Where Is the “Optimal” Fontan Hemodynamics?

Abstract

Fontan circulation is generally characterized by high central venous pressure, low cardiac output, and slightly low arterial oxygen saturation, and it is quite different from normal biventricular physiology. Therefore, when a patient with congenital heart disease is selected as a candidate for this type of circulation, the ultimate goals of therapy consist of 2 components. One is a smooth adjustment to the new circulation, and the other is long-term circulatory stabilization after adjustment. When either of these goals is not achieved, the patient is categorized as having “failed” Fontan circulation, and the prognosis is dismal. For the first goal of smooth adjustment, a lot of effort has been made to establish criteria for patient selection and intensive management immediately after the Fontan operation. For the second goal of long-term circulatory stabilization, there is limited evidence of successful strategies for long-term hemodynamic stabilization. Furthermore, there have been no data on optimal hemodynamics in Fontan circulation that could be used as a reference for patient management. Although small clinical trials and case reports are available, the results cannot be generalized to the majority of Fontan survivors. We recently reported the clinical and hemodynamic characteristics of early and late failing Fontan survivors and their association with all-cause mortality. This knowledge could provide insight into the complex Fontan pathophysiology and might help establish a management strategy for long-term hemodynamic stabilization.

Anesthetic management for non-cardiac surgery in a patient with Fontan palliation

“…7 Es así como estos pacientes se caracterizan por tener una PVC aumentada, bajo gasto cardiaco 8 y una ligera disminución en la saturación arterial de oxígeno, para lo que desarrollan adaptaciones como el aumento de las resistencias vasculares arteriales, la redistribución del gasto cardiaco a los órganos vitales y el aumento en la hemoglobina. 9 Nuestro paciente, aunque conserva una fracción de eyección adecuada, muestra hemoconcentración en hemoglobina y hematocrito como mecanismo de compensación a la hipoxemia crónica.…”

The Janus‐faced Fontan circulation: unravelling its elusive pathophysiology

“…First, the ‘failing Fontan syndrome’ lacks a robust definition, obscuring epidemiological studies and trials. Further, the current data suggest that there are distinct haemodynamic phenotypes in Fontan pathophysiology associated with adverse outcome . One being the ‘traditional’ phenotype stereotyped by a low CI associated with high CVP, elevated PVRi and/or cardiac dysfunction, with decreased or increased ventricular preload respectively, and increased systemic vascular resistance (SVR) ( Figure A ).…”

Providing a framework of principles for conceptualising the Fontan circulation

“…15,16 The clinician may improve output by lowering pulmonary vascular resistance but with limited result as many pulmonary lesions such as hypoplasia, stenosis, exclusion and others are not amenable to dilation; a great desire exists for improving the "suction of the ventricle", but no lusitropic drugs nor efficient manoeuvres to lower VEDP are available. 4,7,8 Increasing lower extremity muscle mass may impact active systemic venous return; however, this is a…”

“…The patient can increase his circulatory output by using peripheral muscles to pump blood into his caval veins to increase systemic venous pressure to drive blood through the critical bottleneck; respiratory pattern and force may also be helpful . The clinician may improve output by lowering pulmonary vascular resistance but with limited result as many pulmonary lesions such as hypoplasia, stenosis, exclusion and others are not amenable to dilation; a great desire exists for improving the “suction of the ventricle”, but no lusitropic drugs nor efficient manoeuvres to lower VEDP are available . Increasing lower extremity muscle mass may impact active systemic venous return; however, this is a concept not yet well studied.…”