Right Atrial Thrombosis in Children: Patient Characteristics, Outcomes, and Interrater Reliability of Echocardiographic Characterization

B.T. Barnes¹, W. Ravekes¹, G. Freire², E. Amankwah^3,4, J. Chiu⁵, A.R. Sellers^6,7, D. Procaccini^1,8, C.M. Takemoto^9,10, N. Goldenberg^6,9,11

¹Johns Hopkins University School of Medicine, Pediatric Cardiology, Baltimore, United States, ²Johns Hopkins All Children's Hospital, Pediatric Cardiology, St. Petersburg, United States, ³Johns Hopkins All Children's Hospital, Health Informatics Core, St. Petersburg, United States, ⁴Johns Hopkins University School of Medicine, Oncology, Baltimore, United States, ⁵Massachusetts General Hospital, Pediatric Cardiology, Boston, United States, ⁶Johns Hopkins All Children's Hospital, Cancer and Blood Disorders Institute, St. Petersburg, United States, ⁷Lake Erie College of Osteopathic Medicine, Office of Medical Education, Bradenton, United States, ⁸The Johns Hopkins Hospital, Pharmacy, Baltimore, United States, ⁹Johns Hopkins University School of Medicine, Hematology, Baltimore, United States, ¹⁰St. Jude Children's Research Hospital, Hematology, Memphis, United States, ¹¹Johns Hopkins All Children's Hospital, Institute for Clinical and Translational Research, St. Petersburg, United States

Abstract Number: PB1277

Meeting: ISTH 2020 Congress

Theme: Pediatrics » Thrombosis in Neonates and Children

Background: Pediatric right atrial thrombosis (RAT) carries potential for morbidity and mortality. However, the benefit of anticoagulation is unknown. Risk-stratification utilizing RAT echocardiographic characteristics has been suggested. RAT clinical outcomes with anticoagulation treatment based on published risk factors have not been reported. Furthermore, interrater reliability (IRR) of RAT characterization by echocardiography has not been studied.

Aims:
1) Describe RAT outcomes managed with and without anticoagulation.
2) Measure IRR of echocardiographic RAT characterization.

Methods: Retrospective single-center cohort study at The Johns Hopkins Hospital. Patients 0 to 21 years with RAT from 2013 to 2018 were included. Anticoagulation was initiated based on discretion of treating clinicians, but informed by presence/absence of echocardiographic RAT characteristics. The medical record was reviewed for demographics, treatments and outcomes. Adverse thromboembolic (TE) outcomes included RAT progression, pulmonary embolism (PE), clinically-relevant bleeding (ISTH-defined), and death due to TE or bleeding. For IRR of RAT characteristics, echocardiograms from 50 randomly selected subjects were reviewed by three mutually-blinded pediatric cardiologists.

Results: We identified 131 patients with RAT (Table 1). Median age was 25 days. A provoking clinical factor was present in 125 (95%). Anticoagulation was given in 67 (51%) patients. Enoxaparin was the most commonly used anticoagulant (46) followed by unfractionated heparin (21). Adverse outcomes included RAT progression in 7, PE in 2, and clinically relevant bleeding in 9. There were no deaths related to TE or bleeding.
IRR assessment demonstrated that all RAT characteristics (Table 2) had poor reliability except acoustic reflection (moderate agreement; K=0.62 [95%CI, 0.47-0.78]).

Conclusions: We report large single-center outcomes of pediatric RAT. While echocardiographic assessment was used in decision-making regarding anticoagulation therapy, our study showed poor reliability for RAT characteristics other than acoustic reflect. Future research must focus on improving risk stratification in pediatric RAT, in order to inform interventional studies of treatment paradigms, including use and duration of anticoagulation.

		Total (n =131)
Demographics	Median (observed range) in age	25d (2d-20y)
	Male (%)	67 (51)
	Weight (Kg)	3.1 (0.6-109.6)
Outcomes	No Adverse Outcome (%)	99 (76)
	Thrombus Progression	7
	Death due to Thromboembolism or Bleeding	0
	Pulmonary Embolism	2
	Clinically Relevant Bleeding	9
	Other	11

[Study patient demographics and outcomes. Multiple adverse outcomes were seen in several patients.]

Categorical Measure	n Patients	Fleiss Kappa	95% CI	Agreement
Acoustic Reflection	42	0.62	(0.47, 0.78)	Moderate
Mass Location	42	0.51	(0.41, 0.61)	Weak
Mobility	42	0.2	(0.07, 0.32)	None

Continuous Measure	n Patients	Carrasco et al´s CCC	95% CI	Agreement
Longest Dimension	44	0.76	(0.64, 0.85)	Poor
Orthogonal Dimension	44	0.78	(0.67, 0.86)	Poor
Longest Adherence Dimension	43	0.6	(0.43, 0.73)	Poor
Pulmonary Valve Dimension	39	0.94	(0.9, 0.96)	Moderate

[Interrater reliability assessment of RAT characterization by echocardiography. Pulmonary valve dimension is a control measurement.]

To cite this abstract in AMA style:

Barnes BT, Ravekes W, Freire G, Amankwah E, Chiu J, Sellers AR, Procaccini D, Takemoto CM, Goldenberg N. Right Atrial Thrombosis in Children: Patient Characteristics, Outcomes, and Interrater Reliability of Echocardiographic Characterization [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/right-atrial-thrombosis-in-children-patient-characteristics-outcomes-and-interrater-reliability-of-echocardiographic-characterization/. Accessed September 29, 2023.

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