Atrial function in Fontan patients assessed by CMR: Relation with exercise capacity and long-term outcomes

Jelle P.G Van Der Ven,Tarek Alsaied,Saeed Juggan,Sjoerd S.M Bossers,Eva Van Den Bosch,Livia Kapusta,Irene M Kuipers,Lucia J.M Kroft,Arend D.J Ten Harkel,Gabrielle G Van Iperen,Rahul H Rathod,Willem A Helbing

doi:10.1016/j.ijcard.2020.02.060

Abstract

ObjectiveTo assess the role of atrial function on exercise capacity and clinical events in Fontan patients. DesignWe included 96 Fontan patients from 6 tertiary centers, aged 12.8 (IQR 10.1–15.6) years, who underwent cardiac magnetic resonance imaging and cardiopulmonary exercise testing within 12 months of each other from 2004 to 2017. Intra-atrial lateral tunnel (ILT) and extracardiac conduit (ECC) patients were matched 1:1 with regard to age, gender and dominant ventricle.The pulmonary venous atrium was manually segmented in all phases and slices. Atrial function was assessed by volume-time curves. Furthermore, atrial longitudinal and circumferential feature tracking strain was assessed.We determined the relation between atrial function and exercise capacity, assessed by peak oxygen uptake and VE/VCO2 slope, and events (mortality, listing for transplant, re-intervention, arrhythmia) during follow-up. ResultsAtrial maximal and minimal volumes did not differ between ILT and ECC patients. ECC patients had higher reservoir function (21.1 [16.4–28.0]% vs 18.2 [10.9–22.2]%, p = .03), lower conduit function and lower total circumferential strain (13.8 ± 5.1% vs 18.0 ± 8.7%, p = .01), compared to ILT patients.Only for ECC patients, a better late peak circumferential strain rate predicted better VE/VCO2 slope. No other parameter of atrial function predicted peak oxygen uptake or VE/VCO2 slope.During a median follow-up of 6.2 years, 42 patients reached the composite end-point. No atrial function parameters predicted events during follow-up. ConclusionsECC patients have higher atrial reservoir function and lower conduit function. Atrial function did not predict exercise capacity or events during follow-up.

Highlights

The Fontan operation provides palliation for univentricular cardiac defects offering these patients long term survival with a reasonable quality of life [1]
This study aims to describe atrial function in contemporary modifications of the Fontan operation by volumetric and feature tracking strain cardiovascular magnetic resonance imaging (CMR)
The study included 165 patients (64 extracardiac conduit (ECC); 101 intra-atrial lateral tunnel (ILT)) who met inclusion criteria. 4 duplicate subjects were excluded from analysis. 96 unique patients (48 ECC; 48 ILT) were matched with regard to age, gender and dominant ventricle. 24 patients were included from Boston Children's Hospital and 72 from the Netherlands

Summary

Introduction

The Fontan operation provides palliation for univentricular cardiac defects offering these patients long term survival with a reasonable quality of life [1]. The ILT modification connects the inferior vena cava to the pulmonary artery by creating a lateral tunnel through the right atrium, incorporating part of the atrial wall in the circuit. In the absence of a prepulmonary pump, blood flows passively over the pulmonary vascular bed. Because of this passive flow Fontan patients have a limited ability to augment this blood flow during exercise [9,10]. Exercise capacity is an important determinant of survival and quality of life in Fontan patients [11,12,13]. Determinants of exercise capacity in the Fontan remain incompletely understood

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Conclusion