Beyond a Broken Heart: Circulatory Dysfunction in the Failing Fontan

Abstract

The role of ventricular dysfunction in late morbidity and mortality of univentricular hearts has been described previously. However, a significant proportion of adult Fontan patients who die or require heart transplantation do so with preserved ventricular function. The clinical deterioration in patients who have undergone Fontan palliation requires a broader view of circulatory dysfunction, one that takes into account the complex interaction of regulatory systems affecting hepatic, renal, and pulmonary blood flow, in addition to cardiac function. This review focuses primarily on the pathophysiology of multiple organ involvement in this circulatory dysfunction, with particular focus on the consequences of hepatic dysfunction and portal hypertension. The authors discuss hepatic perfusion, both in health and disease, and review the current understanding of liver histopathology and liver disease in adult Fontan patients and similar clinicopathologic states. They compare and contrast features of postsinusoidal portal hypertension with more typical adult cirrhotic disease. Finally, they delineate the related effects of portal hypertensive physiology on the systemic and pulmonary vasculature, the kidney, and the heart itself and discuss how these changes affect the care of the adult Fontan patient.

Patient-Specific Surgical Planning, Where Do We Stand? The Example of the Fontan Procedure

“…Reducing these resistances should also lower the central venous pressure and therewith the risks of proteinlosing enteropathy and liver dysfunction. 32 Pulmonary arteriovenous malformations (PAVMs) have been associated with the deprivation of a hepatic factor, either due to liver dysfunction or to mal-distribution of the hepatic flow to one or both of the lungs as a result of suboptimal TCPC geometry. 36 The reviews in Refs.…”

“…36 The reviews in Refs. 17,32 are good starting points for further reading on Fontan complications and failure modes.…”

Fontan Circulation

“…The consequences of this prolonged state of low cardiac output and elevated CVP are apparent when one examines the cardiovascular system itself as well as the other organ systems outside of the heart. 10 Although there is a broad range of cardiovascular fitness levels among patients with Fontan physiology, the general trend is toward a decrease in exercise capacity over time both when viewed in a cross-sectional manner at different time points by age and when evaluated longitudinally in individual patients. 11,12 This has important consequences because exercise capacity is correlated with functional status.…”

“…13,14 The liver and kidney are examples of organ systems that are significantly affected by the Fontan circulation. 10,15 Although not specifically proven, the prevailing understanding of liver fibrosis in the Fontan circulation is that it relates to the chronic congestion associated with elevated CVP and the diminished oxygen delivery associated with low cardiac output. Similarly, diminished renal function is thought to be related to decreased renal perfusion in the setting of low cardiac output.…”

Creation of a transcatheter fenestration in children with failure of fontan circulation: Focus on extracardiac conduit connection

“…Increased PVR may lead to chronic venous congestion and progressively deteriorating function with effusions, protein‐losing enteropathy (PLE), or hepatic dysfunction. Increased pulmonary resistance may additionally lead to reduced preload of the systemic ventricle and is responsible for low cardiac output . Typically, a distinction is made between high PVR with a precapillary pulmonary vascular component and a high transpulmonary gradient and PVR with an elevated systemic venous pressure due to postcapillary pulmonary hypertension.…”