Transesophageal echocardiography of intracardiac thrombus in congenital heart disease and atrial flutter: the importance of thorough examination of the Fontan

Difference in the prevalence of intracardiac thrombus on the first presentation of atrial fibrillation versus flutter in the pediatric and congenital heart disease population

INTRODUCTION

Guidelines recommend trans-esophageal echocardiography (TEE) for patients with atrial fibrillation (AF) or atrial flutter (AFL) for >48 h, due to risk of intracardiac thrombus formation. With growing evidence that AFL in adults with structurally normal hearts has less thrombogenic potential compared to AF, and the need for TEE questioned, we compared prevalence of intracardiac thrombus detected by TEE in pediatric and congenital heart disease (CHD) patients presenting in AF and AFL.

METHODS/RESULTS

Single-center, cross-sectional analysis for unique first-time presentations of patients for either AF, AFL, or intra-atrial reentrant tachycardia (IART) between 2000 and 2019. Patients were categorized by presenting arrhythmia (AF vs. AFL/IART), with the exclusion of other forms of atrial tachycardia, hemodynamic instability, chronic anti-coagulation before TEE, and presentation for a reason other than TEE examination for thrombus. A total of 201 patients had TEE with co-diagnosis of AF or AFL. Of these, 105 patients (29 AF, 76 AFL) met inclusion criteria, with no difference in age between AF (median 24.9 years; IQR 18.6-38.3 years) and AFL/IART (23.3 years; 15.4-38.4 years). The prevalence of thrombus in the entire cohort was 9.5%, with no difference between AF (13.8%) and AFL groups (7.9%), p = .46. Patients with thrombus demonstrated no difference in age, systemic ventricular function, cardiac complexity, or CHADS2/CHA2DS2VASc score at presentation.

CONCLUSIONS

The risk for intracardiac thrombus is high in the pediatric and CHD population, with no apparent distinguishing factors to warrant a change in the recommendations for TEE, with all levels of cardiac complexity being at risk for clot.

Prevalence and outcome of thrombotic and embolic complications in adults after Fontan operation

There are limited studies of thrombotic and embolic complications (TEC) in the adult Fontan population. The purpose of the study was to determine the prevalence, risk factors, and outcomes of TECs in this population.

METHODS

Retrospective review of adults with a previous Fontan operation, with follow-up at Mayo Clinic, 1994-2014. Systemic TEC was defined as intracardiac thrombus, ischemic stroke, or systemic arterial embolus. Nonsystemic TEC was defined as Fontan conduit/right atrial thrombus or pulmonary embolus.

RESULTS

We identified 387 patients with a mean (SD) age of 28 (7) years and a mean follow-up of 8 (2) years. An atriopulmonary connection (APC) was done for 286 patients (74%). Atrial arrhythmias were present in 278 (72%). There were 121 TECs (systemic n=36, nonsystemic n=85) in 98 patients (25%). Risk factors for systemic TEC were atrial arrhythmia (hazard ratio 2.28, P=.001) and APC (hazard ratio 1.98, P=.02); nonsystemic TEC also had similar risk factors. All 98 patients received warfarin. Warfarin was discontinued in 10 of 98 because of bleeding, and 8 of these 10 subsequently had a second TEC. Among the 82 patients who had follow-up imaging, 16 (20%) had resolution of thrombus. In total, 24 of 98 patients had a second TEC, most of whom had inadequate anticoagulation.

CONCLUSIONS

Thrombotic and embolic complication was not uncommon; risk factors for TEC were APC and atrial arrhythmias. Most patients were treated successfully with warfarin alone. A second TEC occurred in most patients whose anticoagulation was discontinued because of bleeding events.

Strategies for thromboprophylaxis in Fontan circulation: a meta-analysis

BACKGROUND

The Fontan circulation is associated with an increased risk of thromboembolic events (TEs). As many as 25% of these thrombotic events result in fatality. More subtle adverse effects on the pulmonary circulation from embolic thrombi may further impair adequate functioning of the circuit. Despite these well-documented phenomena, the most optimal approaches to thromboprophylaxis are still not clearly defined.

OBJECTIVE

A meta-analysis of published trials in English on PubMed and Cochrane libraries that evaluated the role of using TE prophylaxis in patients who underwent the Fontan procedure was conducted.

METHODS

10 studies with a total number of 1200 patients with an average follow-up time of 7.1 years were identified. A random effect model was used.

RESULTS

The incidence of TE was significantly less in patients who received TE prophylaxis (using either aspirin or warfarin) compared with patients who did not receive TE prophylaxis (OR 0.425, 95% CI 0.194 to 0.929, p<0.01, I(2)=37%). The incidence of TE was significantly lower in patients who received aspirin compared with no TE prophylaxis (OR 0.363, 95% CI 0.177 to 0.744, p<0.01, I(2)=0%) and who received warfarin compared with no TE prophylaxis (OR 0.327, 95% CI 0.168 to 0.634, p<0.01, I(2)=2.5%). There was no significant difference in incidence of TE between warfarin and aspirin (OR 0.936, 95% CI 0.609 to 1.438, p=0.54, I(2)=0%). Furthermore, there was no significant difference in incidence of early TE (within 6 months of the operation) or late TE (>6 months) between patients receiving warfarin and aspirin (OR 0.784, 95% CI 0.310 to 1.982, p=0.37, I(2)=8%) and (OR 0.776, 95% CI 0.249 to 2.42, p=0.3, I(2)=45%), respectively. When only total cavopulmonary connection patients were included, there was again no difference between warfarin and aspirin in the incidence of TE (OR 0.813, 95% CI 0.471 to 1.401, p=0.34, I(2)=11%).

CONCLUSIONS

This study shows a significantly lower incidence of TE after Fontan procedure if either aspirin or warfarin is used. This meta-analysis suggests no significant difference in incidence of early or late TE in patients receiving aspirin compared with warfarin.