TY - JOUR
T1 - Reduction of aberrant aortic haemodynamics following aortic root replacement with a mechanical valved conduit
AU - Keller, Eric J.
AU - Malaisrie, S. Chris
AU - Kruse, Jane
AU - McCarthy, Patrick M.
AU - Carr, James C.
AU - Markl, Michael
AU - Barker, Alex J.
AU - Collins, Jeremy D.
N1 - Funding Information:
This work was supported by NIH K25 HL119608, NIH R01 HL115828 and the Northwestern's Melman Bicuspid Aortic Valve Program at the Bluhm Cardiovascular Institute.
Publisher Copyright:
© 2016 The Author 2016. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
PY - 2016/9/1
Y1 - 2016/9/1
N2 - OBJECTIVES Previous work suggests that aortic root and valve prostheses alter blood flow patterns in the ascending aorta, creating aberrant haemodynamics compared with those of healthy volunteers. Various valve designs have been proposed to better restore physiological haemodynamics. In this study, magnetic resonance imaging (MRI) was used to non-invasively assess three-dimensional (3D) ascending aortic haemodynamics after aortic root replacement (ARR) with a mechanical valved conduit postulated to create less turbulent blood flow. METHODS Ten patients (40 ± 9 years) underwent transthoracic echocardiography and contrast-enhanced multidimensional four-dimensional (4D) flow MRI at 1.5 T after ARR with an On-X mechanical valved conduit. Preoperative 4D flow MRI was available in 7 patients. Ten age- and gender-matched healthy volunteers (42 ± 13 years) were also analysed to characterize physiological flow. The presence of vortex/helix formation was graded by two blinded observers. Peak transvalvular pressure gradients were computed using the simplified Bernoulli equation. Patients' postoperative pressure gradients and helicity/vorticity grades were compared with preoperative gradients and those from healthy volunteers. RESULTS Intra- and interobserver ratings showed good agreement (κ = 0.93, P < 0.01 and κ = 0.84, P < 0.01, respectively). Highly helical and/or vortical flow was observed in all patients preoperatively, which was significantly reduced postoperatively (P < 0.01 and <0.01, respectively), restoring similar flow patterns similar to those seen in volunteers (P = 0.56 and 0.56). Peak transvalvular pressure gradients (ΔP) were also significantly reduced [43 ± 21 vs 12 ± 7 mmHg, P < 0.05 (Echo); 48 ± 22 vs 16 ± 9 mmHg, P < 0.05 (MRI)], but remained significantly higher than those of volunteers (6 ± 1 mmHg, P < 0.01). CONCLUSIONS 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.
AB - OBJECTIVES Previous work suggests that aortic root and valve prostheses alter blood flow patterns in the ascending aorta, creating aberrant haemodynamics compared with those of healthy volunteers. Various valve designs have been proposed to better restore physiological haemodynamics. In this study, magnetic resonance imaging (MRI) was used to non-invasively assess three-dimensional (3D) ascending aortic haemodynamics after aortic root replacement (ARR) with a mechanical valved conduit postulated to create less turbulent blood flow. METHODS Ten patients (40 ± 9 years) underwent transthoracic echocardiography and contrast-enhanced multidimensional four-dimensional (4D) flow MRI at 1.5 T after ARR with an On-X mechanical valved conduit. Preoperative 4D flow MRI was available in 7 patients. Ten age- and gender-matched healthy volunteers (42 ± 13 years) were also analysed to characterize physiological flow. The presence of vortex/helix formation was graded by two blinded observers. Peak transvalvular pressure gradients were computed using the simplified Bernoulli equation. Patients' postoperative pressure gradients and helicity/vorticity grades were compared with preoperative gradients and those from healthy volunteers. RESULTS Intra- and interobserver ratings showed good agreement (κ = 0.93, P < 0.01 and κ = 0.84, P < 0.01, respectively). Highly helical and/or vortical flow was observed in all patients preoperatively, which was significantly reduced postoperatively (P < 0.01 and <0.01, respectively), restoring similar flow patterns similar to those seen in volunteers (P = 0.56 and 0.56). Peak transvalvular pressure gradients (ΔP) were also significantly reduced [43 ± 21 vs 12 ± 7 mmHg, P < 0.05 (Echo); 48 ± 22 vs 16 ± 9 mmHg, P < 0.05 (MRI)], but remained significantly higher than those of volunteers (6 ± 1 mmHg, P < 0.01). CONCLUSIONS 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.
KW - Aortic valve replacement
KW - Magnetic resonance imaging
KW - Mechanical heart valve prosthesis
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U2 - 10.1093/icvts/ivw173
DO - 10.1093/icvts/ivw173
M3 - Article
C2 - 27245620
AN - SCOPUS:84985026374
SN - 1569-9293
VL - 23
SP - 416
EP - 423
JO - Interactive Cardiovascular and Thoracic Surgery
JF - Interactive Cardiovascular and Thoracic Surgery
IS - 3
ER -