Prothrombotic state and hypofibrinolysis in patients after Fallot syndrome surgery

Tetralogy of Fallot (ToF) is the most common cyanotic congenital heart defect. Current guidelines do not recommend oral anticoagulation in asymptomatic adults with corrected ToF unless AF coexists, and only if stroke risk (CHA₂DS₂-VASc score) justifies it. The aim of the study was whether ToF patients present a prothrombotic state, which could increase the risk of thromboembolic events.

This pilot study included adult patients (>18 years) post-ToF repair, including those with paroxysmal or persistent AF (CHA₂DS₂-VASc = 0) not receiving anticoagulation.

All participants underwent a standardized clinical assessment, laboratory workup (CBC, lipid profile, creatinine, D-dimer, CRP, glucose using routine laboratory parameters; performed using BCS system, Siemens), and detailed analysis of the fibrin clot phenotype, assessed as described previously [1]. Plasma clot permeability (Ks) and clot lysis time (CLT) were assessed using established protocols with slight modifications. Thrombin generation potential was evaluated via calibrated automated thrombography (CAT), according to the manufacturer [1]. ELISA-based quantification of PAI-1 antigen (Hyphen) and von Willebrand factor (vWF; Abnova) were conducted to assess fibrinolytic inhibition and endothelial dysfunction, according to the manufacturer.

References: 

1. Ząbczyk M, Natorska J, Janion-Sadowska A, et al. Prothrombotic fibrin clot properties associated with NETs formation characterize acute pulmonary embolism patients with higher mortality risk. Sci Rep. 2020 Jul 10;10(1):11433.