Value of Speckle-tracking Echocardiography and MRI-based Feature Tracking Analysis in Adult Patients after Fontan-type Palliation

Schmidt R., Orwat S., Kempny A., Schuler P., Radke R., Kahr P., Hellige A., Baumgartner H., Diller G.

Abstract

Background: Patients are commonly affected by ventricular dysfunction and heart failure after Fontan palliation. Reliable quantification of ventricular function is of interest but hampered by complex ventricular anatomy and physiology. Objectives: We aimed to assess myocardial function using a novel cardiac magnetic resonance imaging (CMR)-based feature-tracking (FT) technique and to study its clinical utility in Fontan patients. Methods: Retrospective study in consecutive patients attending our service. Results: We included 15 adult Fontan patients (age 27 ± 7 years) who underwent a standardized transthoracic echocardiographic investigation (TTE) with measurement of global strain using speckle tracking. Thirteen patients also underwent CMR, with assessment of myocardial deformation by FT, providing longitudinal and circumferential global strain for the single ventricle. The value of TTE-based strain measurements was limited by the fact that in 63% of patients at least one myocardial segment could not be adequately quantified due to limited acoustic windows. In contrast, CMR allowed for a complete visualization of all wall segments. Not surprisingly, there was poor agreement between the techniques but good or moderate interobserver variability for FT (coefficients of variability 6.6% and 14.3% for circumferential and longitudinal strain). Unlike ejection fraction, FT parameters correlated significantly with age at Fontan completion, New York Heart Association (NYHA) class, and peak oxygen uptake on cardiopulmonary exercise testing. Conclusions: Assessment of myocardial function using CMR cine-based feature tracking is feasible in Fontan patients. Unlike echocardiographic techniques, FT is independent of inadequate acoustic windows and FT measurements relate to clinical parameters, suggesting that this approach could have clinical relevance in future.