Expanded polytetrafluoroethylene conduits with curved and handsewn bileaflet designs for right ventricular outflow tract reconstruction.

OBJECTIVE: This study reviewed the application of curved and bileaflet designs to pulmonary expanded polytetrafluoroethylene conduits with diameters of 10 to 16 mm and characterized this conduit on in vitro experiment, including particle image velocimetry. METHODS: All patients who received this conduit between 2010 and 2022 were evaluated. Three 16-mm conduits were tested in a circulatory simulator at different cardiac outputs (1.5-3.6 L/minute) and bending angles (130°-150°). RESULTS: Fifty consecutive patients were included. The median operative body weight was 8.4 kg (range, 2.6-12 kg); 10-, 12-, 14-, and 16-mm conduits were used in 1, 4, 6, and 39 patients, respectively. In 34 patients, the conduit was implanted in a heterotopic position. The overall survival rate was 89% at 8 years with 3 nonvalve-related deaths. There were 10 conduit replacements; 5 16-mm conduits (after 8 years) and 1 12-mm conduit (after 6 years) due to conduit stenosis, and the remaining 4 for reasons other than conduit failure. Freedom from conduit replacement was 89% and 82% at 5 and 8 years, respectively. Linear mixed-effects models with echocardiographic data implied that 16-mm conduits were durable with a peak velocity <3.5 m/second and without moderate/severe regurgitation until the patient's weight reached 25 kg. In experiments, peak transvalvular pressure gradients were 11.5 to 25.5 mm Hg, regurgitant fractions were 8.0% to 14.4%, and peak Reynolds shear stress in midsystolic phase was 29 to 318 Pa. CONCLUSIONS: Our conduits with curved and bileaflet designs have acceptable clinical durability and proven hydrodynamic profiles, which eliminate valve regurgitation and serve as a reliable bridge to subsequent conduit replacement.

Incidence of congenital tracheal stenosis in left pulmonary artery sling diagnosed by bronchoscopy.

PURPOSE: Congenital tracheal stenosis (CTS) has been reported to occur in 50-65% of cases of left pulmonary artery sling (LPAS), but the exact incidence rate is unknown. This study aimed to determine the actual rate using bronchoscopy and to elucidate morphological features in computed tomography (CT) diagnosis. METHODS: We performed a single institutional retrospective review of all patients with LPAS between January 2010 and March 2022. The percentage of complete tracheal rings in patients with LPAS was evaluated using bronchoscopy. The anteroposterior/lateral diameter ratios at the smallest and largest diameters of each CTS patient's trachea were measured on CT. The Wilcoxon signed-rank test was used to analyze the differences between the two parts. RESULTS: Fifty-two patients with LPAS were enrolled. All patients had complete tracheal rings on bronchoscopy. CT analysis of 32 patients with CTS was performed. The median anteroposterior/lateral diameter ratio at the smallest diameter was 1.05 (interquartile range [IQR] 0.95-1.15); the median ratio at the largest diameter was 0.94 (IQR 0.89-0.99). There was a significant difference between the two parts (p = 0.013). CONCLUSION: CTS might be universally associated with LPAS. The circular tracheal cross-section on CT might imply the existence of a complete tracheal ring.

A case of infective endocarditis in an 8-year-old boy 3 months after transcatheter atrial septal defect closure using Figulla Flex II occluder.

Infective endocarditis is a rare complication of atrial septal defect closure using transcatheter procedure. We report about infective endocarditis in an 8-year-old boy 3 months after transcatheter closure using a Figulla Flex II atrial septal defect occluder. Transesophageal echocardiography showed vegetation attached to the left atrium side of the device. Device removal and atrial septal defect closure were performed. The device was less endothelialized on the left than on the right atrium side. Therefore, insufficient endothelialization may cause infective endocarditis.

Surgical outcomes of pulmonary artery sling and congenital tracheal stenosis with right lung anomaly.

OBJECTIVES: This study aimed to investigate whether computed tomographic indices support surgical decision-making in patients with pulmonary artery sling, congenital tracheal stenosis and right lung underdevelopment. METHODS: A total of 38 patients with pulmonary artery sling and congenital tracheal stenosis underwent tracheoplasty. Patients were divided into 3 groups based on anatomical categorization: group normal lung (NL; n = 21), group H (right lung hypoplasia, n = 12) and group A (right lung agenesis or aplasia, n = 5). Using preoperative computed tomographic images, the severity of the tracheal bending due to the right posterior deviation of the aortic arch and the relative length of the left pulmonary artery for reimplantation was evaluated. RESULTS: Slide tracheoplasty posterior to the aortic arch with pulmonary artery reimplantation was performed in 32 patients (21, 10 and 1 in groups NL, H and A, respectively). Slide tracheoplasty anterior to the aortic arch was performed in 4 patients (2 patients each in groups H and A). Among the 6 patients with severe tracheal bending who underwent slide tracheoplasty posterior to the aortic arch, 5 required aortopexy for tracheomalacia. The overall mortality rate was 3% (group NL, n = 1). The relative length of the left pulmonary artery in group H (0.85) was significantly shorter than that in group NL (1.36, P < 0.0001). CONCLUSIONS: In patients with right lung underdevelopment, preoperative computed tomography elucidated the tracheal bending due to right posterior deviation of the aortic arch, which compromised tracheoplasty and shortness of the left pulmonary artery for pulmonary artery sling repair.

Closed-PICU perioperative management of congenital tracheal stenosis.

BACKGROUND: Perioperative management of congenital tracheal stenosis (CTS) is challenging. In the present study, compared the effect of closed-pediatric intensive care unit (PICU) perioperative management by pediatric intensivists and open-PICU management by surgeons. Outcomes in terms of ventilator-free days (VFD) and length of postoperative PICU stay in children with CTS were evaluated. METHODS: This retrospective cohort study was conducted in a PICU in Japan. Children with CTS who underwent slide tracheoplasty were grouped according to whether they were perioperatively managed in an open (January 2015 to April 2016) or a closed (May 2016 to August 2019) PICU. Data were extracted from patients' medical records. RESULTS: In total, 13 and 38 patients were included in the open- and closed-PICU groups, respectively. Compared to the open-PICU group, the closed-PICU group had shorter duration of muscle relaxant administration (median 4 vs 5 days; P < 0.001), earlier enteral nutrition (34/38 [90%] vs 1/13 [8%]; P < 0.001), more 28-day VFD (median 21 vs 20 days; P = 0.04), and shorter duration of postoperative PICU stay (median 16 vs 36 days; P = 0.002), but mortality did not differ significantly between the two groups (0/38 [0%] vs 1/13 [8%]; P = 0.25). CONCLUSIONS: Closed-PICU perioperative management with pediatric intensivists' participation significantly increased 28-day VFD and reduced the length of postoperative PICU stay in patients with congenital tracheal stenosis.

Mid-term outcomes of Contegra implantation for the reconstruction of the right ventricular outflow tract to proximal branch pulmonary arteries: Japan multicentre study.

OBJECTIVES: To reveal the mid-term outcomes of Contegra implantation for the reconstruction of the right ventricular outflow tract to proximal branch pulmonary arteries in a multicentre study. METHODS: Between April 2013 and December 2019, 178 Contegra conduits were implanted at 5 Japanese institutes. The median age and body weight at operation were 16 months (25th-75th percentile: 8-32) and 8.3 kg (6.4-10.6). Sixteen patients were neonates (9.0%). Selected conduit sizes were 12 mm in 28 patients (15.7%), 14 mm in 67 patients (37.6%), 16 mm in 66 patients (37.1%), 18 mm in 5 patients (2.8%) and <12 mm in 12 patients (6.7%). Fifty-six grafts (31.4%) were ring supported. Proximal branch pulmonary arteries were concomitantly augmented in 85 patients (47.5%). Follow-up was completed in all patients and the median follow-up period was 3.1 years (1.3-5.1). RESULTS: The overall, conduit explantation-free and conduit infection-free survival rates at 5 years were 91.3%, 71.0% and 83.7%, respectively. Infection (P = 0.009) and common arterial trunk (P = 0.024) were risk factors for explantation. Conduit durability was shorter in smaller one (P < 0.001). Catheter interventions (for conduit to proximal branch pulmonary artery)-free survival rates at 5 years was 52.9%; however, need for catheter interventions was not a risk factor for conduit explantation. CONCLUSIONS: Mid-term outcomes of reconstruction of the right ventricular outflow tract to the proximal branch pulmonary arteries with Contegra were acceptable. The need for explantation over time was higher in smaller conduits. Conduit infection was a strong risk factor for conduit explantation. Frequently and repeated catheter interventions effectively extended the conduit durability.

Evaluation of Ductal Tissue in Coarctation of the Aorta Using X-Ray Phase-Contrast Tomography.

We assessed the histological accuracy of X-ray phase-contrast tomography (XPCT) and investigated three-dimensional (3D) ductal tissue distribution in coarctation of the aorta (CoA) specimens. We used nine CoA samples, including the aortic isthmus, ductus arteriosus (DA), and their confluences. 3D images were obtained using XPCT. After scanning, the samples were histologically evaluated using elastica van Gieson (EVG) staining and transcription factor AP-2 beta (TFAP2B) immunostaining. XPCT sectional images clearly depicted ductal tissue distribution as low-density areas. In comparison with EVG staining, the mass density of the aortic wall positively correlated with elastic fiber formation (R = 0.69, P < 0.001). TFAP2B expression was consistent with low-density area including intimal thickness on XPCT images. On 3D imaging, the distances from the DA insertion to the distal terminal of the ductal media and to the intima on the ductal side were 1.63 ± 0.22 mm and 2.70 ± 0.55 mm, respectively. In the short-axis view, the posterior extension of the ductal tissue into the aortic lumen was 79 ± 18% of the diameter of the descending aorta. In three specimens, the aortic wall was entirely occupied by ductal tissue. The ductal intima spread more distally and laterally than the ductal media. The contrast resolution of XPCT images was comparable to that of histological assessment. Based on the 3D images, we conclude that complete resection of intimal thickness, including the opposite side of the DA insertion, is required to eliminate residual ductal tissue and to prevent postoperative re-coarctation.

Selective Lesser Curvature Augmentation With Geometric Study for Repair of Aortic Arch Obstruction.

BACKGROUND: We repaired aortic coarctation and interrupted aortic arch with extended end-to-end anastomosis (EAA) through median sternotomy and performed lesser curvature augmentation with a pulmonary autograft patch (PAP) in selected patients with a long gap between anastomotic sites. We reviewed these outcomes and geometric implications. METHODS: All neonates and infants with biventricular morphology who underwent aortic arch reconstruction through median sternotomy between 2005 and 2019 were evaluated. Aortic arch geometry was analyzed with computed tomography routinely performed before and after surgery from 2009 on. RESULTS: There were 91 consecutive patients (median age, 1.2 months). Ten patients received PAP. One early death and no late deaths were noted. Overall survival was 98.9% at 10 years. Two left bronchomalacia and 1 recoarctation occurred in patients with EAA. Freedom from recoarctation was 97.4% at 10 years. We examined 68 patients with computed tomography. We used PAP in patients with a significantly longer gap between anastomotic sites indexed by the square root of the body surface area; its cutoff value was 29.0 mm/m (area under the curve, 0.86 mm/m). The PAP created a significantly greater arch angle (median, 91° versus 83°) and arch/descending diameter ratio (median, 1.2 versus 1.0) and preserved the arch width indexed by the square root of the body surface area (median, before surgery: 35.7 versus 34.4 mm/m; after surgery: 36.5 versus 29.9mm/m), compared with EAA. CONCLUSIONS: Aortic arch reconstruction with the current combined strategy provides satisfactory outcomes. Guided by geometric analysis, lesser curvature augmentation can be applied to patients who might experience recoarctation or airway compression with a directly anastomosed aortic arch.

Cusp-based geometric height-oriented repair of a pediatric aortic valve.

Progressive aortic regurgitation can occur in pediatric patients due to root dilation with conotruncal anomalies or cusp prolapse associated with a ventricular septal defect. It is treated using various approaches influenced by personal preferences and institutional experience. We applied geometrical concepts developed for adult aortic valve repair to pediatric valves. The basal ring and sinotubular junction are downsized in relation to the geometric height of the cusp by external suture annuloplasty. The length of the cusp free margin is then adjusted with central plication, guided by measuring the effective height of the cusp. This approach facilitates the reproducibility and predictability of pediatric aortic valve repair.

Effect of Long-term Administration of Prostaglandin E1 on Morphologic Changes in Ductus Arteriosus.

BACKGROUND: To improve survival of patients with hypoplastic left heart syndrome, combination therapy with bilateral pulmonary artery banding and prostaglandin E1 (PGE1)-mediated ductal patency was developed as an alternative for high-risk neonates in Japan. However, the effect of long-term PGE1 administration on ductus arteriosus remains unclear. Synchrotron radiation-based X-ray phase-contrast tomography (XPCT) enables clear visualization of soft tissues at an approximate spatial resolution of 12.5 µm. We aimed to investigate morphologic changes in ductus arteriosus after long-term PGE1 infusion using XPCT. METHODS: Seventeen ductus arteriosus tissue samples from patients with hypoplastic left heart syndrome were obtained during the Norwood procedure. The median duration of lipo-prostaglandin E1 (lipo-PGE1) administration was 48 days (range, 3 to 123). Structural analysis of ductus arteriosus was performed and compared with conventional histologic analysis. RESULTS: The XPCT was successfully applied to quantitative measurements of ductal media. Significant correlation was found between the duration of lipo-PGE1 infusion and mass density of ductal media (R = 0.723, P = .001). The duration of lipo-PGE1 administration was positively correlated with elastic fiber staining (R = 0.799, P < .001) and negatively correlated with smooth muscle formation (R = -0.83, P < .001). No significant increase in intimal cushion formation was found after long-term lipo-PGE1 administration. Expression of ductus arteriosus dominant PGE2-receptor EP4 almost disappeared in specimens when lipo-PGE1 was administered over 3 days. CONCLUSIONS: Disorganized elastogenesis and little intimal cushion formation after long-term lipo-PGE1 administration suggest that ductus arteriosus remodeled to the elastic artery phenotype. Because EP4 was downregulated and ductus arteriosus exhibited elastic characteristics, the dosage of lipo-PGE1 might be decreased after a definite administration period.

Switch to Extracorporeal Membrane Oxygenation During Cardiac and Tracheal Repair.

Simultaneous repair of congenital tracheal and cardiovascular lesions remains challenging in small patients. We describe two infants weighing less than 3 kg who underwent successful tracheoplasty with concomitant correction of complex heart anomalies. In both operations, cardiopulmonary bypass was switched to extracorporeal membrane oxygenation after cardiac repair to optimize hemostatic function with transfusion and maintain activated clotting time at 200 to 240 seconds. Slide tracheoplasty was performed in a bloodless field, which prevented intraoperative hemorrhage from running down the divided lower trachea into the lung and causing airway obstruction. Both patients were weaned from extracorporeal support during surgery and extubated within 9 days.

Computed tomography-based surgical strategy for total anomalous pulmonary venous connection.

OBJECTIVES: We used computed tomographic angiography (CTA)-based surgical planning to clarify the anatomical indications of sutureless repair technique for total anomalous pulmonary venous connection. The mid-term impact of the current surgical strategies was evaluated. METHODS: One hundred twelve patients underwent repair for total anomalous pulmonary venous connection. The study period was divided into era 1 (1996-2010, n = 56) and era 2 (2011-2018, n = 56). Patients with single ventricular heart (SVH) were included. In era 2, the indications for primary sutureless repair and branch pulmonary vein incision were based on CTA findings. RESULTS: For patients with biventricular heart, the 5-year survival was 69% and 97% in eras 1 and 2, respectively (P = 0.0024). For patients with SVH, the 5-year survival was 21% and 70% in eras 1 and 2, respectively (P = 0.0007). During the follow-up period, the evidence of post-repair pulmonary vein stenosis (PVS) was observed in 12 patients with biventricular heart [era 1, 8 patients (23%); era 2, 4 patients (13%)], and 14 patients with SVH [era 1, 6 patients (60%); era 2, 8 patients (36%)]. Using multivariable analysis, preoperative CTA was associated with improved survival in both biventricular heart and SVH and associated with post-repair PVS-free survival in SVH. Since 2011, 12 patients with post-repair PVS underwent multiple reintervention with 1 recorded death (5-year survival: 88%). CONCLUSIONS: CTA-based surgical strategy for total anomalous pulmonary venous connection provided significant survival benefit. Although post-repair PVS could occur in era 2, aggressive reintervention appeared to be associated with improved survival and vein patency.

Left Atrial Decompression by Minithoracotomy During Extracorporeal Life Support.

Extracorporeal membrane oxygenation through cervical cannulation is an established option for pediatric patients with acute cardiopulmonary failure. However, left-sided heart decompression is sometimes mandatory in patients with severe left ventricular dysfunction. This report describes a fast and less invasive technique for placing a left atrial cannula through a left anterior minithoracotomy approach. In 4 critically ill children, this minimally invasive technique provided satisfactory left-sided heart decompression, and this report describes a representative case.

Three Dimensional Visualization of Human Cardiac Conduction Tissue in Whole Heart Specimens by High-Resolution Phase-Contrast CT Imaging Using Synchrotron Radiation.

BACKGROUND: The feasibility of synchrotron radiation-based phase-contrast computed tomography (PCCT) for visualization of the atrioventricular (AV) conduction axis in human whole heart specimens was tested using four postmortem structurally normal newborn hearts obtained at autopsy. METHODS: A PCCT imaging system at the beamline BL20B2 in a SPring-8 synchrotron radiation facility was used. The PCCT imaging of the conduction system was performed with "virtual" slicing of the three-dimensional reconstructed images. For histological verification, specimens were cut into planes similar to the PCCT images, then cut into 5-µm serial sections and stained with Masson's trichrome. RESULTS: In PCCT images of all four of the whole hearts of newborns, the AV conduction axis was distinguished as a low-density structure, which was serially traceable from the compact node to the penetrating bundle within the central fibrous body, and to the branching bundle into the left and right bundle branches. This was verified by histological serial sectioning. CONCLUSION: This is the first demonstration that visualization of the AV conduction axis within human whole heart specimens is feasible with PCCT.

Clinical equivalency of cardiopulmonary bypass and extracorporeal membrane oxygenation support for pediatric tracheal reconstruction.

OBJECTIVE: Pediatric surgery for congenital tracheal stenosis continues to be a therapeutic challenge, and it often requires cardiopulmonary bypass (CPB) or extracorporeal membrane oxygenation (ECMO) for intra-operative extracorporeal cardiorespiratory support. The purpose of this study was to compare the peri-operative outcomes of CPB with ECMO in pediatric tracheal reconstruction. METHODS: Forty-three consecutive patients who underwent tracheal reconstruction without intra-cardiac repair for congenital tracheal stenosis at Kobe Children's Hospital between January 2000 and August 2012 were enrolled in this retrospective study. They were divided into two groups according to intra-operative extracorporeal cardiopulmonary support [CPB (n = 17) or ECMO (n = 26)]. Peri-operative variables were compared between the two groups. RESULTS: The CPB and ECMO groups had similar patient and operative characteristics. However, the CPB group required larger priming volume and higher doses of total heparin injection. Although the ECMO group exhibited less peri-operative bleeding and lower red blood cell requirement, there were no statistically significant differences between the two groups. Compared to the ECMO group, patients in the CPB group had significantly less positive fluid balance during surgery and in the first 24 h after surgery, and exhibited a trend towards higher ratios of PO2 to the fraction of inspired oxygen and lower PCO2 at the time of ICU admission and on post-operative day 1. CONCLUSIONS: Pediatric tracheal reconstruction should be performed with intra-operative CPB or ECMO, after considering the advantages of utilizing each extracorporeal cardiorespiratory support type according to the patient's specific condition and situation.

Clinical assessment of diastolic retrograde flow in the descending aorta for high-flow systemic-to-pulmonary artery shunting.

OBJECTIVE: To investigate whether echocardiographic characteristics in the descending aorta of patients with cyanotic congenital heart disease who have received a systemic-to-pulmonary artery (SP) shunt can indicate shunt flow volume and predict postoperative adverse events related to high-flow shunting. METHODS: Among the 73 consecutive patients who received an SP shunt between 2010 and 2014, data for 53 patients who underwent postoperative Doppler echocardiographic assessment of diastolic retrograde flow in the descending aorta (dAo-RF) were reviewed retrospectively. RESULTS: The mean dAo-RF ratio was 0.50 ± 0.15 at intensive care unit admission and reached its peak level (0.56 ± 0.12) at 24 hours after surgery. All of the patients with a maximal dAo-RF ratio of ≥0.80 had experienced acute heart failure or cardiogenic shock due to postoperative high-flow shunting and required emergent surgical interventions to reduce pulmonary blood flow. Pulse oximetry-measured oxygen saturation and serum lactate level were significantly correlated with dAo-RF ratio, but they had some clinical dispersion to match the postoperative adverse events. CONCLUSIONS: The dAo-RF ratio is a simple, repeatable, and noninvasive index for postoperative assessment of SP shunt flow volume. A high dAo-RF ratio is a significant predictor of postoperative adverse events of high-flow shunting.