Formation of thrombus in a native aortic sinus of Valsalva after palliation of 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 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.

Neoaortic thrombus after Norwood procedure: complication of extracorporeal life support?

Hypoplastic left heart syndrome is the most common diagnosis among infants requiring cardiac extracorporeal life support (ECLS) in the neonatal period, with more than half of patients experiencing an ECLS-related complication. We present a case of nearly obstructing neoaortic thrombus during ECLS occurring in the early postoperative period after modified Norwood palliation of hypoplastic left heart syndrome. Stasis within the neoaortic root due to the increased ventricular afterload associated with venoarterial ECLS may have potentiated this complication. Echocardiographic monitoring and early cardiac catheterization while on ECLS enabled prompt diagnosis and timely surgical correction.

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.