Risk Factors for Failed Fontan Procedure Following Stage 2 Palliation
PMID: 32828751; DOI: 10.1016/j.athoracsur.2020.06.030
- Retrospective, single center study, retrospectively analyzing 525 patients receiving Stage 2 Palliation (S2P) with superior cavopulmonary connection for single ventricle palliation over 20 years.
- The incidence of Fontan completion following S2P was, 83.9% at 3 years and 87.1% at 5 years.
- HLHS, UAVSD, reduced EF, increased EDP and increased PA pressure were all associated with inability to tolerate S2P.
Commentary from Dr. Barry Deatrick (Baltimore, MD, USA), section editor of Congenital Heart Surgery Journal Watch: The authors analyzed the results of two decades worth of bidirectional superior cavopulmonary (Glenn) shunts (BCPS) in order to understand risk factors that may contribute to failure to complete total cavopulmonary connection. They reviewed 525 patients undergoing BCPS over 20 years in a single institution. Specifically, they were interested in identifying if there were anatomic, physiologic, or hemodynamic scenarios that correlated with inability to reach successful Fontan circulation.
A competitive risk analysis was performed between one of three states: Fontan completion, death, and being alive without Fontan. Overall, the incidence of Fontan completion was good, 83.9% at 3 years and 87.1% at 5 years. The overall mortality was 10.4% at 3 years and 10.7% at 5 years, with a relatively small number (5.7% and 2.2% at 3 and 5 years respectively) being alive and not having completed a Fontan. Risk factor analysis was performed by first completing a Cox regression model, and on univariate analysis, HLHS, UAVSD, dominant RV, significant AVV regurgitation requiring an AVV procedure, higher pulmonary artery pressure (PAP), higher left atrial pressure, elevated ventricular EDP and reduced ventricular ejection fraction were associated with those patients who had not completed a Fontan procedure. On multivariate analysis, HLHS (HR = 4.1), UAVSD (HR 10.1), higher PAP, and reduced function (HR 4.2) emerged as independent risk factors. AV valve regurgitation requiring AV valve repair was not an independent risk factor in all patients, however, the need for an AV valve repair was significantly higher in patients with UAVSD.
The authors conclude that stage 2 palliation is low risk, and leads to excellent rates of Fontan completion, but that some patient groups do have increased risk of complications, mortality, and inability to achieve Fontan circulation. These are, perhaps not surprisingly, anatomic diagnoses of HLHS and UAVSD, impaired ventricular function as assessed by echocardiography or elevated filling pressures, and elevated pulmonary artery pressure. An examination of how each of these factors contribute to failure to progress, specific strategies to mitigate them, or a comparison of techniques applied to achieve stage 2 palliation, remains beyond the scope of this retrospective analysis.