Long-term outcomes of warfarin versus aspirin after Fontan surgery

Comparative effectiveness among thromboprophylaxis strategies after the Fontan operation: A systematic review and network meta-analysis

INTRODUCTION

A variety of thromboprophylaxis regimens have been administered in patients following the Fontan procedure. However, consensus guidelines regarding the optimal thromboprophylaxis strategy have not yet been developed.

METHOD

A network meta-analysis was conducted to evaluate the comparative effectiveness among available thromboprophylaxis regimens and major bleeding events associated with these regimens.

RESULTS

A total of 28 comparative studies with 4430 Fontan patients were included. The incidence of thromboembolic events (TE) was significantly lower in individuals who underwent thromboprophylaxis compared to those who did not. Compared to a no-treatment strategy, nonvitamin K oral anticoagulants (NOACs) showed the largest treatment effect for preventing TE (OR = 0.08, 95 % CI 0.03 to 0.21), followed by warfarin (OR = 0.16, 95 % CI 0.10 to 0.27), and aspirin (OR = 0.23, 95 % CI 0.14 to 0.38). Indeed, NOACs were significantly more effective than aspirin in preventing TE (OR = 0.35, 95 % CI 0.14 to 0.84). Aspirin was associated with the lowest occurrence of major bleeding events, followed by NOACs, no medication, and warfarin. NOACs were shown to possess a highly favorable overall profile.

CONCLUSION

Prescribing thromboprophylaxis drugs, either antiplatelets or anticoagulants, may be more effective in preventing TE after the Fontan operation than not doing so. Among the included regimens, NOACs demonstrated significantly greater efficacy than aspirin; however, they did not show statistically significant superiority over warfarin. Aspirin exhibited lower rates of major bleeding compared to both NOACs and warfarin. Overall, NOACs tended to offer the most advantageous balance of efficacy and safety. However, the findings should be interpreted considering the certainty and limitations of the evidence, including potential residual confounding in observational studies.

Nutritional considerations for people living with a Fontan circulation: a narrative review

The population of people living with a Fontan circulation are highly heterogenous, including both children and adults, who have complex health issues and comorbidities associated with their unique physiology throughout life. Research focused on nutritional considerations and interventions in the Fontan population is extremely limited beyond childhood. This review article discusses the current literature examining nutritional considerations in the setting of Fontan physiology and provides an overview of the available evidence to support nutritional management strategies and future research directions. Protein-losing enteropathy, growth deficits, bone mineral loss, and malabsorption are well-recognised nutritional concerns within this population, but increased adiposity, altered glucose metabolism, and skeletal muscle deficiency are also more recently identified issues. Emergencing evidence suggets that abnormal body composition is associated with poor circulatory function and health outcomes. Many nutrition-related issues, including the impact of congenital heart disease on nutritional status, factors contributing to altered body composition and comorbidities, as well as the role of the microbiome and metabolomics, remain poodly understood.

Apixaban for Prevention of Thromboembolism in Pediatric Heart Disease

BACKGROUND

Children with heart disease frequently require anticoagulation for thromboprophylaxis. Current standard of care (SOC), vitamin K antagonists or low-molecular-weight heparin, has significant disadvantages.

OBJECTIVES

The authors sought to describe safety, pharmacokinetics (PK), pharmacodynamics, and efficacy of apixaban, an oral, direct factor Xa inhibitor, for prevention of thromboembolism in children with congenital or acquired heart disease.

METHODS

Phase 2, open-label trial in children (ages, 28 days to <18 years) with heart disease requiring thromboprophylaxis. Randomization 2:1 apixaban or SOC for 1 year with intention-to-treat analysis.

PRIMARY ENDPOINT

a composite of adjudicated major or clinically relevant nonmajor bleeding. Secondary endpoints: PK, pharmacodynamics, quality of life, and exploration of efficacy.

RESULTS

From 2017 to 2021, 192 participants were randomized, 129 apixaban and 63 SOC. Diagnoses included single ventricle (74%), Kawasaki disease (14%), and other heart disease (12%). One apixaban participant (0.8%) and 3 with SOC (4.8%) had major or clinically relevant nonmajor bleeding (% difference -4.0 [95% CI: -12.8 to 0.8]). Apixaban incidence rate for all bleeding events was nearly twice the rate of SOC (100.0 vs 58.2 per 100 person-years), driven by 12 participants with ≥4 minor bleeding events. No thromboembolic events or deaths occurred in either arm. Apixaban pediatric PK steady-state exposures were consistent with adult levels.

CONCLUSIONS

In this pediatric multinational, randomized trial, bleeding and thromboembolism were infrequent on apixaban and SOC. Apixaban PK data correlated well with adult trials that demonstrated efficacy. These results support the use of apixaban as an alternative to SOC for thromboprophylaxis in pediatric heart disease. (A Study of the Safety and Pharmacokinetics of Apixaban Versus Vitamin K Antagonist [VKA] or Low Molecular Weight Heparin [LMWH] in Pediatric Subjects With Congenital or Acquired Heart Disease Requiring Anticoagulation; NCT02981472).

EASL-ERN position paper on liver involvement in patients with Fontan-type circulation

Fontan-type surgery is the final step in the sequential palliative surgical treatment of infants born with a univentricular heart. The resulting long-term haemodynamic changes promote liver damage, leading to Fontan-associated liver disease (FALD), in virtually all patients with Fontan circulation. Owing to the lack of a uniform definition of FALD and the competitive risk of other complications developed by Fontan patients, the impact of FALD on the prognosis of these patients is currently debatable. However, based on the increasing number of adult Fontan patients and recent research interest, the European Association for The Study of the Liver and the European Reference Network on Rare Liver Diseases thought a position paper timely. The aims of the current paper are: (1) to provide a clear definition and description of FALD, including clinical, analytical, radiological, haemodynamic, and histological features; (2) to facilitate guidance for staging the liver disease; and (3) to provide evidence- and experience-based recommendations for the management of different clinical scenarios.

Adolescents and Adults With Congenital Heart Disease: Why Are They Lost to Follow-Up?

Almost 90% of infants with congenital heart disease (CHD) now reach adulthood but require long-term surveillance to recognize and manage residual and/or evolving lesions. Yet many are lost to follow-up. A scoping review identified four specific domains that pose barriers to consistent follow-up. There are multiple issues associated with transition from pediatric to adult care which included-the lack of a seamless transfer, the establishment of a new trusting relationship, promoting the right balance of patient autonomy and addressing knowledge gaps. Additional issues related to logistic problems of time, distance, cost, and the availability of specialized care, are further compounded by the psychosocial factors and the heterogeneity of the cardiac abnormality affecting our patients. Further study of all these issues is warranted to improve ongoing engagement.

Thromboprophylaxis in Patients With Fontan Circulation

BACKGROUND

The optimal strategy for thromboprophylaxis in patients with a Fontan circulation is unknown.

OBJECTIVES

The aim of this study was to compare the efficacy and safety of aspirin, warfarin, and nonvitamin K oral anticoagulants (NOACs) in a network meta-analysis.

METHODS

Relevant studies published by February 2022 were included. The primary efficacy outcome was thromboembolic events; major bleeding was a secondary safety outcome. Frequentist network meta-analyses were conducted to estimate the incidence rate ratios (IRRs) of both outcomes. Ranking of treatments was performed based on probability (P) score.

RESULTS

A total of 21 studies were included (26,546 patient-years). When compared with no thromboprophylaxis, NOAC (IRR: 0.11; 95% CI: 0.03-0.40), warfarin (IRR: 0.23; 95% CI: 0.14-0.37), and aspirin (IRR: 0.24; 95% CI: 0.15-0.39) were all associated with significantly lower rates of thromboembolic events. However, the network meta-analysis revealed no significant differences in the rates of major bleeding (NOAC: IRR: 1.45 [95% CI: 0.28-7.43]; warfarin: IRR: 1.38 [95% CI: 0.41-4.69]; and aspirin: IRR: 0.72 [95% CI: 0.20-2.58]). Rankings, which simultaneously analyze competing interventions, suggested that NOACs have the highest P score to prevent thromboembolic events (P score 0.921), followed by warfarin (P score 0.582), aspirin (P score 0.498), and no thromboprophylaxis (P score 0.001). Aspirin tended to have the most favorable overall profile.

CONCLUSIONS

Aspirin, warfarin, and NOAC are associated with lower risk of thromboembolic events. Recognizing the limited number of patients and heterogeneity of studies using NOACs, the results support the safety and efficacy of NOACs in patients with a Fontan circulation.

Scaling Peak Oxygen Consumption for Body Size and Composition in People With a Fontan Circulation

Background Peak oxygen consumption (peak V̇O2$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$) is traditionally divided ("ratio-scaled") by body mass (BM) for clinical interpretation. Yet, it is unknown whether ratio-scaling to BM can produce a valid size-independent expression of peak V̇O2$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$ in people with a Fontan circulation. Furthermore, people with a Fontan circulation have deficits in lean mass, and it is unexplored whether using different measures of body composition may improve scaling validity. The objective was to assess the validity of different scaling denominators (BM, stature, body surface area, fat-free mass, lean mass, and appendicular lean mass using ratio and allometric scaling). Methods and Results Eighty-nine participants (age: 23.3±6.7 years; 53% female) with a Fontan circulation had their cardiorespiratory fitness and body composition measured by cardiopulmonary exercise testing and dual-energy x-ray absorptiometry. Ratio and allometric (log-linear regression) scaling was performed and Pearson correlations assessed scaling validity. Scaling denominators BM (r=-0.25, P=0.02), stature (r=0.46, P<0.001), and body surface area (0.23, P=0.03) were significantly correlated with their respective ratio-scaled expressions of peak V̇O2$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$, but fat-free mass, lean mass, or appendicular lean mass were not (r≤0.11; R²=1%). Allometrically expressed peak V̇O2$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$ resulted in no significant correlation with any scaling denominator (r=≤0.23; R²=≤4%). Conclusions The traditional and accepted method of ratio-scaling to BM is invalid because it fails to create a size-independent expression of peak V̇O2$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$ in people with a Fontan circulation. However, ratio-scaling to measures of body composition (fat-free mass, lean mass, and appendicular lean mass) and allometric techniques can produce size-independent expressions of peak V̇O2$$ \dot{\mathrm{V}}{\mathrm{O}}_2 $$ in people with a Fontan circulation.

Edoxaban for Thromboembolism Prevention in Pediatric Patients With Cardiac Disease

BACKGROUND

Standard of care (SOC) anticoagulation for thromboembolism (TE) prevention in children with cardiac disease includes low molecular weight heparins or vitamin K antagonists. Limited data exists for alternate use of direct oral anticoagulants in children.

OBJECTIVES

The investigators aimed to obtain safety and efficacy data for edoxaban in children.

METHODS

We performed a phase 3, multinational, prospective, randomized, open-label, blinded-endpoint trial in patients <18 years of age with cardiac disease (ENNOBLE-ATE [Edoxaban for Prevention of Blood Vessels Being Blocked by Clots (Thrombotic Events) in Children at Risk Because of Cardiac Disease] trial). Patients were randomized 2:1 to age- and weight-based oral edoxaban once daily vs SOC for 3 months (main study period), stratified by cardiac diagnosis. Both groups could continue in an open-label edoxaban extension arm through 1 year. The primary endpoint was adjudicated clinically relevant bleeding (CRB). The main secondary endpoint was symptomatic TE or asymptomatic intracardiac thrombosis.

RESULTS

The modified intention-to-treat cohort included 167 children. One patient per group experienced a nonmajor CRB in the main period. Treatment-emergent adverse events occurred in 46.8% (51 of 109) with edoxaban and 41.4% (24 of 58) with SOC. One SOC patient experienced 2 TE events (DVT with PE). Among 147 children in the extension, 1 CRB event (0.7%) and 4 TEs occurred (2.8%; 2 strokes and 2 of 33 Kawasaki disease patients with coronary artery thromboses and/or myocardial infarctions).

CONCLUSIONS

Edoxaban is a potential alternative mode of thromboprophylaxis in children with cardiac disease showing low rates of CRB and TEs with advantages of once daily dosing and infrequent monitoring requirement. (ENNOBLE-ATE [Edoxaban for Prevention of Blood Vessels Being Blocked by Clots] (Thrombotic Events) in Children at Risk Because of Cardiac Disease trial; NCT03395639).

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.

A Narrative Review of Postoperative Anticoagulation Therapy for Congenital Cardiac Disease

Congenital heart disease encompasses a range of cardiac birth defects. Some defects require early and complex surgical intervention and post-operative thromboprophylaxis primarily for valve, conduit, and shunt patency. Antiplatelet and anticoagulant management strategies vary considerably and may or may not align with recognized consensus practice guidelines. In addition, newer anticoagulant agents are being increasingly used in children, but these medications are not addressed in most consensus statements.

This narrative review evaluated the literature from 2011 through 2021 on the topic of postoperative thromboprophylaxis after congenital heart disease operations. The search was focused on the descriptions and results of pediatric studies for replacement and/or repair of heart valves, shunts, conduits, and other congenital heart disease operations. Wide variability in practice exists and, as was true a decade ago, few randomized controlled trials have been conducted. Aspirin, warfarin, and perioperative heparin remain the most commonly used agents with varying dosing, duration, and monitoring strategies, making comparisons difficult. Only recently have data on direct oral anticoagulants been published in children, suggesting evolving paradigms of care. Our findings highlight the need for more research to strengthen the evidence for standardized thromboprophylaxis strategies.

Increased Risk for Thromboembolism After Fontan Surgery: Considerations for Thromboprophylaxis

The Fontan circulation introduces an increased risk of thromboembolism which is associated with substantial mortality and morbidity. Adverse outcomes of thromboembolic complications post-Fontan surgery vary in both nature and severity, ranging from local tissue infarction and pulmonary embolism to Fontan failure and ischemic stroke. Furthermore, recent studies have identified that subclinical stroke is common yet underdiagnosed in Fontan patients. Fontan patients are commonly treated with antiplatelet agents and/or anticoagulants as primary thromboprophylaxis. Optimal thromboprophylaxis management in the Fontan population is still unclear, and clinical consensus remains elusive despite the growing literature on the subject. This perspective will describe the nature of thromboembolism post-Fontan surgery and provide evidence for the use of both current and emerging thromboprophylaxis options for children and adults living with Fontan circulation.