Abstract

Background

Interrupted aortic arch (IAA) is a rare but severe congenital abnormality often associated with bicuspid aortic valve (BAV). Complex re-interventions are often needed despite surgical advances, but the impact of aortic hemodynamics in repaired patients is unknown.

Objective

Investigate effect of IAA repairs on aortic hemodynamics, wall shear stress and flow derangements via 4-D flow MRI.

Materials and methods

We retrospectively analyzed age- and gender-matched cohorts (IAA [n=6], BAV alone [n=6], controls [n=6]) undergoing cardiac MRI including 4-D flow. Aortic dimensions were measured from standard MR angiography. We quantified peak systolic velocities, regurgitant fractions and wall shear stress in the ascending aorta (AAo), transverse arch and descending aorta (DAo) from 4-D flow, and we graded helix/vortex flow patterns from 3-D blood flow visualization.

Results

Children and young adults with IAA had a wide range of arch dimensions, peak systolic velocities, regurgitant fractions and flow grades. Peak transverse arch systolic velocities were higher in patients with IAA versus controls (P=0.02). Flow derangements in the AAo were found in patients with IAA (median grade=2, 5/6 patients, P=0.04) and BAV (median grade=3, 5/6 patients, P=0.03) versus controls. Flow derangements in the DAo were only seen in patients with IAA (median grade=1, 5/6 patients, P=0.04), and 5/6 people with IAA had helical flow in head and neck vessels. Wall shear stress was increased in people with IAA along the superior transverse arch and proximal DAo versus controls (P=0.02).

Conclusion

Complex congenital aortic arch repairs can change aortic hemodynamics. Associated cardiac defects can further alter findings. Studies are warranted to investigate clinical implications in larger cohorts.

中文翻译：

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复杂先天性主动脉弓修复术中改变后的4D磁共振成像流动特征

摘要

背景

主动脉弓中断（IAA）是一种罕见但严重的先天性异常，通常与双尖瓣主动脉瓣（BAV）相关。尽管外科手术取得了进展，但通常仍需要进行复杂的再次干预，但是主动脉血流动力学对修复患者的影响尚不清楚。

目的

通过4-D流动MRI研究IAA修复对主动脉血流动力学，壁切应力和血流紊乱的影响。

材料和方法

我们回顾性分析了接受包括4-D血流在内的心脏MRI检查的年龄和性别匹配的队列（IAA [ n = 6]，仅BAV [ n = 6]，对照[ n = 6]）。主动脉尺寸是通过标准MR血管造影术测得的。我们从4-D流量中量化了升主动脉（AAo），横弓和降主动脉（DAo）中的峰值收缩速度，反流分数和壁切应力，并根据3-D血流可视化对螺旋/涡流模式进行了分级。

结果

患有IAA的儿童和年轻成年人的弓形尺寸，收缩峰值速度，反流分数和血流等级范围广泛。IAA患者的横弓收缩峰值速度高于对照组（P = 0.02）。与对照组相比，IAA（中位评分= 2，5/6患者，P = 0.04）和BAV（中位评分= 3，5/6患者，P = 0.03）患者的AAo血流紊乱。DAo中的血流紊乱仅在IAA患者（中位= 1、5 / 6患者，P = 0.04）中发现，而5/6 IAA患者的头颈部血管螺旋流。与对照组相比，IAA沿上横弓和近端DAo的患者壁切应力增加（P = 0.02）。

结论

复杂的先天性主动脉弓修补术可以改变主动脉血流动力学。相关的心脏缺陷可进一步改变发现。有必要进行研究以研究较大人群的临床意义。