Comprehensive 4D-Flow Cardiac Magnetic Resonance Evaluation of the Descending Thoracic Aorta in Aortic Regurgitation
J Urmeneta Ulloa, A Álvarez Vázquez, V Martínez de Vega, L Martínez de Vega, C Andreu-Vázquez, I J Thuissard-Vasallo, M Recio Rodríguez, J A CabreraAbstract
Aims
To assess the reproducibility of 4D-Flow cardiac magnetic resonance (CMR) parameters in the descending thoracic aorta -DTAo- (regurgitant fraction [RF], end-diastolic reverse flow [EDRF], and holodiastolic flow reversal [HDR]), and the relationship with RF in the sinotubular junction (STJ), and the left ventricular end-diastolic volume index (LVEDVI) in patients with chronic aortic regurgitation (AR).
Methods and Results
A descriptive study of these variables was conducted. An ROC curve was used to determine the optimal cut-off point. 30 patients had severe AR (RF≥ 30%, STJ) and 60 mild-to-moderate (RF< 30%). The mean age was 59 ± 17 years. Left ventricular ejection fraction (LVEF) was 56% (53-61%) and LVEDVI was 94 (76-128) mL/m2. Flow in the DTAo at the left inferior pulmonary vein (LIPV) was easily identifiable and measurements were highly reproducible. The intraclass correlation coefficient (ICC) was 0.969 (95% CI: 0.954–0.980) for RF and 0.929 (95% CI: 0.893–0.952) for EDRF. Flow parameters measured at the LIPV were all significantly greater in the severe AR group: RF (21% vs. 6%, p<0.001), EDRF (20 vs. 4 mL/s; p<0.001), and HDR (20% vs. 8%; p<0.001). Three parameters—presence of HDR, RF≥ 17%, and EDRF≥ 7 mL/s at the LIPV—were associated with RF≥ 30% in the STJ and elevated LVEDVI.
Conclusions
4D-Flow CMR can reproducibly assess flow in the DTAo in patients with chronic AR. An RF≥ 17%, EDRF≥ 7 mL/s, and/or the presence of HDR in the DTAo (LIPV) were associated with an RF≥ 30% in STJ and elevated LVEDVI.