Abstract 17119: Sufficient Pulmonary Vascular Bed Before Fontan Surgery Secures Favorable Fontan Hemodynamics

Abstract

Introduction: While improvement of perioperative care markedly expanded candidacy of Fontan surgery, increasing number of Fontan patients is currently subjected to advanced heart failure therapies. Low pulmonary flow before Fontan procedure has been considered to be acceptable as it keeps pulmonary resistance low, however, compromised growth of pulmonary vascular bed after Fontan completion may deteriorate potential to preserve better Fontan circulation later. We tested our hypothesis that sufficient growth of pulmonary vascular bed before Fontan surgery chronically preserves favorable Fontan hemodynamics and prevents patients from cardiovascular remodeling. Methods and Results: Consecutive 33 patients who had undergone Fontan operation (median year after the surgery: 5.3years) were enrolled in this study. During cardiac catheterization, pulmonary arterial index (PAI) as the representative of vascular bed both before and after Fontan procedure was measured and hemodynamics as well as blood samples as a marker for end-organ dysfunction were analyzed. Before Fontan procedure, PAI ranged 74-426 and resistance of pulmonary artery (PAR) ranged 0.4-3.1. After median of 5.3 years of Fontan procedure, CVP exhibited modest decline with preserving cardiac index (CI). Interestingly, central venous pressure (CVP) with chronic Fontan circulation was negatively correlated with PAI of pre-Fontan procedure (P=0.02) whereas it was independent of PAR. Consistent with this, higher PAI before Fontan procedure was also significantly associated with higher CI (P<0.01) and lower levels of plasma brain natriuretic peptides (P=0.03). Importantly, patients with low PAI showed markedly elevated activation of renin-angiotensin-aldosterone (RAAS) activation and elevation of serum gamma-gltamyl transferase (P<0.01), a surrogate marker of liver congestion. Multivariate analysis revealed that high PAI was determinant of low CVP in the chronic Fontan patients, independent of body size, postoperative interval and pulmonary arterial resistance. Conclusion: Sufficient pulmonary vascular bed before Fontan procedure independently lowers CVP, may prevent cardiovascular remodeling by RAAS suppression as well as end organ dysfunction in chronic Fontan patients. Our result suggested importance of strategies to accelerate pulmonary vascular growth before Fontan procedure.