Thromboembolic Events Are Independently Associated with Liver Stiffness in Patients with Fontan Circulation

Figure 1. Magnetic resonance elastography images to measure liver stiffness in two patients with history of Fontan palliation. Left images: T2-weighted anatomic images. Right images: MR elastograms showing tissue stiffness. First row of images are from a 31 year-old female with no history of thromboembolism with liver stiffness of 3.0 kPa (upper limit of normal is below 2.5–2.7 kPa). Anatomic images show an enlarged, mildly T2-weighted hyperintense liver compatible with congestion and possible mild fibrosis. The elastogram shows mildly elevated liver stiffness (green and yellow on the color map) with the color scale provided for reference. Second row of images are from a 42-year-old female Fontan patient with liver stiffness of 6.4 kPa. She had atriopulmonary Fontan and a history of bilateral pulmonary embolus due to a right atrial thrombus. Anatomic images show an enlarged liver with subtle surface nodularity and reticular increased T2-weighted signal suggestive of substantial fibrosis in addition to congestion (the hepatic veins appear engorged). There is splenomegaly suggesting portal hypertension. The elastogram shows diffusely increased liver stiffness (e.g., areas of red color).

Figure 2. Magnetic resonance elastography shows increased liver stiffness in patients with a history of thromboembolic event represented as a Tukey box plot.

Figure 3. Increased Fontan pressure leads to liver congestion and fibrosis resulting in Fontan-associated liver disease. In turn, Fontan-associated liver disease results in decreased protein C and S and may worsen the hypercoagulable state. The hypercoagulable state may lead to liver microthrombi, activate liver fibrosis, and worsen hemodynamics, which results in a viscous cycle.