlying disease. We do however know, that right heart failure is an independent risk factor, and therefore, treatments that improve right heart function may improve morbidity and mortality in patients with PH. There are no therapies that directly target and support the failing right heart and translation from therapies that improve left heart failure have been unsuccessful, with the exception of mineralocorticoid receptor antagonists. To understand the underlying pathophysiology of right heart failure and to aid in the development of new treatments we need solid animal models that mimic the pathophysiology of human disease. There are several available animal models of acute and chronic PH. They range from flow induced to pressure overload induced right heart failure and have been introduced in both small and large animals. When initiating new pre-clinical or basic research studies it is key to choose the right animal model to ensure successful translation to the clinical setting. Selecting the right animal model for the right study is hence important, but may be difficult due to the plethora of different models and local availability. In this review we provide an overview of the available animal models of acute and chronic right heart failure and discuss the strengths and limitations of the different models.

Evaluation of right ventricle pulmonary artery coupling on right ventricular function in post operative tetralogy of Fallot patients underwent for pulmonary valve replacement

Background

To evaluate RV-PA coupling in post operative TOF patients with ventricular dilatation underwent for PVR and investigate the correlation between ventricular functions measuring Ea/Emax ratio using cardio magnetic resonance and the effect of surgical type at primary repair of TOF on coupling.

Method

RV-PA coupling was measured noninvasively by Ea/Emax ratio from CMRI and ECHO. From CMRI results the patients were divided in two groups, RV-PA coupling and RV-PA uncoupling. Ea/Emax ≤1 was considered for coupling patients and Ea/Emax > 1 for uncoupling patients.

Results

Ninety patients were uncoupled (Ea/Emax: 1.55 ± 0.46) and 45 were coupled (Ea/Emax: 0.81 ± 0.15). Out of 75 TAP repaired patients 60 were uncoupled RV-PV. In addition, higher pro-BNP is an important factor for uncoupled RV-PV (P = 0.001). CMR evaluation for right ventricular function between uncoupling and coupling were RVEDVi (196.65 ± 63.57 vs. 154.28 ± 50.07, P = 0.001), RVESVi (121.19 ± 51.47 vs. 83.94 ± 20.43, P = 0.001), RVSVi (67.19 ± 19.87 vs. 106.31 ± 33.44, P = 0.001), and RVEF (40.90 ± 8.73 vs. 54.63 ± 4.76, P = 0.001). The increased RVEDVi, RVESVi and RVSVi and decreased RVEF have significant correlation with Ea/Emax. Ea/Emax was also found positively correlated with RVEDVi (P = < 0.05, r = 0.35), RVESVi (P = < 0.001, r = 0.41) and negatively correlated with RVSVi (P = < 0.05, r = 0.22) and RVEF (P = < 0.05, r = 0.78).

Conclusions

Unfavorable RV-PA coupling is present in post operative TOF patients and it is affected by several factors. Our results explain a new concept of RV-PA interactions as a contributing mechanism for the observed decline in RV function.

Evaluation of right ventricle pulmonary artery coupling on right ventricular function in post operative tetralogy of Fallot patients underwent for pulmonary valve replacement

Background

To evaluate RV-PA coupling in post operative TOF patients with ventricular dilatation underwent for PVR and investigate the correlation between ventricular functions measuring Ea/Emax ratio using cardio magnetic resonance and the effect of surgical type at primary repair of TOF on coupling.

Method

RV-PA coupling was measured noninvasively by Ea/Emax ratio from CMRI and ECHO. From CMRI results the patients were divided in two groups, RV-PA coupling and RV-PA uncoupling. Ea/Emax ≤1 was considered for coupling patients and Ea/Emax > 1 for uncoupling patients.

Results

Ninety patients were uncoupled (Ea/Emax: 1.55 ± 0.46) and 45 were coupled (Ea/Emax: 0.81 ± 0.15). Out of 75 TAP repaired patients 60 were uncoupled RV-PV. In addition, higher pro-BNP is an important factor for uncoupled RV-PV (P = 0.001). CMR evaluation for right ventricular function between uncoupling and coupling were RVEDVi (196.65 ± 63.57 vs. 154.28 ± 50.07, P = 0.001), RVESVi (121.19 ± 51.47 vs. 83.94 ± 20.43, P = 0.001), RVSVi (67.19 ± 19.87 vs. 106.31 ± 33.44, P = 0.001), and RVEF (40.90 ± 8.73 vs. 54.63 ± 4.76, P = 0.001). The increased RVEDVi, RVESVi and RVSVi and decreased RVEF have significant correlation with Ea/Emax. Ea/Emax was also found positively correlated with RVEDVi (P = < 0.05, r = 0.35), RVESVi (P = < 0.001, r = 0.41) and negatively correlated with RVSVi (P = < 0.05, r = 0.22) and RVEF (P = < 0.05, r = 0.78).

Conclusions

Unfavorable RV-PA coupling is present in post operative TOF patients and it is affected by several factors. Our results explain a new concept of RV-PA interactions as a contributing mechanism for the observed decline in RV function.

Effects of milrinone and epinephrine or dopamine on biventricular function and hemodynamics in right heart failure after pulmonary regurgitation

Right ventricular failure (RVF) secondary to pulmonary regurgitation (PR) impairs right ventricular (RV) function and interrupts the interventricular relationship. There are few recommendations for the medical management of severe RVF after prolonged PR. PR was induced in 16 Danish landrace pigs by plication of the pulmonary valve leaflets. Twenty-three pigs served as controls. At reexamination the effect of milrinone, epinephrine, and dopamine was evaluated using biventricular conductance and pulmonary catheters. Seventy-nine days after PR was induced, RV end-diastolic volume index (EDVI) had increased by 33% ( P = 0.006) and there was a severe decrease in the load-independent measurement of contractility (PRSW) (−58%; P = 0.003). Lower cardiac index (CI) (−28%; P < 0.0001), mean arterial pressure (−15%; P = 0.01) and mixed venous oxygen saturation (SvO2) (36%; P < 0.0001) were observed compared with the control group. The interventricular septum deviated toward the left ventricle (LV). Milrinone improved RV-PRSW and CI and maintained systemic pressure while reducing central venous pressure (CVP). Epinephrine and dopamine further improved biventricular PRSW and CI equally in a dose-dependent manner. Systemic and pulmonary pressures were higher in the dopamine-treated animals compared with epinephrine-treated animals. None of the treatments improved stroke volume index (SVI) despite increases in contractility. Strong correlation was detected between SVI and LV-EDVI, but not SVI and biventricular contractility. In RVF due to PR, milrinone significantly improved CI, SvO2, and CVP and increased contractility in the RV. Epinephrine and dopamine had equal inotropic effect, but a greater vasopressor effect was observed for dopamine. SV was unchanged due to inability of both treatments to increase LV-EDVI.

Perioperative Considerations for Children With Right Ventricular Dysfunction and Failing Fontan

The survival of patients with congenital heart diseases (CHD) has increased in the past decades, resulting in the identification of new characteristics of chronic comorbidities observed in pediatric and adults with CHD. Patients with CHD can present with a broad clinical spectrum of manifestations of congestive heart failure (CHF) at any point throughout their lives that may be related to anatomical or surgical variables. This article focuses on the perioperative assessment of patients with CHD and CHF, with an emphasis on pathophysiologic, diagnostic, and therapeutic alternatives in patients with right ventricular failure and failing Fontan circulation. We also provide descriptions of the effects of sedatives and anesthetics commonly used in this population in diagnostic or invasive procedures.

Intersurgeon variability in long-term outcomes after transatrial repair of tetralogy of Fallot: 25 years' experience with 675 patients

OBJECTIVE

To compare the long-term reoperation rates among surgeons performing transatrial repair of tetralogy of Fallot.

METHODS

The data set of 675 patients undergoing transatrial repair of tetralogy of Fallot at 1 institution from 1980 to 2005 was analyzed for intersurgeon differences in the reoperation rates.

RESULTS

A follow-up period >15 years was available for 5 surgeons, allowing for comparison (541 patients; >80 patients/surgeon). The reintervention rate at 10 years varied from 8.8% (95% confidence interval [CI], 5.3%-14.5%) to 26.7% (95% CI, 14.9%-44.9%; hazard ratio, 3.4; P = .001). The procedures of 1 surgeon resulted in a reoperation rate of 10.5% at 20 years (95% CI, 5.4%-25.3%). The type of reoperation required varied among the surgeons. One surgeon had had no reoperations for pulmonary artery stenosis. Of the 5 surgeons, 2 (surgeons 2 and 5) had equivalent overall 10-year reoperation rates (24.1%, 95% CI, 12.9%-42.3%; vs 26.7%, 95% CI, 14.9%-44.9%; P = .32). Surgeon 5 had reoperation almost exclusively for right ventricular outflow tract obstruction (20.6%; 95% CI, 12.4%-33.1%) and surgeon 2 for right ventricular dilation (17.4%; 95% CI, 7.8%-36.3%). None of the patients treated by surgeon 5 required implantation of a valved conduit.

CONCLUSIONS

An analysis of the reoperation rate during the long-term follow-up of transatrial repair of tetralogy of Fallot identified variability in the outcomes among 5 surgeons. The analysis of these differences suggested that an optimal amount of opening of the right ventricular outflow tract can lead to a decreased reintervention rate. The analysis of intersurgeon variability in outcomes should be encouraged, because it will lead to improvements in cardiac surgery outcomes.

Surgical management of tetralogy of fallot: in defense of the infundibulum

Surgical treatment of the Tetralogy of Fallot (ToF) is one of the great successes of medicine and also a topic of controversy. Different strategies have been proposed, including age-based (neonatal) management strategies as well as anatomic-based management strategies. Regardless of the management strategy entailed, the surgical management of ToF has considerably evolved over the years. As a result, patients can now expect excellent early results with survival approaching 100% for those without genetic syndromes. The goals of current surgical therapy should be to mitigate the late right ventricular (RV) dysfunction that may occur by minimizing the extent of surgical injury during the intial repair. As the surgical techniques continue to advance, the outcomes will continue to improve.