4D flow cardiovascular magnetic resonance for monitoring of aortic valve repair in bicuspid aortic valve disease

Lenz et al. Journal of Cardiovascular Magnetic Resonance https://doi.org/10.1186/s12968-020-00608-0 (2020) 22:29 RESEARCH Open Access 4D flow cardiovascular magnetic resonance for monitoring of aortic valve repair in bicuspid aortic valve disease Alexander Lenz1* , Johannes Petersen2, Christoph Riedel1, Julius M. Weinrich1, Hendrik Kooijman3, Bjoern P. Schoennagel1, Gerhard Adam1, Yskert von Kodolitsch4, Hermann Reichenspurner2, Evaldas Girdauskas2 and Peter Bannas1 Abstract Background: Aortic valve repair has become a treatment option for adults with symptomatic bicuspid (BAV) or unicuspid (UAV) aortic valve insufficiency. Our aim was to demonstrate the feasibility of 4D flow cardiovascular magnetic resonance (CMR) to assess the impact of aortic valve repair on changes in blood flow dynamics in patients with symptomatic BAV or UAV. Methods: Twenty patients with adult congenital heart disease (median 35 years, range 18–64; 16 male) and symptomatic aortic valve regurgitation (15 BAV, 5 UAV) were prospectively studied. All patients underwent 4D flow CMR before and after aortic valve repair. Aortic valve regurgitant fraction and systolic peak velocity were estimated. The degree of helical and vortical flow was evaluated according to a 3-point scale. Relative flow displacement and wall shear stress (WSS) were quantified at predefined levels in the thoracic aorta. Results: All patients underwent successful aortic valve repair with a significant reduction of aortic valve regurgitation (16.7 ± 9.8% to 6.4 ± 4.4%, p < 0.001) and systolic peak velocity (2.3 ± 0.9 to 1.9 ± 0.4 m/s, p = 0.014). Both helical flow (1.6 ± 0.6 vs. 0.9 ± 0.5, p < 0.001) and vortical flow (1.2 ± 0.8 vs. 0.5 ± 0.6, p = 0.002) as well as both flow displacement (0.3 ± 0.1 vs. 0.25 ± 0.1, p = 0.031) and WSS (0.8 ± 0.2 N/m2 vs. 0.5 ± 0.2 N/m2, p < 0.001) in the ascending aorta were significantly reduced after aortic valve repair. Conclusions: 4D flow CMR allows assessment of the impact of aortic valve repair on changes in blood flow dynamics in patients with bicuspid aortic valve disease. Keywords: 4D flow MRI, Congenital heart disease, Bicuspid aortopathy, Adult congenital heart disease, Aortic valve repair, Aorta, Hemodynamics, Aortic regurgitation Background Bicuspid (BAV) and unicuspid (UAV) aortic valve malformations represent two forms of adult congenital heart disease with a prevalence of 1–2 and 0.02%, respectively [1–4]. BAV and UAV are associated with aortic valve dysfunction (regurgitation and/or stenosis), dissection, and proximal aortic dilatation, the so-called bicuspid aortopathy [5]. Genetic and hemodynamic factors * Correspondence: 1 Department of Diagnostic and Interventional Radiology and Nuclear Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg, Germany Full list of author information is available at the end of the article contribute to the progression of BAV and UAV disease [6, 7] and play a role in the development of bicuspid aortopathy, including the increased risk for aortic dissection [5, 8]. Surgical treatment for regurgitation and/or stenosis, particularly aortic valve repair techniques, underwent major development during the last decades. Surgical repair is a promising alternative to prosthetic aortic valve replacement, especially in young patients [2, 9–11]. Aortic valve repair has several advantages compared to aortic valve replacement, including absence of the need for chronic anticoagulation, lower infection rate, and better hemodynamic performance [12]. From a technical point © The Author(s). 2020 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Lenz et al. Journal of Cardiovascular Magnetic Resonance (2020) 22:29 Page 2 of 10 Fig. 1 Intraoperative situs of aortic valve repair in bicuspid aortic valve (BAV) disease. The surgical repair consists of reduction of the aortic valve anulus using suture annuloplasty and correction of the prolapse of the fused cup. The aim is the recreation of the optimal aortic root geometry. This includes reduction of the basal ring diameter to less than 25 mm and restoration of effective cusp height (coaptation length) above 8 mm. a and b Correction of cusp prolapse by means of plication sutures (arrows). c Surgery results in a symmetric configuration of the bicuspid aortic valve (arrow heads) with a commissural angle of 180°, resembling a Sievers type 0 valve. In this patient, additional replacement of the aortic root with Dacron prosthesis for aneurysm has been performed of view, aortic valve repair is a two-component surgery, consisting of cusp repair and aortic valve annulus stabilization (Fig. 1) [2]. However, recurrent aortic valve regurgitation is still a major issue in patients after aortic valve repair as compared to those after surgical aortic valve replacement [12–14]. Therefore, the development of more durable aortic valve repair techniques remains an important clinical challenge. In this context, a comprehensive marker for accurate assessment of changes in hemodynamics after aortic valve repair is needed to evaluate surgical success. Four-dimensional (4D)-flow cardiovascular magnetic resonance imaging (CMR) has been successfully used to visualize abnormal hemodynamic flow patterns such as helical and vortical flow [15–18], wall shear stress [19–23], and flow displacement (indicator of outflow asymmetry) [24–27] in untreated adult congenital heart disease and after aortic valve replacement surgery [28–31]. We hypothesize that 4D flow CMR might be a comprehensive tool to monitor aortic valve competence and hemodynamic changes after aortic valve repair. Therefore, the aim of this study was to demonstrate the feasibility of 4D flow CMR to assess the impact of aortic valve repair on changes in blood flow dynamics in adult congenital heart disease patients with symptomatic BAV or UAV. Methods Patients This prospective study was approved by the local ethics board. Written informed consent was obtained from all patients. Patients with adult congenital heart disease (BAV or UAV) and symptomatic, predominant aortic regurgitation who were referred for minimally invasive aortic valve repair between April 2017 and February 2019 were included in the study. Patients with contraindications for CMR or younger than 18 years were excluded. Diagnosis of aortic regurgitation was based on transthoracic echocardiography. Echocardiography was also used to assess the quality (...truncated)