Single Ventricular Torsional Mechanics After Fontan Palliation and Their Impact on Outcomes

• Published in: JACC. Advances (Online) Vol. 2; no. 4; p. 100360
• Main Authors: Gearhart, Addison, Bassi, Sunakshi, Liddle, David, Thatte, Nikhil, Harrington, Jamie K, Rathod, Rahul H, Ghelani, Sunil J
• Format: Journal Article
• Language: English
• Published: United States Elsevier 01.06.2023
• Subjects: Original Research; congenital heart disease; Fontan palliation; ventricular mechanics; cardiac magnetic resonance imaging; torsion
• ISSN: 2772-963X; 2772-963X
• DOI: 10.1016/j.jacadv.2023.100360

Abnormal left ventricular (LV) rotational mechanics in biventricular hearts are associated with adverse outcomes; however, these are less well characterized for hearts with functionally single ventricles. The purpose of this study was to characterize ventricular rotational mechanics in the Fontan circulation and their relationship to outcomes. Single-center, retrospective analysis of magnetic resonance examinations for 329 Fontan patients (15 [IQR: 10-21] years) and 42 controls. The ventricular cine short-axis stack was analyzed to derive torsion metrics. Torsion calculated as the difference between apical and basal rotation normalized to ventricular length. Fontan patients had higher indexed ventricular end-diastolic volume (97 mL/body surface area vs 72 mL/body surface area ), lower ejection fraction (53% vs 60%), and lower proportion of basal clockwise rotation (62% vs 93%), apical counterclockwise rotation (77% vs 95%), and positive torsion (82% vs 100%); < 0.001 for all. A composite outcome of death or heart transplant-listing occurred in 31 (9%) patients at a median follow-up of 3.9 years. Torsion metrics were associated with the outcome; although, on multivariate analysis only right ventricular (RV) morphology and indexed ventricular end-diastolic volume were independently associated. LVs with negative torsion, and RVs regardless of torsional pattern, had worse outcomes compared to LVs with positive torsion ( = 0.020). Single ventricles in a Fontan circulation exhibit abnormal torsional mechanics, which are more pronounced for RV morphology. Abnormal torsion is associated with death or need for heart transplantation. Fontan patients with LV morphology and preserved torsion exhibit the highest transplant-free survival and torsion may offer incremental prognostic data in this group of patients.