Vortex formation time as an index of left ventricular filling efficiency: comparison between children volunteers and patients with tetralogy of Fallot

Li-Wei Hu; Yang Xiang; Su-Yang Qin; Rong-Zhen Ouyang; Jin-Long Liu; Ya-Feng Peng; Wei-Hui Xie; Yong Zhang; Hong Liu; Yu-Min Zhong

doi:10.21037/tp-22-67

Vortex formation time as an index of left ventricular filling efficiency: comparison between children volunteers and patients with tetralogy of Fallot

Transl Pediatr. 2022 Jun;11(6):869-881. doi: 10.21037/tp-22-67.

Authors

Affiliations

¹ Diagnostic Imaging Center, Shanghai Children's Medical Center Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China.
² J.C. Wu Center for Aerodynamics, School of Aeronautics and Astronautics, Shanghai Jiao Tong University, Shanghai, China.
³ Department of Cardiovascular and Thoracic Surgery, Shanghai Children's Medical Center Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China.
⁴ MR Research, GE Healthcare, Shanghai, China.

Abstract

Background: Vortex formation time (VFT) had been considered a useful marker for assessing diastolic performance. the VFT assessment of diastolic function using four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has not been used in repair of tetralogy of Fallot (rTOF) patient. The aims of this study were as follows: (I) establish reference ranges for VFT measurements in healthy children and adolescents using 4D flow CMR imaging; and (II) analyze VFT parameters to assess diastole dysfunction in rTOF patients group.

Methods: We acquired the CMR data was of 62 healthy participants (aged 6-18 years; male: 40, female: 22) and 20 patients with rTOF (aged 10-13 years; male: 15, female: 5) using 4D flow and cine sequence in routine chamber view. The VFT was calculated based on comparison of different algorithms from cine measurements (VFT_volume) and 4D flow measurements (VFT_blood). Then, VFT measurements were compared to subject peak filling rate (PFR), age, and cardiac mass using simple linear regression and multiple regression analyses. Data were also categorized according to age for VFT and cardiac functional assessment comparisons between 3 age groups (Group 1: 6-9 years; Group 2: 10-13 years; Group 3: 14-18 years). The correlation of VFT and cardiac function parameters were analyzed in the rTOF group.

Results: Normal mean value of VFT_volume and VFT_blood were 4.25±0.92 and 3.77±1.11 in healthy children participants. The VFT_volume was correlated with VFT_blood (r=0.61, P<0.001). There was a moderately significant correlation between VFT_volume and PFR (r=0.46, P<0.001) and between VFT_blood and PFR (r=0.47, P<0.001), age (r=0.41, P=0.002) and left ventricular (LV) mass (r=0.48, P<0.001). Multiple regression analyses demonstrated that VFT_volume was independently associated with PFR (T=2.239; P<0.05) and VFT_blood (T=4.361; P<0.001). There was a significant difference in VFT_volume between healthy controls and rTOF patients (5.44±1.93 vs. 4.27±0.88, P=0.018).

Conclusions: The VFT measurements showed that the LV that had appropriate space to form the optimal vortex ring in normal children and adolescents aged 6-18 years old. The VFT_volume could potentially be helpful in improving our understanding of LV diastolic dysfunction in rTOF patients.

Keywords: 4D flow; Cardiovascular magnetic resonance (CMR); intra-cardiac blood flow patterns; vortex flow; vortex formation time (VFT).