Late thrombosis of the native aortic root after Norwood reconstruction for hypoplastic left heart syndrome

Native Aortic Root Thrombosis in Hypoplastic Left Heart Syndrome: An Unusual Presentation (Soon after Atrial Septal Stenting) of a Relatively Unusual Complication-Experience and Literature Review with an Outlook to Diagnosis and Management

We started with the experience of thrombus formation in the native aorta of a 3-year-old male child with hypoplastic left heart syndrome (HLHS) and severely hypoplastic but patent mitral and aortic valves after Glenn palliation, which occurred soon after left heart decompression by percutaneous stenting of the atrial septum. The diagnosis was incidental, with the child completely asymptomatic, and progressively subsided in a few days with heparin infusion and chronic warfarin therapy. We reviewed the incidence, diagnosis, and management of native aortic thrombosis in HLHS after different stages of Fontan palliation through a systematic literature search. In all 32 cases, native aortic thrombosis in HLHS was found. The HLHS anatomic subtypes included mitral stenosis/aortic stenosis (fourteen cases or 45.2%), mitral stenosis/aortic atresia (eleven cases or 35.5%), and mitral atresia/aortic atresia (four cases or 12.9%). The age at diagnosis ranged from 13 days to 18 years. Clinical presentation varied from incidental findings, chest pain and/or electrocardiographic abnormalities, cardiac arrest, and transient ischemic attack. Diagnosis was feasible in most of the cases with only transthoracic echocardiography. Mostly (59.4%), patients were treated with anticoagulation, while others underwent surgical (18.7%), direct (12.5%), or systemic (9.3%) thrombolysis. Transplant-free survival was 56.2%, and fatal events occurred in 25%. Major events occurred in 26.3% of those treated with anticoagulation, in 33.3% of patients treated with surgical/systemic thrombolysis, and in 100% of patients treated with direct thrombolysis. In summary, native aortic thrombosis in HLHS may occur at different ages, with a wide spectrum of presentation from incidental finding to a sudden major event. Diagnosis is feasible with transthoracic echocardiography, and management with anticoagulation is effective despite the incidence of major events remaining high.

Spontaneous thrombus formation in native aortic root in patients with hypoplastic left heart syndrome: clinical presentation, treatment, and outcomes

We report a neonate who presented with spontaneous thrombus formation in the native aortic root after Norwood palliation for hypoplastic left heart syndrome. Thrombus formation led to myocardial ischaemia due to decreased coronary blood flow with electrocardiographic signs of ischaemia and elevated cardiac enzymes. Aggressive thrombolysis and anticoagulation therapy were major contributors to successful outcome.

Native Aortic Root Thrombosis in Single-Ventricle Patients with Native-to-Neoaortic Anastomoses

In single-ventricle patients with native-to-neoaortic anastomoses, the native aortic root serves as a conduit to the coronary arteries. Thrombosis of the native aortic root has been described only in small, limited reports. We described our center's experience with this rare adverse event. All single-ventricle patients who underwent native-to-neoaortic anastomosis from 2002 to 2017 were compiled from institutional databases. Chart review identified cases of native aortic root thrombosis. Of 467 patients, there were 9 (2%) cases of native aortic root thrombosis; all had hypoplastic left heart syndrome. Timing of thrombosis varied and occurred following each stage of single-ventricle palliation. For treatment, 8 patients received systemic anticoagulation and one patient did not receive any treatment. One patient also underwent percutaneous thrombectomy. Three patients (33.3%) died during the follow-up period. Among survivors, 4/6 had right ventricular systolic function that was mildly depressed or worse at a median follow-up of 8.3 years (interquartile range 1.3-10.8). Native aortic root thrombosis is a rare complication occurring at various stages of single-ventricle palliation. In this series, 6 of 9 patients (66.6%) survived; however, ventricular function was often compromised. No risk factors were identified to focus preventative therapies.

The Characteristics and Outcomes of Native Aortic Valve Thrombosis: A Systematic Review

BACKGROUND

There is a lack of knowledge in the current medical literature about native aortic valve thrombosis.

OBJECTIVES

The aim of this systematic review was to summarize the characteristics, presentations, underlying etiologies, and outcomes of native aortic valve thrombosis and to present a meta-analysis of the best available data.

METHODS

The authors performed a literature search, identified published cases of patients with native aortic valve thrombosis, and pooled the data in this meta-analysis. The statistical analysis included calculations of the prevalence of the various presentations, underlying etiologies, aortic cusp involvement, as well as choices of diagnostic testing. They calculated the sensitivities of the various diagnostic testing as well as in-hospital mortality event rates and the univariate ORs of the risk factors for poor outcomes.

RESULTS

The search strategy and screening process yielded 74 cases of native aortic valve thrombosis, which are included in this meta-analysis. The data revealed that the most common presentation was myocardial infarction in 36%, and the most common underlying etiology was hypercoagulable state in 30%. In-hospital clinical deterioration after presentation including recurrent embolism occurred in ∼38%, and in-hospital mortality rate was ∼20%.

CONCLUSIONS

Native aortic valve thrombosis is clinically relevant, especially in patients presenting with embolic events. Awareness about native aortic valve or root thrombosis as well as its underlying etiologies, diagnostic work-up, and management is essential, because this condition can be associated with poor outcomes.

Native Aortic Root Thrombosis After Norwood Palliation for Hypoplastic Left Heart Syndrome

BACKGROUND

Norwood palliation for hypoplastic left heart syndrome typically results in retrograde perfusion of the native aortic root. This may predispose to native aortic root thrombosis (NART).

METHODS

Patients who underwent stage 1 Norwood palliation at Children's Hospital Colorado between 2003 and 2019 were retrospectively reviewed for NART. Additional patients were identified by a systematic literature review. Patient factors, operative details, presentation, diagnostic methods, treatments, and outcomes were analyzed.

RESULTS

Three patients with NART were identified among 241 patients who had undergone stage 1 Norwood palliation at Children's Hospital Colorado (mean follow-up, 48 months). A fourth patient identified at Children's Hospital Colorado had undergone stage 1 palliation elsewhere. The systematic literature review identified 12 additional patients. Among the 16 patients, patients presented with new arrhythmias (38% [n = 6]), evidence of ischemia (31% [n = 5]), incidentally (19% [n = 3]), inability to wean from postoperative support (6% [n = 1]), and cardiac arrest (6% [n = 1). The diagnosis was made by transthoracic echocardiography (TTE) in 50% (n = 8), transesophageal echocardiography in 19% (n = 3), cardiac catheterization in 25% (n = 4), and cardiac computed tomography in 6% (n = 1). Importantly, 44% (n = 7) of patients were missed by TTE and subsequently diagnosed by other methods. Treatment strategies were surgical thrombectomy in 38% (n = 6), anticoagulation alone in 38% (n = 6), direct catheter thrombolysis in 19% (n = 3), and systemic thrombolysis in 6% (n = 1). The rate of mortality or transplant listing was 44% (n = 7).

CONCLUSIONS

NART is an underappreciated complication of Norwood palliation with high mortality. There should be a high index of suspicion for NART in patients after Norwood palliation with an unexplained complicated clinical course. Importantly, NART is frequently missed by TTE.

Hypoplastic left heart syndrome: From bedside to bench and back

Hypoplastic Left Heart Syndrome (HLHS) is a complex Congenital Heart Disease (CHD) that was almost universally fatal until the advent of the Norwood operation in 1981. Children with HLHS who largely succumbed to the disease within the first year of life, are now surviving to adulthood. However, this survival is associated with multiple comorbidities and HLHS infants have a higher mortality rate as compared to other non-HLHS single ventricle patients. In this review we (a) discuss current clinical challenges associated in the care of HLHS patients, (b) explore the use of systems biology in understanding the molecular framework of this disease, (c) evaluate induced pluripotent stem cells as a translational model to understand molecular mechanisms and manipulate them to improve outcomes, and (d) investigate cell therapy, gene therapy, and tissue engineering as a potential tool to regenerate hypoplastic cardiac structures and improve outcomes.

Aortic root thrombosis with coronary embolization following neo-aortic reconstruction in a child with hypoplastic left heart syndrome

In the recent era, the diagnosis, treatment options, postoperative management and outcomes of infants born with hypoplastic left heart syndrome (HLHS) have undergone dramatic changes. As is the case with many other novel treatment modalities used for congenital heart diseases, data concerning the long-term outcomes and complications of the various strategies become gradually more available as the numbers of survivors grow. In general, complications of the three-stage surgical palliation used for HLHS tend to occur most commonly following the first-stage surgery. Post-stage 2 complications are substantially less common, and centre on the procedure itself and the unique physiology of the cavopulmonary connection. In the following case report, we describe a relatively rare adverse outcome that occurred following a stage 2 surgery in the form of native aortic root thrombosis extending to the coronary arteries. The selected methods of treatment used in the catheterization laboratory and later in the operating theatre, as well as its outcomes are described.

Left mammary artery bypass grafting rescued a patient with hypoplastic left heart syndrome with ascending aorta obstruction after norwood stage I procedure

A three-month-old boy with hypoplastic left heart syndrome (mitral atresia, aortic atresia) and moderate tricuspid regurgitation developed ascending aorta obstruction two months after a Norwood stage I procedure. An emergent left mammary artery bypass grafting to the ascending aorta and extracorporeal membrane oxygenator support resulted in successful salvage. The patient subsequently underwent a bidirectional Glenn procedure and tricuspid valve repair at the age of five months. Follow-up at an outpatient clinic reveals no electrocardiographic evidence of ischemia, and echocardiography shows recovery of ventricular function.

Predictors of Long-Term Adverse Outcomes in Patients With Congenital Coronary Artery Fistulae

Background— Significant morbidities, including angina, symptomatic heart failure, and myocardial infarction, have been reported after coronary artery fistula (CAF) closure; however, predictors that may be associated with adverse outcomes have not been established. The goal of this investigation is to describe the long-term outcomes witnessed in patients with either treated or untreated CAF at our institution and to investigate whether certain features predicted adverse outcomes.

Methods and Results— The records and angiograms of patients with CAF who underwent a diagnostic cardiac catheterization at Children’s Hospital Boston from 1959 through 2008 were reviewed. Of 76 patients identified, 20% were associated with additional congenital heart disease. Forty-four underwent transcatheter closure, 20 underwent surgical repair, and no intervention was performed in the remaining 12 subjects. Three patients who had initially undergone surgical closure had a second intervention, 1 underwent repeat surgery, and 2 underwent transcatheter closure. One patient who had undergone transcatheter closure underwent a second transcatheter closure for residual fistula. Major complications, including myocardial infarction, angina with coronary thrombosis, and symptomatic cardiomyopathy, occurred in 11 (15%) patients. The sole angiographic feature that was predictive of adverse outcome was drainage of the CAF into the coronary sinus ( P <0.001). Clinical predictors associated with adverse outcomes included older age at diagnosis ( P <0.001), tobacco use ( P =0.006), diabetes ( P =0.05), systemic hypertension ( P <0.001), and hyperlipidemia ( P <0.001).

Conclusions— Long-term complications of CAF closure may include coronary thrombosis, myocardial infarction, and cardiomyopathy. CAF that drain into the coronary sinus are at particularly high-risk of long-term morbidities after closure, and strategies including long-term anticoagulation should be considered.

Antithrombotic therapy in neonates and children: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

This chapter about antithrombotic therapy in neonates and children is part of the Antithrombotic and Thrombolytic Therapy: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs, and Grade 2 suggests that individual patient values may lead to different choices (for a full understanding of the grading, see Guyatt et al in this supplement, pages 123S-131S). In this chapter, many recommendations are based on extrapolation of adult data, and the reader is referred to the appropriate chapters relating to guidelines for adult populations. Within this chapter, the majority of recommendations are separate for neonates and children, reflecting the significant differences in epidemiology of thrombosis and safety and efficacy of therapy in these two populations. Among the key recommendations in this chapter are the following: In children with first episode of venous thromboembolism (VTE), we recommend anticoagulant therapy with either unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH) [Grade 1B]. Dosing of IV UFH should prolong the activated partial thromboplastin time (aPTT) to a range that corresponds to an anti-factor Xa assay (anti-FXa) level of 0.35 to 0.7 U/mL, whereas LMWH should achieve an anti-FXa level of 0.5 to 1.0 U/mL 4 h after an injection for twice-daily dosing. In neonates with first VTE, we suggest either anticoagulation or supportive care with radiologic monitoring and subsequent anticoagulation if extension of the thrombosis occurs during supportive care (Grade 2C). We recommend against the use of routine systemic thromboprophylaxis for children with central venous lines (Grade 1B). For children with cerebral sinovenous thrombosis (CSVT) without significant intracranial hemorrhage (ICH), we recommend anticoagulation initially with UFH, or LMWH and subsequently with LMWH or vitamin K antagonists (VKAs) for a minimum of 3 months (Grade 1B). For children with non-sickle-cell disease-related acute arterial ischemic stroke (AIS), we recommend UFH or LMWH or aspirin (1 to 5 mg/kg/d) as initial therapy until dissection and embolic causes have been excluded (Grade 1B). For neonates with a first AIS, in the absence of a documented ongoing cardioembolic source, we recommend against anticoagulation or aspirin therapy (Grade 1B).

Formation of thrombus in a native aortic sinus of Valsalva after palliation of hypoplastic left heart syndrome

An eight-month-old girl with hypoplastic left heart syndrome, who underwent a modified Norwood operation at the age of two days, and a Hemifontan operation at five months of age, had severely impaired ventricular function and new electrocardiographic changes. Coronary angiography demonstrated a small adherent thrombus in the non-coronary sinus of Valsalva of the native aortic root, which may be the cause of unexplained ventricular dysfunction.

Left ventricular thrombosis following a Norwood procedure

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Neoaortic Root Modification for Late Thrombosis After Norwood Palliation

A 5-year-old child with hypoplastic left heart syndrome presented with myocardial infarction 2 years after Fontan completion. Evaluation identified a thrombus in his native aortic root. Retrospective review of a prior catheterization revealed stasis in the native aortic root. Surgical thrombectomy was performed after failed medical management. The neoaortic root was revised at the time of thrombectomy in an attempt to reduce stasis in the native aortic root. This case suggests the need to identify anatomic findings that may predispose to coronary artery thrombus formation after Norwood palliation.

Thrombus formation in the native aortic root in patients with hypoplastic left heart syndrome

Thrombus formation in the native aortic root is a rare but potentially life-threatening complication in patients with hypoplastic left heart syndrome. The native aortic root in these patients serves as a conduit for the retrograde filling of the coronary arteries. Thrombus in this location could result in myocardial ischemia. We present three cases of native aortic root thrombosis at our institution with clinical presentations ranging from asymptomatic to sudden cardiac arrest. Our experience with these patients argues for careful and consistent evaluation of the native aortic root regardless of clinical symptoms.