Is the Extracardiac Conduit the Preferred Fontan Approach for Patients With Univentricular Hearts?

Abstract

W ith improvements in technology, operative technique, and critical care medicine, more and more children with congenital heart disease are surviving into adulthood. As they age, these patients are providing physicians with new challenges, and we are realizing the long-term consequences of our previous interventions. This oftentimes has changed the mode of treatment for subsequent children. Response by Khairy and Poirier on p 2515Fontan palliation for single-ventricle patients was first described in 1971. 1 The original approach was in the form of a classic atriopulmonary Fontan connection, bypassing the nonfunctional right ventricle. After recognizing the long-term complication of an atriopulmonary connection (right atrial dilation, arrhythmias, and thrombus formation), modifications have been made. The atriopulmonary connection has been abandoned in favor of modified Fontan anatomy and physiology.The modified Fontan can be performed by the use of an extracardiac conduit approach or a lateral tunnel approach. The extracardiac Fontan uses an external conduit to anastomose the inferior vena cava into the pulmonary arteries, whereas a lateral tunnel Fontan uses a baffle within the right atrium (Figure 1). Because the systemic venous pathway is completely separated from the right atrium with the extracardiac Fontan, it is more challenging for the electrophysiologist to access the heart for ablation. My aim is to demonstrate why "the extracardiac conduit is the preferred Fontan approach for patients with univentricular hearts."The extracardiac Fontan has several advantages over the lateral tunnel Fontan. Advantage 1: Reduced Cardiopulmonary Bypass and Ischemic TimesMinimizing cardiopulmonary bypass and ischemia may optimize early postoperative outcomes. In multiple studies, both prolonged cardioplegic arrest and extended cardiopulmonary bypass times have been associated with an increased risk of early postoperative death or Fontan failure. [2][3][4] The technique of Fontan construction often dictates whether cardiopulmonary bypass or a period of ischemic arrest are required. With the lateral tunnel Fontan, the right atrium is opened for creation of the inferior vena cava baffle, necessitating the use of cardiopulmonary bypass. In addition, a period of cardioplegic arrest is required to stop the heart to prevent air embolic events until the atrium is closed. With the extracardiac Fontan, the right atrium is not opened. Vascular control is achieved at the right atrial-inferior vena cava junction. The inferior vena cava is transected and sewn to the extracardiac conduit, and the cardiac opening is oversewn. Vascular control of the pulmonary arteries is then achieved, and the conduit is sewn to the right pulmonary artery. Last, side-biting clamps are placed on the right atrium and conduit to create a fenestration if desired. With the use of this

Fontan Pathway Growth: A Quantitative Evaluation of Lateral Tunnel and Extracardiac Cavopulmonary Connections Using Serial Cardiac Magnetic Resonance

“…In general, the LT pathway is created by suturing a synthetic baffle inside the atrium[2] and the EC conduit is created from a synthetic tubular graft[3, 4]. Previous studies have shown that the different geometric features of the two connection types are associated with different hemodynamic characteristics, but there is no consensus on which is superior[5, 6]. …”

Characterization of Flow Efficiency, Pulsatility, and Respiratory Variability in Different Types of Fontan Circuits Using Quantitative Parameters

“…ECC Fontan has several advantages over LT Fontan, particularly in terms of energy efficiency 1224. The definite difference between LT and ECC Fontan tract is the method of anastomosing the IVC to the PA: baffle in LT and conduit in ECC.…”

State of the art of the Fontan strategy for treatment of univentricular heart disease

“…Two large meta-analyses have recently compared surgical strategies and found no differences in early or late mortality and Fontan takedown between ECC and ILT 33 , 149 . Theoretical advantages of both techniques have been discussed extensively in the literature 150 , 151 . Further research should assess contemporary differences in outcomes between modifications and help guide the preferred procedure for future Fontan patients.…”