Abstract
Systemic-to-pulmonary collateral arteries (SPCs) are common in patients with single-ventricle physiology, but their impact on clinical outcomes is unclear. The aim of this study was to use retrospective cardiac magnetic resonance data to determine the relation between SPC flow and palliative stage and clinical status in single-ventricle physiology. Of 116 patients, 78 were after Fontan operation (median age 19 years) and 38 were at an earlier palliative stage (median age 2 years). SPC flow was quantified as aortic flow minus total caval flow or total pulmonary vein flow minus total branch pulmonary artery flow. Median SPC flow/body surface area (BSA) was higher in the pre-Fontan group (1.06 vs 0.43 L/min/m(2), p <0.0001) and decreased nonlinearly with increasing age after the Fontan operation (r(2) = 0.17, p <0.0001). In the Fontan group, patients in the highest quartile of SPC flow had larger ventricular end-diastolic volume/BSA (p <0.0001) and were older at the time of Fontan surgery (p = 0.04), but SPC flow/BSA was not associated with heart failure symptoms, atrial or ventricular arrhythmias, atrioventricular valve regurgitation, the ventricular ejection fraction, or peak oxygen consumption. In multivariate analysis of all patients (n = 116), higher SPC flow was independently associated with pre-Fontan status, unilateral branch pulmonary artery stenosis, a diagnosis of hypoplastic left-heart syndrome, and previous catheter occlusion of SPCs (model r(2) = 0.37, p <0.0001). In conclusion, in this cross-sectional study of single-ventricle patients, BSA-adjusted SPC flow was highest in pre-Fontan patients and decreased after the Fontan operation with minimal clinical correlates aside from ventricular dilation.