Official communication of the SSC: Recommendations for future research in catheter-related arterial thrombosis in children

Results of a multinational survey on the diagnostic and management practices of catheter-related arterial thrombosis in children and neonates: communication from the ISTH SSC Subcommittee on Pediatric and Neonatal Thrombosis and Hemostasis

BACKGROUND

Arterial thrombosis is increasingly recognized in children and is most commonly related to the presence of an arterial catheter. Diagnosis and treatment of arterial thrombosis in children varies widely and consists of commonly available anticoagulants and antiplatelet drugs. No evidence-based guidelines exist for management strategies for catheter-related arterial thrombosis (CAT).

OBJECTIVES

To understand pediatric hematologists' current practices and opinions in the management of CAT in children and neonates.

METHODS

A multinational survey on diagnostic and management practices from experts and practitioners in the field was conducted by means of a questionnaire with general questions and specific clinical CAT scenarios in regard to umbilical arterial catheters, extremity indwelling arterial catheters, and cardiac catheterization.

RESULTS

Of 54 complete survey responses, there was agreement that Doppler ultrasound is the preferred diagnostic modality to identify CAT and unfractionated heparin and low-molecular-weight heparin are the preferred antithrombotic treatments, while thrombolysis/thrombectomy is used in life-/limb-threatening CAT, long-term follow-up is necessary to detect adverse outcomes, and generally no thrombophilia testing is indicated. There was considerable heterogeneity in treatment indications on when to start antithrombotic treatment, treatment duration, timepoint of catheter removal, and length of follow-up.

CONCLUSION

These results highlight some congruency, but also considerable heterogeneity, in the management practices of CAT. Based on these findings, an international guidance document is necessary to harmonize management practices and further clinical investigations of CAT.

Pediatric arterial thrombosis: A single-institution cohort study of patient characteristics and thrombosis outcomes

BACKGROUND

Arterial thrombosis (AT) is an increasingly recognized complication in pediatrics. Consensus clinical practice guidelines suggest immediate removal of the indwelling arterial catheter and a short course (5-7 days) of anticoagulation. The optimal duration and modality of antithrombotic therapy in children are yet to be determined.

AIMS

Describe treatment patterns and outcomes in pediatric patients with AT and explore predictors for complete thrombus resolution or long-term complications.

METHODS

Single-institution retrospective study. Patients were identified by ICD-9 and ICD-10 codes for the diagnosis of AT or reports of AT on ultrasound from January 1, 2012, to October 1, 2022. Descriptive and logistic regression analyses were used.

RESULTS

101 patients were included. The median age was 2.2 months. The most common underlying diagnoses were congenital heart disease (39.6%) and infection (22.8%). A majority of patients had symptomatic thrombosis in an extremity, and 78% were catheter-associated. 81% of patients received anticoagulation with a median duration of 35 days. Out of the 70 patients who were treated with anticoagulation alone and had a follow-up imaging, 70% had complete resolution after 90 days of anticoagulation. No clear predictors of complete resolution were identified. Eighteen patients had long-term sequelae secondary to arterial insufficiency. Those with infection-associated AT were more likely to have long-term complications. The major and clinically relevant non-major bleeding rate was 11%.

CONCLUSION

Duration of anticoagulation was widely variable, and 70% of patients achieved complete resolution by 90 days of anticoagulation. A significant proportion of patients developed long-term sequelae secondary to arterial insufficiency. Sepsis/infection at the time of diagnosis with AT was more likely to be associated with long-term complications.

Risk factors and frequency of acute and permanent femoral arterial occlusion in neonates with CHD who undergo ultrasound-guided femoral arterial access

OBJECTIVE

We investigated frequency and risk factors of acute loss of the arterial pulse and permanent femoral arterial occlusion in neonates with CHD who underwent ultrasound-guided femoral arterial access.

METHODS

We divided the patients into groups according to the presence of acute loss of the arterial pulse and permanent femoral arterial occlusion. We obtained data related to patient characteristics and access variables of ultrasound-guided femoral arterial access from our database of cardiac catheterisation between August, 2017 and May, 2021. We used an echocardiography-S6, 12-MHz linear probe, 21-gauge needle, 0.018"guidewire, and a 4F sheath for arterial access.

RESULTS

Ultrasound-guided femoral arterial access was obtained in 323 (98.8%) of the 327 neonates. We identified acute loss of the arterial pulse in 130 (40.2%) patients and permanent femoral arterial occlusion in 19 (5.9%) patients. Median weight was 3.05 (Interquartile range (IQR): 2.80-3.40) kg, first attempt success rate was 88.2%, and median access time was 46 sec (IQR: 23-94). Logistic regression analysis identified coarctation of the aorta (odds ratio: 2.46; 95% CI: 1.30-4.66; p = 0.006) as independent risk factor for acute loss of the arterial pulse, but did not identify any independent risk factors for permanent femoral arterial occlusion.

CONCLUSIONS

This study showed coarctation of the aorta as an independent risk factor for acute loss of the arterial pulse, but did not identify any independent factors for permanent femoral arterial occlusion in neonates with CHD. Although most cases of acute loss of the arterial pulse resolve in the early period, the frequency of permanent femoral arterial occlusion remains high despite effective treatment.

Daytime administration of melatonin has better protective effects on bone loss in ovariectomized rats

OBJECTIVE

To explore the difference in the protective effects of intraperitoneal injection of exogenous melatonin of daytime or nighttime on bone loss in ovariectomized (OVX) rats.

METHODS

After bilateral ovariectomy and sham surgery, 40 rats were randomly divided into four groups: sham operation group (Sham), ovariectomy (OVX), and daytime melatonin injection group (OVX + DMLT, 9:00, 30 mg/kg/d) and nighttime injection of melatonin (OVX + NMLT, 22:00, 30 mg/kg/d). After 12 weeks of treatment, the rats were sacrificed. The distal femur, blood and femoral marrow cavity contents were saved. The rest of the samples were tested by Micro-CT, histology, biomechanics and molecular biology. Blood was used for bone metabolism marker measurements. CCK-8, ROS, and Cell apoptosis are performed using MC3E3-T1 cells.

RESULTS

Compared with treatment at night, the bone mass of the OVX rats was significantly increased after the daytime administration. All microscopic parameters of trabecular bone increased, only Tb.Sp decreased. Histologically, the bone microarchitecture of the OVX + DMLT was also more dense than the bone microarchitecture of the OVX + LMLT. In the biomechanical experiment, the femur samples of the day treatment group were able to withstand greater loads and deformation. In molecular biology experiments, bone formation-related molecules increased, while bone resorption-related molecules decreased. After treatment with melatonin administration at night, the expression of MT-1β was significantly decreased. In cell experiments, the MC3E3-T1 cells treated with low-dose MLT had higher cell viability and greater efficiency in inhibiting ROS production than the MC3E3-T1 cells treated with high-dose MLT, which in turn more effectively inhibited apoptosis.

CONCLUSION

Daytime administration of melatonin acquires better protective effects on bone loss than night in OVX rats.

Treatment of Catheter-Related Arterial Thrombosis in Children: A 15-Year Single- Center Experience

OBJECTIVE

To investigate treatment modalities for children with extremity indwelling catheter (EIC)- or cardiac catheter-related arterial thrombosis.

STUDY DESIGN

The treatment of consecutive cases of catheter-related arterial thrombosis (CAT) at our institution between 2002 and 2017 was analyzed retrospectively.

RESULTS

A total of 242 CATs developed in 224 children. Of these, 125 (52%) were EIC-related and 117 (48%) were cardiac catheter-related. Treatment included heparin alone in 60 cases (25%), acetylsalicyclic acid (ASA) alone in 6 cases (2%), heparin followed by ASA in 171 cases (71%), heparin followed by vitamin K antagonist (VKA) in 4 cases (1.5%), and VKA alone in 1 case (0.5%). Complete resolution of CAT was observed in 173 cases (71.5%), partial resolution in 13 cases (5.4%), and no resolution in 56 cases (23.1%). No statistical significance in the resolution rate was observed between treatment groups (P = .23). In 66% of cases, complete resolution occurred at a median of 18 days (range, 4-44 days) with heparin alone. A switch from heparin to ASA in children with partial or no resolution of CAT did not increase the resolution rate at follow-up.

CONCLUSIONS

Heparin is an efficient treatment modality for CAT in pediatric patients. Long-term, subsequent treatment with ASA does not increase the resolution rate.

Patient Characteristics and Treatment Outcomes of Symptomatic Catheter-Related Arterial Thrombosis in Infants: A Retrospective Cohort Study

OBJECTIVE

To describe the clinical characteristics, outcomes, and adverse events of treatment for symptomatic infant catheter-related arterial thrombosis.

STUDY DESIGN

Single-center retrospective medical record review of 99 infants (age <365 days) with catheter-related arterial thrombosis, either following indwelling arterial catheter placement or cardiac catheterization, who were treated with anticoagulation over an 8-year span at a pediatric tertiary care center. Outcomes measured include thrombosis progression, bleeding events, and thrombus resolution following the treatment period.

RESULTS

Thromboses were secondary to indwelling arterial catheter placement in 51 (51.5%) and cardiac catheterization in 48 (48.5%). The median age at diagnosis of catheter-related arterial thrombosis was 52 days. All patients received therapeutic anticoagulation with either unfractionated heparin or low molecular weight heparin for a maximum of 28 days. Progression of catheter-related arterial thrombosis occurred in 8 (8.1%) patients. One (1%) major and 3 (3%) minor bleeding events occurred within the cohort. Complete thrombus resolution was observed in 60 (60.6%), partial resolution in 33 (33.3%), and no resolution in 6 (6.1%) following the treatment period. Factors associated with complete thrombus resolution included time from intervention to catheter-related arterial thrombosis diagnosis (median of 1 day vs 5 days in those who experienced thrombus resolution vs those who did not, P = .035), and iliac and/or femoral artery involvement (P = .015).

CONCLUSIONS

Our treatment approach to infant catheter-related arterial thrombosis is safe and effective. Limitations of the study are its retrospective nature with a limited number of patients from a single institution. Additional prospective studies are needed to determine the optimal treatment approach to catheter-related arterial thrombosis in infants.

International pediatric thrombosis network to advance pediatric thrombosis research: Communication from the ISTH SSC subcommittee on pediatric and neonatal thrombosis and hemostasis

Pediatric thromboembolism is a rare and heterogenous disease. As a result, there is a paucity of knowledge with regard to natural history, management, and outcomes of most types of pediatric venous and arterial thromboembolism. International research collaboration is needed to fill these knowledge gaps. Not only randomized controlled trials, but also representative observational studies are required to answer all research questions. Therefore, the ISTH SSC Subcommittee on Pediatric and Neonatal Thrombosis and Hemostasis initiated the International Pediatric Thrombosis Network (IPTN). The aims of the IPTN include (1) development of the Throm-PED registry to facilitate international prospective observational studies, and (2) establishment of a network of pediatric thrombosis centers experienced in effectively conducting clinical trials and observational studies. The IPTN needs dedicated clinicians all over the world and several funding sources to obtain high-quality research data to reach its ultimate goal of improving care in children with thrombosis. The aim of this communication is to call for active participation in the IPTN to all physicians taking care of children with thrombosis worldwide.