Transseptal coronary artery-a pictorial review

A transseptal coronary artery course, also known as a transconal course, is an anomalous course of the left main coronary artery (LMCA) or the left anterior descending artery (LAD) through the conal septal myocardium. The conal septal myocardium is the posterior wall of the right ventricular outflow tract (RVOT), acting as a dividing myocardial wall between the subaortic and subpulmonary outflow tracts. The initial segment of a transseptal coronary artery has an extraconal course between the aorta and the RVOT cranial to the true intramyocardial segment. The transseptal coronary artery then emerges out of the conal septal myocardium at the epicardial surface on the lateral aspect of the RVOT. Many consider the transseptal coronary artery to be a benign entity. However, there are few case reports of severe cardiac symptoms such as myocardial ischemia, arrhythmia, and even sudden cardiac deaths due to potential coronary artery compression in the systolic phase.​ In this article, we seek to describe the imaging findings of transseptal coronary artery course on coronary computed tomography angiography (CTA), discuss their clinical analysis, and briefly discuss the management of these lesions.

Lessons from the Pandemic: Role of Percutaneous ECMO and Balloon Atrial Septostomy in Multi-System Inflammatory Syndrome in Children

Multi-system inflammatory syndrome in children (MIS-C) in the setting of COVID-19 can be associated with severe cardiopulmonary dysfunction. This clinical deterioration may sometimes necessitate veno-arterial extracorporeal membrane oxygenation (VA-ECMO) support. We describe an algorithmic approach including the role of balloon atrial septostomy in this cohort. This is the first reported series of percutaneous VA-ECMO in pediatric patients with MIS-C for better outcomes. The lessons from this approach can be replicated in other pediatric clinical conditions and adds to the armament of multiple pediatric specialties.

Strategies and techniques for percutaneous Veno-Arterial ECMO cannulation and decannulation in children

OBJECTIVES

To describe the techniques used for percutaneous veno-arterial extracorporeal membrane oxygenation (VA-ECMO) cannulation and decannulation in children with the pediatric interventional cardiologist (PIC) as the primary operator, and present outcomes of this initial clinical experience.

BACKGROUND

Percutaneous VA-ECMO during cardiopulmonary resuscitation (CPR) has been successfully performed in adults, but currently, not much data exists on children.

METHODS

This is a single-center study including VA-ECMO cannulations performed by the PIC between 2019 and 2021. Efficacy was defined as the successful initiation of VA-ECMO without surgical cutdown. Safety was defined as the absence of additional procedures related to cannulation.

RESULTS

Twenty-three percutaneous VA-ECMO cannulations were performed by PIC on 20 children with 100% success. Fourteen (61%) were performed during ongoing CPR, and nine for cardiogenic shock. The Median age was 15 (0.15-18) years, and the median weight was 65 (3.3-180) kg. All arterial cannulations were via the femoral artery except in one, 8-week-old infant who was cannulated in the carotid artery. A distal perfusion cannula was placed in the ipsilateral limb in 17 (78%). The median time from initiating cannulation to ECMO flow was 35 (13-112) minutes. Two patients required arterial graft placement at the time of decannulation and one needed below-knee amputation. ECMO support was maintained for a median of 4 (0.3-38) days. Thirty-day survival was 74%.

CONCLUSION

Percutaneous VA-ECMO cannulations can be effectively performed, even during CPR with the Pediatric Interventional Cardiologist being the primary operator. This is an initial clinical experience. Future outcome studies compared with standard surgical cannulations are necessary to advocate routine percutaneous VA-ECMO in children.

Incidence of Acute Neurological Events in Neonates and Infants Undergoing Cardiac Surgery Using a High-Hematocrit/ High-Flow Bypass Strategy

Background: The incidence of new acute neurological injury occurring in neonates and infants during cardiac surgery utilizing cardiopulmonary bypass is reportedly 3% to 5%. In 2013, we adopted a high flow rate, and high hematocrit bypass strategy, and sought to assess the incidence of early neurological injuries associated with this strategy. Methods: Neonates and infants undergoing cardiopulmonary bypass between January 2013 and December 2019 (n  =  714) comprise the study. Adverse neurological events (ANEs) were defined as any abnormality of pupils, delayed awakening, seizures, focal neurological deficits, concerns prompting neurological consultation, or any abnormality on neurological imaging in the postoperative period. Our bypass strategy included a high flow rate (150-200 mL/kg/min), without reduction of flow rates during cooling and maintaining a target hematocrit on bypass > 32% with a terminal hematocrit of > 42%. Results: Median weight at the time of the procedure was 4.6 kg (IQR 3.6-6.1 kg) with the smallest patient weighing 1.36 kg. There were 46 premature patients (6.4%). There were 149 patients (20.9%) patients who underwent deep hypothermic circulatory arrest with a median time of 26 min (IQR 21-41 min). Hospital mortality was 3.5% (24/714, 95% CI: 2.28-5.13). The incidence of neurological events as defined above was 0.84% (6/714, 95% CI: 0.31-1.82). Neurological imaging identified ischemic injury in 4 patients and intraventricular hemorrhage in 2. Conclusions: High flow/high hematocrit bypass strategy was associated with a low incidence of ANE in this vulnerable population.

Novel use of cangrelor in pediatrics: A pilot cohort study demonstrating use in ventricular assist devices

Thromboembolic events and bleeding are major sources of morbidity among pediatric patients supported on a ventricular assist device (VAD). Pharmacokinetics and pharmacodynamics of enteral antiplatelet agents are affected and variable due to erratic enteral absorption in end-stage heart failure and VAD circulation. Additionally, 20%-40% of the population are poor metabolizers of clopidogrel, a prodrug, making cangrelor an alternative when antiplatelet therapy is crucial. Cangrelor has been used effectively and safely for short durations in adults during percutaneous coronary interventions, but the use of cangrelor is still under investigation in pediatrics. This case series utilized cangrelor, a novel short-acting, reversible, intravenous P2Y₁₂ platelet inhibitor in managing pediatric patients supported with a VAD. We performed a retrospective, single-center review of patients admitted to a tertiary medical center with end-stage heart failure requiring mechanical circulatory support and concomitant cangrelor administration between January 2019 and March 2020. Platelet function testing, cangrelor dose, bleeding complications, thromboembolic events, and frequency of circuit interventions during the use of cangrelor were recorded. Optimal platelet reactivity, defined as P2Y₁₂ < 180 platelet reaction units (PRU), was measured with serial point-of-care testing (VerifyNow). Seven patients, median age of 4.9 years, met the above criteria. Three patients had a diagnosis of complex congenital heart disease. Four patients had dilated or restrictive cardiomyopathy. All patients were on continuous flow VADs. The median VAD duration was 84.5 days (IQR 61.5-103). The median duration on cangrelor was 43 days (IQR 8-70). The median cangrelor dose to reach the therapeutic threshold was 0.75 μg/kg/min with the mean P2Y₁₂ , while on cangrelor of 164.75 PRU. Bleeding complications included mild gastrointestinal bleeding and hematuria. There was one patient with pump thrombosis requiring intervention. There were no cerebrovascular events while on cangrelor. We report the first successful long-term use of cangrelor in pediatric patients. The reversibility and short half-life of cangrelor make it a feasible antiplatelet agent in selected patients. This data supports the use of cangrelor in children as a viable antiplatelet option; with minimal bleeding complications and no cerebrovascular events demonstrated in this cohort.

Experience of a single institution with femoral vein homograft as right ventricle to pulmonary artery conduit in stage 1 Norwood operation

OBJECTIVE

Femoral vein homograft can be used be used as valved right ventricle to pulmonary artery conduit in the Norwood operation. We describe the results of this approach, including pulmonary artery growth and ventricular function.

METHODS

A retrospective chart review of 24 consecutive neonates with hypoplastic left heart syndrome or complex single ventricle undergoing this approach between June 2012 and December 2017 was performed. Conduit valve competency and ventricular function were estimated using transthoracic echocardiogram, and pulmonary artery growth was measured using Nakata's index. Changes in ventricular function pre-Glenn and at latest follow-up were assessed by ordinal logistic regression with a general linear model to account for the correlation within the same patient over time.

RESULTS

Median age at surgery was 4 days, and mean weight was 3 kg. There was no interstage mortality. A total of 21 patients have undergone Glenn operation, and 9 patients have completed the Fontan operation. None of the conduits developed thrombosis. Sixty-three percent of conduits remained competent in the first month, and 33% remained competent after 3 months of operation. Catheter interventions on conduits were necessary in 14 patients. Median Nakata index at pre-Glenn catheterization was 228 mm²/m² (interquartile range, 107-341 mm²/m²). Right ventricular function was preserved in 83% of patients at a median follow-up of 34 (interquartile range, 10-46) months.

CONCLUSIONS

Femoral vein homograft as a right ventricle to pulmonary artery conduit in the Norwood operation is safe and associated with good pulmonary artery growth and preserved ventricular function as assessed by subjective echocardiography. Catheter intervention of the conduit may be necessary.

Ross-Konno Operation in an Infant With a Quadricuspid Pulmonary Valve and Anomalous Aortic Origin of the Right Coronary Artery

Anomalous aortic origin of the right coronary artery from the left aortic sinus is a rare congenital anomaly that is generally repaired during adolescence when the condition is associated with symptoms. It is rarely diagnosed in infancy. Similarly, a quadricuspid pulmonary valve is also a rare finding, and there are scant data to evaluate whether this malformation of the pulmonary valve is suitable to be used for a Ross operation. This report describes a case in which both these anomalies coexisted in an infant who underwent a successful Ross-Konno operation.

Effect of patent ductus arteriosus on pulmonary vascular disease

The hemodynamic effects of a patent ductus arteriosus (PDA) are well known including systemic hypoperfusion and volume overload on the left ventricle. This article aims to provide a review of the long-standing effect of a hemodynamically significant PDA on the pulmonary vasculature and the role of cardiac catheterization in preterm infants with a PDA and pulmonary hypertension.

Successful Heart Transplantation in Two Infants With Dextrocardia-Heterotaxy Syndrome

Infants with dextrocardia-heterotaxy syndrome pose significant surgical challenges to a successful orthotopic heart transplant. Herein we report on 2 infants with dextrocardia-heterotaxy syndrome who underwent complex heart transplantation. A combination of preoperative 3-dimensional chest computed tomography to predict optimal donor size and unique surgical technique resulted in successful outcomes.

Improved Outcomes in Management of Hypoplastic Left Heart Syndrome Associated With Congenital Diaphragmatic Hernia: an Algorithmic Approach

Hypoplastic left heart syndrome (HLHS) is the second most common congenital heart disease associated with congenital diaphragmatic hernia (CDH). The reported survival rate of neonates with CDH and HLHS is only 1%-5%. We review our experience with CDH and HLHS and compare our outcomes with published literature. Retrospective review of all neonates with CDH and HLHS at our institution over a 10-year period was performed. The morphology of cardiac and diaphragm defects, clinical course, treatment strategies, and outcomes were reviewed, and an algorithmic approach was proposed. Five patients with CDH and HLHS were treated between 2006 and 2016. All had mitral stenosis with aortic stenosis. Four patients had a left-sided Bochdalek diaphragmatic hernia and 1 patient had a large bilateral Morgagni hernia. Two (2/4) of the Bochdalek hernias were associated with significant pulmonary hypoplasia and required patch closure of the CDH; both were palliated with percutaneous ductal stents and both died. Three patients underwent primary Norwood operation followed by repair of less severe CDH defect. All 3 patients are currently well and have survived bidirectional Glenn anastomosis; one patient is well after Fontan operation. Successful palliation of neonates with HLHS and associated CDH is possible in the current era. Outcome is determined primarily by the severity of the CDH and the degree of associated pulmonary hypoplasia. An algorithmic team approach is helpful in management of this difficult group of patients.

Diaphragmatic fenestration for refractory chylothorax after congenital cardiac surgery in infants

OBJECTIVE

Medically refractory chylous pleural effusion after congenital heart surgery is associated with significant morbidity and mortality, especially in infants. We reviewed our experience with diaphragmatic fenestration procedure in this group of patients.

METHODS

A retrospective chart review of all patients who had diaphragmatic fenestrations for chylous effusion at our institution over a 2-year period was performed.

RESULTS

A total of 9 diaphragmatic fenestration procedures were performed in 8 patients who had failed medical management of chylous pleural effusions. All procedures except 1 were performed on the right side. The median age at time of procedure was 4.6 months (range, 3 weeks to 14 months). The average time between primary congenital cardiac surgery and fenestration was 26 days (range, 4-53 days). Three patients had single ventricle repair. Average time of chest tube removal after procedure was 4 days. Average time to extubation was 3 days. All patients but 1 were able to advance to full feedings without reaccumulation of chylous effusion within 12 days. No complications developed in the patients. Recurrent effusion over a median follow-up period of 19 months did not develop in the patients.

CONCLUSIONS

Diaphragmatic fenestration is an effective and safe strategy for management of persistent chylous effusions after congenital cardiac surgery.

Right ventricular function after repair of tetralogy of Fallot: a comparison between bovine pericardium and porcine small intestinal extracellular matrix

BACKGROUND

The porcine small intestinal extracellular matrix reportedly has the potential to differentiate into viable myocardial cells. When used in tetralogy of Fallot repair, it may improve right ventricular function. We evaluated right ventricular function after repair of tetralogy of Fallot with extracellular matrix versus bovine pericardium.

METHOD

Subjects with non-transannular repair of tetralogy of Fallot with at least 1 year of follow-up were selected. The extracellular matrix and bovine pericardium groups were compared. We used three-dimensional right ventricular ejection fraction, right ventricle global longitudinal strain, and tricuspid annular plane systolic excursion to assess right ventricular function.

RESULTS

The extracellular matrix group had 11 patients, whereas the bovine pericardium group had 10 patients. No differences between the groups were found regarding sex ratio, age at surgery, and cardiopulmonary bypass time. The follow-up period was 28±12.6 months in the extracellular matrix group and 50.05±17.6 months in the bovine pericardium group (p=0.001). The mean three-dimensional right ventricular ejection fraction (55.7±5.0% versus 55.3±5.2%, p=0.73), right ventricular global longitudinal strain (-18.5±3.0% versus -18.0±2.2%, p=0.44), and tricuspid annular plane systolic excursions (1.59±0.16 versus 1.59±0.2, p=0.93) were similar in the extracellular matrix group and in the bovine pericardium group, respectively. Right ventricular global longitudinal strain in healthy children is reported at -29±3% in literature.

CONCLUSION

In a small cohort of the patients undergoing non-transannular repair of tetralogy of Fallot, there was no significant difference in right ventricular function between groups having extracellular matrix versus bovine pericardium patches followed-up for more than 1 year. Lower right ventricular longitudinal strain noted in both the groups compared to healthy children.

B-type natriuretic peptide trends after pediatric heart transplantation

BNP is increasingly utilized in the management of pediatric HT recipients. Performing a retrospective single-center chart review, we sought to describe BNP changes during the first year after HT and identify factors that affect its trend. After exclusion for rejection, 316 BNP levels from 50 patients were evaluated. BNP underwent an exponential decline 120 days after HT followed by a plateau. Log10 BNP decline strongly correlated with time (r = -0.70, p < 0.0001). Initial BNP was less in pretransplant VAD (p = 0.0016) and lower post-HT inotrope use (p = 0.0043). Infant recipients, IT >4 h, and those bridged medically were associated with higher plateau BNP. Multivariable logistic regression demonstrated IT >4 h independently predicted plateau BNP in the upper quartile (OR 7.1, p = 0.02). No significant change in BNP coincided with rejection (N = 6 patients) without severe hemodynamic compromise. BNP correlated modestly with right atrial pressure (r = 0.4652, p < 0.0001) and pulmonary capillary wedge pressure (r = 0.2660, p < 0.001), but poorly with echocardiogram (r = -0.18, p = 0.003). Trending BNP could help provide insight into how the graft recovers after HT and IT >4 h independently predicted higher plateau BNP and may reflect subtle changes in graft performance.

Liver cirrhosis in Fontan patients does not affect 1-year post-heart transplant mortality or markers of liver function

BACKGROUND

Liver cirrhosis is recognized with long-term follow-up of patients after the Fontan procedure. The effect of liver cirrhosis on the use of heart transplant (HT) and on post-HT outcomes is unknown.

METHODS

We reviewed Fontan patients evaluated for HT from 2004 to 2012 with hepatic computed tomography (CT) imaging, classified as normal, non-cirrhotic changes, or cirrhosis. The primary outcome was 1-year all-cause mortality, and the secondary outcome was differences in serial post-HT liver evaluation.

RESULTS

CT imaging in 32 Fontan patients evaluated for HT revealed 20 (63%) with evidence of liver disease, including 13 (41%) with cirrhosis. Twenty underwent HT, including 5 non-cirrhotic and 7 cirrhosis patients. Characteristics at listing between normal or non-cirrhotic (n = 13) and cirrhosis (n = 7) groups were similar, except cirrhosis patients were older (median 17.6 vs 9.6 years, p = 0.002) and further from Fontan (median 180 vs 50 months, p < 0.05). Serial liver evaluation was similar, including aspartate aminotransferase, alanine aminotransferase, bilirubin, albumin, and tacrolimus dose at 1, 3, 6, 9, and 12 months. Overall patient survival was 80% at 1 year, with no difference between cirrhosis and non-cirrhosis patients (86% vs 77%, p = 0.681). Liver biopsies were performed in 7 patients before HT, and all specimens showed architectural changes with bridging fibrosis.

CONCLUSIONS

Most patients evaluated for HT had abnormal liver findings by CT, with cirrhosis in 41%. One-year mortality and serial liver evaluation were similar between groups after HT. Liver cirrhosis identified by CT imaging may not be an absolute contraindication to HT alone in this population.