Background/Objectives: Myocarditis is a major cause of morbidity and mortality in children and can lead to long-term heart failure, dilated cardiomyopathy, the need for heart transplantation, or death. New systemic inflammatory indices that combine lymphocyte, neutrophil, and platelet counts have been recently used as strong prognostic markers of some inflammatory diseases and adverse outcomes of neoplasms. This study aimed to investigate the use of new systemic indices as early predictive markers for adverse outcomes in patients with pediatric myocarditis. Methods: This study retrospectively examined patients between the ages of >1 month and <18 years who were monitored in our clinic with a diagnosis of myocarditis between 1 January 2022 and 31 December 2024. The cases were divided into two groups: fulminant myocarditis (requiring the use of inotropes or extracorporeal membrane oxygenation due to hemodynamic disturbance) and non-fulminant myocarditis. The systemic inflammatory index values of these groups (calculated in the first 6 h) were compared, and the results were statistically analyzed. Results: The study included 122 pediatric myocarditis cases treated during the study period (80 boys; median age: 11 (IQR: 8–14) years). Twenty-six of these patients (21.3%) developed fulminant myocarditis. The median systemic immune-inflammation index (SII) value in the group with fulminant myocarditis was 1300 (IQR: 1000–1600), while this value was 500 (IQR: 350–650) for the non-fulminant group (p < 0.05). The median systemic inflammatory response index (SIRI) values were 2.9 (IQR: 2.5–3.2) in the fulminant myocarditis group and 1.5 (IQR: 1.2–1.8) in the non-fulminant group (p < 0.05). The cut-off values for fulminant myocarditis were found to be 1050 for the SII, with an AUC value of 0.76 (95% confidence interval: 0.80–0.96; p < 0.001), and 1.9 for the SIRI, with an AUC value of 0.64. Conclusions: The SII and SIRI may independently predict adverse myocarditis prognoses in children. These new biomarkers are easy to calculate using routine blood parameters.

Background: Among infants undergoing cardiac surgery, AKI may affect as many as 40% of this population and carries an unfavorable prognosis. A range of contributors has been implicated, including early age, cyanotic physiology, and extended time on cardiopulmonary bypass (CPB). Nadir-indexed oxygen delivery (DO₂) is an important determinant for early detection of hypoperfusion and anaerobic metabolism during CPB. This study aimed to explore the relationship between nadir DO₂ during pediatric CPB and postoperative acute kidney injury. Methods: Between 1 October 2024 and 1 December 2024, we enrolled 40 children who underwent cardiac surgery with CPB [median age 6 months (IQR 4–8), median weight 5.5 kg (IQR 5–7 kg)] into an observational cohort. DO₂ was tracked intraoperatively for every patient, and pre- as well as intraoperative variables were examined for independent links to AKI. Postoperative outcomes were then compared between patients who did and did not develop AKI. Results: In our patient population (n = 40), 16 patients (40%) developed AKI according to the pRIFLE criteria (75% risk; 18.7% injury; 6.2% failure; no patient was in the loss or end-stage renal disease categories). Lower nadir DO₂ values were associated with postoperative AKI in this exploratory pilot cohort. ROC analysis identified an exploratory nadir DO₂ threshold of 360 mL/min/m² (sensitivity 70%, specificity 80%) associated with postoperative AKI. Because this threshold was both derived and evaluated within the same cohort without validation, it should be regarded only as a preliminary, hypothesis-generating observation with no implication of clinical applicability and requires validation in larger independent cohorts. Conclusions: In this exploratory pilot cohort, lower nadir DO₂ during cardiopulmonary bypass was independently associated with postoperative AKI. An exploratory ROC-derived threshold of 360 mL/min/m² was identified; however, this threshold should be considered hypothesis-generating rather than clinically validated. The consistency of findings across both dichotomous and continuous DO₂ analyses strengthens the robustness of the observed association, although larger prospective studies are required to externally validate this threshold, which at present carries no implication of clinical applicability.

Background: Double-outlet right ventricle is a complex congenital cardiac anomaly in which both great arteries arise predominantly from the right ventricle. Accurate anatomical evaluation is critical for surgical planning. While transthoracic echocardiography is commonly used for intracardiac assessment, its limitations in visualising extracardiac structures highlight the need for additional imaging modalities like CT angiography. Objective: To compare the diagnostic accuracy and clinical utility of transthoracic echocardiography and CT angiography in the pre-operative evaluation and surgical planning of infants with double-outlet right ventricle. Methods: This retrospective, single-centre study included 78 infants diagnosed with double-outlet right ventricle. All patients underwent both transthoracic echocardiography and CT angiography before surgical intervention. Imaging findings were compared with intraoperative surgical results to assess sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy for each modality. Results: CT angiography was significantly more effective than transthoracic echocardiography in identifying extracardiac anomalies such as coronary artery anomalies ( p = 0.014), aortic arch hypoplasia ( p = 0.024), aortopulmonary collateral vessels ( p = 0.039), anomalous pulmonary venous connections ( p = 0.001), and persistent left superior vena cava ( p = 0.001). In contrast, transthoracic echocardiography was more sensitive in detecting small ventricular septal defects ( p = 0.035). Conclusion: Transthoracic echocardiography remains the first-line modality for intracardiac evaluation in double-outlet right ventricle, but CT angiography provides superior visualisation of extracardiac structures. The combined use of both imaging techniques improves diagnostic accuracy and surgical planning, supporting better outcomes in the management of CHD.

Background: Conotruncal anomalies frequently involve extracardiac vascular structures that are critical for surgical planning yet incompletely assessed by transthoracic echocardiography (TTE). We evaluated the incremental diagnostic value of CT angiography (CTA) beyond TTE using intraoperative findings as the reference standard. Methods: In this single-center retrospective study, 239 children who underwent surgical repair of a conotruncal anomaly and had both preoperative TTE and CTA were analyzed. The incremental contribution of CTA was graded as none, minor, or major by two independent reviewers. Diagnostic performance of each modality was compared with operative findings for coronary artery anomalies, right aortic arch, aortic arch hypoplasia, interrupted aortic arch, and pulmonary artery atresia, non-confluence, and hypoplasia. Results: CTA provided incremental information beyond TTE in 232 patients (97.1%), classified as major in 51.9% and minor in 45.2%; interobserver agreement was almost perfect (quadratic-weighted κ = 0.825). CTA was superior for coronary artery anomalies (sensitivity 91.7% vs. 50.0%), branch pulmonary artery hypoplasia (97.3% vs. 89.3%), and aortic arch hypoplasia (100% vs. 87.5%; all p < 0.05), and identified aortopulmonary collaterals and a persistent left superior vena cava more frequently than TTE. The two modalities performed comparably for aortic arch sidedness and interrupted aortic arch, and pulmonary atresia. Conclusions: CTA provides additional, operatively confirmed anatomical information beyond TTE in the majority of children with conotruncal anomalies, with the greatest value for extracardiac vascular anatomy. Rather than replacing echocardiography, CTA should be regarded as a complementary modality that refines preoperative anatomical assessment.

Background: Extracorporeal membrane oxygenation (ECMO) is lifesaving in pediatric patients with respiratory and/or cardiovascular failure. Cardiac catheterization is an important diagnostic and therapeutic tool in patients with congenital heart disease supported by ECMO, allowing the assessment of residual lesions, hemodynamically significant anatomical abnormalities, and unexplained indications for ongoing ECMO support. The timing and clinical contribution of cardiac catheterization in these patients are still debated. Objective: This study aimed to evaluate the indications, safety, and impact of cardiac catheterization on clinical management in pediatric patients receiving postoperative ECMO support. Methods: This single-center, retrospective study examined 39 pediatric patients under the age of 18 who underwent postoperative cardiac catheterization with ECMO support between January 2022 and December 2025. Demographic data, procedure characteristics, and clinical outcomes were analyzed. Results: Of the 190 patients under postoperative ECMO support, 39 underwent catheterization. The median age of the patients was 2.5 months (range, 6 days–180 months) and median weight was 4.2 kg (range, 2.8–57 kg). The most frequent diagnoses were ventricular septal defect-pulmonary atresia (VSD-PA) in 20.5% (n = 8) and transposition of the great arteries (TGA) in 15.3% (n = 6). The indication for catheterization was to investigate the reason for ECMO placement in 26 patients (66.6%). Most patients underwent catheterization within the first 24 h after ECMO initiation. Patients who underwent catheterization represented a higher-risk subgroup, with a greater proportion of STAT 4-5 procedures (59% vs. 40%) compared with the overall ECMO cohort. Cardiac catheterization resulted in a change in clinical management in 25.6% of patients through catheter-based intervention or surgical revision. Survival in the catheterized subgroup was 12.8%, reflecting the high-risk nature of this population. Conclusions: Cardiac catheterization in pediatric patients on postoperative ECMO support can be performed with a low complication rate and can significantly alter clinical management. Cardiac catheterization should be considered an important diagnostic and therapeutic modality, particularly in the presence of suspected residual lesions or unexplained hemodynamic instability. Additionally, we recommend that cardiac catheterization be performed promptly within the first 24–48 h in this patient group on ECMO support.

Objectives: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease in infancy, frequently requiring early surgical repair. Detailed pre-operative imaging is essential for assessing cardiovascular and extracardiac anatomy to guide surgical planning. While conventional invasive catheter angiography (ICA) has traditionally been used for this purpose, computed tomography angiography (CTA) has emerged as a promising non-invasive alternative with lower risk, shorter procedure times, and reduced radiation exposure. Given the vulnerability of pediatric patients, optimizing radiation dose and understanding its determinants – such as body size – are critical. The objective of the study is to compare radiation exposure, contrast agent usage, and procedural duration between CTA and ICA in the pre-operative evaluation of TOF patients under 1 year of age and to evaluate the correlation between patient anthropometric measurements and radiation dose. Methods: This retrospective single-center study included 120 TOF patients who underwent complete surgical repair between 2021 and 2024. Seventy-four patients underwent CTA and 46 underwent ICA. Data on radiation dose, contrast volume, and procedure time were collected. Correlations between effective dose and patient age, weight, height, and BMI were analyzed. Results: CTA significantly reduced effective radiation dose (1.21±0.19 mSv) compared to ICA (5.28±1.71 mSv, p<0.01), required less contrast agent (8.02±2.38 cc vs. 38.8±13.01 cc), and had a shorter procedure time (3.1±0.58 min vs. 21.03±10.79 min; p<0.001). Radiation dose was positively correlated with weight (CTA: r=0.41, p=0.0006; ICA: r=0.52, p=0.0009), height (CTA: r=0.32, p=0.0012; ICA: r=0.24, p=0.0014), and BMI (CTA: r=0.35, p=0.0008; ICA: r=0.39, p=0.0053), while no significant correlation was observed with age. Conclusion: CTA is a safe, non-invasive, and time-efficient imaging modality for the pre-operative evaluation of TOF patients, offering significant reductions in radiation dose and contrast use compared to ICA. The observed correlation between radiation dose and body size underscores the need for individualized imaging protocols in pediatric practice.