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.

Machine learning predicts blood lactate levels in children after cardiac surgery in paediatric ICU.

BACKGROUND: Although serum lactate levels are widely accepted markers of haemodynamic instability, an alternative method to evaluate haemodynamic stability/instability continuously and non-invasively may assist in improving the standard of patient care. We hypothesise that blood lactate in paediatric ICU patients can be predicted using machine learning applied to arterial waveforms and perioperative characteristics. METHODS: Forty-eight post-operative children, median age 4 months (2.9-11.8 interquartile range), mean baseline heart rate of 131 beats per minute (range 33-197), mean lactate level at admission of 22.3 mg/dL (range 6.3-71.1), were included. Morphological arterial waveform characteristics were acquired and analysed. Predicting lactate levels was accomplished using regression-based supervised learning algorithms, evaluated with hold-out cross-validation, including, basing prediction on the currently acquired physiological measurements along with those acquired at admission, as well as adding the most recent lactate measurement and the time since that measurement as prediction parameters. Algorithms were assessed with mean absolute error, the average of the absolute differences between actual and predicted lactate concentrations. Low values represent superior model performance. RESULTS: The best performing algorithm was the tuned random forest, which yielded a mean absolute error of 3.38 mg/dL when predicting blood lactate with updated ground truth from the most recent blood draw. CONCLUSIONS: The random forest is capable of predicting serum lactate levels by analysing perioperative variables, including the arterial pressure waveform. Thus, machine learning can predict patient blood lactate levels, a proxy for haemodynamic instability, non-invasively, continuously and with accuracy that may demonstrate clinical utility.

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.

Surgical management of congenital lobar emphysema associated with CHD.

Congenital lobar emphysema is often associated with CHD in early infancy; however, the surgical strategy for this condition is still controversial. We report three successful cases of emphysematous lung lobectomy before the surgical repair of associated CHD. Aggressive lobectomy preceding cardiac interventions is advised when the management of congenital lobar emphysema is difficult.

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.

Clinical application of a new ternary polymer, SEC-1 coat™, for pediatric cardiopulmonary bypass circuits: a prospective randomized pilot study.

OBJECTIVE: The use of biocompatible materials to reduce the systemic activation of inflammation and coagulation pathways is expanding rapidly. However, there have been few clinical studies of biocompatible circuits for pediatric cardiopulmonary bypass. This pilot study aimed to preliminarily evaluate the biocompatibility of SEC-1 coat™ (SEC) for cardiopulmonary bypass circuits in pediatric cardiac surgery. METHODS: Twenty infants undergoing cardiac surgery for isolated ventricular septal defects at Kobe Children's Hospital were assigned randomly to an SEC-coated (SEC group, n = 10) or heparin-coated (control group, n = 10) circuit. Perioperative data and the following markers were prospectively analyzed: platelet counts and interleukin-6, interleukin-8, C3a, ß-thromboglobulin, and thrombin-antithrombin complex levels. RESULTS: Neither patient characteristics nor postoperative clinical outcomes differed significantly between the SEC and control groups. Platelet counts markedly decreased during cardiopulmonary bypass in both groups, but were significantly better preserved in the SEC group. Fewer patients needed postoperative platelet transfusions in the SEC group. After cardiopulmonary bypass termination, serum levels of ß-thromboglobulin and thrombin-antithrombin complex were significantly lower in the SEC than in the control group. Although the differences were not statistically significant, serum levels of interleukin-6, interleukin-8, and C3a had a tendency toward being lower in the SEC group, with good preservation of leukocyte counts, fibrinogen, and antithrombin III. CONCLUSION: SEC-1 coat™ for cardiopulmonary bypass circuits have good biocompatibility with regard to platelet preservation and in terms of attenuating inflammatory reaction or coagulation activation during pediatric cardiac surgery. It can be beneficial in pediatric as well as adult cardiac surgery.

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.

Visualization and quantification of the atrioventricular conduction axis in hearts with ventricular septal defect using phase contrast computed tomography.

OBJECTIVE: To visualize and quantify the atrioventricular conduction axis in the setting of ventricular septal defect using phase contrast computed tomography. METHODS: We used the SPring-8 synchrotron radiation facility in Hyogo prefecture in Japan, processing and reconstructing the data with 3-dimensional software. RESULTS: We studied 8 hearts obtained from patients known to have had ventricular septal defects, aged from 6 to 150 days, with a median of 24.5 days. None of the individuals, however, had undergone corrective surgery. The penetrating bundle was found at a median of 1.43 mm from the septal crest, with a range of 0.99 to 1.54 mm. The distance to the nonbranching bundle to the right ventricular endocardium was 1.10 mm, with a range from 0.49 to 2.49 mm, to the origin of the left bundle branch was 2.46 mm, with a range from 1.7 to 3.18 mm, and to the origin of the right bundle branch was 2.34 mm, with a range from 0.50 to 2.59 mm. The median distance from the edge of the caudal limb of the septomarginal trabeculation to the right bundle branch was 1.04 mm, with a range from 0.81 to 1.16 mm. CONCLUSIONS: We were able to show the precise location of the axis, with our findings suggesting that longitudinal sutures placed along the posteroinferior rim should be effective in avoiding iatrogenic injury, but sutures should not be placed in the valley between the limbs of the septomarginal trabeculation.

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.

Clinical outcomes after tracheoplasty in patients with congenital tracheal stenosis in 1997-2014.

BACKGROUND: Mortality and morbidity of congenital tracheal stenosis (CTS) remain high. The aim of this study was to determine the factors predicting 12-month survival and 2-month successful extubation after tracheoplasty in patients with CTS. METHODS: Retrospective chart reviews were conducted in patients with CTS undergoing tracheoplasty at a single institution between 1997 and 2014. Patients' characteristics at disease onset and tracheoplasty were summarized. Twelve-month survival rate and 2-month extubation rate without tracheotomy after tracheoplasty were analyzed. RESULTS: We reviewed 81 patients' records. Multivariate analysis for 12-month survival revealed that older age (>2 months, hazard ratio [HR]: 0.08, 95% confidence interval [CI]: 0.02-0.36) or heavier body weight (>4.4 kg, HR: 0.13, 95% CI: 0.02-0.73) at tracheoplasty was a predictive factor for survival. Body weight at tracheoplasty (>8.2 kg, HR: 3.83, 95% CI: 1.88-7.79), preoperative balloon dilatation (HR: 0.30, 95% CI: 0.12-0.78), and carina involvement (HR: 0.36, 95% CI: 0.19-0.69) were predictive factors for successful extubation. CONCLUSIONS: Although CTS management is individualized, age or body weight at tracheoplasty needs to be considered and assessed for survival, as well as preoperative balloon dilatation, and carina involvement for successful extubation. LEVELS OF EVIDENCE: Level III.

Management of congenital tracheal stenosis in the neonatal period.

PURPOSE: Few reports have focused on the management of congenital tracheal stenosis (CTS) in the neonatal period. The aim of this study was to determine appropriate management strategies for CTS in the neonatal period. METHODS: The medical records of eight neonatal patients with CTS at a single institution between January 2007 and December 2016 were retrospectively reviewed. RESULTS: Three patients with frequent ventilatory insufficiency despite assisted ventilation underwent surgical intervention (balloon tracheoplasty: n = 1, slide tracheoplasty: n = 2). Ventilatory insufficiency improved after surgery in all three patients. One patient who underwent slide tracheoplasty died due to non-airway-related causes. Observation or conservative management was performed in five patients with minimal respiratory symptoms or stable ventilation under assisted ventilation. All five patients were safely managed non-operatively in the neonatal period. CONCLUSION: Depending on the severity of ventilatory insufficiency, there are two management strategies for CTS in the neonatal period. Surgical intervention, such as balloon tracheoplasty or slide tracheoplasty, is indicated for patients with unstable ventilatory status despite assisted ventilation. Observation or conservative management is a more suitable option for neonates with stable ventilation.

Functional near-tricuspid atresia in a patient with absent pulmonary valve and an intact ventricular septum.

Absent pulmonary valve with an intact ventricular septum is a rare malformation. We report a case of absent pulmonary valve and intact ventricular septum with functional near-tricuspid atresia caused by pulmonary regurgitation. Initial palliation with main pulmonary artery ligation and bilateral pulmonary artery banding was performed at 1 day of age. More antegrade flow across the tricuspid valve was recognised postoperatively, resulting in a successful right ventricular outflow tract reconstruction by a hand-sewn bileaflet polytetrafluoroethylene valve and modified Blalock-Taussig shunt at 11 days of age.