P2737Changes of the amount of myocardial fibrosis after cardiac surgery in adult congenital heart disease patients: a cardiovascular magnetic resonance T1 mapping study

Abstract

Abstract Background Myocardial fibrosis is not uncommon in patients with adult congenital heart disease (ACHD). Whether myocardial fibrosis can be resolved after cardiac surgery is questionable. Purpose We aimed to investigate the change of myocardial fibrosis after cardiac surgery in ACHD patients using T1 mapping CMR technique. The amount of myocardial fibrosis and cardiac function including myocardial strain were compared between non-ACHD and surgically-corrected ACHD patients. Methods All patients underwent cardiovascular magnetic resonance (CMR) on a 1.5T system before and after cardiac surgery. The protocol was approved by the local ethnic review board, and informed consent was obtained from each participant. Pre- and post-contrast T1 mapping were performed in the mid-cavity short-axis level with a 5(3)3 MOLLI scheme and ECG-gated acquisition. Myocardial fibrosis was expressed by the percentage of ECV. Ventricular and clinical parameters including 6-minute walk distance (6MWD), ejection fraction and myocardial strain were also analyzed. Mean ± standard deviation (SD) was reported. Paired t-test and independent sample t-test were used. Results Total 13 ACHD patients underwent CMR before and after surgery (34±16 years old, 9 female, 5 cyanotic, 5 underwent second operation). Median duration between CMR scanning and surgery was 308 days. Despite of increased 6 minutes-walk distance after surgery, the myocardial ECV did not significantly change (table 1). Compared with non-ACHD patients, the ECV in ACHD patients after surgery remained significantly higher (figure 1) although ventricular function including myocardial strain was not significantly different in both group (p=0.15 and 0.78 for ventricular function and strain rate respectively). Table 1. Comparison of clinical and imaging parameter before and after surgery in ACHD patients Before surgery After surgery p LVEDVi (ml/m2) 77.5±29.1 70.8±10.4 0.34 LVEF (%) 61.0±8.3 61.8±7.5 0.72 RVEDVi (ml/m2) 122.2±74.4 80.6±26.4 0.02 RVEF (%) 60.4±13.6 56.9±10.8 0.14 6 minutes walk distance (meter) 287.3±93.0 350.4±61.6 0.05 ECV (%) 27.2±5.7 26.2±4.3 0.59 Figure 1 Conclusions The amount of myocardial fibrosis, as expressed by percentage of the ECV, remained unchanged after surgery despite of clinical improvement. Compared with non-ACHD patients, the amount of fibrosis was significantly higher in ACHD patients after surgery.