1356899 - Right atrial remodeling after cardiac operation in adult patients with congenital heart disease: a cardiovascular magnetic resonance study

The right atrium remodeling has been extensively studied recently in patients with atrial fibrillation and patients with pulmonary hypertension¹. Congenital heart disease has affected both the right ventricle and right atrium. Cardiac MRI (CMR) is considered as the gold standard for right heart evaluation, especially in congenital heart diseases. Despite of extensive CMR data in right ventricular (RV) remodeling after cardiac surgery, there is a paucity of right atrial remodeling information in patients with adult congenital heart disease (ACHD). We aim to evaluate the right atrial remodeling after cardiac surgery in ACHD patients using CMR as the reference imaging.

Methods: A retrospective study in single university hospital was conducted. Patients with adult congenital heart disease who underwent CMR after cardiac surgery from 2011 – 2020 were recruited. Patients with significant residual lesion after surgery were excluded. Right ventricular end-diastolic volume index (RVEDVi), right ventricular end-systolic volume index (RVESVi), right ventricular stroke volume index (RVSVi), right ventricular ejection fraction (RVEF), right ventricular systolic strain, right atrial maximal and minimal volume index (RAVImax and RAVImin), right atrial stroke volume index (RASVi) and right atrial total ejection fraction (RAEF) were evaluated. Data were compared between different physiological type of congenital heart diseases (pressure-load RV vs. volume-load RV) and between patients and healthy volunteers.

Results:

Of all ACHD patients who underwent CMR after cardiac surgery, total 37 patients without significant residual lesions were included. There were 23 females (62.2%), mean age of 33 + 10 years old, 11 patients with pressure-load RV and 26 patients with  volume-load RV (19 patients with rTOF and 7 patients with shunt).  Median time between surgery and CMR was 387 days. There was no significant age-difference between patients and healthy volunteers (33 + 10 years vs. 32 + 3 years, p=0.63) and between pressure-load and volume-load patients (31 + 13 years vs. 34 + 9 years, p=0.52). After cardiac surgery, the right atrial volume and function was not significantly different between patients with pressure-load RV and volume-load RV. However, when compared with healthy volunteers, both groups demonstrated significantly lower RAVImin, RASVi and RAEF (table 1). In addition, data from patients who underwent both pre- and post-surgery CMR showed that the RAEF did not improve significantly after cardiac surgery in both group of patients (p=0.08 and 0.34 respectively).

Conclusion: After cardiac surgery, the right atrial function did not significantly improve and remained significantly lower than healthy volunteers even in patients without significant residual lesion. Long-term follow-up to demonstrate clinical significance in this finding is needed.