Embolization of Veno-venous Collaterals after the Fontan Operation Is Associated with Decreased Survival

ObjectiveAfter Fontan operation, hemodynamically significant veno-venous collateral (VVC) vessels can lead to systemic arterial desaturation. Outcomes after embolization of VVCs have not been determined. We sought to determine the frequency of and outcomes for patients undergoing VVCs embolization after Fontan operation. DesignWe retrospectively analyzed clinical and hemodynamic data of patients who underwent cardiac catheterization after the Fontan operation from 1995 to 2014 at Mayo Clinic. Clinical, imaging, and hemodynamic data from patients with VVCs were compared based on intervention (embolization) vs. nonintervention. ResultsFour hundred ninety-six patients with prior Fontan operation had catheterization; 109 VVCs were identified in 72 patients (37 males, mean age 26 12 years). Embolization was performed in 31/72 patients (43%). Following embolization, no improvement was demonstrated in oxygen saturation or hemoglobin concentration at ambulatory follow-up (2.5 +/- 2 years), and cardiac index declined at follow-up catheterization (5.6 +/- 3 years). Overall, 15 patients (21%) died at a mean of 2.8 +/- 4 years after embolization. Fifty percent of deaths after embolization occurred in patients with Fontan pressures 18mmHg. Five-year survival of patients with VVCs undergoing embolization was 74% compared with 92% in those patients who did not undergo embolization (P < .01). In multivariate analysis, significant predictors of death on follow-up were embolization [hazard ratio (HR) = 9.3 (95% confidence interval [CI], 2.8-42), P = .0001], atrio-pulmonary Fontan (HR = 4.2 [95% CI, 1.4-15], P = .01), and heterotaxy (HR = 3.7 [95% CI, 1.0-15], P = .05). ConclusionWe observed decreased 5-year survival in patients who had VVC embolization. Embolization of VVC in patients after Fontan should be evaluated very carefully in patients with atrio-pulmonary type Fontan, heterotaxy, and those with Fontan pressure above 18mmHg. These patients may benefit from the natural fenestration that VVCs provide.