Acute Kidney Injury With a Miniaturized Extracorporeal Circuit for Neonatal Cardiopulmonary Bypass.

OBJECTIVES: The objectives of this study were to evaluate the incidence and to identify risk factors for acute kidney injury (AKI) in neonates undergoing cardiopulmonary bypass (CPB) with a miniaturized bloodless primed extracorporeal circuit. DESIGN: A retrospective cohort study. SETTING: A single-center, tertiary academic hospital. PARTICIPANTS: Data of 462 patients were analyzed. INTERVENTIONS: With a retrospective analysis of neonates undergoing CPB with bloodless priming between May 2007 and August 2019, the incidence of AKI was determined according to the neonatal Kidney Disease: Improving Global Outcomes classification. Multivariate logistic regression analyses were performed to determine risk factors for AKI. MEASUREMENTS AND MAIN RESULTS: The incidence of AKI was 41.1% (190 of 462); 30.3% (n = 140) had mild stage 1, 6.5% (n = 30) reached stage 2, and 4.3% (n = 20) reached stage 3. Multivariate logistic regression showed that degree of hypothermia (p = 0.05), duration of CPB (p = 0.03), and lower baseline serum creatinine (p < 0.001) were associated independently with AKI. In the authors' patient population, patients without transfusion of donor-derived erythrocytes had a lower incidence of AKI (p = 0.003). AKI stages 2 and 3 were associated with longer duration of mechanical ventilation (p = 0.008) and increased length of stay in the intensive care unit (p = 0.03). CONCLUSIONS: With a miniaturized CPB circuit and bloodless priming, the AKI incidence was well within the range consistent with previously reported studies from other institutions.

Coagulation Profile of Neonates Undergoing Arterial Switch Surgery With Crystalloid Priming of the Cardiopulmonary Bypass Circuit.

OBJECTIVES: The aim was to evaluate changes in the coagulation profile of cyanotic neonates, to analyze the effects of cardiopulmonary bypass (CPB) with crystalloid priming on their coagulation status, and to determine factors predicting a requirement for hemostasis-derived transfusion. DESIGN: Retrospective cohort. SETTING: Single-center, tertiary academic hospital. PARTICIPANTS: In total, 100 consecutive neonates who underwent arterial switch surgery between December 2014 and June 2020. INTERVENTIONS: Rotational thromboelastometry (ROTEM) and coagulation parameters before surgery and before termination of CPB were evaluated. Transfusion of platelets, fresh frozen plasma, and fibrinogen, defined as hemostasis-derived transfusion (HD transfusion), were determined. Patients with and without HD transfusion were compared to identify predictors. MEASUREMENTS AND MAIN RESULTS: After CPB, fibrinogen was reduced by 24.5% (interquartile range [IQR] 8.9-32.1) to 201 mg/dL (IQR 172-249), resulting in a reduction of FIBTEM A10 by 20% (1.8-33.3) to 8 mm (6-11). The platelet count decreased by a median of 47.2% (25.6-61.3) to 162 × 103/µL (119-215). However, the median fibrinogen concentration and platelet count remained within normal range. Neonates with abnormal ROTEM results were more likely to receive HD transfusions. The HD transfusions were more likely with lower preoperative FIBTEM maximum clot firmness values (p = 0.031), lower hemoglobin concentrations at termination of CPB (p = 0.02), and longer CPB duration (p = 0.017). Perioperative hemostasis without any HD transfusion was achieved in 64 neonates. CONCLUSIONS: Guidance from ROTEM analyses facilitates hemostasis management after neonatal CPB. Circuit miniaturization with transfusion-free CPB is associated with acceptable changes in ROTEM in most patients, and allows sufficient hemostasis without any HD transfusions in most patients.

The Impact of Prematurity on Morbidity and Mortality in Newborns with Dextro-transposition of the Great Arteries.

Prematurity is a risk factor for adverse outcomes after arterial switch operation in newborns with D-TGA (D-TGA). In this study, we sought to investigate the impact of prematurity on postnatal and perioperative clinical management, morbidity, and mortality during hospitalization in neonates with simple and complex D-TGA who received arterial switch operation (ASO). Monocentric retrospective analysis of 100 newborns with D-TGA. Thirteen infants (13.0%) were born premature. Preterm infants required significantly more frequent mechanical ventilation in the delivery room (69.2% vs. 34.5%, p = 0.030) and during the preoperative course (76.9% vs. 37.9%, p = 0.014). Need for inotropic support (30.8% vs. 8.0%, p = 0.035) and red blood cell transfusions (46.2% vs. 10.3%, p = 0.004) was likewise increased. Preoperative mortality (23.1% vs 0.0%, p = 0.002) was significantly increased in preterm infants, with necrotizing enterocolitis as cause of death in two of three infants. In contrast, mortality during and after surgery did not differ significantly between the two groups. Cardiopulmonary bypass times were similar in both groups (median 275 vs. 263 min, p = 0.322). After ASO, arterial lactate (34.5 vs. 21.5 mg/dL, p = 0.007), duration of mechanical ventilation (median 175 vs. 106 h, p = 0.038), and venous thrombosis (40.0% vs. 4.7%, p = 0.004) were increased in preterm, as compared to term infants. Gestational age (adjusted unit odds ratio 0.383, 95% confidence interval 0.179-0.821, p = 0.014) was independently associated with mortality. Prematurity is associated with increased perioperative morbidity and increased preoperative mortality in D-TGA patients.

Coronary Interventions in Pediatric Congenital Heart Disease.

Coronary artery lesions represent rare conditions in pediatric congenital heart disease and mainly include coronary artery stenoses (CAS) or coronary artery fistulae (CAF). Due to the small vessel size, pediatric percutaneous coronary interventions (PCI) are demanding and studies concerning long-term results are missing. In this retrospective study, we analyzed indications, procedural details, and post-procedural outcomes in pediatric patients who underwent PCI in our institution. For CAS treatment, procedural success was defined as efficient coronary revascularization with a significant improvement of coronary perfusion. CAF treatment was considered successful, when no residual shunt was detectable. From 1995 to 2020, 32 pediatric patients aged ≤ 18 years received interventional treatment for CAS (n = 24/32) or CAF (n = 8/32). Reasons for CAS were post-surgical (n = 15/24) or post-transplant (n = 9/24). Interventional treatment strategies included coronary angioplasty (20/43), stent placement (10/43), and a combination of both (13/43). In-hospital mortality occurred in 6/24 patients and late mortality in 5/24 patients leading to an overall 5-year survival of 62.5%. Early mortality mainly occurred due to post-ischemic myocardial failure. CAF occlusion was performed using coil embolization (n = 3), placement of vascular plugs (n = 3), a combination of both (n = 1), or a combination of coil embolization and a covered stent (n = 1). Treatment of coronary fistulae was successful in all patients with excellent post-procedural results and no follow-up death. PCI in pediatric patients with congenital heart disease can be performed safely and effectively. However, the overall 5-year survival probability of patients with CAS is reduced due to severe ischemic myocardial damage.

Anatomic Repair of Congenitally Corrected Transposition: Reappraisal of Eligibility Criteria.

Several criteria to identify suitable candidates for anatomic repair in congenitally corrected transposition (cc-TGA) have been proposed. The purpose of this study was to critically re-evaluate adequacy of these recommendations in our patient cohort. All cc-TGA patients undergoing anatomic repair between 2010 and 2019 were reviewed. Evaluated eligibility criteria for repair included age ≤ 15 years, LV mass index ≥ 45-50 g/m2, LV mass/volume ratio > 0.9-1.5 and systolic LV to right ventricle pressure ratio > 70-90% among others. Repair failure was defined as postoperative early mortality or LV dysfunction requiring mechanical circulatory support. Twenty-five patients were included (median [interquartile range] age at surgery 1.8 years [0.7;6.6]; median postoperative follow-up 3.2 years [0.7;6.3]). Median preoperative LV ejection fraction was 60% [56;64], indexed LV mass 48.5 g/m2 [43.7;58.1] and LV mass/volume ratio 1.5 [1.1;1.6], respectively. A total of 12 patients (48%) did not meet at least one of the previously recommended criteria, however, all but two patients (92%) experienced favorable early outcome. Of 7 patients (28%) with indexed LV mass < 45 g/m2, 6 were successfully operated. There were two early repair failures (8%) with LV dysfunction: one patient died and one required mechanical circulatory support but recovered well. Surgery was performed successfully in patients with LV mass and volume Z-scores as low as - 2 and - 2.5, respectively. Anatomic correction for cc-TGA can be performed with excellent early outcome and is feasible even in patients with LV mass below previously recommended cut-offs. The use of LV mass and volume Z-scores might help to refine eligibility criteria.

Endothelial-to-Mesenchymal Transition as Underlying Mechanism for the Formation of Double-Chambered Right Ventricle.

Double-chambered right ventricle (DCRV) is a progressive division of the right ventricular outflow tract (RVOT) often associated with a subaortic ventricular defect (VSD). The septation is caused by a mixture of hypertrophied muscle bundles and fibrous tissue, whereof the latter is of unclear pathogenesis. Our group has previously reported that flow disturbances lead to formation of fibroelastic tissue through a process called endothelial-to-mesenchymal transition (EndMT) but it is unclear whether the same mechanism exists in the RV. Tissue from patients undergoing repair of DCRV was examined to identify the histomorphological substrate of this tissue. Demographic and pre-/post-operative echocardiographic data were collected from nine patients undergoing surgery for DCRV. RVOTO tissue samples were histologically analyzed for myocardial hypertrophy, fibrosis, elastin content, and active EndMT (immunohistochemical double-staining for endothelial and mesenchymal markers and transcription factors Slug/Snail) and compared to four healthy controls. Indication for surgery were symptoms and progressive RVOT gradients. A highly turbulent flow jet through the RVOTO and VSD was observed in all patients with a preoperative median RVOT peak gradient of 77 mmHg (IQR 55.0-91.5), improved to 6 mmHg (IQR 4.5-17) postoperatively. Histological analysis revealed muscle and thick infiltratively growing fibroelastic tissue. EndMT was confirmed as underlying patho-mechanism of this fibroelastic tissue but the degree of myocardial hypertrophy was not different compared to controls (P = 0.08). This study shows for the first time that an invasive fibroelastic remodeling processes of the endocardium into the underlying myocardium through activation of EndMT contributes to the septation of the RVOT.

Can Left Atrioventricular Valve Reduction Index (LAVRI) Predict the Surgical Strategy for Repair of Atrioventricular Septal Defect?

Despite improved survival, surgical treatment of atrioventricular septal defect (AVSD) remains challenging. The optimal technique for primary left atrioventricular valve (LAVV) repair and prediction of suitability for biventricular approach in unbalanced AVSD are still controversial. We evaluated the ability of our recently developed echocardiographic left atrioventricular valve reduction index (LAVRI) in predicting LAVV reoperation rate and surgical strategy for unbalanced AVSD. Retrospective echocardiographic analysis was available in 352 of 790 patients with AVSD treated in our institution and included modified atrioventricular valve index (mAVVI), ventricular cavity ratio (VCR), and right ventricle/left ventricle (RV/LV) inflow angle. LAVRI estimates LAVV area after complete cleft closure and was analyzed with regard to surgical strategy in primary LAVV repair and unbalanced AVSD. Of the entire cohort, 284/352 (80.68%) patients underwent biventricular repair and 68/352 (19.31%) patients underwent univentricular palliation. LAVV reoperation was performed in 25/284 (8.80%) patients after surgical correction of AVSD. LAVRI was significantly lower in patients requiring LAVV reoperation (1.92 cm2/m2 [IQR 1.31] vs. 2.89 cm2/m2 [IQR 1.37], p = 0.002) and significantly differed between patients receiving complete and no/partial cleft closure (2.89 cm2/m2 [IQR 1.35] vs. 2.07 cm2/m2 [IQR 1.69]; p = 0.002). Of 82 patients diagnosed with unbalanced AVSD, 14 were suitable for biventricular repair (17.07%). mAVVI, LAVRI, VCR, and RV/LV inflow angle accurately distinguished between balanced and unbalanced AVSD and predicted surgical strategy (all p < 0.001). LAVRI may predict surgical strategy in primary LAVV repair, LAVV reoperation risk, and suitability for biventricular approach in unbalanced AVSD anatomy.

Survival and Mid-Term Neurologic Outcome After Extracorporeal Cardiopulmonary Resuscitation in Children.

OBJECTIVES: Extracorporeal cardiopulmonary resuscitation in children with refractory cardiac arrest has been shown to improve survival, however, risk factors associated with mortality and neurologic impairments are not well defined. We analyzed our recent institutional experience with pediatric extracorporeal cardiopulmonary resuscitation to identify variables associated with survival and neurocognitive outcome. DESIGN: Retrospective observational study. SETTING: Pediatric cardiology and congenital heart surgery departments of a tertiary referral heart center. PATIENTS: Seventy-two consecutive children (median age, 0.3 yr [0.0-1.9 yr]) who underwent extracorporeal cardiopulmonary resuscitation at our institution during the study period from 2005 to 2016. INTERVENTIONS: Not applicable. MEASUREMENTS AND MAIN RESULTS: Median duration of resuscitation was 60 minutes (42-80 min) and median extracorporeal support duration was 5.4 days (2.2-7.9 d). Forty-three (59.7%) extracorporeal cardiopulmonary resuscitation events occurred during off-hours, however, neither duration of resuscitation (65 min [49-89 min] vs 51 min [35-80 min]; p = 0.16) nor survival (34.9% vs 37.9%; p = 0.81) differed significantly compared to working hours. Congenital heart disease was present in 84.7% of the patients. Survival to hospital discharge was 36.1%; younger age, higher lactate levels after resuscitation, acute kidney injury, renal replacement therapy, hepatic injury, and complexity of prior cardiothoracic surgical procedures were significantly associated with mortality. At mid-term follow-up (median, 4.1 yr [3.7-6.1 yr]), 22 patients (84.6% of discharge survivors) were still alive with 77.3% having a favorable neurologic outcome. High lactate levels, arrest location other than ICU, and requirement for renal replacement therapy were associated with unfavorable neurologic outcome. Interestingly, longer duration of resuscitation did not negatively impact survival or neurologic outcome. CONCLUSIONS: Extracorporeal cardiopulmonary resuscitation is a valuable tool for the treatment of children with refractory cardiac arrest and a favorable neurologic outcome can be achieved in the majority of survivors even after prolonged resuscitation. Mortality after extracorporeal cardiopulmonary resuscitation in postcardiac surgery children is associated with procedural complexity.

Cardiopulmonary Bypass Strategy to Facilitate Transfusion-Free Congenital Heart Surgery in Neonates and Infants.

Priming the cardiopulmonary bypass (CPB) circuit without the addition of homologous blood constitutes the basis of blood-saving strategies in open-heart surgery. For low-weight patients, in particular neonates and infants, this implies avoidance of excessive hemodilution during extracorporeal circulation. The circuit has to be miniaturized and tubing must be cut as short as possible to reduce the priming volume to prevent unacceptable hemodilution with initiating CPB. During perfusion, measures should be taken to prevent blood loss from the primary circuit to avoid replacement by additional volume. Favorable factors such as mild hypothermia/normothermia and high heparin concentrations during extracorporeal circulation promote earlier hemostasis after coming off bypass.Lower mortality score, first chest entry, higher hemoglobin concentration before going on bypass, and shorter CPB duration support transfusion-free CPB procedure. Reduced postoperative morbidity and mortality were observed when CPB was performed without blood transfusion. In our experience, this can be achieved in at least 70% of CPBs, even in low-weight patients.Bloodless CPB circuit priming should become a widespread reality, even in neonates and young infants, in any open-heart procedure.

Asanguineous Cardiopulmonary Bypass in Infants: Impact on Postoperative Mortality and Morbidity.

BACKGROUND: We routinely start cardiopulmonary bypass (CPB) for pediatric congenital heart surgery without homologous blood, due to circuit miniaturization, and blood-saving measures. Blood transfusion is applied if hemoglobin concentration falls under 8 g/dL, or it is postponed to after coming off bypass or after operation. How this strategy impacts on postoperative mortality and morbidity, in infants weighing ≤ 7 kg? METHODS: Six-hundred fifteen open-heart procedures performed from January 2014 to June 2018 were selected. One-hundred sixty-three patients (26.5%) were transfused on CPB (group 1), while 452 (73.5%) patients were not transfused on CPB (group 2). Operative risk and complexity were similar in both groups. Postoperative mortality and morbidity were compared. Multiple logistic regression was used to detect factors independently associated with outcome. RESULTS: Observed mortality in nontransfused group (0.7% = 3/452) was significantly lower than expected (4.2% = 19/452): p = 0.0007, and much lower than in transfused group (6.7% = 11/163): p < 0.0001. CPB transfusion (p = 0.001) was independently associated with mortality, either acting as the sole factor or in combination with the Society of Thoracic Surgeons morbidity score (p = 0.013). Patients not transfused during CPB required less frequently vasoactive inotropic drugs (p = 0.011) and duration of their mechanical ventilation was shorter (93 ± 134 hours) than for transfused patients (142 ± 170 hours): p = 0.0003. CPB transfusion was an independent determinant factor for morbidity (p = 0.05), together with body weight (p < 0.0001), vasoactive inotropic score (p < 0.0001), CPB duration (p = 0.001), and postoperative transfusion (p = 0.009). CONCLUSION: The strategy of transfusion-free CPB course, feasible in most patients ≤ 7kg, was associated with improved outcome. Asanguineous priming of CPB circuit should become standard, even in neonates and infants.

Bilateral Pulmonary Artery Banding before Norwood Procedure: Survival of High-Risk Patients.

BACKGROUND: This study reports midterm results of high-risk patients with hypoplastic left ventricle treated with initial bilateral pulmonary artery banding (PAB) before secondary Norwood procedure (NP). METHODS: Retrospective study of 17 patients admitted between July 2012 and February 2017 who underwent this treatment strategy because diagnosis or clinical status was associated with high risk for NP. Survival was compared with that of patients who underwent primary NP. RESULTS: Mean Aristotle comprehensive complexity score for NP would have been 19.7 ± 2.6. Risk factors included obstructed pulmonary venous return (n = 9), body weight < 2.5 kg (n = 7), total anomalous pulmonary venous connection (n = 3), and necrotizing enterocolitis (n = 1). Ten patients had a score ≥ 19.5. Early survival after PAB was 82.4% (14/17). NP was performed in 14 patients after improvement of clinical condition at a median age of 56 days and a weight ≥2,500 g. There was no 30-day mortality, but one interstage death. One patient died later after Glenn operation. One-year survival after primary PAB followed by NP was 70.6 ± 11.1%. During the same period, 35 patients with overall lower risk factors underwent primary NP; early postoperative survival and 1-year survival were 88.6 ± 5.4% and 68.6 ± 7.8%, respectively. There was no significant difference in survival between the two groups (p = 0.83) despite higher risk in the secondary Norwood group (p <0.0001). CONCLUSIONS: PAB before NP in high-risk patients constituted salvage management. Primary PAB provided enough time for stabilization and control of most risk factors. It allowed midterm survival equivalent to the survival after primary NP in lower risk neonates.

Treatment strategies for protein-losing enteropathy in Fontan-palliated patients.

OBJECTIVE: Protein-losing enteropathy is an infrequent but severe condition occurring after Fontan procedure. The multifactorial pathogenesis remains unclear and no single proposed treatment strategy has proven universally successful. Therefore, we sought to describe different treatment strategies and their effect on clinical outcome and mortality. MATERIAL AND METHODS: We performed a retrospective observational study. From the total cohort of 439 Fontan patients treated in our institution during the study period 1986-2019, 30 patients (6.8%) with protein-losing enteropathy were identified. Perioperative, clinical, echocardiographic, laboratory, and invasive haemodynamic findings and treatment details were analysed. RESULTS: Median follow-up after disease onset was 13.1 years [interquartile range 10.6]. Twenty-five patients received surgical or interventional treatment for haemodynamic restrictions. Medical treatment, predominantly pulmonary vasodilator and/or systemic anti-inflammatory therapy with budesonide, was initiated in 28 patients. In 15 patients, a stable remission could be achieved by medical or surgical procedures (n = 3 each), by combined multimodal therapy (n = 8), or ultimately by cardiac transplantation (n = 1). Phrenic palsy, bradyarrhythmia, Fontan pathway stenosis, and absence of a fenestration were significantly associated with development of protein-losing enteropathy (p = 0.001-0.48). Ten patients (33.3%) died during follow-up; 5-year survival estimate was 96.1%. In unadjusted analysis, medical therapy with budesonide and pulmonary vasodilator therapy in combination was associated with improved survival. CONCLUSIONS: Protein-losing enteropathy is a serious condition limiting survival after the Fontan procedure. Comprehensive assessment and individual treatment strategies are mandatory to achieve best possible outcome. Nevertheless, relapse is frequent and long-term mortality substantial. Cardiac transplantation should be considered early as treatment option.

Fontan completion during winter season is not associated with higher mortality or morbidity in the early post-operative period.

OBJECTIVES: The aim of our study was to compare post-operative outcome after total cavopulmonary connection between patients operated during winter and summer season. METHODS: We retrospectively studied 211 patients who underwent extracardiac total cavopulmonary connection completion at our institution between 1995 and 2015 (median age 4 (1-42) years). Seventy (33%) patients were operated during winter (November to March) and 141 (67%) patients during summer season (April to October). RESULTS: Patients operated during winter and summer season showed no difference in early mortality (7% versus 5%, p = 0.52) and severe morbidity like need for early Fontan takedown (1% versus 1%, p = 0.99) and need for mechanical circulatory support (9% versus 4%, p = 0.12). The post-operative course and haemodynamic outcome were comparable between both groups of patients (ICU (4 versus 3 days, p = 0.44) and hospital stay (15 versus 14 days, p = 0.28), prolonged pleural effusions (36% versus 31%, p = 0.51), need for dialysis (16% versus 11%, p = 0.37), ascites (37% versus 33%, p = 0.52), supraventricular tachyarrhythmia (16% versus 13%, p = 0.56) and chylothorax (26% versus 16%, p = 0.12), change of antibiotic treatment (47% versus 36%, p = 0.06), prolonged inotropic support (24% versus 14%, p = 0.05), intubation time (15 versus 12 hours, p = 0.33), and incidence of fast-track extubation (11% versus 22%, p = 0.06). CONCLUSION: Outcomes after total cavopulmonary connection completion during winter and summer season were comparably related to mortality, severe morbidity, or longer hospital stay in the early post-operative period. These results suggest that total cavopulmonary connection completion during winter season is as safe as during summer season.

Bloodless priming of the cardiopulmonary bypass circuit: determinants of successful transfusion-free operation in neonates and infants with a maximum body weight of 7 kg.

We currently perform open-heart procedures using bloodless priming of cardiopulmonary bypass circuits regardless of a patient's body weight. This study presents results of this blood-saving approach in neonates and infants with a body weight of up to 7 kg. It tests with multivariate analysis factors that affect perioperative transfusion. A total of 498 open-heart procedures were carried out in the period 2014-2016 and were analysed. Priming volume ranged from 73 ml for patients weighing up to 2.5 kg to 110 ml for those weighing over 5 kg. Transfusion threshold during cardiopulmonary bypass was 8 g/dl of haemoglobin concentration. Transfusion factors were first analysed individually. Variables with a p-value lower than 0.2 underwent logistic regression. Extracorporeal circulation was conducted without transfusion of blood in 335 procedures - that is, 67% of cases. Transfusion-free operation was achieved in 136 patients (27%) and was more frequently observed after arterial switch operation and ventricular septal defect repair (12/18=66.7%). It was never observed after Norwood procedure (0/33=0%). Lower mortality score (p=0.001), anaesthesia provided by a certain physician (p=0.006), first chest entry (p=0.013), and higher haemoglobin concentration before going on bypass (p=0.013) supported transfusion-free operation. Early postoperative mortality was 4.4% (22/498). It was lower than expected (6.4%: 32/498). In conclusion, by adjusting the circuit, cardiopulmonary bypass could be conducted without donor blood in majority of patients, regardless of body weight. Transfusion-free open-heart surgery in neonates and infants requires team cooperation. It was more often achieved in procedures with lower mortality score.

Lung function in very low birth weight infants after pharmacological and surgical treatment of patent ductus arteriosus - a retrospective analysis.

BACKGROUND: The indications and strategies for treatment of patent ductus arteriosus (PDA) are controversial, and the safety and long-term benefits of surgical PDA closure remain uncertain. The aim of this study was to compare the lung function of very low birth weight (VLBW) infants after successful PDA treatment with a cyclooxygenase inhibitor or secondary surgical ligation. METHODS: A total of 114 VLBW infants (birth weight < 1500 g), including 94 infants (82%) with a birth weight < 1000 g, who received treatment for hemodynamically significant PDA (hsPDA), were examined at a median postmenstrual age of 48 weeks. All infants were initially given pharmacological treatment, and 40 infants (35%) required PDA ligation. Lung function testing (LFT) included tidal breathing measurements, measurement of respiratory mechanics assessed by the occlusion test, whole-body plethysmography, SF6 multiple breath washout, forced expiratory flow (V'maxFRC) by the rapid thoracoabdominal compression technique, exhaled NO (FeNO), and arterialized capillary blood gas analysis. RESULTS: On the day of the LFT, the 2 groups had similar postconceptional age and body weight. However, the PDA ligation group was more immature at birth (p < 0.001) and had reduced respiratory compliance (p < 0.001), lower V'maxFRC (p = 0.006), increased airway resistance (Raw) (p < 0.001), and impaired blood gases (p < 0.001). Multivariate analysis showed that PDA surgery was an independent risk factor for increased Raw. CONCLUSION: PDA ligation after failed pharmacological treatment is associated with impaired lung function as compared to successful pharmacological closure in infants at a postmenstrual age of 48 weeks. However, only Raw was independently affected by PDA ligation, while all other differences were merely explained by patient characteristics.

Routine Application of Bloodless Priming in Neonatal Cardiopulmonary Bypass: A 3-Year Experience.

A restrictive transfusion strategy led us to routinely try to conduct donor-blood free open-heart surgery even in neonates. The cardio-pulmonary bypass (CPB) circuit was minimized by priming volumina at 73 ml for the smallest patients with body weight up to 2.5 kg and 85-95 ml for those with body weight of more than 2.5 kg, and by positioning the console as close as possible to operation table. Measures were applied to save blood during the procedure. Transfusion threshold of 8 g/dl hemoglobin was retained. Effort was made to avoid transfusion while on CPB or to postpone transfusion towards CPB end. From 2013 to 2015, 149 consecutive neonates underwent 150 open-heart procedures without blood in priming volume. Weight was lower than 2.5 kg in five instances. The most frequent operations were arterial switch operation (n = 54) and Norwood procedure (n = 17). Transfusion-free operation was achieved in 44 procedures. The great majority (42/44 = 95%) involved biventricular repair and included 50% (27/54) of arterial switch operations. 106 patients were transfused: 63 mostly towards CPB end, and 43 after coming off bypass. Transfusion-free procedures were associated with postoperative lower lactate concentration (p = 0.0013) and shorter duration of mechanical ventilation (p = 0.0009). Seven patients were discharged from hospital without getting any transfusion of blood or blood products. In conclusion, routine application of bloodless priming in neonatal cardiopulmonary bypass is safe and beneficial. It results into a good number (29%= 44/150) of transfusion-free operations. Postponing transfusion towards CPB end favors an overall restrictive transfusion strategy for all patients.

Complex Cardiac Surgery on Patients with a Body Weight of Less Than 5 kg without Donor Blood Transfusion.

Performing safe cardiac surgery in neonates or infants whose parents are Jehovah's Witnesses is only possible in a coordinated team approach. An unconditional prerequisite is a cardiopulmonary bypass (CPB) circuit with a very low priming volume to minimize hemodilution. In the past decade, we have developed a functional blood-sparing approach at our institution. The extracorporeal circuit was miniaturized. This had to be recently adapted, faced with a challenge associated with the switch to high-volume crystalloid cardioplegia. A filtration circuit was added. Here, we report an open heart surgery on three consecutive children of Jehovah's Witness parents with a body weight of 2.7, 4.5, and 4.8 kg, respectively. Procedures consisted of one arterial switch operation and two repairs of complete atrioventricular septal defects. Our static priming volume of less than 90 mL resulted in a nadir hematocrit during CPB of 27.7% (Hb 8.9 g/dL) in a patient which happened to have the lowest body weight of 2.7 kg. The two other patients had their lowest hematocrit at 31.4% (Hb 10.2 g/dL). The three children could be treated without any kind of transfusion of blood which had left the circulation or its extensions, in accordance with the parents' wishes, and enjoy favorable outcomes without transfusion of blood products during their entire hospital stay.

Tissue-engineered and autologous pericardium in congenital heart surgery: comparative histopathological study of human vascular explants.

OBJECTIVES: The goal of this histological study was to assess the biocompatibility of vascular patches used in the repair of congenital heart defects. METHODS: We examined tissue-engineered bovine (n = 7) and equine (n = 7) patches and autologous human pericardium (n = 7), all explanted due to functional issues or follow-up procedures. Techniques like Movat-Verhoeff, von Kossa and immunohistochemical staining were used to analyse tissue composition, detect calcifications and identify immune cells. A semi-quantitative scoring system was implemented to evaluate the biocompatibility aspects, thrombus formation, extent of pannus, inflammation of pannus, cellular response to patch material, patch degradation, calcification and neoadventitial inflammation. RESULTS: We observed distinct material degradation patterns among types of patches. Bovine patches showed collagen disintegration and exudate accumulation, whereas equine patches displayed edematous swelling and material dissolution. Biocompatibility scores were lower in terms of cellular response, degradation and overall score for human autologous pericardial patches compared to tissue-engineered types. The extent of pannus formation was not influenced by the type of patch. Bovine patches had notable calcifications causing tissue hardening, and foreign body giant cells were more frequently seen in equine patches. Plasma cells were frequently detected in the neointimal tissue of engineered patches. CONCLUSIONS: Our results confirm the superior biocompatibility of human autologous patches and highlight discernible variations in the changes of patch material and the cellular response to patch material between bovine and equine patches. Our approach implements the semi-quantitative scoring of various aspects of biocompatibility, facilitating a comparative quantitative analysis across all types of patches, despite their inherent differences.

Repair of complex transposition of great arteries: What is the best technique to avoid outflow tract obstructions?

OBJECTIVES: This study aimed to evaluate the short-/mid-term outcome of patients with complex dextro (d)-/levo (l)-transposition of the great arteries (TGA), ventricular septal defect and left ventricular outflow tract obstructions. METHODS: A single-centre, retrospective review of all complex dextro-TGA (n = 85) and levo-TGA (n = 22) patients undergoing different surgeries [Arterial switch operation + left ventricular outflow tract obstruction-resection (ASO-R), half-turned truncal switch/Mair (HTTS), Nikaidoh and Rastelli] between May 1990 and September 2022 was performed. Groups were analysed using Kruskal-Wallis test with post hoc pairwise comparison and Kaplan-Meier time-to-event models. RESULTS: A total of 107 patients [ASO-R (n = 20), HTTS (n = 23), Nikaidoh (n = 21), Rastelli (n = 43)] were included, with a median age of 1.0 year (0.5-2.5) and surgical repair median follow-up was 3.8 years (0.3-10.5). Groups did not differ in respect to early postoperative complications/early mortality. Five-year overall survival curves were comparable: ASO-R 78.9% (53.2-91.5), HTTS 75.3% (46.8-89.9), Nikaidoh 85% (60.4-94.9) and Rastelli 83.9% (67.5-92.5), P = 0.9. Highest rates of right ventricular outflow tract (RVOT) reinterventions [33.3% and 32.6% (P = 0.04)] and reoperations [28.6% and 32.6% (P = 0.02)] occurred after Nikaidoh and Rastelli procedures. However, overall freedom from RVOT reinterventions and RVOT reoperations at 5 years did not differ statistically significantly between the groups (ASO-R, HTTS, Nikaidoh and Rastelli): 94.4% (66.6-99.2), 69.1% (25.4-90.5), 67.8% (34-86.9), 64.4% (44.6-78.7), P = 0.2, and 90.0% (65.6-97.4), 91% (50.8-98.7), 65.3% (32.0-85.3) and 67.0% (47.4-80.6), P = 0.3. CONCLUSIONS: Surgical repair of complex dextro-/levo-TGA can be performed with satisfying early/mid-term survival. RVOT reinterventions/reoperations were frequent, with highest rates after Nikaidoh and Rastelli procedures. Left ventricular outflow tract obstruction reoperations were rare with zero events after Nikaidoh and HTTS procedures.

Changes in waiting time, need for mechanical circulatory support and outcomes in paediatric heart transplant recipients.

AIMS: Heart transplantation is a well-established treatment for end-stage heart failure in paediatric patients, demonstrating excellent long-term outcomes. METHODS: This retrospective study analyses 35 years of data on 244 paediatric recipients (<18 years) at a single institution from 1986 to 2022. The analysis explores changes in diagnoses, survival, waiting times and mechanical circulatory support (MCS) over three decades (1991-2000, 2001-2010 and 2011-2020). RESULTS: Survival outcomes significantly improved over the study period, with 1-year survival rates increasing from 79.3% (1991-2000) to 92.3% (2011-2020, P = 0.041). The median overall survival was 18.0 years, and median conditional survival to 1 year post-transplant was 20.9 years. Survival differences were noted among age groups, with infants under 1 year of age experiencing higher early mortality, and adolescents (aged 11-17 years) facing increased long-term risks, possibly linked to adult donor characteristics. Waiting times for heart transplantation increased, especially for younger age groups (0-5 and 6-10 years), reflecting the growing demand for donor organs. The use of MCS, including ventricular assist devices (VAD), surged, with 67% of recipients in the most recent decade receiving pre-transplant VAD support. Importantly, despite prolonged waiting times and increased VAD use, overall survival continued to be favourable. CONCLUSIONS: Early and long-term results after paediatric heart transplantation have been continuously improving over the past decades. Despite an increased demand for donor organs and the growing reliance on VAD as bridge to transplantation, post-transplantation survival is not compromised.