The blalock and taussig shunt revisited

Transcatheter-Based Interventions for Tetralogy of Fallot Across All Age Groups

Tetralogy of Fallot (TOF) is the most common form of cyanotic congenital heart disease. Palliative procedures, either surgical or transcatheter, aim to improve oxygen saturation, affording definitive procedures at a later stage. Transcatheter interventions have been used before and after surgical palliative or definitive repair in children and adults. This review aims to provide an overview of the different catheter-based interventions for TOF across all age groups, with an emphasis on palliative interventions, such as patent arterial duct stenting, right ventricular outflow tract stenting, or balloon pulmonary valvuloplasty in infants and children and transcatheter pulmonary valve replacement in adults with repaired TOF, including the available options for a large, dilated native right ventricular outflow tract.

Ductal stenting vs. surgical shunting in late presenting duct-dependent pulmonary circulation: a single-center experience

Introduction

PDA stenting is an option to mBTT shunt for younger patients; nevertheless, few reports of this palliative approach have been made for the late presenter population, especially for patients who are older than 30 days but under 5 years. This study aimed to evaluate the clinical result and intra-hospital costs of ductal stenting in late-presenting patients in comparison to surgical shunting.

Methods

A single-center, retrospective cohort study was conducted from August 2016 to August 2022. This study included patients with pulmonary duct dependent CHD who were hospitalized for palliative therapy. The extracted data were baseline characteristics, clinical findings, supportive examination findings, complications, outcomes, and length of stay of the patients. Monitoring was carried out during treatment up to 30 days after the procedure.

Results

A total of 143 patients were included in the analysis; 43 patients underwent PDA stent and 100 patients underwent mBTT shunt with median age of PDA stent group 110 (31-1,498) days and mBTT shunt group 174.5 (30-1,651) days. Primary outcome composite was not significant in both groups including 30 days mortality [6 (14%) vs. 14 (14%), p = 1.000], reintervention [1 (2.3%) vs. 7 (7%), p = 0.436], and 30 days rehospitalization [0 (0%) vs. 2 (2%), p = 0.319]. Secondary outcome analysis showed shorter ICU length of stay in the PDA stent group [2 (0-16) days vs. 4 (1-63) days, p = 0.002].

Conclusions

PDA stent has an outcome that is non inferior from the mBTT shunt procedure in the composite outcome including 30 days mortality, reintervention, and 30 days rehospitalization but significantly lower in ICU length of stay.

The Evolution of Paediatric Cardiology Service in Oman

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The outcomes of fetal aortic valvuloplasty in critical aortic stenosis: A systematic review and meta-analysis

BACKGROUND

Critical aortic stenosis that appears in mid-gestation tends to develop to growth retardation of left ventricle, known as hypoplastic left heart syndrome (HLHS). Despite better clinical management of HLHS, the morbidity and mortality rates of univentricular circulation patients remain high. In this paper, we sought to perform a systematic review and meta-analysis to know the outcomes of fetal aortic valvuloplasty in critical aortic stenosis patients.

METHODS

This systematic review and meta-analysis was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statement. A systematic search on fetal aortic valvuloplasty procedure for critical aortic stenosis was performed through PubMed, Scopus, EBSCOhost, ProQuest, and Google Scholar. The primary endpoint of each group was overall mortality. We used R software (version 4.1.3) to estimate the overall proportion of each outcome using random-effects model of proportional meta-analysis.

RESULTS

A total of 389 fetal subjects from 10 cohort studies were included in this systematic review and meta-analysis. Fetal aortic valvuloplasty (FAV) was successfully performed in 84% of patients. It revealed a successful conversion to biventricular circulation rate of 33% with a mortality rate of 20%. Bradycardia and pleural effusion requiring treatment were two most common fetal complications, whereas maternal complication reported was only placental abruption in one patient.

CONCLUSIONS

FAV has a high technical success rate with the ability to achieve biventricular circulation and a low rate of procedure-related mortality if carried out by experienced operators.

Patent Ductus Arteriosus Stent Versus Surgical Aortopulmonary Shunt for Initial Palliation of Cyanotic Congenital Heart Disease with Ductal-Dependent Pulmonary Blood Flow: A Systematic Review and Meta-Analysis

Background In patients with ductal-dependent pulmonary blood flow, initial palliation includes catheter-based patent ductus arteriosus (PDA) stent or surgical aortopulmonary shunt (APS). This meta-analysis aimed to compare outcomes between PDA stent and APS. Methods and Results A comprehensive literature search yielded six retrospective observational studies. Pooled adjusted hazard ratios (HR) were included to control for covariates and assess time to event analysis. Of 757 patients, 243 (32.1%) underwent PDA stent and 514 (67.9%) underwent APS. Pulmonary atresia with intact ventricular septum and expected biventricular repair were more common with PDA stent compared with APS (39.6% versus 21.2%, P<0.001 and 57.9% versus 46.6%, P=0.007, respectively). There was no statistically significant difference in mortality between PDA stent and APS (HR, 0.71; [95% CI, 0.26-1.93]; P=0.50). PDA stent was associated with lower risk of postprocedural complications (odds ratio [OR], 0.45; [95% CI, 0.25-0.81]; P=0.008), mechanical circulatory support (OR, 0.27; [95% CI, 0.09-0.79]; P=0.02), and shorter intensive care unit length of stay (-4.03 days; [95% CI, -5.99 to -2.07]; P<0.001), hospital length of stay (-5.54 days; [95% CI, -9.20 to -1.88]; P=0.003), and duration of mechanical ventilation (-3.41 days; [95% CI, -5.29 to -1.52]; P<0.001). There was no difference in pulmonary artery growth or hazard of unplanned reintereventions. Conclusions PDA stent has a similar hazard of mortality compared with APS. Benefits to PDA stent include shorter duration of mechanical ventilation, shorter hospital length of stay, and fewer complications. Differences in patient characteristics exist with more patients with pulmonary atresia with intact ventricular septum and expected biventricular repair undergoing PDA stent.

An Up-to-Date Narrative Review on Congenital Heart Disease Percutaneous Treatment in Children Using Contemporary Devices

Background: Congenital heart pathology has a significant burden regarding morbidity and mortality in the pediatric population. Several transcatheter interventions and devices have been designed as an alternative to surgical repair. Percutaneous interventions have been proven to yield good results in most cases but with less stress and trauma than that attributed to surgical treatment, especially in frail pediatric patients. We aimed to review the literature and to investigate the feasibility and efficacy of transcatheter interventions and implantable devices for congenital heart disease management in children. Methods: We performed a search in Scopus and MEDLINE databases using prespecified keywords to retrieve clinical studies published between 2000 and 2021. Results: This article provides an up-to-date review regarding the applicability of interventional techniques in simple inter-atrial or inter-ventricular defects, and in challenging congenital defects, such as hypoplastic left heart syndrome, tetralogy of Fallot, or coronary artery fistula. Furthermore, we reviewed recent indications for defibrillator and cardiac resynchronization therapy, and new and promising devices currently being tested. Conclusion: Transcatheter treatment represents a feasible and efficient alternative to surgical repair of congenital heart defects. Novel devices could extend the indications and possibilities of percutaneous interventions in pediatric patients with congenital heart diseases.

Complex adult congenital heart disease on cross-sectional imaging: an introductory overview

Congenital heart disease is the most common group of congenital pathology. Over the past few decades, advances in surgical treatment have resulted in a rising population of adult patients with repaired complex congenital heart disease. Although the quality of life has greatly improved, a significant proportion of morbidities encountered in clinical practice is now seen in adults rather than in children. These patients often have significant haemodynamic pathophysiology necessitating repeat intervention. CT and MRI are excellent imaging modalities, which help elucidate potential complications that may need urgent management. Although imaging should be performed in specialised centres, occasionally patients may present acutely to emergency departments in hospitals with little experience in managing potentially complex patients. The purpose of this article is to provide an introductory overview to the radiologist who may not be familiar with complex congenital heart disease in adult patients. This educational review has three main sections: (1) a brief overview of the post-operative anatomy and surgical management of the most common complex conditions followed by (2) a discussion on CT/MRI protocols and (3) a review of the various complications and their CT/MRI findings.

Tissue engineering: Relevance to neonatal congenital heart disease

Congenital heart disease (CHD) represents a large clinical burden, representing the most common cause of birth defect-related death in the newborn. The mainstay of treatment for CHD remains palliative surgery using prosthetic vascular grafts and valves. These devices have limited effectiveness in pediatric patients due to thrombosis, infection, limited endothelialization, and a lack of growth potential. Tissue engineering has shown promise in providing new solutions for pediatric CHD patients through the development of tissue engineered vascular grafts, heart patches, and heart valves. In this review, we examine the current surgical treatments for congenital heart disease and the research being conducted to create tissue engineered products for these patients. While much research remains to be done before tissue engineering becomes a mainstay of clinical treatment for CHD patients, developments have been progressing rapidly towards translation of tissue engineering devices to the clinic.

Novel technique of achieving hemodynamic stability during systemic to pulmonary artery shunt

Historically, the Blalock Taussig (BT) shunt has been an off-pump procedure. For the last two decades, the number of BT shunt operations has come down globally with the adoption of neonatal early corrective surgery. BT shunts are still performed for augmentation of pulmonary arterial (PA) growth or as a part of univentricular palliation. Many infants do not tolerate PA branch clamping while undergoing the graft to PA anastomosis, necessitating institution of cardiopulmonary bypass (CPB). Since the threshold to go on CPB for shunt placement is quite low at most institutions, our technical modification described can avoid deleterious effect of CPB. Our point of interest is to maintain lung perfusion by adopting few principles of off-pump coronary artery bypass surgery.

Ebstein Anomaly and Right Aortic Arch in Patient with Charge Syndrome

Ebstein anomaly is a rare congenital heart disease characterized by a varying degree of anatomical and functional abnormalities of tricuspid valve and right ventricle. It often coexists with other congenital cardiac malformations. Up to 79–89% of patients with Ebstein anomaly have interatrial communication in the form of patent oval foramen or atrial septal defect and more than one-third has other types of cardiac malformations. Association between Ebstein anomaly and right aortic arch is extremely rare and only few cases have been described in the literature so far. Much rarer than with other cardiac malformations, Ebstein anomaly is associated with non-cardiac malformations or genetic syndromes. Several cases of association between Ebstein anomaly and Charge syndrome have been reported, nevertheless, Ebstein anomaly accounts for less than 1% of cardiac defects seen in patients with Charge syndrome. In this case report, we present a unique case of a patient with Charge syndrome where both Ebstein anomaly and right aortic arch are present. The diagnosis of Ebstein anomaly and right aortic arch was established prenatally. In the first years of life, the patient did not exhibit any remarkable symptoms. However, over time, deterioration of right ventricle function and increased tricuspid regurgitation were observed, requiring consideration of surgical treatment at the age of five. In addition, delay in physical, motor, and mental development was observed and thus, at the age of five, the patient was consulted by a medical geneticist and a gene panel to test for structural heart defects was ordered. The test showed a mutation in chromodomain helicase DNA binding protein 7 (CHD7) gene, which, along with clinical features, allowed to establish a diagnosis of Charge syndrome. To the best of the authors’ knowledge, this is the first case report of a patient with Charge syndrome, Ebstein anomaly, and right aortic arch that has been described in the literature.

Outcomes of Infants Undergoing Modified Blalock-Taussig Shunt Procedures in Oman: A retrospective study

Objectives

A modified Blalock-Taussig (mBT) shunt procedure is a common palliative surgery used to treat infants and children with cyanotic congenital heart disease (CCHD). This study aimed to report the outcomes of infants and children undergoing mBT shunt procedures in Oman. In addition, risk factors associated with early mortality, inter-stage mortality and reintervention were assessed.

Methods

This retrospective cohort study was conducted from January 2016 to December 2018 at the National Heart Centre, Muscat, Oman. All paediatric patients with CCHD undergoing mBT shunt procedures as a primary palliative procedure during this period were included. Data were retrieved from electronic hospital records. Kaplan-Meier survival curves were used to describe overall survival.

Results

A total of 50 infants and children were included in this study. The in-hospital mortality and interstage mortality rates were 10% and 6.7%, respectively. Preoperative mechanical ventilation (odds ratio [OR] = 3.00, 95% confidence interval [CI]: 1.98–4.76; P = 0.007) and cardiopulmonary bypass (OR = 4.09, 95% CI: 2.44–6.85; P = 0.002) were significant risk factors for early mortality. In-hospital and interval surgical reintervention rates were 12% and 13.3%, respectively. Following the primary shunt procedure, the median time to second-stage surgery was 15.5 months (range: 5.0–34.0 months).

Conclusion

The findings of this study support those reported in international research regarding the risks associated with mBT shunt surgeries. In particular, preoperative mechanical ventilation and cardiopulmonary bypass were significant risk factors for early mortality.

Blalock-Taussig Shunt versus Ductal Stent in the Palliation of Duct Dependent Pulmonary Circulation; A Systematic Review and Metanalysis

In infants with ductal dependent pulmonary blood flow, Blalock-Taussig (BT) shunt and Patent Ductus Arteriosus (PDA) stent, are two palliative procedures aimed to restore circulation. A systematic review and metanalysis was performed on studies comparing PDA stents and BT shunts, in accordance with PRISMA guidelines. Meta-analysis revealed the following; (1) a reduced risk of mortality [RR = 0.585 [0.399-0.859], (P = 0.006)], (2) a reduced risk of complications [RR = 0.523 [0.318-0.860], (P = 0.011), and (3) a reduced risk of ECMO use [R = 0.267 [0.101-0.706] (P = 0.008)], all in the stent group. Additionally, stent group showed higher post procedure oxygen saturation [SMD = 1.307 [95% CI 1.065-1.550], (P < 0.001)], and Nakata index [SMD = 0.679 95% CI [0.513 to 0.845], (P < 0.001)]. PDA stenting presents a viable alternative to BT shunt procedure with better post procedure stability.

Case report of recurrent haemoptysis in an older patient with repaired tetralogy of Fallot

Background

Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart defect. Although most infants nowadays undergo surgical repair approximately at the age of 6 months with excellent outcomes, older patients typically underwent a staged approach with an initial systemic-to-pulmonary Blalock–Taussig–Thomas (BTT) shunt reducing hypoxaemia, followed by surgical TOF repair at an older age (with takedown of the BTT shunt). Late complications related to the BTT shunt are rare.

Case summary

We report a case of recurrent haemoptysis late after classic BTT shunt and subsequent surgical TOF repair. Axial imaging indicated a stellate nodule with isotope accumulation in the right upper lung lobe, whereas bronchoscopy showed a rope-like structure in the bronchus to the right upper lung lobe. The patient underwent a lobectomy of the superior right lobe, with identification of what appeared to be the old suture around the BTT shunt. Anatomopathology confirmed diffuse necrotizing inflammation with erosion into the bronchus which eventually caused haemoptysis.

Discussion

Management of older patients with congenital heart disease requires a thorough knowledge of the anatomy and surgical history of the patient. Although late complications related to a BTT shunt are rare, a residual shunt, endocarditis, pseudoaneurysm, or chronic inflammation with haemoptysis may occur.

Computed Tomography in the Evaluation of Fontan Circulation

The Fontan procedure is a well-established surgical technique to improve survival in patients with univentricular heart disease. The procedure reroutes the systemic venous flow to the lungs, bypassing the right ventricle. The originally proposed method involved direct anastomosis of the right atrium to the pulmonary artery. Since then, several modifications have been made in the original technique leading to the modern Fontan, or total cavopulmonary connection. The modern Fontan technique has shown improved surgical outcomes and increased life expectancy in patients with univentricular disease. Due to the increased survival of these patients, long-term complications are becoming more prevalent. Common complications of Fontan procedure include right atrial dilatation and thrombosis; conduit stenosis and thrombosis; right-to-left and left-to-right shunts; hepatic congestion and cirrhosis; and lymphovascular. Computed tomography (CT) can reliably depict the normal Fontan anatomy and various postoperative complications. A fundamental understanding of the techniques of CT, including imaging protocols and common interpretive pitfalls, allows targeted imaging and precise reporting of clinically significant findings. Radiologists should be familiar with the multiple stages of single-ventricle palliation, normal Fontan anatomy, pathophysiology, and imaging features of common Fontan-related complications.

Comparison of diameter and length of subclavian arteries to external jugular veins in variably sized dogs: A cadaveric study

OBJECTIVE

To evaluate the length and diameter of a left external jugular vein graft as a substitute for the left subclavian artery in the modified Blalock-Thomas-Taussig shunt (mBTTS) in differently sized dogs.

STUDY DESIGN

Cadaveric study.

ANIMALS

Dog cadavers of three weight categories (10/group): <9.5 kg, 9.5 to 27 kg, and > 27 kg.

METHODS

The length and infused external diameters of harvested vessels were measured with vernier calipers and recorded. A matched-pairs t test was used to test the difference in vessel lengths. The agreement in vessel diameters was assessed by using Lin's concordance correlation coefficient (CCC). Pearson's correlation coefficients (CC) were determined for vessel diameter to weight category and vessel length to weight category.

RESULTS

The external jugular vein measured longer than the subclavian artery in all dogs (52.0 ± 20.8 mm and 23.0 ± 8.9 mm, respectively), with a mean difference of 28 ± 14.3 mm (P < .001). The mean external infused subclavian and external jugular diameters measured 7.8 ± 2.2 mm and 8.0 ± 2.5 mm, respectively (P = .32). Lin's CCC was 0.87. Pearson's CC were 0.74 in both vessel diameters (P < .001); they were 0.36 and 0.43, respectively, for subclavian artery and external juglar vein length (P < .001).

CONCLUSION

Autologous external jugular vein grafts had an external diameter similar to subclavian artery and a significantly longer length in variably sized dogs.

CLINICAL SIGNIFICANCE

External jugular vein grafts may be an acceptable graft choice for mBTTS.

Persistent left superior vena cava: clinical importance and differential diagnoses

Persistent left superior vena cava (PLSVC) is the most common thoracic venous anomaly and may be a component of the complex cardiac pathologies. While it is often asymptomatic, it can lead to significant problems such as arrhythmias and cyanosis. Besides, it can cause serious complications during vascular interventional procedures or the surgical treatment of cardiac anomalies (CA). The clinical significance of PLSVC depends on the drainage site and the accompanying CA. In this article, we will describe the epidemiology, embryology, and anatomic variations of PLSVC. Possible accompanying CA and heterotaxy spectrum will be reviewed with the help of multidetector computed tomography (MDCT) images. Radiological pitfalls, differential diagnoses, and the clinical importance of PLSVC will be highlighted.

Current outcomes and treatment of tetralogy of Fallot

Tetralogy of Fallot (ToF) is the most common type of cyanotic congenital heart disease. Since the first surgical repair in 1954, treatment has continuously improved. The treatment strategies currently used in the treatment of ToF result in excellent long-term survival (30 year survival ranges from 68.5% to 90.5%). However, residual problems such as right ventricular outflow tract obstruction, pulmonary regurgitation, and (ventricular) arrhythmia are common and often require re-interventions. Right ventricular dysfunction can be seen following longstanding pulmonary regurgitation and/or stenosis. Performing pulmonary valve replacement or relief of pulmonary stenosis before irreversible right ventricular dysfunction occurs is important, but determining the optimal timing of pulmonary valve replacement is challenging for several reasons. The biological mechanisms underlying dysfunction of the right ventricle as seen in longstanding pulmonary regurgitation are poorly understood. Different methods of assessing the right ventricle are used to predict impending dysfunction. The atrioventricular, ventriculo-arterial and interventricular interactions of the right ventricle play an important role in right ventricle performance, but are not fully elucidated. In this review we present a brief overview of the history of ToF, describe the treatment strategies currently used, and outline the long-term survival, residual lesions, and re-interventions following repair. We discuss important remaining challenges and present the current state of the art regarding these challenges.

Postoperative cerebral oximetry monitoring helps in early detection of diminished flow in Blalock-Taussig shunt

Cerebral oximeter is a noninvasive device which provides continuous monitoring of the regional cerebral saturation using near-infrared spectroscopy (NIRS). After gaining popularity as an intraoperative monitoring tool, use of NIRS monitoring has also expanded to postoperative period of congenital heart diseases now. Shunt underflow is a known complication after Blalock–Taussig (BT) shunt, which is conventionally detected by a drop in oxygen saturation and metabolic acidosis. We report a case where cerebral regional saturation monitoring by NIRS helped in early detection of low pulmonary flow state during postoperative period of neonatal BT shunt. We observed that the drop in regional cerebral oxygen saturation preceded fall in peripheral oxygen saturation during shunt underflow.