Abnormalities in blood coagulation, fibrinolysis, and platelet activation in adult patients after the Fontan procedure

Abstract

Adult Fontan patients are characterized by enhanced platelet activation and endothelial injury, heightened thrombin formation, and impaired fibrinolysis. Patients showed reduced free protein S levels, increased platelet activation, and endothelial damage after thromboembolic events observed late after Fontan surgery. Our findings indicate novel prothrombotic mechanisms in adult Fontan patients, which might help to optimize thromboprophylaxis.

Diagnosis and Management of Noncardiac Complications in Adults With Congenital Heart Disease: A Scientific Statement From the American Heart Association

“…230,231 In addition, platelet activation and thrombin formation are enhanced and fibrinolysis is reduced, resulting in a prothrombotic state in most adult patients with Fontan physiology. 218 This is supported by the relatively high rate of thrombosis and the relatively low rates of clinical bleeding seen in adult patients with Fontan physiology. Defining coagulation abnormalities with standard laboratory testing is difficult; prothrombin time and partial thromboplastin time are often prolonged despite a procoagulant state.…”

“…217 Thrombosis occurs in 8% to 33% of patients with Fontan physiology, and incidentally discovered asymptomatic thrombosis is more common than clinically apparent thrombosis. 65,[218][219][220][221] Thrombi can be seen in the venous pathway, the pulmonary arteries, the pulmonary venous atrium (particularly in the setting of atrial arrhythmias), or a ligated pulmonary artery stump. Thrombus is most commonly discovered in the first several years after surgery, and prevalence appears to diminish over time, 222,223 with a possible second peak in prevalence in later adulthood when hemodynamics deteriorate.…”

Aspirin resistance in adult patients after Fontan surgery

“…ACCEPTED MANUSCRIPT 5 Increased platelet activation has been described in some patients with FC (4,6). Accordingly, long-term antiplatelet therapy for prevention of thrombosis after Fontan operations is a reasonable consideration, even though thrombosis is a common feature (2)(3)(4).…”

“…Accordingly, long-term antiplatelet therapy for prevention of thrombosis after Fontan operations is a reasonable consideration, even though thrombosis is a common feature (2)(3)(4). However, it is not known whether patients after Fontan operation respond to aspirin and whether aspirin resistance is prevalent in them (11)(12)(13).…”

“…Abnormalities in any of the regulatory mechanisms in hemostasis -plasma coagulation/fibrinolytic proteins, platelets, and endothelial function -might contribute to increased thrombotic risk (4). Indeed, changes in plasma activity of coagulation factors and inhibitors, endothelial dysfunction, and enhanced platelet activation have been reported in children after Fontan surgery (5)(6)(7).…”