Fontan Surgical Planning: Previous Accomplishments, Current Challenges, and Future Directions

Abstract

The ultimate goal of Fontan surgical planning is to provide additional insights into the clinical decision-making process. In its current state, surgical planning offers an accurate hemodynamic assessment of the pre-operative condition, provides anatomical constraints for potential surgical options, and produces decent post-operative predictions if boundary conditions are similar enough between the pre-operative and post-operative states. Moving forward, validation with post-operative data is a necessary step in order to assess the accuracy of surgical planning and determine which methodological improvements are needed. Future efforts to automate the surgical planning process will reduce the individual expertise needed and encourage use in the clinic by clinicians. As post-operative physiologic predictions improve, Fontan surgical planning will become an more effective tool to accurately model patient-specific hemodynamics.

Keywords: Fontan; Hepatic flow distribution; Patient specific; Pre-operative planning; Surgical planning.

Fig. 1

Staged palliation for single ventricle congenital heart defects. Blood volume is colored by blue (deoxygenated) and red (oxygenated). ASD: atrial septal defect, BDG: bidirectional Glenn anastomosis, BT: Blalock-Taussig, FF: Fontan fenestration, FT: Fontan tunnel, IVC/SVC: inferior/superior vena cava, LA: left atrium, LV: left ventricle, PA: pulmonary artery, PDA: patent ductus arteriosus, PV: pulmonary vein, RA: right atrium, RV: right ventricle, TCPC: total cavopulmonary connection

Fig. 2

Surgical planning paradigm

Fig. 3

Interaction and types of data transfer between clinical and academic settings. Events are positioned chronologically from top to bottom

Fig. 4

Creation of surgical options. (a) Fontan extracardiac baffle option. (b) Fontan bifurcated Y-graft option. (c) Automatic creation of baffle insertion angle/offset variations. (d) Preview of unioned (pre-op anatomy with proposed graft placement) mesh

Fig. 5

General process for patient-specific CFD simulations

Fig. 6

Total time and user input required for surgical planning. These estimates are repreentative of modeling one surgical option at one physiologic condition

Fig. 7

Representative surgical planning case. Only inlet waveforms are shown for clarity. Streamlines colored by outlet vessel (LPA=red, RPA=blue) HFD to the right lung is indicated by percentage. The Y-graft (offset) option was implemented in the patient. Post-operative assessment was conducted at a 2 month follow up visit. To compare anatomies, the proposed option (red) is overlaid with the actual post-operative anatomy (blue). (ECC: extracardiac conduit)

Fig. 8

Comparison of proposed (red) and post-operative (blue) anatomies for three representative cases. (a) 8 year follow up, (b) ½ year follow up, (c) 3 year follow up

Fig. 9

Potential Fontan surgical planning clinical timeline Events color-coded by blue (clinical) and gold (academic)