Configuration of the neoaortic root after chimney reconstruction in the Norwood procedure.

OBJECTIVES: After staged reconstruction for hypoplastic left heart syndrome, the neoaortic root tends to dilate, and the incidence of significant neoaortic valve insufficiency increases with time. This study aimed to evaluate the mid-term outcomes of the neoaortic root geometries and valve function after chimney reconstruction in the Norwood procedure. METHODS: Between 2013 and 2021, 20 consecutive patients who underwent chimney reconstruction during the Norwood procedure for hypoplastic left heart syndrome and its variants in our institution were enrolled. The actual diameters of the following points were measured, and Z-scores were calculated based on the normal aortic root geometries using the long axis view of echocardiography at the pre-Norwood stage and the lateral view of angiography at pre-Glenn, pre-Fontan, post-Fontan and follow-up (age 5-6 years) stages: neoaortic valve annulus; sinus of Valsalva; sinotubular junction; and ascending aorta just proximal to the anastomosis to the aortic arch. The degree of neoaortic valve regurgitation was evaluated by echocardiography at each stage. RESULTS: The median follow-up period was 3.9 years. Neoaortic roots after chimney reconstruction were spared from progressive dilation over time. With growth, the conical configuration of the neoaortic roots was preserved without geometrical distortion. The Z-scores of the annulus, sinus of Valsalva, sinotubular junction and ascending aorta ranged roughly from 4 to 6, 4 to 6, 2 to 4 and 0 to 2, respectively. All neoaortic valves at each stage had mild or no regurgitation. CONCLUSIONS: Chimney reconstruction prevented neoaortic root dilation and avoided significant neoaortic valve regurgitation in the mid-term. These neoaortic dimensions with smooth flow profiles in the neoaorta after chimney reconstruction may have contributed to the current results. Further studies are needed to clarify the long-term outcomes.

[Supra-annular Mitral Valve Replacement Using a Composite Valve for an Infant with Acute Rupture of Chordae Tendineae].

Acute rupture of the chordae tendineae of the mitral valve could lead to severe mitral regurgitation and circulatory collapse in infants. Mitral valve replacement may be often challenging because of the valve-annulus size mismatch in small infants when mitral valve repair cannot be accomplished. We present an infant with acute massive rupture of the chordae tendineae of the mitral valve who successfully underwent supra-annular mitral valve replacement using the short composite valve of an expanded polytetrafluoroethylene( ePTFE) graft and a mechanical valve. His mechanical valve has been functioning without complications such as thrombosis and pulmonary venous obstruction for 20 months after surgery. This technique could be helpful even infants with acute rupture of the chordae tendineae of the mitral valve whose left atrium may not be dilated.

A Case of Successful Biventricular Repair of the Transposition of the Great Arteries with a Coronary Anomaly Associated with an Atrioventricular Septal Defect.

The transposition of the great arteries (TGA) associated with a complete atrioventricular septal defect is a rare and serious congenital cardiac anomaly. In this report, we describe the successful biventricular repair of a TGA with a complete atrioventricular septal defect in an infant. Due to the low body weight of the patient and a complex coronary pattern anomaly, an arterial switch operation was executed, with the Mee procedure and pulmonary arterial banding as initial palliative measures when the infant was 22 days old and weighed 2.5 kg. Subsequently, atrioventricular septal defect repair using the modified one-patch method was performed when the patient was 1.3 years old and weighed 8.8 kg. Remarkably, the postoperative course of the patient demonstrated no notable incidents. To our knowledge, this is the first time a two-stage strategy was applied to repair these complex defects, presenting a promising approach for managing similar cases in future medical practice.

A new predictor of the optimal pulmonary artery reconstruction method during the arterial switch operation.

OBJECTIVES: The aim of this study was to more accurately predict the optimal pulmonary artery (PA) reconstruction procedure (Lecompte manoeuvre or original Jatene procedure) during the arterial switch operation, we focused on the horizontal sectioning (HS) angle between the left hilum PA and the great arteries using preoperative computed tomography imaging. METHODS: We defined the HS angle α (ß) as the angle between the tangential line from the posterior (anterior) wall of the left PA at the hilum to the left anterior (right posterior) surface of the main PA and the tangential line from the left surface of the ascending aorta to the left anterior (right posterior) surface of the main PA. We identified 14 consecutive patients diagnosed with transposition of the great arteries or transposition of the great artery-type double-outlet right ventricle who underwent preoperative computed tomography imaging. The original Jatene or Lecompte procedure was used for 9 (OJ group) and 5 (L group) patients. Relationships of the great arteries of the OJ and L groups were side by side in 8 and 2 patients, oblique in 1 and 1 patient and anteroposterior in 0 and 2 patients, respectively. RESULTS: In the OJ group, ß was greater than α in all patients. The median α/ß value was 0.618. In group L, α was greater than ß in all patients. The median α/ß was 1.307. Left PA stenosis caused by stretching was not observed in the L group. Coronary obstruction was not identified in the OJ group. Left PA stenosis behind the neo-ascending aorta was observed in 1 patient in the OJ group and required reoperation. CONCLUSIONS: The HS angle may be a useful predictor of optimal intraoperative PA reconstruction during arterial switch operation, especially for side-by-side or oblique relationships.

Multiple Pulmonary Artery Plasty With Tissue-Engineered Vascular Grafts.

In pediatric cardiovascular surgery, the autologous pericardium is useful for pulmonary artery augmentation. However, in some cases, the autologous pericardium may not be available for various reasons. Since 2014, we have developed tissue-engineered vascular grafts (TEVGs) and obtained good results. We report a successful case of multiple pulmonary artery plasty with TEVGs for pulmonary atresia/ventricular septal defect with major aortopulmonary collateral arteries. TEVGs are useful alternatives to autologous pericardium in pediatric cardiovascular operations that often require multistage procedures.

Surgical repair of a posterior left ventricular aneurysm in a 4-year-old boy.

Left ventricular aneurysms are rarely encountered in pediatric patients. A 4-year-old boy was diagnosed with severe mitral regurgitation and a posterior left ventricular aneurysm associated with a viral infection. The aneurysm was surgically resected and plicated longitudinally with a combination of an interrupted mattress and continuous over-and-over sutures with an outer felt reinforcement. The mitral regurgitation was reduced to a trivial degree postoperatively. The patient's postoperative recovery was good. He was discharged 31 days after surgery without cardiac dysfunction or lethal arrhythmia. Considering the location and spread of the aneurysm, an appropriate surgical procedure should be adopted for pediatric patients.

Coronary artery bypass grafting for coronary artery anomalies in infants and young children.

OBJECTIVES: Coronary artery bypass grafting (CABG) has been reported for coronary artery diseases in patients with Kawasaki disease and coronary artery complications after arterial switch operations for transposition of the great arteries. However, only a few studies have explored this modality for congenital coronary artery anomalies. As congenital coronary artery anomalies, particularly left coronary artery atresia and stenosis, are one of the reasons for sudden death, coronary revascularization is often required in infants and young children. Therefore, we aimed to investigate the outcome of CABG for such anomalies in infants and young children. METHODS: From 2014 to 2018, 3 infants and 2 children (median age: 10 months; range: 6-40 months) with coronary artery anomalies underwent CABG at our hospital. The indications for the procedure included left main coronary artery atresia and stenosis in 2 and 3 patients, respectively. Graft patency was evaluated postoperatively by contrast-enhanced computed tomography or coronary angiography, and postoperative outcomes (including death and cardiac events) were assessed during the follow-up period. RESULTS: No 30-day or in-hospital mortalities were noted. Postoperative examinations revealed patent grafts in all patients. They were discharged without any cardiac complications. Regarding the outcomes at the follow-up period, the graft patency rate was 80.0% (4/5 grafts), with no deaths or cardiac events. CONCLUSIONS: CABG is a useful strategy for coronary revascularization in infants and young children with coronary artery anomalies. Although the mid-term outcomes and patency are satisfactory, careful follow-up is necessary because the long-term outcomes remain unknown.

Pulmonary artery augmentation and aortic valve repair using novel tissue-engineered grafts.

Objectives: The objectives of this study were to evaluate the results when tissue-engineered vascular grafts (TEVGs) are used as alternatives to autologous pericardium for surgically augmenting the pulmonary artery (PA) or aortic valve. Methods: TEVG molds were embedded into subcutaneous spaces for more than 4 weeks preoperatively. Since 2014, 6 patients have undergone PA reconstruction, whereas 1 has undergone aortic valve plasty (AVP) with TEVGs. The time from mold implantation to the operation was 8.9 (range, 6.0-26.4) months. The age and body weight at the time of operation were 2.7 (range, 1.8-9.2) and 11.6 (range, 7.9-24.4) kg, respectively. Concomitant procedures comprised the Rastelli, palliative Rastelli, and Fontan operations in 2, 2, and 1 patient, respectively. Results: The median follow-up period was 14.4 (range, 3-39.6) months. There were no early or late mortalities. Moreover, there were no TEVG-related complications, including aneurysmal changes, degeneration, and infection. In 5 patients who underwent PA augmentation, the postoperative PA configuration was satisfactorily dilated. The reconstructed aortic valve function was good in the patient who underwent AVP. Decreased leaflet flexibility due to leaflet thickening was not observed. One patient had postoperative PA re-stenosis; therefore, re-PA augmentation with TEVGs was performed. On histological examination, TEVGs consisted of collagen fibers and few fibroblasts, and elastic fiber formation and/or smooth muscle cells were not observed. Conclusions: The midterm results of PA reconstruction and AVP with TEVGs were satisfactory. TEVGs might be a useful alternative to autologous pericardium in pediatric cardiovascular surgeries that often require multistage operations.

Expanded Polytetrafluoroethylene Conduits With Bulging Sinuses and a Fan-Shaped Valve in Right Ventricular Outflow Tract Reconstruction.

We developed a handmade expanded polytetrafluoroethylene (ePTFE) pulmonary valvular conduit (PVC) with bulging sinuses and a fan-shaped ePTFE valve for right ventricular outflow tract (RVOT) reconstruction. We aimed to investigate the results of this device in this multicenter study. From 2001 to 2020, 1776 patients underwent RVOT reconstruction using ePTFE PVCs at 65 institutions in Japan. The median age and body weight were 4.1 years (range, 3 days to 67.1 years) and 13.3 (range, 1.8-91.3) kg, respectively. The median PVC size was 18 (range, 8-24) mm. The median Z-value of the ePTFE PVC was 1.1 (range, -3.8 to 5.0). The ePTFE PVC conditions were investigated by cardiac echocardiography and catheterization. The median follow-up period was 3.3 years (range, 0 day to 16.2 years). There were only 9 cases (0.5%) with PVC-related unknown deaths. Reintervention was performed in 283 patients (15.9%), and 190 patients (10.7%) required explantation. Freedom from reintervention and explantation at 5/10 years were 86.7/61.5% and 93.0/69.1%, respectively. At the latest echocardiography, PVC regurgitation grade was better than mild in 88.4% patients. The average peak RVOT gradient was 15.7 ± 15.9 mm Hg at the latest cardiac catheterization. ePTFE PVC infection was detected in only 8 patients (0.5%). Relative stenosis due to somatic growth was the most common cause of PVC explantation. The performance of ePTFE in terms of durability, valvular performance, and the resistance against infection is considerable and may replace conventional prosthetic materials. Further improvement of the ePTFE membrane is essential to prevent valvular dysfunction.

A case of redo tricuspid valve repair after neonatal cone operation for Ebstein's anomaly.

Cone reconstruction for Ebstein's anomaly, although effective, is challenging in neonatal cases. Very few reports have discussed recurrent regurgitation. Herein, we report a successful redo tricuspid valve repair for recurrent regurgitation 5 years after cone reconstruction. A 5-year-old boy underwent cone reconstruction for Ebstein's anomaly in the neonatal period. Although tricuspid regurgitation reduced initially, it subsequently worsened. The mechanisms of regurgitation are dilatation of the anteroseptal commissure, indentation in the septal leaflet, and foreshortening of the anterior leaflet. Augmentation of the anterior leaflet using an elliptic autologous pericardium and mending of the gaping commissure and indentation markedly reduced the regurgitation.

Chimney reconstruction provides a wider subaortic space and reduces the risk of pulmonary artery compression in the Norwood-type aortic arch reconstruction without patch supplementation.

OBJECTIVES: Pulmonary artery (PA) compression by the neoaorta is a serious complication after the Norwood-type palliation (NP) for hypoplastic left heart syndrome. Either excess patch tailoring or limited use of autologous tissue may cause narrowing of the subaortic space. The chimney technique could theoretically provide a wide subaortic space. METHODS: Twenty-nine patients with both pre- and post-NP computed tomography data available of the 37 consecutive patients who underwent NP in our institution were reviewed. Arch height, arch width, sinus of Valsalva diameter, area under the neoaortic arch and arch angle were measured. These patients were divided according to the neo-arch reconstruction technique, chimney reconstruction technique (CR) or conventional direct reconstruction technique (DR). RESULTS: Median age and weight at NP were 2.1 months and 3.5 kg, respectively. Twenty-two patients underwent previous bilateral PA banding. During NP, 17 CR and 12 DR were performed. Four patients in the DR group developed PA compression. No neoaortic arch dilatation was found in either group. Post-NP arch width, area under the neo-arch and the arch angle were significantly larger in the CR group. Pre-NP arch height was significantly smaller in DR patients with PA compression than in those without. CONCLUSIONS: The chimney technique decreased the risk of PA compression and provided a wider subaortic space and a less acute arch angle. This technique had no short-term effect on the neoaortic root. Small preoperative arch height is a potential risk factor for PA compression in DR, and the chimney technique could be an effective solution.

Comparison of half-turned truncal switch and conventional operations.

OBJECTIVES: To compare conventional procedures with the half-turned truncal switch operation (HTTSO) for the management of complete transposition of the great arteries with left ventricular outflow tract (LVOT) obstruction using time-resolved 3-dimensional magnetic resonance phase-contrast imaging. METHODS: We identified 2 cases that underwent the Rastelli procedure and one case that underwent the Réparation a l'étage ventriculaire before 2002 [conventional procedures group (group C)], and 16 cases of HTTSO that were performed between 2002 and 2020 [HTTSO group (group H)]. Postoperative haemodynamics were assessed using time-resolved 3-dimensional magnetic resonance phase-contrast imaging in cases in both groups. RESULTS: The median follow-up period was 20.4 years in group C, and 6.1 years in group H. In group C, all 3 patients underwent reoperation because of postoperative right ventricular outflow tract obstruction and/or insufficiency. In addition, permanent pacemaker implantation was needed in 1 patient because of complete atrioventricular block complicated by ventricular septal defect enlargement. In group H, reoperation for LVOT/right ventricular outflow tract obstruction was not needed. A time-resolved 3-dimensional magnetic resonance phase-contrast imaging examination revealed high energy loss and wall shear stress in the winding LVOT in the group C. In contrast, low energy loss and wall shear stress, with straight and smooth LVOT, were identified in group H. CONCLUSIONS: HTTSO was shown to be superior to conventional procedures because a straight and wide LVOT could be obtained. Therefore, HTTSO should be the first choice for complete transposition of the great arteries with LVOT obstruction.

Midterm results of pulmonary artery plasty with in vivo tissue-engineered vascular grafts.

We evaluated the application of in vivo tissue-engineered vascular graft (in vivo TEVG) in pulmonary artery (PA) reconstruction as a substitute for autologous pericardium. From July 2017 to April 2020, 4 patients (male:female = 2:2) with major aortopulmonary collateral arteries underwent PA reconstruction with in vivo TEVGs. Graft moulds were embedded into the subcutaneous spaces in the first palliative surgery. In the second surgery used in vivo TEVGs were used as patch materials to treat PA stenosis. Preoperative and postoperative PA configurations were evaluated by computed tomography. Patients' median age and body weight were 1.6 (1-4) years and 8.7 (7.3-15.4) kg, respectively. Two patients underwent PA reconstruction during staged repair and 2 underwent reconstruction during definitive repair. One patient had postoperative PA restenosis due to bronchial compression; re-PA reconstruction with in vivo TEVGs was performed. On histological examination, the in vivo TEVG wall mainly comprised collagen fibres and a small number of fibroblasts. The midterm results of this technique are satisfactory. in vivo TEVGs could be a promising alternative to autologous pericardium for paediatric cardiovascular surgeries requiring multi-stage operations. CLINICAL TRIAL REGISTRATION: ERB-C-162.

Alternative pulmonary artery reconstruction technique in the arterial switch operation.

OBJECTIVES: Late complications of arterial switch operations (ASO) for transposition of the great arteries, such as neo-pulmonary artery (PA) stenosis and/or neoaortic regurgitation, have been reported. We developed an alternative reconstruction method called the longitudinal extension (LE) method to prevent PA bifurcation stenosis (PABS). METHODS: We identified 48 patients diagnosed with transposition of the great arteries and performed ASO using the Lecompte manoeuvre for neo-PA reconstruction. In 9 consecutive patients (from 2014), the LE method was performed (LE). Before 2014, conventional techniques were performed in 39 patients (C). The median body weight and age in the LE and C groups were 3.0 and 3.1 kg and 12 and 26 days, respectively. In the LE group, 1 patient underwent bilateral PA banding before ASO. In C, PA banding and arch repair were performed in 1 patient each. Patients who received concomitant procedures were included. RESULTS: The median follow-up in LE and C groups was 1.9 and 10.1 years, respectively. Early mortality/late death was not found in group LE and in 1 patient in group C. Only 1 case required ascending aorta sliding plasty in LE, and 8 patients needed PA augmentation for PABS in C. The median velocity of right/left PA was measured as 1.6/1.9 m/s in LE and 2.1/2.3 m/s in C, so it showed a lower value in LE. CONCLUSIONS: Excellent mid-term results were obtained with the LE method. It was considered a useful procedure in preventing PABS, which is a primary late complication of ASO. Further follow-up and investigations are needed.

Long-term results of large-calibre expanded polytetrafluoroethylene-valved conduits with bulging sinuses.

OBJECTIVES: In Japan, homograft and bovine jugular vein are available in very limited institutions for the reconstruction of the right ventricular outflow tract, and handmade expanded polytetrafluoroethylene (ePTFE)-valved conduits have been widely used instead. This study aimed to clarify the long-term outcomes and the durability of the ePTFE-valved conduits purely by narrowing down to those with large sizes to eliminate the influence of the body growth. METHODS: Between January 2002 and December 2015, patients who underwent right ventricular outflow tract reconstruction in 34 Japanese institutions using ePTFE-valved conduits with a diameter of ≥18 mm were included. All the valved conduits were made in the authors' institution and delivered to each participating institution. RESULTS: Overall, 502 patients were included. Early mortality was 1.4% and not related to conduit failure. The overall survival rate was 98.2% at 5 years and 96.6% at 10 years. Freedom from conduit explantation was 99.5% at 5 years and 89.0% at 10 years. Three patients (0.13 per 100 patient-years) developed infective endocarditis of the conduit, and only 1 patient required conduit removal. Pulmonary insufficiency was mild or less in 480 (96%) patients, and conduit stenosis was mild or less in 436 (88%) patients at the latest follow-up. CONCLUSIONS: By narrowing the analyses down to only ePTFE conduits with a large size, satisfactory long-term outcomes of these conduits with a fan-shaped valve and bulging sinuses were shown. These conduits would be among the optimal choices for right ventricular outflow tract reconstruction.

Energetic performance index improvement after Glenn and Damus-Kaye-Stansel procedure using vector flow mapping analysis: a case report.

BACKGROUND: Echocardiography vector flow mapping can assess dynamic flow to treat congenital heart diseases. We evaluated intracardiac flow, energy loss, left ventricular output kinetic energy, and energetic performance index using vector flow mapping during Glenn and Damus-Kaye-Stansel procedures in order to assess the efficacy of the surgery. CASE PRESENTATION: A 9-month-old boy underwent Glenn and Damus-Kaye-Stansel procedures. The energy loss depends on the left ventricular preload; therefore, energy loss decreased after the Glenn procedure. After the Damus-Kaye-Stansel procedure, the kinetic energy would increase owing to the integrated systemic outflow; however, in our case, kinetic energy decreased, which was potentially explained by the fact that kinetic energy also depends on the left ventricular preload. After the Glenn and Damus-Kaye-Stansel procedures, we detected an improvement in energetic performance index, indicating that the cardiac workload improved as well. CONCLUSION: We revealed the efficiency of the Glenn and Damus-Kaye-Stansel procedures using vector flow mapping.

The effect of a valved small conduit on systemic ventricle-pulmonary artery shunt in the Norwood-type palliation.

OBJECTIVES: The aim of this study was to clarify the impact of valved systemic ventricle-pulmonary artery (SV-PA) shunt on outcomes after stage-1 Norwood-type palliation (NP) compared with the modified Blalock-Taussig shunt. METHODS: Consecutive patients who underwent NP between 2003 and 2019 were enrolled. SV-PA shunts using the expanded polytetrafluoroethylene valved conduit were implanted in 18 patients (valved SV-PA group), and another 18 patients underwent modified Blalock-Taussig shunt during NP (modified Blalock-Taussig shunt group). All valved conduits were made in our institution in advance. RESULTS: No differences in baseline characteristics were found between the groups, except for shunt size. During a median 2.9 (interquartile range 0.4-6.4, maximum 14.2) years of follow-up, 8 (22.2%) patients died across both groups. There were no statistically significant differences in early mortality (5.5% vs 11.1%, P = 0.55) and overall survival rates at 5 years (80.8% vs 71.4%, P = 0.48) in the valved SV-PA and modified Blalock-Taussig shunt groups. No statistically significant difference was observed in the frequency of interventions between the groups (31% vs 33%, P = 1.0). At the time of the bidirectional Glenn procedure, the systemic ventricular end-diastolic volume index was significantly lower (84 ± 24 vs 106 ± 31 ml/m2, P = 0.05) and the ejection fraction was significantly greater (62 ± 8% vs 55 ± 9%, P = 0.03) in the valved SV-PA group. There was no statistically significant difference in the pulmonary artery index (228 ± 85 vs 226 ± 60 mm2/m2, P = 0.92). CONCLUSIONS: A valved SV-PA shunt using an expanded polytetrafluoroethylene valved conduit was associated with preserved ventricular function after NP and did not impair pulmonary artery growth by controlling pulmonary regurgitation.

Histopathologic Analysis of Explanted Polytetrafluoroethylene-Valved Pulmonary Conduits.

The expanded polytetrafluoroethylene (ePTFE)-valved conduits as alternative material for right ventricular outflow reconstruction provides satisfactory long-term outcomes. The purpose of this study was to investigate degenerative changes in failed conduits through histopathologic analysis of the explanted specimens. All leaflets of explanted conduits were observed macroscopically, and their longitudinal sections were examined microscopically. Three typical findings, that is, calcification of the leaflet, neointimal proliferation, and proteinaceous infiltration into the leaflet, were evaluated quantitatively by measuring their degree and appearance probability. A total of 15 leaflets from 5 failed conduits (group F) and 12 leaflets from 5 nonfailed conduits (group non-F) were included. The median duration of implantation was 7.6 years (5.3-10.9 years) in group F and 1.3 years (0.7-3.9 years) in group non-F (P = 0.003). In group F, calcification tended to occur in the middle and upper third of the leaflet, causing stiffening, distortion, and exophytic concretion of the leaflet, and mean neointimal thickness on inflow and outflow surfaces were 0.33 ± 0.02 mm and 0.22 ± 0.01 mm, respectively. There was a moderately strong correlation between appearance probability of calcification in group F and that of proteinaceous infiltration in group non-F (correlation coefficient 0.67, P < 0.001). Proteinaceous infiltration into the leaflet was presumed be responsible for future calcification of the leaflet and subsequent stenotic conduit failure. Modification of the ePTFE material to prevent proteinaceous infiltration may contribute to improving the durability of ePTFE-valved conduit.