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Blood flow characteristics in the ascending aorta after aortic valve replacement--a pilot study using 4D-flow MRI.

ABSTRACT: BACKGROUND:Aortic remodeling after aortic valve replacement (AVR) might be influenced by the postoperative blood flow pattern in the ascending aorta. This pilot study used flow-sensitive four-dimensional magnetic resonance imaging (4D-flow) to describe ascending aortic flow characteristics after various types of AVR. METHODS:4D-flow was acquired in 38 AVR patients (n=9 mechanical, n=8 stentless bioprosthesis, n=14 stented bioprosthesis, n=7 autograft) and 9 healthy controls. Analysis included grading of vortex and helix flow (0-3 point scale), assessment of systolic flow eccentricity (1-3 point scale), and quantification of the segmental distribution of peak systolic wall shear stress (WSS(peak)) in the ascending aorta. RESULTS:Compared to controls, mechanical prostheses showed the most distinct vorticity (2.7±0.5 vs. 0.7±0.7; p<0.001), while stented bioprostheses exhibited most distinct helicity (2.6±0.7 vs. 1.6±0.5; p=0.002). Instead of a physiologic central flow, all stented, stentless and mechanical prostheses showed eccentric flow jets mainly directed towards the right-anterior aortic wall. Stented and stentless prostheses showed an asymmetric distribution of WSS(peak) along the aortic circumference, with significantly increased local WSS(peak) where the flow jet impinged on the aortic wall. Local WSS(peak) was higher in stented (1.4±0.7 N/m(2)) and stentless (1.3±0.7 N/m(2)) compared to autografts (0.6±0.2 N/m(2); p=0.005 and p=0.008) and controls (0.7±0.1 N/m(2); p=0.017 and p=0.027). Autografts exhibited lower absolute WSS(peak) than controls (0.4±0.1 N/m(2) vs. 0.7±0.2 N/m(2); p=0.003). CONCLUSIONS:Flow characteristics in the ascending aorta after AVR are different from native aortic valves and differ between various types of AVR.

SUBMITTER: von Knobelsdorff-Brenkenhoff F

PROVIDER: S-EPMC5099073 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature

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Blood flow characteristics in the ascending aorta after aortic valve replacement--a pilot study using 4D-flow MRI.

von Knobelsdorff-Brenkenhoff Florian F Trauzeddel Ralf F RF Barker Alex J AJ Gruettner Henriette H Markl Michael M Schulz-Menger Jeanette J

International journal of cardiology 20131125 3

<h4>Background</h4>Aortic remodeling after aortic valve replacement (AVR) might be influenced by the postoperative blood flow pattern in the ascending aorta. This pilot study used flow-sensitive four-dimensional magnetic resonance imaging (4D-flow) to describe ascending aortic flow characteristics after various types of AVR.<h4>Methods</h4>4D-flow was acquired in 38 AVR patients (n=9 mechanical, n=8 stentless bioprosthesis, n=14 stented bioprosthesis, n=7 autograft) and 9 healthy controls. Analy ...[more]

PMID: 24315151

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Project description:BackgroundAlthough a bicuspid aortic valve (BAV) is known to be associated with progressive ascending aortic dilatation, the fate of the residual aorta after aortic valve and ascending aorta surgery is unknown. We reviewed surgical outcomes and explored serial changes in the size of the sinus of Valsalva (SOV) and distal ascending aorta (DAAo) in 89 patients with a BAV undergoing aortic valve replacement (AVR) and graft replacement (GR) of the ascending aorta.MethodsWe retrospectively examined patients who underwent AVR and GR of the ascending aorta for BAV-and related disease and thoracic aortic dilatation at our institution between January 2009 and December 2018. Patients who underwent AVR alone or required intervention for the aortic root and aortic arch and patients with connective tissue diseases were excluded. Aortic diameters were examined using computed tomography (CT). Late CT more than 1 year after surgery was performed in 69 patients (78%) with a mean follow-up of 4.9±2.8 years.ResultsThe surgical indication for aortic valve etiology was stenosis in 61 patients (69%), regurgitation in 10 (11%), and mixed in 18 (20%). Preoperative maximum short diameters of the ascending aorta, SOV, and DAAo were 47.3±4.7, 36.0±5.2, and 37.2±3.6 mm, respectively. The diameter of the SOV increased non-significantly by 0.08±0.45 mm per year [95% confidence interval (CI): -0.12 to 0.11, P=0.150], while that of the DAAo increased significantly by 0.11±0.40 mm per year (95% CI: 0.02-0.21, P=0.005). One patient required reoperation 6 years postoperatively due to a pseudo-aneurysm at the proximal anastomotic site. No patient required reoperation due to progressive dilatation of the residual aorta. According to the Kaplan-Meier analysis, the long-term survival rates were 98.9%, 98.9%, and 92.7% at 1, 5, and 10 years postoperatively, respectively.ConclusionsRapid dilatation of the residual aorta rarely occurred in patients with a BAV who underwent AVR and GR of the ascending aorta in the mid-term follow-up. For selected patients with a surgical indication for ascending aortic dilatation, simple AVR and GR of the ascending aorta may be sufficient surgical options.

Project description:BackgroundLimited studies have focused on the performance of self-expandable valves (SEVs) and balloon-expandable valves (BEVs) in patients with dilatated ascending aorta (AA) undergoing transcatheter aortic valve replacement (TAVR). The present study compared the performance of widely used Edwards BEVs and domestic SEVs in patients with dilatated AA among Chinese population.MethodsWe identified and reviewed 207 patients who had baseline AA diameter ≥40 mm and underwent transfemoral TAVR. Patients were divided into two groups: SEV and BEV. The SEVs were locally manufactured valves that have received Chinese regulatory approval (Venus-A, Taurus One, and VitaFlow), while the BEVs were Edwards Sapien XT and Sapien3. Procedural device success and post-procedural changes of AA diameters were compared.ResultsThe sample size of SEV group was larger than that of BEV group because BEVs were not available in China in the early clinical practice. The overall device success was slightly lower in SEV group compared with BEV group (84.2% vs. 95.8%, P=0.213). However, in the univariable and multivariable logistic regression analyses, only bicuspid aortic valve (BAV) was found to be an independent risk factor for device failure (OR: 2.632, CI: 1.107-6.257, P=0.029). During the median follow-up of 21 months, no statistical difference was found between the two groups regarding the overall survival (83.1%±4.7% vs. 95.8%±4.1%, P=0.533), and no aortic dissection nor rupture was observed. In a subgroup of patients who had follow-up CTs ≥12-month intervals, the AA diameter appeared to remain stable in SEV group with an aortic expansion rate of 0 (-0.4 to 0.8) mm (P=0.102), while it slightly enlarged in BEV group with an aortic expansion rate of 0.4 (-0.4 to 0.6) mm/y (P=0.038). In addition, the AA diameter also slightly enlarged in patients with BAV [0.2 (0 to 1.0) mm/y, P=0.015], while it remained stable in patients with tricuspid aortic valve (TAV) [0 (-0.8 to 0.6) mm/y, P=0.640].ConclusionsIn patients with dilatated AA who underwent TAVR, the type of THVs did not affect the procedural device success. BAV appeared to be a risk factor for both device failure and higher aortic expansion rate in these patients.

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Blood flow characteristics in the ascending aorta after aortic valve replacement--a pilot study using 4D-flow MRI.

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Blood flow characteristics in the ascending aorta after aortic valve replacement--a pilot study using 4D-flow MRI.

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