Persistent neo-aortic root dilatation and aortic valve insufficiency after arterial switch operation following prior pulmonary artery banding.

Although there have been great improvements in the short- and medium-term outcomes of the arterial switch operation (ASO) for transposition of the great arteries (TGA), some complications including pulmonary artery stenosis, aortic valve insufficiency, and aortic root dilatation have also been reported. After ASO, the original pulmonary root and valve, which function in the systemic position as the neo-aortic root and valve respectively, are exposed to the systemic blood pressure, resulting in aortic root dilatation and valve insufficiency in some patients. One of the risk factors for these complications is a history of prior pulmonary artery banding (PAB). Complex TGA anatomy, including transposition of the great arteries and ventricular septal defect (TGA-VSD) or double outlet right ventricle and ventricular septal defect (DORV-VSD), is also an independent risk factor for neo-aortic dilatation and aortic valve regurgitation. Aortic valve and root replacement is sometime necessary for the patients with these pathologies long-term after ASO. Here, we present a patient who had persistent aortic sinus dilatation and aortic valve insufficiency since ASO and necessitating aortic root and valve replacement 15 years after ASO preceded by PAB. The patient underwent Bentall operation and his clinical course was favorable. Histological findings after root replacement revealed no remarkable structural difference between neo-aortic wall (originally pulmonary artery) and original aortic wall.

[Total Arch Replacement Using Bilateral Axillary Artery Perfusion].

OBJECTIVES: The selection of arterial cannulation site is an important decision to avoid cerebral complication for total arch replacement(TAR). We report the surgical outcome of TAR using bilateral axillary artery perfusion in our hospital. METHODS: Between January 2012 and June 2020, 97 patients who underwent elective TAR for atherosclerotic aneurysms were enrolled in this study. Among them, bilateral axillary artery perfusion was used for 81 patients, and frozen elephant trunk( FET) procedure were used for 34 patients. In the case of FET procedure, translocated TAR was performed with distal anastomosis between the left common carotid artery and the left subclavian artery. The left subclavian artery was reconstructed by rerouting the graft used for the left axillary artery perfusion. RESULTS: There were no perioperative cerebral infarction and no hospital deaths. The mean operation time was 420 minutes. Compared to the conventional elephant trunk method, the FET method significantly reduced the operation time to 381 minutes. CONCLUSIONS: Bilateral axillary artery perfusion could contribute to reduce the cerebral infarction in TAR and facilitate the FET procedure.

Serum Cystatin C Level as a Biomarker of Aortic Plaque in Patients with an Aortic Arch Aneurysm.

AIM: During surgery for an aortic arch aneurysm, aortic plaque in the descending aorta should be evaluated, but there are currently no suitable biomarkers for it. Surgeons should be especially aware of cerebral embolism from femoral perfusion and of peripheral embolism from stent graft deployment. Cystatin C is a known useful marker of renal dysfunction with a role as a biomarker for severity of coronary artery disease. In the absence of a suitable biomarker for aortic plaque in the descending aorta, we examine cystatin C as a candidate. METHODS: In all, 75 patients who underwent surgery for an aortic arch aneurysm were enrolled. They were divided into two groups, depending on whether they had chronic kidney disease or not. The serum cystatin C value and creatinine value were evaluated preoperatively. The aortic plaque volume ratio and components in the descending aorta were calculated from preoperative enhanced computed tomography. RESULTS: The soft plaque volume ratio was higher in patients with chronic kidney disease than in patients without it. Cystatin C positively correlated with the total aortic plaque volume ratio in all cases, and it positively correlated with the soft plaque volume ratio in both groups. Creatinine had no correlation with any type of plaque volume ratio in either group. In patients without chronic kidney disease, the soft plaque volume ratio was higher in patients with higher cystatin C levels than in patients with normal levels. CONCLUSION: The preoperative serum cystatin C level could be a biomarker of aortic plaque in the descending aorta in patients with an aortic arch aneurysm.

Corridor technique for coronary arteries from a single arterial sinus.

The introduction of the arterial switch operation has improved the surgical outcome of transposition of the great arteries. However, coronary anomalies such as intramural coronary arteries, single coronary artery, or coronary arteries originating from a single arterial sinus have been reported as independent risk factors for early mortality and late morbidity after an arterial switch operation. We performed an arterial switch operation using a unique technique for translocation of the coronary arteries originating from a single left-side arterial sinus, to prevent coronary artery distortion and subsequent coronary malperfusion.

Reassessment of the Location of the Conduction System in Atrioventricular Septal Defect Using Phase-Contrast Computed Tomography.

The location of the atrioventricular conduction axis in the setting of atrioventricular septal defect has previously been shown by histology and intraoperative recordings. We have now reassessed the arrangement using phase-contrast computed tomography, aiming to provide precise measurements so as to optimize future surgical repairs. We used the system based on an X-ray Talbot grating interferometer using the beamline BL20B2 in a SPring-8 synchrotron radiation facility available in Japan. We analyzed 18 specimens. The atrioventricular node was found within a nodal triangle 1.7 mm from the coronary sinus, with 95% confidence intervals from 1.45 to 2.0 millimeters. The depth of the node from the right atrial endocardium was 1.0 mm, with 95% confidence intervals from 0.73 to 1.34 mm. The overall length of the scooped-out ventricular septum was 30.8 mm, with 95% confidence intervals from 27.5 to 34.1 millimeters. The length from the inferior atrioventricular junction to the take-off of the right bundle branch was 12.8 mm, with 95% confidence intervals from 11.12 to 14.38 mm, giving a ratio of 0.43 for the extent of the axis along the inferior septum, with 95% confidence intervals of 0.38-0.48. The length of the non-branching bundle was 6.6 mm, with 95% confidence intervals from 5.57 to 7.7 mm. The proportion of septum occupied by the non-branching bundle was 0.22, with 95% confidence intervals from 0.18 to 0.26. Our findings confirm previous histological studies, extending them by providing precise measurements to guide placement of sutures during surgical repair.

Usefulness of routine use of bilateral axillary artery perfusion in total arch replacement.

OBJECTIVES: To avoid cerebral infarction for aortic arch aneurysm and malperfusion for acute aortic dissection, the site of cannulation during total arch replacement remains important. Recently, we have used bilateral axillary artery perfusion in total arch replacement and in acute aortic dissection. Herein, we report the surgical outcomes. METHODS: Seventy-eight patients with aortic arch aneurysm and 45 patients with acute aortic dissection were enrolled in this study. During surgery, translocation of the total arch was performed on 67 patients using a 'frozen elephant trunk technique'. RESULTS: In patients with aortic arch aneurysm, there was no postoperative cerebral infarction. New postoperative cerebral infarction was observed in only one patient who underwent acute aortic dissection. Two patients who had aortic arch aneurysm and 2 patients who had acute aortic dissection died at the hospital. Complications related to bilateral axillary perfusion were not observed. CONCLUSIONS: The routine use of bilateral axillary artery perfusion in total arch replacement for aortic arch aneurysm to avoid cerebral infarction has the potential to be a useful procedure. It can facilitate the frozen elephant trunk procedure in acute aortic dissection.

Successful staged tricuspid valve replacement following cardiac resynchronization therapy in a congenitally corrected transposition of the great arteries.

Simple tricuspid valve surgery for complex heart disease with systemic right ventricular dysfunction is a high-risk procedure; however, staged tricuspid valve surgery following cardiac resynchronization therapy seems to be a beneficial method to expect reverse systemic ventricular remodeling.

Functional assessment of improvement of myocardial ischemia using coronary flow velocity reserve after coronary artery bypass surgery in hemodialysis.

BACKGROUND: In patients with end-stage renal disease requiring hemodialysis (HD patients), myocardial ischemia after coronary artery disease is a major cause of mortality. Coronary pathophysiology, namely myocardial microvascular dysfunction, appears to differ from patients not requiring HD (non-HD patients). OBJECTIVES: We compared functional improvement of myocardial ischemia after coronary artery bypass surgery (CABG) between HD and non-HD patients by transthoracic coronary flow velocity reserve (CFVR). METHODS: We retrospectively reviewed isolated CABG patients from between 2008 and 2017. Finally, 161 patients were enrolled; each underwent pre- and postoperative CFVR assessment, and left anterior descending (LAD) artery revascularization with "in-situ" internal mammary artery (IMA). Graft patency was confirmed, and after successful CABG, postoperative CFVR improvement between the two groups was compared. RESULTS: Preoperative CFVR value in group H was 1.81 ± 0.52, group N was 1.93 ± 0.66. There was no significant difference between the groups. IMA to LAD grafts were patent in postoperative evaluation in all patients. Postoperative CFVR in group H was 2.48 ± 0.72 and group N was 2.83 ± 0.73 (P = .042). Significant difference was observed. CONCLUSION: In both groups, CFVR values improved after successful CABG, but postoperative CFVR values were significant different. In younger populations CFVR values are generally higher. Our HD group was significantly younger than the non-HD group, but CFVR values were postoperatively significantly lower. CFVR values are reportedly affected by both epicardial and microcoronary circulation. In this study population, as all grafts to the LAD were patent, the lower CFVR value in the HD group was considered to have resulted in microvascular disorders.

Functional Evaluation of the Myocardial Ischemia After Coronary Artery Bypass Surgery Using Coronary Flow Velocity Reserve in Left Ventricular Hypertrophy.

Patients with left ventricular hypertrophy (LVH) have reportedly higher than normal mortality and incidences of cardiovascular events. Coronary microvascular pathophysiology also appears to differ from other populations. Such coronary microcirculation dysfunctions are considered strong causes of cardiac events. We compare the functional improvement of myocardial ischemia between LVH patients and other patients after successful coronary artery bypass surgery (CABG) using coronary flow velocity reserve (CFVR) by transthoracic echo cardiography. Patients who underwent isolated coronary artery bypass surgery, including left anterior descending artery (LAD) revascularization via "in situ" internal thoracic artery (ITA) between June 2008 and July 2017 (n = 155), were retrospectively reviewed. ITA grafts were patent in postoperative graft evaluation in all patients. CFVR was evaluated pre- and postoperatively, and data were compared between patients with severe LVH group and those without (non-LVH group). Preoperative mean CFVR was 1.77 ± 0.75 in LVH group and 1.91 ± 0.63 in non-LVH group (P = 0.188). After the operation, ITA to LAD graft patency was confirmed in all patients. Postoperative CFVR was 2.23 ± 0.70 in LVH group and 2.85 ± 0.71 in non-LVH group, respectively (P = 0.002). Significant difference was observed between the 2 groups. CFVR values improved after ITA to LAD bypass grafting in both LVH and non-LVH groups, but postoperative CFVR was significantly lower in patients with severe LVH than in patients without. Myocardial ischemia may exist in patients with LVH, despite patent graft, due to microvascular dysfunction. Comprehensive treatment, including long-term oral medication to improve microvascular dysfunction, is necessary for patients with LVH.

Long-term outcomes of Ross and Ross-Konno operations in patients under 15 years of age.

OBJECTIVE: The Ross operation is an excellent surgical option for young children, regardless of aortic pathology type. However, failure rates are concerning during the second postoperative decade. We sought to determine the predictors of long-term outcomes after Ross and Ross-Konno operation performed in childhood. METHODS: We performed 34 Ross and 9 Ross-Konno operations in pediatric patients (age < 15 years) from 1996 to 2016, and retrospectively evaluated the long-term results. RESULTS: The postoperative follow-up period was 13.5 ± 3.9 years. In the Ross group, there were one inpatient death and one death after discharge. There were no inpatient deaths in the Ross-Konno group. There were 6 reoperations in the Ross group and 1 in the Ross-Konno group for left ventricular outflow tract (LVOT). Cumulative survival rates were 96.8% and 100% in the Ross and Ross-Konno groups, respectively. The reoperation free rate for LVOT /RVOT (right ventricular outflow tract) were 98.6/85.5% and 91.9/63.4% in the 5th and 10th years of follow-up, respectively. Patients who underwent the operations at age > 8.6 years had higher risks of reoperation for LVOT. Aortic annulus measurements > 24 mm or aorta/pulmonary artery diameter (Ao/PA) ratios > 1.2 conferred higher risks of reoperation for LVOT. CONCLUSIONS: Long-term outcomes after Ross and Ross-Konno operations in children were satisfactory. However, new-onset aortic regurgitation was progressive and reoperation was needed in some children. Age, aortic annulus diameter, and Ao/PA ratio may be able to predict of long-term outcomes after Ross and Ross-Konno operations.

Twenty-year experience with the Konno operation: Konno incision does not impair LV function.

BACKGROUND: There has been no report observing the LV function of Konno incision. We examined the outcomes of the Konno operations over 20 years. METHODS: We investigated 63 Konno operations with mechanical valves performed from 1984. This study aimed to evaluate the effects of Konno incision including LV function changes and the long-term outcomes of patient survival and reoperation rate (RVOT and LVOT complications). RESULTS: The postoperative follow-up period was 20.6 ± 6.2 years. Early death occurred in 1 case and late death occurred in 9 cases. The cumulative survival rate was 89.6, 87.5, and 84.5% in the 5th, 10th, and 20th follow-up years. Five patients required reoperation for the aortic valve. The recurrence avoidance rate for LVOT reoperation was 96.6, 94.7, and 92% in the 5th, 10th, and 20th follow-up years of the Konno operation. Konno incision did not show significant decline in postoperative LV ejection fraction. (Pre, 62% vs 20 years later, 58%; P = 0.052.) There were no cases requiring intervention at the event of ventricular arrhythmia, but 13 cases were Complete Right bundle branch block, and 11 cases were Left bundle branch block. CONCLUSIONS: The survival rate associated with Konno operation throughout 20 years was excellent. Konno incision can secure sufficient LV outflow tract and is a safe treatment for complex LVOTO without deteriorating LV ejection fraction.

Long-term outcomes of total correction for isolated total anomalous pulmonary venous connection: lessons from 50-years' experience.

OBJECTIVES: Isolated total anomalous pulmonary venous connection (TAPVC) is a relatively rare congenital cardiac defect, while pulmonary venous obstruction (PVO) is associated with poor prognosis. We reviewed the long-term outcome of total correction for isolated TAPVC at our institute and analysed the risk factors for mortality and morbidity. METHODS: A total of 290 isolated TAPVC patients evaluated between 1965 and 2016 were divided into 2 groups: Group Early (n = 151) underwent surgery before 1989; Group Late (n = 139) underwent surgery after 1990. The mean age at operation was 10.4 ± 30.2 months (range 0 day to 23 years), and the mean body weight was 5.5 ± 6.0 kg (range 1.6-48 kg). Group Late included more patients with the infracardiac type of TAPVC and preferably used the posterior approach. RESULTS: There were 53 hospital deaths and 16 late deaths. Postoperative PVO was recognized in 28 patients. The mean follow-up time was 18.2 ± 9.7 years (range 2 months to 42.4 years). The actuarial survival rate was improved to 87.8% at 20 years in Group Late. Multivariable analysis revealed that death rate was significantly increased in patients of Group Early, with a body weight <2 kg and with postoperative PVO (P < 0.0001, P = 0.0041, P = 0.0003, respectively). Reoperations were performed 27 times in 22 patients (PVO repair, 11; staged repair, 4 and others, 12). PVO repair was performed at a mean of 2.5 ± 1.6 months later. The actuarial freedom from reoperation rates were 88.8% and 83.2% at 20 and 30 years, respectively. Multivariable analysis revealed that the risk of reoperation was associated with mixed-type TAPVC and postoperative PVO (P = 0.0064 and P < 0.0001, respectively). CONCLUSIONS: Long-term surgical outcomes of isolated TAPVC have improved over the past 25 years. Postoperative PVO, the mixed-type TAPVC and a body weight <2 kg might be the important factors contributing to mortality and morbidity.

Long-term Effect of Enlargement of a Ventricular Septal Defect in the Rastelli Procedure.

We investigated the effect of ventricular septal defect (VSD) enlargement on long-term surgical results, late arrhythmia, and left ventricular (LV) function in the Rastelli procedure for D-transposition of the great arteries with LV outflow tract obstruction (LVOTO). From 1979 to 2001, 74 patients (D-transposition of the great arteries, n = 56; double outlet right ventricle, n = 18) underwent the Rastelli procedure. In group A, 46 patients underwent the Rastelli procedure with VSD enlargement, and in group B, 28 patients underwent the Rastelli procedure without enlargement. There were no hospital deaths. Actuarial survival at 20 years was 80% in group A and 91% in group B (P = 0.50). Freedom from reoperations at 20 years was 40.1% in group A and 52.0% in group B. Reoperations for LVOTO were performed in 2 patients in both groups. In postoperative catheterization, LV ejection fraction in group A was 57.1% ± 8.7% vs 57.2% ± 8.1% in group B (P = 0.97); LV end-diastolic volume, 150.0% ± 47.2% vs 142.0% ± 36.9% of the normal volume (P = 0.97). In long-term postoperative echocardiography, the pressure gradient of the LV to the aorta was 12.0 ± 12.8 vs 17.7 ± 26.0 mm Hg in groups A and B (P = 0.31). There were no differences between the groups regarding basal rhythms, anti-arrhythmic agents, and pacemaker implantation rate. VSD enlargement in the Rastelli procedure can be safely performed without early mortality and with long-term low mortality and morbidity regarding arrhythmia, LV function, and reoperation for late LVOTO. VSD enlargement should be considered as an option for avoiding long-term LVOTO.

[Atrial Septal Hematoma after Repair of Ventricular Septal Defect;Report of a Case].

A 3-month-old female with ventricular septal defect underwent definitive repair. In the operation, a venting tube was inserted through the incised patent foramen ovale. The ventricular septal defect was closed using a patch and the incised patent foramen ovale was directly closed. A transesophageal echography showed no abnormal findings in the operating room. On 1st postoperative day, the patient's heart rate and pressure of the superior vena cava increased while blood pressure decreased. A transthoracic echocardiography revealed an atrial septal hematoma. After conservative therapy, the heart rate and pressure of the superior vena cava gradually decreased while blood pressure increased. The atrial septal hematoma disappeared spontaneously. The patient was discharged on 16th postoperative day. The atrial septal hematoma appears to have a good prognosis, but sometimes can be poor resulting and death. Meticulous and constant observation is required to detect an atrial septal hematoma.

Long-term follow-up of Fontan completion in adults and adolescents.

BACKGROUND: The Fontan procedure is rarely performed in adults and adolescents in the present era. We review our results with the Fontan procedure in adolescents and young adults. METHODS: Between 1974 and 2010, 79 consecutive patients underwent the Fontan procedure at an age ≥ 15 years (mean age at Fontan operation, 20.3 years ± 4.5 years). Forty-five patients underwent atriopulmonary connection, 11 underwent the Bjork procedure, and 23 underwent total cavopulmonary connection. RESULTS: Ten hospital deaths (HDs) and/or early Fontan takedowns (TDs) occurred. The median follow-up period was 18.2 years (range, 0.6-37.6 years). The estimated freedom from death or TD rates was 79.7% at 5 years, 77.0% at 10 years, 73.9% at 15 years, and 63.9% at 20 years. Age was not a predictor of HD and/or TD. Freedom from death or TD after 1998 was 69.1% at 5 years, 69.1% at 10 years, and 69.1% at 15 years, and before 1997 was 82.3% at 5 years, 79.0% at 10 years, 75.5% at 15 years, and 65.1% at 20 years; there were no significant differences between the two groups. In 19 late-death patients, nine (47.4%) experienced sudden death. Among these patients, five had known arrhythmias before sudden death. CONCLUSIONS: In patients who were ≥15 years old, the surgical results of the Fontan operation were acceptable. Approximately half of the late deaths were sudden deaths, mainly occurring 10-20 years postoperatively.

Surgical repair of a truncus arteriosus with unilateral absence of the right proximal pulmonary artery.

The unilateral absence of a proximal pulmonary artery (UAPPA) is rare and is most frequently accompanied by cardiovascular anomalies such as tetralogy of Fallot or septal defects. We report a patient with truncus arteriosus with UAPPA in which we performed a two-stage surgical repair. During the first palliative operation, a right modified Blalock-Taussig shunt was constructed to develop the hypoplastic right pulmonary artery. At 10 months, the patient underwent patch closure of a ventricular septal defect with integration of both pulmonary arteries, and reconstruction of the right ventricular outflow tract using a conduit. Four years postoperatively, he continues to do well.

Fontan circulation over 30 years. What should we learn from those patients?

BACKGROUND: This study aimed to evaluate Fontan circulation which was observed over 30 years. METHODS: Forty patients who underwent a Fontan operation between 1974 and 1986 and survived (group S, n = 20) or died in the late period (group LD, n = 20) were evaluated. The median age at operation was 10 years (range 2-32 years). The diagnoses were tricuspid atresia in 21, single ventricle in 9, and others in 10. The Fontan procedure was a right atrium-pulmonary artery graft in 2, atriopulmonary connection in 28, and right atrium-right ventricle anastomosis in 10 (Björk in 4, graft in 6). RESULTS: Causes of late death were congestive heart failure in 6, sudden death in 4, arrhythmia in 4, and others in 6. Sixteen patients underwent reoperation 23.3 ± 6.5 years after Fontan. Cardiac catheterization was performed at 1 month and 12 years. There were no significant differences in central venous pressure, ventricular ejection fraction, or pulmonary vascular resistance between the two groups. However, changes in ventricular end-diastolic volume suggested volume and pressure overload in group LD. In group S, the latest chest radiographs showed cardiothoracic ratio 51.3% ± 7.6%, oxygen saturation 94% ± 2%, brain natriuretic peptide 153 ± 111 pg c mL-1, and Holter monitoring revealed sinus rhythm in 10 patients. New York Heart Association class was I in 12 patients, II in 6, and III in 2. CONCLUSIONS: For long-term Fontan survival, timely total cavopulmonary connection conversion and medication to decrease ventricular volume and pressure load might be important.

Long-Term Outcome of Arterial Switch Operation Conversion After Failed Senning/Mustard Procedure.

BACKGROUND: We evaluated long-term outcomes of the arterial switch operation (ASO) conversion after a failed Senning/Mustard operation among patients with dextro-transposition of the great arteries. METHODS: Between 1986 and 2006, 9 patients with dextro-transposition of the great arteries underwent ASO conversion at our institute. All patients had systemic right ventricle failure, 6 had supraventricular tachycardia, and 8 had moderate or severe tricuspid valve regurgitation. All patients had New York Heart Association classification II or III. The median age of patients at the ASO conversion operation was 7.4 years (range, 0.6 to 32.4 years). Pulmonary artery banding for left ventricle training was performed in 8 of the 9 patients before conversion. RESULTS: There was 1 early death from low-output syndrome at 5 days postoperatively and 1 late sudden death at 5 months. Median follow-up time was 23.1 years (range, 0.08 to 28.0 years). The actuarial survival rate was 76.1% at 20 years. Long-term survivors revealed good New York Heart Association classification (class I, 6 patients; class II, 1 patient), with less than mild tricuspid regurgitation and brain natriuretic peptide levels of 40.6 ± 16.2 pg/mL. Cardiac catheterization revealed significant improvements of right ventricle end-diastolic volume (decreased from 243.2% to 117.7% of normal), and right ventricle ejection fraction (increased from 0.42 to 0.572; p < 0.05). Three patients underwent new pacemaker implantation for sick sinus syndrome, and moderate neoaortic valve regurgitation developed in 1 patient. CONCLUSIONS: Excellent long-term outcomes can be achieved after ASO conversion; however, careful observation for new-onset sick sinus syndrome and aortic regurgitation is mandatory.

Arterial Switch Operation With and Without Coronary Relocation for Intramural Coronary Arteries.

BACKGROUND: The arterial switch operation (ASO) for the transposition of the great arteries (TGA) with intramural coronary arteries has been performed using several techniques to avoid coronary events. We mainly performed ASO without coronary relocation by creating an aortopulmonary fenestration (Imai technique). Coronary circulation was rerouted by covering the aortopulmonary window and coronary orifices with a nonfacing sinus flap. Long-term results have not been reported. We describe our early and late results. METHODS: Among 551 patients who underwent an ASO between 1985 and 2014, intramural coronary arteries were detected in 15 of them. Coronary arteries were managed using 2 techniques: the double-button method in 5 patients (with unroofing and trapdoor incision in 1 patient) and the Imai technique in 10 patients. RESULTS: There were 3 hospital deaths and 3 deaths after discharge, 5 of which showed coronary complications. Actual survival and freedom from coronary complications at 15 years were 70% and 67%, respectively, with the Imai technique and 40% and 20%, respectively, with the double-button method. Late coronary intervention was performed for a long intramural coronary artery stenosis in 1 patient who underwent the Imai technique. In the others, late aortography showed good patency of the aortopulmonary window and growth of the coronary pouch after the Imai technique. CONCLUSIONS: The Imai technique can be an option for coronary management in the presence of high-risk coronary anatomy, particularly distal intramural coronary artery stenosis and inseparable coronary arteries with an almost single orifice. Adequate neopulmonary artery augmentation must be performed to prevent right ventricular outflow stenosis.