Aortic root thrombosis with coronary embolization following neo-aortic reconstruction in a child with 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.

Native Aortic Root Thrombus in 3-Year-Old Fontan Patient with Hypoplastic Left Heart Syndrome: Presentation and Echocardiographic Findings of This Life-Threatening Complication

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Native aortic root thrombus is a life-threatening complication in patients with HLHS.

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Echo evaluation of the native aortic root is an important consideration.

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Echo monitoring is a useful tool for assessment of thrombus response to therapy.

Myocardial infarction due to thrombosis of native aorta late after Fontan procedure for hypoplastic left heart syndrome

Patients with single ventricle physiology who have undergone the Fontan procedure are at risk for long-term complications such as thrombus formation. Thrombus formation in the native aortic root (NAR) can be life-threatening if retrograde filling of the coronary arteries (CAs) is impaired. We present three cases of NAR thrombus with embolization to the CA, resulting in myocardial infarction. Thromboembolic events are well-documented complications of Fontan physiology, and optimal prevention and treatment strategies are poorly defined.

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.

Norwood Procedure With Left Ventricle Exclusion in Complex Single Ventricle Patients: A Novel Technique

Background:

Hypoplastic left heart disease and its variants complicated by severe semilunar and atrioventricular valve insufficiency are associated with a high mortality risk in utero and postnatally. Through the description of three cases, this report outlines the evolution of a successful strategy of morphological left ventricle isolation (ie, “left-sided Starnes”) in caring for this rare cohort of patients with hypoplastic left heart syndrome (HLHS).

Methods:

This study includes three patients: two patients prenatally diagnosed and one transferred from an outside hospital. All patients presented with complex univentricular heart disease with a nonfunctional left ventricle and severe left-sided atrioventricular and/or semilunar valve insufficiency.

Results:

Two patients were delivered with an operating room on standby due to the possibility of emergent surgery being necessary; however, all patients were able to be medically stabilized after birth. Patient 1 underwent successful left ventricle exclusion with a fenestrated polytetrafluoroethylene (PTFE) patch, despite severe mitral valve regurgitation. Patient 2 reinforced the efficacy of PTFE patch occlusion in addition to having aortic valve closure with a small washing jet. Patient 3’s clinical course was successfully predicted based on the previous patients and outlined for the family prenatally. All patients are currently growing well at home, awaiting Fontan with marked improvement in cardiac function.

Conclusion:

This rare cohort of patients with HLHS having severe left-sided atrioventricular and/or semilunar valve insufficiency appear to survive to birth and can be medically stabilized prior to semiurgent intervention. The Norwood procedure with left ventricle exclusion appears to be a successful strategy for these unique patients.