Four-dimensional flow magnetic resonance imaging assessment of left ventricular hemodynamics in transplanted hearts with good postoperative course

Heart transplantation (HTx) is an established treatment for patients with advanced heart failure, although postoperative rejection responses hamper favorable long-term treatment outcomes. Medical imaging is a non-invasive diagnostic modality that can provide attractive insights into cardiac physiology for HTx, including morphological characteristics and cardiac hemodynamics. This study aimed to achieve a basic understanding of left ventricular (LV) hemodynamics in patients with good treatment outcomes following HTx. Specifically, four-dimensional magnetic resonance imaging was performed on 10 patients with a good postoperative course following HTx and 24 controls without a prior history of heart diseases nor HTx. LV hemodynamics were evaluated from the LV flow kinetic energy. We found that LV volumetric functions and kinetic energy ranges were not significantly different between the HTx and control groups, supporting good efficacy of HTx. Nevertheless, a temporal increase in the kinetic energy in late diastole owing to atrial contraction was present in the control group but absent in the HTx group except for one HTx patient. These findings raise the need of further evaluation of cardiac hemodynamics and the pathophysiology of HTx patients even within normal ranges of volumetric and flow transport functions.