Assessment of Late Thromboembolic Complications Post-Fontan Procedure in Relation to Different Antithrombotic Regimens: 30-Years' Follow-up Experience

Thromboembolic Complications in Adult Patients Following Fontan Procedure-A Multicenter Study

BACKGROUND

Morbidity and mortality following Fontan (FO) surgery are primarily thromboembolic in nature. However, follow-up data regarding thromboembolic complications (TECs) in adult patients after FO procedure are inconsistent. In this multicenter study, we investigated the incidence of TECs in FO patients.

METHODS

We studied 91 patients who underwent FO procedure. Clinical data, laboratory, and imaging investigations were collected prospectively during the scheduled medical appointments in 3 Adult Congenital Heart Disease Departments in Poland. TECs were recorded during a median follow-up of 31 months.

RESULTS

Four patients (4.4%) were lost to follow-up. The mean age of patients was 25.3 (±6.0) years at enrollment, and the mean time between FO operation and investigation was 22.1 (±5.1) years. A total of 21 out of 91 patients (23.1%) had a history of 24 TECs since an FO procedure, mainly pulmonary embolism (PE; n = 12, 13.2%), including 4 (33.3%) silent PE. The mean time since FO operation to the first TEC was 17.8 (±5.1) years. During follow-up, we documented 9 TECs in 7 (8.0%) patients, mainly PE (n = 5, 5.5%). Most patients with TEC had a left type of systemic ventricle (57.1%). Three patients (42.9%) were treated with aspirin, 3 (3.4%) with Vitamin K antagonists or novel oral anticoagulants, and 1 patient had no antithrombotic treatment at the time of TEC occurrence. Supraventricular tachyarrhythmias were present in 3 patients (42.9%).

CONCLUSIONS

This prospective study shows that TECs are common in FO patients, and a significant number of these events occur during adolescence and young adulthood. We also indicated how much TECs are underestimated in the growing adult FO population. The complexity of the problem requires more studies, especially to standardize the prevention of TECs in the whole FO population.

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.

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.

Thrombosis Prevention and Anticoagulation Management in the Pediatric Patient with Congenital Heart Disease

Thrombosis is one of the most frequent complications affecting children with congenital heart disease (CHD). Palliative and reparative cardiac surgeries are some of the main players contributing to the thrombosis risk in this patient population. Additional risk factors related to the CHD itself (e.g., cardiac dysfunction, arrhythmias, and polycythemia in cyanotic cardiac disorders) can contribute to thrombogenicity alone or combined with other factors. Thrombotic complications have been recognized as a significant cause of morbidity and mortality in this patient population. Here, we provide an overview of the pathophysiology and risk factors for thrombosis as well as the indications for and use of different anticoagulation, antiplatelet, and thrombolytic agents. In addition, we describe some of most common thrombotic complications and their management in the pediatric CHD population.