Postoperative pulmonary and aortic 3D haemodynamics in patients after repair of transposition of the great arteries

Abstract

Objectives To characterise aortic and pulmonary haemodynamics and investigate the correlation with post-surgical anatomy in patients with dextro-transposition of the great arteries (d-TGA). Methods Four-dimensional (4D) MRI was performed in 17 patients after switch repair of TGA and 12 healthy controls (age, 11.9±5.4 vs 23.3±1.6 years). Patients were divided according to the pulmonary trunk (TP) position in relation to the ascending aorta (AAo): anterior (n =10) and right/left anterior position (n =7). Analysis included visual grading (ranking 0–2) of pulmonary and aortic vortical and helical flow, flow velocity quantification, blood-flow distribution to the right and left pulmonary arteries (flow ratio rPA:lPA), and vessel lumen areas. Results Anterior TP position was associated with increased vortices in six out of ten patients compared with right anterior TP position (one out of seven) and controls (none). Reduced systolic lPA and TP lumina in patients resulted in significantly increased peak systolic velocities (P <0.001). Flow ratio rPA:lPA was more heterogeneous in patients (rPA:lPA=1.56 ±0.78 vs volunteers 1.09±0.15; P <0.05) with predominant flow to the rPA. Eleven patients presented increased helices in the AAo (grade 1.6). Conclusions Evaluation of post-surgical haemodynamics in TGA patients revealed increased vortical flow for anterior TP position, asymmetric flow and increased systolic flow velocity in the pulmonary arteries owing to reduced vascular lumina.

4-D flow magnetic resonance imaging: blood flow quantification compared to 2-D phase-contrast magnetic resonance imaging and Doppler echocardiography

“…Additionally, data manipulation is possible any time after acquisition of the full 4-D flow volume. Four-dimensional flow also gives insight into blood flow hemodynamics by employing the option of blood flow 3-D visualization and the investigation of blood flow patterns and direction [13, 15, 16]. Therefore 4-D flow has the potential to provide the more quantitative and qualitative flow parameter information than multiple 2-D phase-contrast MRI acquisitions.…”

Aneurysms of the Pulmonary Artery

“…20,[34][35][36]40,41 Furthermore, magnetic resonance imaging (Figure 4) or 4-dimensional magnetic resonance imaging may show arterial wall thickening, provide information on blood flow, and characterize aortic and pulmonary hemodynamics without any radiation exposure. 43 …”

Magnetic resonance imaging

“…In contrast, aortic aneurysms with a tricuspid aortic valve have shown a decrease in wall shear stress and an increase in vortical flow pattern [122]. Furthermore, aortic and pulmonary blood flow has been assessed in different surgical approaches of the arterial switch procedure in transposition of the great arteries [125]. Marfan syndrome also showed a marked increase in vortical flow in the sinuses and an increase in helical flow in the proximal descending aorta [123], which may explain the increased risk for aortic dissection in these areas in Marfan syndrome.…”