Approaches to Establish Extracardiac Total Cavopulmonary Connections in Animal Models-A Review

Long-term survival of patients with a single ventricle palliated with a Fontan procedure is still limited. No curative treatment options are available. To investigate the pathophysiology and potential treatment options, such as mechanical circulatory support (MCS), appropriate large animal models are required. The aim of this review was to analyze all full-text manuscripts presenting approaches for an extracardiac total cavopulmonary connection (TCPC) animal model to identify the feasibility and limitations in the acute and chronic setting.

A literature search was performed for full-text publications presenting large animal models with extracardiac TCPCs on Pubmed and Embase. Out of 454 reviewed papers, 23 manuscripts fulfilled the inclusion criteria. Surgical procedures were categorized and hemodynamic changes at the transition from the biventricular to the univentricular condition analyzed.

Surgical procedures varied especially regarding coronary venous flow handling and anatomic shape of the TCPC. In most studies (n = 14), the main pulmonary artery was clamped and the coronary venous flow redirected by additional surgical interventions. Only in five reports, the caval veins were connected to the right pulmonary artery to create a true TCPC shape, whereas in all others (n = 18), the veins were connected to the main pulmonary artery. An elevated pulmonary vascular resistance was identified as a limiting hemodynamic factor for TCPC completion in healthy animals.

A variety of acute TCPC animal models were successfully established with and without MCS, reflecting the most important hemodynamic features of a Fontan circulation; however, chronic animal models were not reported.