Clinical significance of thrombosis in an intracardiac blind pouch after a Fontan operation

Pulmonary Artery Stump Thrombus in a Patient With Remote History of Rastelli Procedure

•Atrial tachyarrhythmia may develop in Rastelli patients after decades. •Thrombus can form in the PA stump after the Rastelli procedure. •TEE remains crucial to rule out intracardiac thrombus before cardioversion.

Coagulation and Anticoagulation in Fontan Patients

Patients with a Fontan circulation for single-ventricle physiology are at increased risk of developing thromboembolic events. Thromboembolic events can lead to failure of the Fontan circulation, chronic sequelae in case of stroke, and early mortality. Controversies exist regarding the substrates, risk factors, and optimal detection methods for thromboembolic events. Despite the major clinical implications, there is currently no consensus regarding the optimal antithrombotic therapy to prevent or treat thromboembolic events after the Fontan procedure. In this review we aimed to untangle the available literature regarding antithrombotic prophylaxis and treatment for pediatric and adult Fontan patients. A decision-tree algorithm for thromboprophylaxis in Fontan patients is proposed. Additionally, the current state of knowledge is reviewed with respect to the epidemiology, pathophysiology, and detection of thromboembolic events in Fontan patients, and important evidence gaps are highlighted.

Silent in situ thrombus within a hypoplastic left ventricle in a teenager with Fontan palliation

Thrombosis, especially in the Fontan pathway, is one of the major concerns in patients who underwent Fontan surgery, with reported prevalence of 5-33%. We report a case of thrombus in a rudimentary left ventricle in teenager with no arrhythmia or neurological complications. We also report the special concerns of silent thrombus and role of cardiac MRI in diagnosing an intracardiac thrombus.

Clinical features and treatment results in preterm infants with intracardiac thrombus

INTRODUCTION

Thrombus incidence is higher among neonates, especially in preterm infants, due to the associated additional risk factors.

MATERIALS AND METHODS

The medical recordings of premature infants who had been diagnosed as having intracardiac thrombus between January 2016 and January 2019 were evaluated retrospectively. We use recombinant tissue plasminogen activator when the thrombus is relatively large compared to left atrium, pedunculated, mobile, or snake shaped.

RESULTS

A total of 13 premature patients were diagnosed as having intracardiac thrombus during the 3-year period. All were diagnosed during echocardiographic studies. Low molecular weight heparin was administered in four patients. In three, recombinant tissue plasminogen activator was started with low dose (0.01 mg/kg/h) and increased gradually to 0.06 mg/kg/h. In three, recombinant tissue plasminogen activators were started with standard dose (0.5 mg/kg/h). In one recombinant tissue, plasminogen activator was started with low dose (0.01 mg/kg/h) and increased to standard dose. Two patients died before treatment, three patients died during treatment, follow-up was not available for two patients, and thrombus completely resolved in six patients.

DISCUSSION

In preterm babies with risk factors, intracardiac thrombus should be kept in mind during all echocardiographic studies. In our patients, low and standard dose regimens were used, and the treatment results were similar.

Pulmonary embolism and in situ pulmonary artery thrombosis in paediatrics

Data on paediatric pulmonary embolism (PE) are scarce. We sought to systematically review the current literature on childhood PE and conducted a search on paediatric PE via PubMed (1946–2013) and Embase (1980–2013). There was significant heterogeneity in reported data. Two patterns were noted: classic thromboembolic PE (TE-PE) and in situ pulmonary artery thrombosis (ISPAT). Mean age of presentation for TE-PE was 14.86 years, and 51% of cases were males. The commonest method for diagnosis of TE-PE was contrast CT with angiography (74% of patients). The diagnosis of TE-PE was often delayed. Although 85% of children with TE-PE had an elevated D-dimer at presentation, it was non-discriminatory for the diagnosis. In paediatric TE-PE, the prevalence of central venous catheters was 23%, immobilisation 38%, systemic infection 31% and obesity 13%, elevated Factor VIII or von Willebrand factor levels 27%, Protein C deficiency 17%, Factor V Leiden 14% and Protein S deficiency 7%. In patients with TE-PE, pharmacologic thrombolysis was used in 29%; unfractionated heparin was the most common initial anticoagulant treatment in 64% and low-molecular-weight heparins the most common follow-up treatment in 83%. Duration of anticoagulant therapy was variable and death was reported in 26% of TE-PE patients. In contrast to TE-PE, patients with ISPAT were not investigated systematically for presence of thrombophilia, had more surgical interventions as the initial management and were often treated with anti-platelet medications. This review summarises important data and identifies gaps in the knowledge of paediatric PE, which may help to design future studies.

Cerebral Thromboembolism From Ligated Blalock-Taussig Shunt in an Adult Patient

A 26-year-old woman underwent tetralogy of Fallot repair and classic Blalock-Taussig shunt (BTS) ligation. On postoperative day 4 she developed severe left-sided hemiplegia due to cerebral infarction. Thrombi in the BTS stump, right brachiocephalic artery, and its branches were removed surgically and the BTS stump was resected. The patient gradually recovered from hemiplegia and is leading a normal life with moderate left hemiparesis and is in good functional status 4 years after the event. An aggressive approach in treating this complication was crucial to prevent further thrombosis and neurologic deficit progression in this patient. We recommend reducing the size of the BTS stump during definitive repair.

Recombinant Tissue Plasminogen Activator in the Treatment of Neonates with Intracardiac and Great Vessels Thrombosis

Life-threatening intracardiac and great vessels thrombi are rare in neonates. Recombinant tissue plasminogen activator (rTPA) is used in adults to stimulate fibrinolysis and facilitate thrombus resolution. Its use in neonates, along with heparin, remains controversial because of potential risk of serious bleeding. We aim to present our experience with the use of thrombolytic agents in seven neonates and young infants. In a retrospective study, over a period of 6 years, the medical records of neonates and young infants, who were diagnosed with intracardiac and great vessels thrombi, were reviewed. The following factors were collected: demographic data, primary diagnosis, thrombus site, risk factors, method of diagnosis, thrombolytic and/or anticoagulation agent, route, dose and duration of treatment, complications, and outcome. Six neonates and one 45-day-old infant were analyzed. Age ranged from 5 to 45 days (median age 12 days), and median weight was 2.9 kg (range 0.9-3.8 kg). The thrombi were diagnosed by echocardiography in five and by angiography in two cases. All patients had life-threatening thrombi; four were treated with rTPA (0.5 mg kg(-1) h(-1)) and heparin infusions with complete dissolution of the thrombi, within a median time of 60 h (6-72 h), and without complications. The remaining three patients (two who were premature, at 28 and 34 weeks of gestation, and the third who had a deranged coagulation profile) were treated with unfractionated heparin due to fear of bleeding. The thrombi dissolved in the premature babies (within 2 weeks and 3 months, respectively) but embolized and resulted in the death of the third infant after 2 weeks of treatment. The current case series confirmed the effectiveness and safety of intravenous rTPA infusion, at the dosages used, in neonates and young infants with life-threatening thrombi.

Perventricular closure of pulmonary stump in a 16-kg child

Blind pouch formation of the pulmonary artery (PA) in patients having undergone a Fontan operation can present a serious risk for thromboembolic events. Either primary or secondary closure of this stump is necessary to reduce this risk. Unfortunately, secondary closure is oftentimes difficult due to the size and anatomy of the presenting patient. We describe the insertion of a muscular ventricular septal defect (VSD) device via a perventricular approach for successful closure of a pulmonary stump in a 3-year old, 16-kg child. To our knowledge, this is the first report of a perventricular approach for successful closure of a PA stump.

Decision-Making for Surgery in the Management of Patients with Univentricular Heart

A series of technical refinements over the past 30 years, in combination with advances in perioperative management, have resulted in dramatic improvements in the survival of patients with univentricular heart. While the goal of single-ventricle palliation remains unchanged - normalization of the pressure and volume loads on the systemic ventricle, the strategies to achieve that goal have become more diverse. Optimal palliation relies on a thorough understanding of the changing physiology over the first years of life and the risks and consequences of each palliative strategy. This review describes how to optimize surgical decision-making in univentricular patients based on a current understanding of anatomy, physiology, and surgical palliation.

Prevalence and predictors of haemostatic complications in 412 Fontan patients: their relation to anticoagulation and haemodynamics

OBJECTIVES

Our aim in the present study was to determine the prevalence of haemostatic events in our Fontan patients, to identify predictive factors and to determine their association with haemodynamics and anticoagulant therapy.

METHODS

We retrospectively evaluated 424 Fontan patients and examined correlations between postoperative haemodynamics and anticoagulant regimens with haemostatic events.

RESULTS

After exclusion of 12 patients with a mechanical valve at the time of Fontan operation, our 412 patients were sub-divided into 21 groups based on the therapeutic duration of warfarin and antiplatelet agent therapy. During the early 5- to 10-year postoperative period, patients receiving warfarin showed higher central venous pressure and lower arterial oxygen saturation (Sat) (P < 0.05-0.001). During a mean follow-up of 11.2 years, 29 (7.0%) haemostatic events occurred. With regard to haemorrhagic events, haemoptysis was most common (n = 13, 45%), followed by cerebral bleeds in 3 (10%). Of thrombo-embolic events, thrombosis in the Fontan pathway was the most common (n = 7, 24%), followed by cerebral infarction in 3. Early haemorrhagic events were associated with late Fontan operation and use of preoperative renin-angiotensin system blockers, while late events were related to heterotaxy syndrome, male gender and low Sat (P < 0.05-0.01). A low Sat was the only predictor of early postoperative thrombo-embolic events (P = 0.0192). Among the three subgroup analyses of fixed anticoagulant regimens, the most frequent haemorrhagic events were associated with long-term use of warfarin (P = 0.0033). None of the anticoagulant regimens that included warfarin and/or antiplatelet agents were independently associated with haemostatic events throughout the follow-up.

CONCLUSIONS

Anticoagulant regimens in Fontan patients varied widely with a significant trend for warfarin use in patients with impaired haemodynamics. Low arterial oxygenation may predict haemostatic events. The relatively high prevalence of haemorrhagic complications indicates the need for individualized anticoagulant administration throughout the follow-up.

Fontan conversion templates: patient-specific hemodynamic performance of the lateral tunnel versus the intraatrial conduit with fenestration

Intraatrial-conduit Fontan is considered a modification of both extracardiac and lateral-tunnel Fontan. In this study, the patient-specific hemodynamic performance of intraatrial-conduit and lateral-tunnel Fontan with fenestration, considered as conversion templates, was investigated based on the authors' patient cohort. Pulsatile computational fluid dynamics simulations were performed using patient-specific models of intraatrial-conduit and lateral-tunnel Fontan patients. Real-time "simultaneous" inferior and superior vena cava, pulmonary artery, and fenestration flow waveforms were acquired from ultrasound. Multiple hemodynamic performance indices were investigated, with particular focus on evaluation of the pulsatile flow performance. Power loss inside the lateral-tunnel Fontan appeared to be significantly higher than with the intraatrial-conduit Fontan for patient-specific cardiac output and normalized connection size. Inclusion of the 4-mm fenestration at a 0.24 L/min mean flow resulted in a lower cavopulmonary pressure gradient and less time-averaged power loss for both Fontan connections. Flow structures within the intraatrial conduit were notability more uniform than within the lateral tunnel. Hepatic flow majorly favored the left lung in both surgical connections: conversion from lateral-tunnel to intraatrial-conduit Fontan resulted in better hemodynamics with less power loss, a lower pressure gradient, and fewer stagnant flow zones along the conduit. This patient-specific computational case study demonstrated superior hemodynamics of intraatrial-conduit Fontan over those of lateral-tunnel Fontan with or without fenestration and improved performance after conversion of the lateral tunnel to the intraatrial conduit. The geometry-specific effect of the nonuniform hepatic flow distribution may motivate new rationales for the surgical design.