Temporal changes of left atrial function after orthotopic heart transplantation using cardiac magnetic resonance imaging in a single-center prospective study

Abstract

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): ÚNKP-19-3-I New National Excellence Program of the Ministry for Innovation and Technology; National Research, Development and Innovation Office of Hungary (NKFIA; NVKP_16-1-2016-0017 National Heart Program) Background The geometry and function of the left atrium (LA) change after orthotopic heart transplantation (HTX) with bicaval technique, as the LA has a recipient part around the pulmonary veins and a donor part, and these often contract separately. Because of this altered LA function, the recognition of left ventricular diastolic dysfunction can be challenging. The standard echocardiographic diastolic parameters are often in abnormal range in HTX patients despite of normal left ventricular diastolic function. Purpose The aim of our prospective study was to investigate the LA volumes and function and their temporal changes after HTX using cardiac magnetic resonance (CMR). Method To better understand the cardiac characteristics of HTX patients, we started a prospective trial in January 2018. CMR was performed at one, three and six months after HTX. Left atrial contour detection was performed in 2- and 4-chamber views. Patients who had ≥Grade II allograft rejection before the CMR examination, were excluded (n = 6). In the remaining HTX patients (n = 37, 52 ± 12y, 29 male) and in a control group (n = 20, 49 ± 5y, 15 male) LA ejection fraction (EF), BSA-corrected maximum and minimum LA volume (Vi), stroke volume (SVi) were evaluated using bi-plane mode. LA global longitudinal strain (GLS) was defined with CMR based deformation imaging, called feature tracking. Results HTX patients had significantly higher LA volumes (maxLAVi 65 ± 22 vs. 46 ± 7 ml/m2, minLAVi 47 ± 21 vs. 18 ± 6 ml/m2) lower LASVi (19 ± 5 vs. 29 ± 4 ml/m2), LAEF (31 ± 10 vs. 62 ± 8%) and LA-GLS (10 ± 4 vs. 39 ± 11%) compared to the control group (p < 0.0001). Analysing the temporal changes in HTX patients, we found an increase in the LA-GLS already at three months (10 ± 4 vs. 12 ± 3%, p < 0.05). The LAEF improved significantly at six months (29 ± 10 vs. 33 ± 10%, p < 0.05). Conclusion After HTX the LA volumes and function differ markedly from the normal population. The LA funcional parameters showed a moderate improvement after HTX. Better understanding the changes of left atrial function after HTX could help us to recognise pathological conditions. Abstract Figure. Strain analysis of the left atrium