Restoration of 3D Aortic Hemodynamics after Ross Procedure for Unicuspid Aortic Valve Disease Using 4D Flow MRI
Presented During:
Thursday, April 25, 2024: 5:38PM - 7:00PM
Sheraton Times Square
Posted Room Name:
Central Park
Abstract No:
P0287
Submission Type:
Abstract Submission
Authors:
Andrew Zbihley (1), Anthony Maroun (1), Justin Baraboo (1), Bradley D. Allen (2), Michael Markl (1), S. Chris Malaisrie (2), Christopher Mehta (2), Meilynn Shi (3)
Institutions:
(1) Northwestern University, Chicago, IL, (2) Northwestern Memorial Hospital, Chicago, IL, (3) N/A, United States
Submitting Author:
Andrew Zbihley
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Northwestern University
Northwestern University
Co-Author(s):
Anthony Maroun
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Northwestern University
Northwestern University
Justin Baraboo
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Northwestern University
Northwestern University
Bradley D. Allen
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Northwestern Memorial Hospital
Northwestern Memorial Hospital
Michael Markl
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Northwestern University
Northwestern University
*S. Chris Malaisrie
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Northwestern Memorial Hospital
Northwestern Memorial Hospital
Christopher Mehta
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Northwestern Memorial Hospital
Northwestern Memorial Hospital
Meilynn Shi
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Presenting Author:
Andrew Zbihley
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Abstract:
OBJECTIVE: The Ross procedure in patients with unicuspid aortic valve (UAV) disease is the only aortic valve replacement performed using a living valve substitute. We evaluated the efficacy of the pulmonary autograft in restoration of select aortic 3D hemodynamic parameters-ascending aorta (AAo) wall shear stress (WSS) and systolic peak velocity (PV)-in patients with UAV using 4D flow MRI. Our hypothesis was that patients would have restored aortic hemodynamics following pulmonary autograft replacement.
METHODS: Twenty-five patients with UAV disease who underwent pulmonary autograft replacement of their UAV between February 2020 and August 2023 were identified. Thirteen patients had pre- and post-operative 4D flow MRI exams between July 2018 and August 2023. All MRIs were performed using 1.5 or 3.0T systems (Siemens, Germany) and were retrospectively gated. Data were processed to correct for eddy currents, velocity noise, and aliasing, and to generate a 3D segmentation of the thoracic aorta. The systolic PV in the AAo was determined using a voxel-wise approach as the maximum velocity within the AAo segmentation at peak systole. The systolic peak WSS was calculated as the average of the top 5% of magnitude WSS values mapped on the AAo surface at peak systole. Normality was assessed with the Shapiro-Wilk test. Paired t-tests were utilized to analyze any differences in AAo hemodynamics before and after UAV replacement. Two-sample t-tests were used to compare UAV patients with healthy controls.
RESULTS: Thirteen patients (37.1±10.1 yrs, 11 males) who underwent pulmonary autograft replacement of UAV (11/13 (85%) primarily severe aortic stenosis; 2/13 (15%) primarily unicuspid aortic valve indication) with n=26 MRIs (2/patient, pre/post-Ross) acquired between 2018 to 2023 were included. Twelve of 13 patients demonstrated a reduction in their AAo systolic PV and 10 of 13 demonstrated a reduction in AAo WSS. Thirteen healthy controls were age (±2yrs) and gender matched and analyzed. Mean systolic PV and WSS of healthy controls were 1.51±0.25 m/s and 1.27±0.21 Pa. In the UAV cohort, mean systolic PV before and after pulmonary autograft replacement were 3.72±1.08 m/s and 1.86±0.34 m/s, respectively (p<0.01), and mean AAo WSS before and after pulmonary autograft replacement were 2.34±0.66 Pa and 1.56±0.36 Pa, respectively (p<0.01).
CONCLUSIONS: Ascending aorta systolic PV and WSS are significantly reduced in UAV patients after undergoing the Ross procedure and very closely resemble AAo hemodynamics of healthy controls. These preliminary results suggest that replacement of UAV with a pulmonary autograft can potentially restore AAo hemodynamics similar to that of healthy controls. Further restoration of normal hemodynamics to the level of healthy controls may occur after the perioperative period and warrants further investigation.
METHODS: Twenty-five patients with UAV disease who underwent pulmonary autograft replacement of their UAV between February 2020 and August 2023 were identified. Thirteen patients had pre- and post-operative 4D flow MRI exams between July 2018 and August 2023. All MRIs were performed using 1.5 or 3.0T systems (Siemens, Germany) and were retrospectively gated. Data were processed to correct for eddy currents, velocity noise, and aliasing, and to generate a 3D segmentation of the thoracic aorta. The systolic PV in the AAo was determined using a voxel-wise approach as the maximum velocity within the AAo segmentation at peak systole. The systolic peak WSS was calculated as the average of the top 5% of magnitude WSS values mapped on the AAo surface at peak systole. Normality was assessed with the Shapiro-Wilk test. Paired t-tests were utilized to analyze any differences in AAo hemodynamics before and after UAV replacement. Two-sample t-tests were used to compare UAV patients with healthy controls.
RESULTS: Thirteen patients (37.1±10.1 yrs, 11 males) who underwent pulmonary autograft replacement of UAV (11/13 (85%) primarily severe aortic stenosis; 2/13 (15%) primarily unicuspid aortic valve indication) with n=26 MRIs (2/patient, pre/post-Ross) acquired between 2018 to 2023 were included. Twelve of 13 patients demonstrated a reduction in their AAo systolic PV and 10 of 13 demonstrated a reduction in AAo WSS. Thirteen healthy controls were age (±2yrs) and gender matched and analyzed. Mean systolic PV and WSS of healthy controls were 1.51±0.25 m/s and 1.27±0.21 Pa. In the UAV cohort, mean systolic PV before and after pulmonary autograft replacement were 3.72±1.08 m/s and 1.86±0.34 m/s, respectively (p<0.01), and mean AAo WSS before and after pulmonary autograft replacement were 2.34±0.66 Pa and 1.56±0.36 Pa, respectively (p<0.01).
CONCLUSIONS: Ascending aorta systolic PV and WSS are significantly reduced in UAV patients after undergoing the Ross procedure and very closely resemble AAo hemodynamics of healthy controls. These preliminary results suggest that replacement of UAV with a pulmonary autograft can potentially restore AAo hemodynamics similar to that of healthy controls. Further restoration of normal hemodynamics to the level of healthy controls may occur after the perioperative period and warrants further investigation.
Aortic Symposium:
Aortic Root
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