Adverse pulmonary vascular remodeling in the Fontan circulation

Histopathological abnormalities in the central arteries and veins of Fontan subjects

“…In this series, inflammation in the caval veins of Fontan subjects was rare. The histological findings in the central conduit pulmonary arteries were similar to reports on intra-acinar pulmonary arteries 14. Apart from a single case study,18 to our knowledge, these findings represent the first description of histopathological remodelling that occurs within these central vessels in this group of patients.…”

“…Vascular remodelling has attracted some interest owing to the potential influence on conductance properties of the vessel 14. Prior histopathological studies in Fontan patients have focused on the smaller pulmonary vasculature using lung tissue obtained intraoperatively at the time of Fontan or using postmortem specimens from patients who died perioperatively 15–17.…”

Cardiopulmonary adaptation to short-term high altitude exposure in adult Fontan patients

“…In adults with a long-standing Fontan circulation, remodelling of the pulmonary vasculature with a reduction of vascular smooth muscle cells can be observed, probably due to the lack of pulsatile flow in the pulmonary vasculature 17 18. Vascular remodelling and the non-pulsatile flow may be at the origin of an endothelial dysfunction described by different authors 19–21.…”

Elevated Low-Shear Blood Viscosity is Associated with Decreased Pulmonary Blood Flow in Children with Univentricular Heart Defects

“…While children normally have significant pulmonary artery growth until around 8 years of age, those with univentricular hearts have almost complete arrest of growth after the Glenn [24] and Fontan procedures [18]. Histologic studies of autopsy specimens have shown that these patients have adverse pulmonary vascular remodeling, including intimal thickening from fibrosis and collagen deposition as well as time-dependent alterations in medial smooth muscle [21]. A porcine model of a unilateral cavopulmonary anastomosis suggests that chronic non-pulsatile flow to the lungs resulting in endothelial dysfunction may be the underlying mechanism of this pathology [10].…”