Reduction of aberrant aortic haemodynamics following aortic root replacement with a mechanical valved conduit†

Abstract

Preliminary evidence suggests that ARR with an On-X mechanical valve significantly reduces aberrant aortic haemodynamics, producing flow patterns that resemble those in healthy volunteers.

Numerical Investigation of the Effects of Prosthetic Aortic Valve Design on Aortic Hemodynamic Characteristics

“…These flow patterns agree well with the previous clinical observations of aorta flow in healthy subjects. Even though the helix grades of all cases are within the normal range at the acceleration peak (1.1 ± 0.1 to 2.03 ± 0.67) [32,88], the SPAC tubular valve presents a 16.7% higher helix than that of the rest of the cases due to its smaller EOA. In addition to the higher helix grade, the smaller EOA of the SPAC molded valve also caused higher V mean and V max in the ascending aorta at the systolic peak.…”

“…where τ w is the WSS, µ is the dynamic viscosity, u is the velocity and y is the distance to the wall. Helix: the helix quantitatively describes the rotation degree of helical flow along the longitudinal axis of an arterial segment in a grading scale of 1 to 3, which represents rotation degree less than 180 • , greater than 180 • and greater than 360 • , respectively [32].…”

“…Previous studies have demonstrated that the complex morphology and flow condition in the aorta lead to right-handed helical flow in AAo as well as left-handed helical flow in DAo among healthy subjects [14,16,32,88,89]. Morbiducci et al further investigated the development of helical flow in the aorta during the systolic phase by using in vivo four-dimensional phase contrast magnetic resonance imaging (4D PC-MRI), and concluded that the helical flow pattern in the aorta could optimize the blood flow in the aorta by avoiding excessive energy dissipation and reducing flow instabilities [14,15].…”

Multimodality Imaging of Complications of Cardiac Valve Surgeries

“…complex hemodynamics. Abnormal flow patterns have been shown to normalize with placement of some mechanical valves such as the On-X valve (On-X Life Technologies, Austin, Tex) (19) but persist with bioprosthetic valves (20), and insight into this difference may potentially play a role in understanding the development of complications (19). The safety of performing MRI with metallic valves has been well established, even at high field strengths (21).…”

Estudo Numérico Da Influência Da Inclinação Da Prótese Valvar Aórtica No Fluxo Sanguíneo Em Aorta Ascendente

“…De acordo com o levantamento bibliográfico realizado nesta tese, a técnica 4D-flow é utilizada para auxiliar a conhecer o desempenho hemodinâmico na aorta nas seguintes circunstâncias: i) após a instalação de uma prótese valvar (Von Knobelsdorff-Brenkenhoff et al, 2014;Collins et al, 2015;Trauzeddel et al, 2016;Van Kesteren et al, 2018); ii) após o procedimento cirúrgico stent-enxerto (V-SARR) (Semaan et al, 2013;Stephens et al, 2015;Keller et al, 2016); iii) na presença da valva aórtica tricúspide saudável ou valva aórtica bicúspide (Von Knobelsdorff-Brenkenhoff et al, 2014;Garcia et al, 2015;Mirabella et al, 2015;Von Spiczak et al, 2015;Ha et al, 2018;Masutani et al, 2018;Raghav et al, 2018;Shen et al, 2018); iv) seguimento da evolução do aneurisma na aorta (Canstein et al, 2008;Callaghan et al, 2015;Collins et al, 2015;Masutani et al, 2018;Shen et al, 2018) e v) caracterização da doença aterosclerótica na aorta (Harloff et al, 2013;Markl et al, 2013).…”