Recommendations for future research in relation to pediatric pulmonary embolism: communication from the SSC of the ISTH

Pediatric pulmonary thromboembolism: a 3-year Canadian Pediatric Surveillance Program study

BACKGROUND

Pediatric pulmonary embolism (PE) is a rare event associated with significant morbidity and mortality. Awareness of clinical presentation and practices unique to children may aid clinicians in prompt identification and treatment.

OBJECTIVES

To describe the incidence, risk factors, clinical presentation, diagnostic and therapeutic practices, and short-term outcomes of pediatric PE.

METHODS

We conducted a 3-year national surveillance study through the Canadian Pediatric Surveillance Program. Over 2800 pediatric specialists and subspecialists were contacted monthly from 2020 to 2022 and requested to report all new cases of PE in patients up to 18 years of age. Case-specific data were obtained through voluntary completion of a detailed questionnaire.

RESULTS

Fifty-eight cases (78% female, n = 45) were reported (2.4 cases per million children), with rates highest in adolescents 15 to 18 years (6.6 cases per million). Detailed information, available for 31 (53%) cases, documented at least 1 risk factor in 28 (90%) cases; 24 (77%) patients presented with 2 or more symptoms. Computed tomography pulmonary angiography was used for diagnostic confirmation in 25 (81%) cases. Anticoagulation was initiated in 24 (77%) of 31 cases; fewer than 5 patients underwent thrombolysis or surgical interventions. Of 28 patients who received therapeutic interventions, 8 (29%) experienced treatment-related complications. Fewer than 5 mortalities were reported.

CONCLUSION

Pediatric PE is a rare event, with female adolescents at the highest risk. Although the presentation is often nonspecific, clinicians should maintain a high index of suspicion, particularly in patients with risk factors and when other diagnoses that may explain symptoms have been excluded.

Considerations for instituting pediatric pulmonary embolism response teams: A tool kit

The incidence of pediatric pulmonary embolism (PE) has increased by 200 % in the last decade, but at a single center, it is still infrequent. Given the unique epidemiologic features of pediatric PE, diagnosis is often delayed, and the management is empiric, based on individual physician experience or preference. Thus, there is a strong need for center-specific uniform management of pediatric PE patients. In adults, the development of pulmonary embolism response teams (PERTs) or PE critical care pathways has shortened the time to diagnosis and the initiation of definitive management. Evidence to support an improvement in PE outcomes after the development of PERTs does not exist in children. Nonetheless, we have summarized the practical practice guidelines that physicians and institutions can adopt to establish their institutional PERTs or critical pathways. We also provide strategies for resource-challenged institutions for partnering with centers with expertise in the management of pediatric PE.

Clinical prediction tool to identify children at risk of pulmonary embolism

INTRODUCTION

The diagnosis of pediatric pulmonary embolism (PE) is often delayed due to non-specific symptoms, and clinical prediction tools designed for adults are unsuitable for children. This study aimed to create a PE predictive model and to evaluate the reported tools in the Thai pediatric population.

MATERIALS AND METHODS

A multi-center retrospective study from 4 university hospitals included children ≤18 years of age undergoing computed tomography pulmonary angiogram from 2000 to 2020 with the suspicion of PE. Patients' clinical presentations and risk factors of venous thromboembolism (VTE) were compared between the PE-positive and PE-negative groups. Significant risk factors from univariate and multivariate logistic regression were included to create a clinical prediction tool. The performance of the model was demonstrated by sensitivity, specificity, area under the curve (AUC), Hosmer Lemeshow test, ratio of observed and expected outcomes and bootstrapping.

RESULTS

Of the 104 patients included, 43 (41.3 %) were grouped as PE-positive and 61 (58.7 %) as PE-negative. Five parameters, including congenital heart disease/pulmonary surgery, known thrombophilia, previous VTE, nephrotic syndrome and chest pain showed significant differences between the two groups. Score ≥ 2 yielded a 74.4 % sensitivity and a 75.4 % specificity with an AUC of the model of 0.809. The model performance and validation results were within satisfactory ranges.

CONCLUSION

The study created a clinical prediction tool indicating the likelihood of PE among Thai children. A score ≥2 was suggestive of PE.

A retrospective study of the clinical characteristics of 9 children with pulmonary embolism associated with Mycoplasma pneumoniae pneumonia

OBJECTIVE

The aim of this study was to analyze the clinical characteristics and treatment of children with Mycoplasma pneumoniae pneumonia (MPP) who also present with pulmonary embolism (PE).

METHODS

This retrospective analysis examined the demographic data, clinical manifestations, laboratory tests, imaging characteristics, therapy, and prognosis of nine cases of children with Mycoplasma pneumoniae pneumonia (MPP) complicated by pulmonary embolism (PE). The study focused on patients admitted to the respiratory department of Tianjin Children's Hospital between January 2018 and December 2021.

RESULTS

The age range of the patients was 3 to 8 years old, with a median age of 7.5 years. The median number of days from pulmonary infection to the diagnosis of embolism was 14 days. All patients had refractory Mycoplasma pneumoniae pneumonia (RMPP). Among them, three patients reported chest pain, one of whom had hemoptysis, while five patients had dyspnea, and six patients experienced radiating pain at unusual sites. Five out of the nine children tested positive for lupus anticoagulant (LA), five for anticardiolipin antibody (ACA), three for anti-2-glycoprotein antibody IgM, four for reduced protein S or protein C activity, and three for elevated coagulation factor VIII. Moreover, six out of the nine children tested positive for antinuclear antibodies. All the children underwent CT pulmonary angiograms, which revealed filling defects. After sequential low-molecular heparin anticoagulation with rivaroxaban, nine children in this study showed a good prognosis, with two of them receiving thrombolytic therapy for combined cardiac embolism. Follow-up at 0.5-9 months showed the gradual resolution of the emboli in all 9 children, with no thrombotic recurrences and normalized autoantibodies and thrombophilia markers.

CONCLUSIONS

The majority of cases involving Mycoplasma pneumoniae pneumonia (MPP) combined with pulmonary embolism (PE) were diagnosed with refractory MPP (RMPP). However, PE did not always occur in the advanced stages of the disease. Most patients presented with transient autoantibody positivity, abnormal coagulation, and fibrinolytic balance. With timely treatment, the prognosis of MPP combined with PE is generally good. Additionally, rivaroxaban treatment has been shown to be safe and effective.

Pulmonary embolism in pediatrics: A 10-year experience from a tertiary center in Brazil

INTRODUCTION

Although still rare, pulmonary embolism (PE) in children has been increasing over the years. Data regarding this group of patients are still sparse, which contributes to the lack of standardized prophylaxis protocols and the misdiagnosis. This study aimed to determine the incidence of pediatric PE at a Brazilian tertiary hospital, describe clinical characteristics and identify possible risk factors. We also analyzed the diagnosis and management of PE.

METHODS

This was a retrospective review of tertiary Brazilian single-center data of all pediatric patients (0 - 18 years) with acute PE, diagnosed radiologically, from September 2009 to May 2019.

RESULTS

The incidence of PE was 3.3 cases per 10,000 hospitalized children. All the twenty-three cases had some risk factor identified and sixteen of them (69.5%) had more than one risk factor. The most important were central venous catheter (39.1%), malignancy (34.8%) and recent surgery (34.8%). Among the children with identifiable symptoms (69.5%), the most common was dyspnea (56.2%). Only one patient did not receive antithrombotic therapy because of the high bleeding risk and most patients (70.6%) were treated for 3 to 6 months. Among the nineteen patients alive at the end of the six-month follow-up, ten (52.6%) repeated the PE image control. Seven of them (70.0%) had complete or partial resolution of the thrombosis and none had worsening images.

CONCLUSION

Our lower incidence than that of the current literature may reflect underdiagnosis due to low suspicion of PE. At least one risk factor was identified in all patients, which emphasizes the importance of increasing awareness of high-risk children.

Pulmonary embolism in pediatric age: A retrospective study from a tertiary center

INTRODUCTION

Pediatric pulmonary embolism (PE) is rare but associated with adverse outcomes. We aimed to characterize PE cases admitted in a tertiary hospital and to evaluate sensitivity of selected PE diagnostic prediction tools.

METHODS

Retrospective, descriptive study of PE cases admitted from 2008 to 2020 using data collected from hospital records. Patients were grouped according to PE severity and setting (outpatients vs. inpatients). Links and correlation with demographic characteristics, risk factors, clinical presentation, management, and outcomes were analyzed. PE diagnostic prediction tools were applied.

RESULTS

Twenty-nine PE episodes occurred in 27 patients, 62.9% female, mean age 14.1 years. Most PE were central and split between massive or submassive. One was diagnosed in autopsy. Twenty outpatients, all adolescents, were admitted for classic PE symptoms; in half of them the diagnosis had been previously missed. Risk factors included contraceptives (65%), thrombophilia (35%), obesity (20%) and auto-immunity (20%). Eight inpatients, diagnosed during cardiorespiratory deterioration (n = 5), or through incidental radiological findings (n = 3), were younger and had immobilization (87.5%), complex chronic diseases (75%), infections (75%) and central venous catheter (62.5%) as risk factors. Retrospectively, d -dimer testing and adult scores performed better than pediatric scores (sensitivity 92.9%-96% vs. 85.7%-92.9%). Both pediatric scores missed a case with a positive family history.

DISCUSSION

Pediatric PE diagnosis is often delayed or missed. Development of pediatric prediction tools from validated adult scores merits being explored. We argue clinical presentation and risk factors may be different in inpatients and outpatients and propose broader reliance on family history.

Illustrated State-of-the-Art Capsules of the ISTH 2020 Congress

This year's Congress of the International Society of Thrombosis and Haemostasis (ISTH) was hosted virtually from Philadelphia July 17-21, 2021. The conference, now held annually, highlighted cutting-edge advances in basic, population and clinical sciences of relevance to the Society. Despite being held virtually, the 2021 congress was of the same scope and quality as an annual meeting held in person. An added feature of the program is that talks streamed at the designated times will then be available on-line for asynchronous viewing. The program included 77 State of the Art (SOA) talks, thematically grouped in 28 sessions, given by internationally recognized leaders in the field. The SOA speakers were invited to prepare brief illustrated reviews of their talks that were peer reviewed and are included in this article. The topics, across the main scientific themes of the congress, include Arterial Thromboembolism, Coagulation and Natural Anticoagulants, COVID-19 and Coagulation, Diagnostics and Omics, Fibrinogen, Fibrinolysis and Proteolysis, Hemophilia and Rare Bleeding Disorders, Hemostasis in Cancer, Inflammation and Immunity, Pediatrics, Platelet Disorders, von Willebrand Disease and Thrombotic Angiopathies, Platelets and Megakaryocytes, Vascular Biology, Venous Thromboembolism and Women's Health. These illustrated capsules highlight the major scientific advances with potential to impact clinical practice. Readers are invited to take advantage of the excellent educational resource provided by these illustrated capsules. They are also encouraged to use the image in social media to draw attention to the high quality and impact of the science presented at the congress.

Catheter-directed thrombolysis for submassive pulmonary embolism in children: A case series

Incidence of venous thromboembolism, including pulmonary embolism (PE), continues to rise in children. Optimum management of submassive PE is unclear. The principal objective of this retrospective study was to investigate the radiological and clinical outcomes in children with submassive PE treated with catheter-directed thrombolysis (CDT). Five patients underwent six episodes of CDT. No patient developed major/clinically relevant non-major bleeding. Most patients had complete radiological thrombus resolution and no patient had evidence of chronic thromboembolic pulmonary hypertension. There is an urgent need for larger prospective cohort studies/randomized controlled trials to investigate the role of CDT in pediatric PE.