Department of Radiology, Feinberg School of Medicine, Northwestern University, 737 North Michigan Avenue Suite 1600, Chicago, IL, 60611, USA.
Division of Cardiac Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
J Cardiovasc Magn Reson. 2023 Jan 26;25(1):3. doi: 10.1186/s12968-022-00906-9.
Bicuspid aortic valve (BAV) disease is associated with increased risk of aortopathy. In addition to current intervention guidelines, BAV mediated changes in aortic 3D hemodynamics have been considered as risk stratification measures. We aimed to evaluate the association of 4D flow cardiovascular magnetic resonance (CMR) derived voxel-wise aortic reverse flow with aortic dilation and to investigate the role of aortic valve regurgitation (AR) and stenosis (AS) on reverse flow in systole and diastole.
510 patients with BAV (52 ± 14 years) and 120 patients with trileaflet aortic valve (TAV) (61 ± 11 years) and mid-ascending aorta diameter (MAAD) > 35 mm who underwent CMR including 4D flow CMR were retrospectively included. An age and sex-matched healthy control cohort (n = 25, 49 ± 12 years) was selected. Voxel-wise reverse flow was calculated in the aorta and quantified by the mean reverse flow in the ascending aorta (AAo) during systole and diastole.
BAV patients without AS and AR demonstrated significantly increased systolic and diastolic reverse flow (222% and 13% increases respectively, p < 0.01) compared to healthy controls and also had significantly increased systolic reverse flow compared to TAV patients with aortic dilation (79% increase, p < 0.01). In patients with isolated AR, systolic and diastolic AAo reverse flow increased significantly with AR severity (c = - 83.2 and c = - 205.6, p < 0.001). In patients with isolated AS, AS severity was associated with an increase in both systolic (c = - 253.1, p < 0.001) and diastolic (c = - 87.0, p = 0.02) AAo reverse flow. Right and left/right and non-coronary fusion phenotype showed elevated systolic reverse flow (> 17% increase, p < 0.01). Right and non-coronary fusion phenotype showed decreased diastolic reverse flow (> 27% decrease, p < 0.01). MAAD was an independent predictor of systolic (p < 0.001), but not diastolic, reverse flow (p > 0.1).
4D flow CMR derived reverse flow associated with BAV was successfully captured even in the absence of AR or AS and in comparison to TAV patients with aortic dilation. Diastolic AAo reverse flow increased with AR severity while AS severity strongly correlated with increased systolic reverse flow in the AAo. Additionally, increasing MAAD was independently associated with increasing systolic AAo reverse flow. Thus, systolic AAo reverse flow may be a valuable metric for evaluating disease severity in future longitudinal outcome studies.
二叶式主动脉瓣（BAV）疾病与主动脉病变风险增加相关。除了目前的介入指南外，主动脉瓣 3D 血流动力学的变化也被认为是风险分层的措施。我们旨在评估 4D 流心血管磁共振（CMR）衍生的体素式主动脉反流与主动脉扩张之间的关联，并研究主动脉瓣反流（AR）和狭窄（AS）对收缩期和舒张期反流的作用。
回顾性纳入 510 例 BAV 患者（52±14 岁）和 120 例三叶式主动脉瓣（TAV）患者（61±11 岁）和升主动脉中段直径（MAAD）>35mm，这些患者均接受了包括 4D 流 CMR 的 CMR 检查。选择了一个年龄和性别匹配的健康对照组（n=25，49±12 岁）。在主动脉中计算体素式反流，并通过收缩期和舒张期升主动脉（AAo）的平均反流来量化。
无 AS 和 AR 的 BAV 患者与健康对照组相比，收缩期和舒张期的反流明显增加（分别增加 222%和 13%，p<0.01），与主动脉扩张的 TAV 患者相比，收缩期反流也明显增加（增加 79%，p<0.01）。在孤立性 AR 患者中，随着 AR 严重程度的增加，收缩期和舒张期 AAo 反流显著增加（c=-83.2 和 c=-205.6，p<0.001）。在孤立性 AS 患者中，AS 严重程度与收缩期（c=-253.1，p<0.001）和舒张期（c=-87.0，p=0.02）AAo 反流的增加相关。右和左/右和非冠状动脉融合表型显示收缩期反流升高（>17%，p<0.01）。右和非冠状动脉融合表型显示舒张期反流降低（>27%，p<0.01）。MAAD 是收缩期（p<0.001）但不是舒张期（p>0.1）反向流量的独立预测因子。
即使在没有 AR 或 AS 的情况下，与 TAV 患者的主动脉扩张相比，4D 流 CMR 衍生的反向流量也能成功地捕捉到与 BAV 相关的反向流量。舒张期 AAo 反流随 AR 严重程度增加而增加，而 AS 严重程度与 AAo 收缩期反流增加密切相关。此外，MAAD 的增加与 AAo 收缩期反流的增加独立相关。因此，AAo 收缩期反流可能是未来纵向预后研究中评估疾病严重程度的一个有价值的指标。
