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.