Diagnosis and management of catheter-related infected intracardiac thrombosis in premature infants

Intracardiac thrombi in pediatrics: anticoagulation approach and treatment outcomes

Background

Intracardiac thrombi (ICT) are associated with significant morbidity and mortality. Anticoagulation is the first line of treatment and may be complemented by thrombectomy or thrombolysis. However, optimal anticoagulant duration remains ill-defined. High-risk features of ICT that may warrant long-term anticoagulation therapy have not been established.

Objectives

To describe anticoagulation duration and patterns of ICT resolution. To identify potential risk factors for persistent ICT despite anticoagulation.

Methods

A single-institution retrospective chart review identified patients diagnosed with ICT by echocardiogram between January 2014 and March 2022. Descriptive statistics and logistic regression were used.

Results

Fifty-one patients with ICT were identified. Median age at diagnosis was 9.2 years (IQR, 0.4-15.2). The most common underlying diagnoses were congenital heart disease (41%), infection (25%), and malignancy (24%). The majority of ICT were in the right atrium (n = 30). The median longest ICT dimension was 1.5 cm (range, 0.4-4.0). The median duration of anticoagulation was 4.3 months (IQR, 2.2-9.1). Among 48 patients who received anticoagulation as first-line treatment, 32 had partial or complete response with 3 to 6 months of anticoagulation, while remaining 16 patients had no response to anticoagulation. Patients with a central venous line had a delayed resolution of ICT [hazards ratio = 0.45 (95% CI, 0.22-0.93)].

Conclusion

Our study demonstrates the wide variability in duration of anticoagulation for children with ICT. Majority of the individuals benefit from 3-to-6 month treatment; however, individuals with a central venous line may benefit from a longer course of anticoagulation. Further large-scale studies are recommended to validate our findings.

Intracardiac thrombus in children: the fine equilibrium between the risk and the benefit

The medical records of 16 patients diagnosed as intracardiac thrombus were searched. The size, location and outcome of thrombus together with demographic data of patients were assessed. The median age of the patients was 2.2 years. Six patients were newborn and two patients were infant. The median size of thrombus was 9 mm. The localization was right atrium in seven, right ventricle in five, left ventricle in one, pulmonary artery in one, and superior vena cava in two patients. There was prematurity in five, ciyanotic congenital heart disease in one, blood culture positivity in three, malignancy in four, nephrotic syndrome in one, indwelling catheters in 10, and acquired or genetic thrombophilia in six patients as risk factors. In the treatment, the first choice was tissue plasminogen activator in two patients, heparin infusion in one patient and low molecular weight heparin in remaining 12 patients. In nine patients, therapy included parenteral antimicrobials together with anticoagulants. The result was complete resolution in 15 patients and in one patient thrombus was surgically removed. The median time was 16 (2-70) days for 50% resolution and 26 (3-93) days for complete resolution. There was a statistically significant (P = .027 and r = 0.5) correlation between the size and the complete resolution time. There was no anticoagulant therapy related major complication. In patients with intracardiac thrombus, selection of anticoagulant therapy may decrease the risk of complications. Surgery is rarely required and thrombolytics are not usually necessary for resolution of thrombus.

Outcome of cardiac thrombi in infants

Use of central lines in the neonatal intensive care unit (NICU) has led to the formation of intracardiac thrombi. A paucity of data exists on the management of neonatal cardiac thrombi, with the few reported cases focusing on outcomes following thrombolytic therapy. This study was undertaken to evaluate the outcome of cardiac thrombi in neonates who do not receive thrombolytic therapy. Nineteen patients younger than 3 months of age diagnosed with cardiac thrombi were included. All 19 patients had a central line. Management consisted of a combination of antibiotics and low-molecular-weight heparin (n = 16) or surgical removal (n = 2). In one case, no treatment was instituted. One patient was lost to follow-up after partial resolution of the thrombus. Complete thrombus resolution occurred in 18 patients, 9 with negative blood cultures and 9 with positive blood cultures. It took longer for resolution of thrombi associated with positive blood cultures than for sterile thrombi. No patient had evidence of thrombus embolization. From these data we concluded that the natural history of cardiac thrombi is resolution. Infected thrombi require more prolonged therapy. Surgery is seldom required and thrombolytics are not usually necessary for clot resolution.

Intracardiac thrombi in pediatric patients: presentation profiles and clinical outcomes

We document the presentation profiles, treatment strategies, and clinical outcomes in a relatively large cohort of pediatric patients with intracardiac thrombi (ICT). We performed a retrospective review of patients diagnosed with ICT by echocardiography at a tertiary pediatric hospital during a 10-year period. These patients received medical therapy or thrombectomy. We provided echocardiographic descriptions of the ICT-size, chamber location, and mobility/morphology. The outcome measures were ICT (persistence, resolution, or embolization), effectiveness of therapy, and patient morbidity and mortality. There were 40 ICT diagnosed in 31 patients (22 males and 9 females). Mean age at diagnosis was 8.8 years (range, 15 days to 18 years). Overall mortality was 12/31 patients (39%); only one death was attributed to ICT embolization. Embolic events occurred in 4/31 patients (13%). The most common initial therapies included heparin infusion (n = 15), warfarin (n = 7), and aspirin (n = 7). The ICT resolved with medical therapy alone in 19/30 patients (63%). One patient required surgical thrombectomy. The cohort was divided into group 1 (dilated cardiomyopathy), group 2 (status post Fontan operation), and group 3 (other diagnoses). In group 1 (n = 11), there were 8 deaths. Embolization occurred in 2/5 large ICT, resulting in cerebral infarction and death (n = 1) and renal infarction (n = 1). The most common ICT location was the left ventricle (n = 10). Severe ventricular systolic dysfunction was present in 10/11 patients (91%). In group 2 (n = 9), there was 1 death. Embolization occurred in 1/7 large ICT, resulting in seizures and temporary paresis. All ICT were located in the Fontan pathway. Severe ventricular systolic dysfunction was present in 2/9 patients (22%). In group 3 (n = 11), there were 3 deaths. Embolization occurred in 1/9 small ICT, resulting in coronary emboli. ICT are most commonly diagnosed in pediatric patients with dilated cardiomyopathy or patients status post Fontan operation. The majority of ICT resolve with medical therapy. Larger ICT tend to embolize more frequently, and the morbidity secondary to embolization is significant. Rarely is mortality due to ICT embolization. The prognosis is poor for patients with left ventricular ICT or ICT in the presence of ventricular systolic dysfunction.

Management of preterm infants with intracardiac thrombi: use of thrombolytic agents

Improvement in neonatal care has led to improvements in survival and patient outcome in preterm infants; however, this improved survival has been associated with the development of secondary complications, such as catheter-associated intravascular and intracardiac thrombus formation with a non-negligible morbidity and mortality. The sick preterm infant is at high risk of catheter-related thrombus formation because of the combination of a high prothrombotic activity, low levels of natural anticoagulants, and various imbalances in the fibrinolytic systems. Based on clinical experience in adults and children, and several neonatal case reports demonstrating the efficacy and tolerability of specific thrombolytic treatment, this approach should be recommended as a first choice treatment in the premature infant with intracardiac or intravascular thrombosis. The thrombolytic agents of choice are urokinase or tissue plasminogen activator (tPA); however, none of them have proven to be superior to the other in terms of efficacy or tolerability, either in adult patients or premature infants. In the past, it has been suggested that newborn infants may require higher doses of thrombolytic agents than adults for effective systemic thrombolysis; however, based on more recent in vitro studies, it seems unlikely that this is true. Nevertheless, systemic (high dose) fibrinolysis is of concern as premature neonates present an increased risk of cerebral haemorrhage during the first weeks of life; therefore, low dose treatment has been proposed with, if possible, direct infusion of the fibrinolytic agent into, or close to, the thrombus. This approach has proven to be efficient and well tolerated in several small case series of newborn and preterm infants. Recommended doses are 1000 to 3000 U/kg/h for urokinase or 0.01 to 0.05 mg/kg/h for tPA. A systemic proteolytic state will not be induced by this low dose; however, specific monitoring of fibrinogen plasma levels has to be recommended. Fibrinogen levels should remain above 100 mg/dL during low dose treatment. Lower levels of fibrinogen will indicate the presence of an unwanted systemic fibrinolytic state. After successful thrombolysis, a follow-up treatment, preferentially with low-molecular-weight heparin for neonates at adjusted doses, should be instituted for at least 6 weeks in the absence of any persisting thrombophilic factor. A longer course (3 to 6 months) of anticoagulation therapy is recommended when thrombophilic factors (i.e. hereditary thrombophilia or central venous catheter still in place) are present. Furthermore, it is recommended that any neonate with thrombosis should be evaluated for hereditary thrombophilia later in life.

Evaluation and treatment of thrombocytopenia in the neonatal intensive care unit

Thrombocytopenia is a very frequent problem among sick neonates, affecting up to 35% of all infants admitted to the NICU. Although multiple clinical conditions have been causally associated with neonatal thrombocytopenia, the cause of the thrombocytopenia is unclear in up to 60% of affected neonates. This article provides neonatologists with a practical approach to the thrombocytopenic neonate, with an emphasis on conditions that could be life-threatening or could have significant implications for further pregnancies. An overview of the current therapeutic modalities is also presented, including a discussion of the possible use of recombinant thrombopoietic cytokines to treat certain groups of thrombocytopenic neonates.

Negative outcomes of intravascular therapy in infants and children

Intravascular therapy is essential in the care of acutely ill infants and children, but it is not without risks. The purpose of this article is to discuss potential intravascular, extravascular, and systemic complications related to peripheral and central intravascular therapy in infants and children. The formation of thrombi, infiltration, and sepsis are the most common complications. Less common complications are phlebitis, arterial spasm, catheter retention, catheter embolus, air emboli, dysrhythmias, and hemorrhage. Financial implications of long-term negative outcomes and nursing liability are discussed, and a proposed standard of preventative nursing care for intravascular therapy is presented.