Abstract 12942: Association of Exercise Performance With Hemodynamic and Imaging Parameters in Fontan Patients

Abstract

Introduction: The Fontan operation results in hemodynamic, anatomic and functional alterations in single ventricle (SV) heart disease. Studies have shown that SV patients have reduced exercise capacity. We sought to determine hemodynamic and anatomic associations with exercise capacity in our Fontan cohort. Methods: We performed a retrospective chart review of all patients born 2002-2012 who underwent Fontan palliation and followed in our Fontan Surveillance Program. Surveillance cardiac magnetic resonance (cMR), cardiac catheterization (cath), and exercise stress test (EST) data were collected. Primary analysis was association of cMR and cath data on EST outcomes including percent-predicted maximum oxygen consumption (ppVO 2 max) and oxygen pulse (ppO 2 Pulse). Results: A total of 222 patients were included, 45.5% with a systemic left ventricle (LV). Hypoplastic left heart syndrome was the underlying cardiac diagnosis in 1/3 of patients. The vast majority of the Fontan procedures performed were fenestrated, 44% extracardiac conduits and 42% with a lateral tunnel graft. A total of 185 cMRs, 274 caths, and 136 ESTs were performed. The median respiratory exchange ratio and ppVO 2 max were 1.11 L/sec and 73% respectively, with a preserved ppO 2 Pulse of 93.5%. Results of correlational analysis are shown in the table. Over serial ESTs, patients with a single RV had a more gradual, but not significant decline in ppVO 2 max than patients with a single LV, r s -0.321 and -0.544 respectively (p = 0.28). Conclusions: While hemodynamic parameters do not correlate with EST functional endpoints, anatomic factors such as the Nakata index are associated with EST performance. Surveillance of Fontan patients should include regular cMR to assess for subtle changes in ejection fraction, pulmonary artery diameter and differential pulmonary blood flow. Multicenter longitudinal studies with protocolized timing are needed to further elucidate correlates of good exercise capacity.