Modification of the Warden Procedure for Surgical Repair of Partial Anomalous Pulmonary Venous Connection.

Warden procedure is a popular technique for repairing partial anomalous pulmonary venous connection. We describe a modification of this technique for surgical repair of this condition by raising both a superior vena cava (SVC) flap and right atrial appendage flap to create a tension-free SVC-RA continuity (neo-SVC). The anomalous pulmonary veins are routed via the remanent of proximal SVC and baffled to the left atrium across a surgically created or enlarged atrial septal defect using autologous pericardium.

Zoom and its Discontents: Group Decision Making in Pediatric Cardiology in the Time of COVID (and Beyond) : Aurthors.

The emergence of Covid-19 has led to change within hospital-based healthcare. An example, has been to reconfigure clinical decision making meetings from traditional in-person (Face-to-face, FtF) to online video-conferencing (VC) format inorder to decrease contagion risk. Despite its widespread uptake, there is minimal empirical data evaluating this format. This narrative review considers the implications on medical decision-making when clinicians communicate remotely via Microsoft Teams. The discussion is informed by the psychological literature and by commentary obtained from a survey of paediatric cardiac clinicians who participated in clinical meetings when video-conferencing was first introduced. Whist video-conferencing can optimize clinician presence, this is potentially offset by compromises in current imaging quality, the group discussion, information sharing and decision quality. Implementing a shift from face-to-face to VC within the group decision-making process requires an appreciation of the changed environment, appropriate adaptations and the implemention of new technology solutions. Meanwhile, healthcare should carefully consider the potential implications of clinical decision making using online video conferencing, be prepared to adapt and evaluate prior to a shift away from face-to-face formats.

Outcomes of adults with repaired tetralogy of Fallot from the national Scottish Cohort.

BACKGROUND: The adult population of repaired tetralogy of Fallot is increasing and at risk of pre-mature death and arrhythmia. This study evaluates risk factors for adverse outcome and the effect of pulmonary valve replacement within a national cohort. METHODS: A retrospective cohort study of 341 adult repaired tetralogy of Fallot (16-72 years) managed through a single national service was undertaken incorporating over 1200 patient-years of follow-up. Demographics, cardiopulmonary exercise testing, cardiac magnetic resonance, reintervention (including pulmonary valve replacement), and clinical events were analysed. The influence of these parameters on a primary outcome (death or arrhythmia) was evaluated. RESULTS: Compared with an age-/gender-matched population, patients experienced a reduced survival, particularly males over 55 years (standardised mortality ratio : 6.12, 95% CI: 1.64-15.66, p = 0.004). Cox proportional hazards modelling identified increased indexed right ventricle (RV) end-diastolic volume (hazard ratio (HR): 2.86, 95% CI: 1.4-5.85, p = 0.004) and female gender (HR (male): 0.37, 95% CI: 0.14-0.98, p = 0.045) to be predictors significantly associated with the primary outcome. Pulmonary valve replacement undertaken at indexed RV end-diastolic volume = 145 ml/m2 reduced RV volumes and QRS duration but did not improve cardiopulmonary exercise testing nor NYHA class. Pulmonary valve replacement during cohort period was associated with increased risk of primary outcome (HR: 2.82, 95% CI: 1.36-5.86, p = 0.005). CONCLUSIONS: Although the majority of adult tetralogy of Fallot were asymptomatic in NYHA 1, cardiopulmonary exercise testing revealed important deficits. Tetralogy of Fallot survival was reduced compared to the general population. Female gender and increasing RV end-diastolic volume predicted adverse events. Pulmonary valve replacement reduced RV volumes and QRS duration but did not improve primary outcome.

Blood flow simulations in the pulmonary bifurcation in relation to adult patients with repaired tetralogy of Fallot.

Understanding the haemodynamic environment of the pulmonary bifurcation is important in adults with repaired conotruncal congenital heart disease. In these patients, dysfunction of the pulmonary valve and narrowing of the branch pulmonary arteries are common and can have serious clinical consequences. The aim of this study was to numerically investigate the underlying blood flow characteristics in the pulmonary trunk under a range of simplified conditions. For that, an in-depth analysis was conducted in idealised two-dimensional geometries that facilitate parametric investigation of healthy and abnormal conditions. Subtle variations in morphology influenced the haemodynamic environment and wall shear stress distribution. The pressure in the left pulmonary artery was generally higher than that in the right and main arteries, but was markedly reduced in the presence of a local stenosis. Different downstream pressure conditions altered the branch flow ratio, from 50:50% to more realistic 60:40% ratios in the right and left pulmonary artery, respectively. Despite some simplifications, this study highlights some previously undocumented aspects of the flow in bifurcating geometries, by clarifying the role of the stagnation point location on wall shear stress and differential branch pressures. In addition, measurements of the mean pressure ratios in the pulmonary bifurcation are discussed in the context of a new haemodynamic index which could potentially contribute to the assessment of left pulmonary artery stenosis in tetralogy of Fallot patients. Further studies are required to confirm the results in patient-specific models with personalised physiological flow conditions.

A Prospective Randomized Blinded Trial of Remote Ischemic Preconditioning in Children Undergoing Cardiac Surgery.

Remote ischemic preconditioning (RIPC) has been proposed as an intervention to protect myocardium and attenuate end-organ dysfunction associated with cardiopulmonary bypass. We investigated the effect of RIPC in children undergoing cardiopulmonary bypass involving clinical outcome, cardiac and end-organ function, inflammatory response, and myocardial gene expression. A prospective, investigator-blinded, randomized, controlled trial was performed. Patients were randomized into RIPC or Control; RIPC consisted of three 5-minute cycles of limb ischemia-reperfusion taking place 1 and 12 hours preoperatively. Clinical outcomes included cardiac function, ICU surveillance, and renal function. In addition, inflammatory markers and myocardial gene expression were evaluated. RIPC patients required shorter ICU stay (days), RIPC: 1.8 (0.94-3.88) vs Control: 4.9 (1.63-7.20), P = 0.029. Echocardiography parameters demonstrated reduced biventricular function following surgery showing no difference between groups. A nonsignificant trend for reduced troponin was observed following RIPC: AUC analysis, RIPC: 393.05 (98.85-1038.73) vs Control: 596.10 (225.38-954.24) P = 0.75. B-type natriuretic peptide and renal function parameters were similar between groups. Postoperative TNF-α was significantly reduced after RIPC, RIPC: 15.42 (7.81-114.86) vs Control: 108.98 (42.28-301.19) P = 0.02. Remaining inflammatory markers demonstrated no significant difference between groups. HSP-60 showed lower myocardial expression following RIPC, RIPC: 3.95 (2.69-6.28) vs Control: 6.83 (4.74-8.81), P = 0.05. Expression of other analyzed genes was not influenced by RIPC. RIPC was associated with shorter ICU stay and reduced TNF-α but did not influence other clinical outcomes, not confer protection against cardiac injury or renal dysfunction. The association between RIPC and ICU stay may be influenced by unaccounted latent variables, including cardiac morphology.

Larger Centers Produce Better Outcomes in Pediatric Cardiac Surgery: Regionalization is a Superior Model - The Con Prospective.

Regionalization, in the context of congenital heart surgery, describes a process where smaller units close and patients are redistributed to larger centers. Proponents argue this will produce superior patient outcome based primarily on a volume-outcome effect. The potential disadvantage is that, as distance to center increases, access to service is compromised. In this article the volume-outcome effect is appraised and the effect of risk-stratification and threshold volumes explored. Access to service, and how certain congenital lesions and demographics might be disadvantaged, is reviewed. Alternative models are considered including collaborative programing and a standardizing approach of agreed parameters in personnel and infrastructure. Finally the influence of newer developments and quality metrics, including outcome databases, digital technologies and team-cognitive performance, needs to be factored in as the future unfolds. Ultimately, the design of a national congenital cardiac program should aspire to deliver care that is optimal, equitable and economic for the whole population. The solution lies in the distillation of competing variables cognizant of regional demographics and geography.

Two-Strip Technique to Repair Common Atrioventricular Valve Regurgitation in Single-Ventricle Palliation.

A common atrioventricular valve (CAVV) presents a challenge in single-ventricle palliation (SVP) because of its propensity to leak, with CAVV regurgitation being an important risk factor for repeated operation and mortality. We propose a new technique of CAVV repair in the context of SVP. The method uses the techniques of complete repair of antrioventricular septal defect while maintaining free communication at atrial and ventricular levels necessary for single-ventricle physiology.

Computational modelling of the hybrid procedure in hypoplastic left heart syndrome: a comparison of zero-dimensional and three-dimensional approach.

Previous studies have employed generic 3D-multiscale models to predict haemodynamic effects of the hybrid procedure in hypoplastic left heart syndrome. Patient-specific models, derived from image data, may allow a more clinically relevant model. However, such models require long computation times and employ internal pulmonary artery band [dint] dimension, which limits clinical application. Simpler, zero-dimensional models utilize external PAB diameters [dext] and provide rapid analysis, which may better guide intervention. This study compared 0-D and 3-D modelling from a single patient dataset and investigated the relationship dint versus dext and hemodynamic outputs of the two models. Optimum oxygen delivery defined at dint=2mm corresponded to dext=3.1 mm and 3.4 mm when models were matched for cardiac output or systemic pressure, respectively. 0-D and 3-D models when matched for PAB dimension produced close equivalence of hemodynamics and ventricular energetics. From this study we conclude that 0-D model can provide a valid alternative to 3D-multiscale in the hybrid-HLHS circulation.

Circumflex retroesophageal aorta mimicking aortic interruption: a rare cause of aortic obstruction in a neonate.

Critical obstruction of the aorta presenting in the neonate typically occurs with aortic interruption or coarctation, following ductus arteriosus closure. Circumflex retroesophageal aortic arch is a rare aortic arch anomaly in which a right aortic arch continues as a retroesophageal component and descends on the left of the spine. Obstruction within the arch can occur, usually identified incidentally in older children. We report a neonate with circumflex aorta with ventricular septal defect in which there was hypoplasia of the retroesophageal segment. The patient presented with cardiovascular collapse following duct closure mimicking aortic interruption. The case is presented, together with the surgical repair.

Apelin receptor (APJ) expression during cardiopulmonary bypass in children undergoing surgical repair.

BACKGROUND AND AIMS: In human adults, and animals, the Apelin-APJ ligand-receptor system is emerging as having a role in the pathogenesis of cardiovascular function and heart failure. The aim was to investigate expression, and regulation by oxygen, of the Apelin APJ receptor (APJ) in myocardium obtained from children undergoing corrective surgery with cardiopulmonary bypass for repair of congenital heart defects. METHODS: Western blotting and Real-time PCR were used to determine if APJ was expressed in the infant myocardium, if expression was influenced by the duration of myocardial ischemia and if any relationship existed between APJ expression and early post-operative outcome. The next aim was to determine if there was a difference in mRNA expression of APJ in myocardium from cyanotic patients compared with acyanotic patients and if re-perfusing myocardium in vitro with either hypoxic, normoxic or hyperoxic oxygen affected APJ mRNA expression. RESULTS: APJ was expressed in all myocardial samples and myocardium exposed to longer durations of ischemia and cardioplegia expressed higher levels of APJ (p<0.05). There was a significant correlation between APJ expression in myocardium resected after 10 min with both oxygen extraction ratio (p=0.021, rho= -0.523) and mixed venous oxygen saturation (p=0.028, rho 0.52). This association did not exist for myocardium collected before 10 min. There was no difference in APJ expression between cyanotic and acyanotic patients. No difference was found in APJ expression whether re-perfused with low, normal or high oxygen. CONCLUSIONS: Changes in APJ expression were observed during cardiopulmonary bypass in children and the reasons for this require further investigation.

Repair of early left main stem stenosis after switch operation using an autologous innominate vein patch.

We describe the repair of the postoperative left main stem stenosis of a 24-day old male patient who initially underwent arterial switch operation for dextro-transposition of the great arteries. The repair was facilitated by using an autologous left innominate vein patch, while there was a shortage of suitable repair material in this neonate. Postoperative echocardiogram prior to discharge confirmed a satisfactory flow through the left main stem and improved left ventricle function.

Computational modelling to optimize the hybrid configuration for hypoplastic left heart syndrome.

OBJECTIVES: Hybrid palliation for hypoplastic left heart syndrome (HLHS) is associated with mortality and late ventricular dysfunction. Increased ventricular workload and coronary perfusion limitation may be the important factors. Using mathematical modelling, this study investigated the effects of differing hybrid configurations on the demands on this single ventricle circulation. METHODS: A multicompartmental Windkessel model of hybrid HLH-aortic atresia circulation was adopted, with a time-varying elastance representing ventricular functionality. The effects of diameter increases in bilateral pulmonary artery bandings (PABs) (+0.5, 2.5-4 mm) and ductal stent (+1, 4-10 mm) on cardiovascular haemodynamics, systemic oxygenation and ventricular energetics were assessed. RESULTS: Simulations showed that an increase in PAB diameter of 2.5-4 mm resulted in an increased Q (0.61-2.66), and diastolic stent backflow (-0.2 to -0.78 l/min) with reduced systemic perfusion (0.82-0.77 l/min) and diastolic pressures (48.3-41.2 mmHg). Arterial and venous saturations increased, SaO2 (%) was 62-88 and SvO(2) 41-65. To maintain mean systemic pressures, substantial increases in cardiac output (1.3-2.8 l/min) and ventricular stroke work (576-1360 mmHg ml) were required. A decrease in the ductal stent diameter over the range 10-7 mm had a negligible haemodynamic effect: reduced systemic systolic pressure (77-72 mmHg) and increase in ventricular stroke work (781-790 mmHg ml). When the ductal diameter was restricted to <7 mm, it resulted in a significant reduced systemic flow and increased stroke work. Optimal hybrid configuration was defined at PAB 3 mm and ductal stent ≥7 mm. CONCLUSIONS: In this model, increasing the PAB diameter, or a stent diameter <7 mm, substantially increased single ventricle workload and reduced systemic perfusion and diastolic pressure. This may compromise myocardial oxygen demand-supply, particularly in the setting of retrograde-dependent coronary perfusion.

Acute B-type natriuretic peptide response and early postoperative right ventricular physiology following tetralogy of Fallot's repair.

B-type natriuretic peptide (BNP) response early after a tetralogy of Fallot's repair remains unclear. BNP was measured pre- and post-operatively (immediately, day 1) in 18 children undergoing corrective repair with concurrent echocardiography (pre-, post-op day 1) to assess right ventricular (RV) systolic dysfunction, restrictive physiology, wall motion and pulmonary regurgitation (PR). In the first 24 h postoperatively, BNP rose acutely in all patients (mean 34.9 vs 144.4 vs 716.9 pg/ml at pre-op, days 0 and 1; P < 0.001). Immediate postoperative BNP correlated with preoperative haematocrit (rho = 0.52, P = 0.03) and inversely with preoperative oxygen saturation (rho = -0.63, P = 0.007). All patients showed reduced RV systolic function and abnormal wall motion with at least moderate PR in six patients (33.3%) and restrictive physiology in four (24%). Subsequent BNP expression (post-op day 1) correlated with a low RV fractional area change (rho = -0.51, P = 0.04), high oxygen extraction ratio (rho = 0.56, P = 0.02) and high central venous pressure (rho = 0.79, P < 0.001). The LV function and wall motion remained preserved in all patients. The mechanism of BNP expression is likely to be multi-factorial in the presence of a complex postoperative RV physiology in tetralogy of Fallot. An acute BNP response in the early postoperative period reflects an important physiological role and may be used as an adjunct biomarker to assess the RV function.

Cystatin C: influence of perfusion and myocardial injury on early (<24 h) renal function after pediatric cardiac surgery.

BACKGROUND: Cardiopulmonary bypass (CPB)-associated renal dysfunction following cardiac surgery is well recognized. In patients with renal disease, cystatin C has emerged as a new biomarker which in contrast to creatinine (Cr) is sensitive to minor changes in glomerular filtration rate (GFR). AIM: We utilized cystatin C to investigate the association of CPB perfusion parameters with acute renal injury after pediatric cardiac surgery. METHODS: Twenty children, aged 4-58 months (AVSD, n = 7; VSD, n = 9; and ASD, n = 4), were prospectively studied. Glomerular filtration rate was quantified postoperatively by creatinine clearance (first and second 12-h periods; CrCl(0-12) and CrCl(12-24) ). Serum cystatin C and Cr were measured preoperatively and on days 0-3. Recorded CPB parameters included bypass duration (BP), perfusion pressure (PP), lowest pump flow (Q(min) ), lowest hematocrit, and corresponding lowest oxygen delivery (DO(2 min) ). Myocardial injury was determined by troponin-I. RESULTS: Postoperatively, GFR remained unchanged (CrCl(0-12) 63.6 ± 37.0 vs CrCl(12-24) 65.1 ± 27.5; P = 0.51) and only correlated with cystatin C (CrCl(0-12) vs cystatin C(Day 0) [r = 0.58, P = 0.018] and Cr(Day 0) [r = 0.09, P = 0.735]). Cr and cystatin C increased postoperatively to peak on days 2 and 3, respectively (Cr(PreOp) 31 ± 6.9 vs Cr(Day 2) 36.9 ± 12.2, P = 0.03; cystatin C(Day 0) 0.83 ± 0.27 vs cystatin C(Day 3) 1.45 ± 0.53, P = 0.02). Increased cystatin C was significantly associated with BP (P = 0.001), mean PP (P = 0.029), Q(min) (P = 0.005), troponin-I (P < 0.001), and DO(2 min) <300 ml·min(-1) ·m(-2) (P = 0.007). Receiver-operator cutoff >1.044 mg·l(-1) for cystatin C exhibited 100% sensitivity and 67% specificity for detecting renal dysfunction, defined as GFR <55 ml·min(-1) ·1.73 m(-2). CONCLUSIONS: Cystatin C is a sensitive marker of early renal dysfunction following pediatric heart surgery. Variations in bypass parameters, myocardial injury, and ultimately critical oxygen delivery are significantly associated with the degree of renal impairment.

Myocardial expression of heat shock protein 70i protects early postoperative right ventricular function in cyanotic tetralogy of Fallot.

BACKGROUND: Right ventricular dysfunction occurs after tetralogy of Fallot repair and may relate to greater myocardial vulnerability to ischemia-reperfusion injury in cyanotic patients. The inducible form of heat shock protein 70 (HSP-70i), a molecular chaperone, is upregulated in response to cellular stress and limits myocardial injury against ischemia-reperfusion. We evaluated the myocardial expression of HSP-70i and its relation to right ventricular function and clinical outcome in patients with tetralogy of Fallot undergoing corrective surgery. METHODS: Twenty patients with tetralogy of Fallot were studied: 10 cyanotic (group Cy) and 10 noncyanotic (group noCy). Western blot was used to quantify HSP-70i from resected right ventricular outflow tract myocardium at baseline and subsequent ischemic time. Biventricular function was quantified by tissue Doppler echocardiography and compared with that of 15 age-matched healthy children. Postoperative systemic perfusion was assessed by mixed venous oxygen saturation, oxygen extraction ratio, and lactate. RESULTS: Group Cy had thicker septum (median 0.85 vs 0.66 cm; P = .01) and longer crossclamp time (median 100.0 vs 67.5 minutes; P = .004). There were no difference in HSP-70i between groups at baseline (4.12 vs 3.44 relative optical density; P = .45) or subsequent ischemic time. Preoperative biventricular systolic function was reduced in patients with tetralogy compared with controls with further postoperative right ventricular impairment. Group Cy had higher troponin-I levels (median 16.5 vs 11.1 ng/mL; P = .04) and inotrope scores (14.0 vs 6.5; P = .05) but no differences in ventricular function, mixed venous oxygen saturation, oxygen extraction ratio, and lactate between groups. In group Cy, baseline HSP-70i correlated with better postoperative right ventricular function (rho = 0.80; P = .009), mixed venous oxygen saturation (rho = 0.68; P = .04), and oxygen extraction ratio (rho = -0.71; P = .03). These relationships were absent in group noCy. CONCLUSIONS: The association of HSP-70i expression with improved right ventricular function and systemic perfusion suggests an important cardioprotective effect of HSP-70i in cyanotic tetralogy of Fallot.