Four-Dimensional Magnetic Resonance Flow Analysis Clarifies Paradoxical Symptoms in a Patient With Aortic Bypass and Retrograde Flow Mimicking Subclavian Steal
2012; Lippincott Williams & Wilkins; Volume: 125; Issue: 6 Linguagem: Inglês
10.1161/circulationaha.111.064634
ISSN1524-4539
AutoresSumitKumar Gupta, Andrada Popescu, Roger Andrew de Freitas, Darshit Thakrar, Jyothy Puthumana, James Carr, Michael Markl,
Tópico(s)Cerebrovascular and Carotid Artery Diseases
ResumoHomeCirculationVol. 125, No. 6Four-Dimensional Magnetic Resonance Flow Analysis Clarifies Paradoxical Symptoms in a Patient With Aortic Bypass and Retrograde Flow Mimicking Subclavian Steal Free AccessBrief ReportPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissionsDownload Articles + Supplements ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toSupplemental MaterialFree AccessBrief ReportPDF/EPUBFour-Dimensional Magnetic Resonance Flow Analysis Clarifies Paradoxical Symptoms in a Patient With Aortic Bypass and Retrograde Flow Mimicking Subclavian Steal S. Gupta, A.R. Popescu, R.A. De Freitas, D. Thakrar, J. Puthumana, J. Carr and M. Markl S. GuptaS. Gupta From the Feinberg School of Medicine (S.G.), Medical Imaging, Children's Memorial Hospital (A.P.), Pediatric and Adult Cardiology (A.D., J.P.), Department of Radiology (D.T., J.C., M.M.), and Department of Biomedical Engineering (M.M.), Northwestern University, Chicago, IL. , A.R. PopescuA.R. Popescu From the Feinberg School of Medicine (S.G.), Medical Imaging, Children's Memorial Hospital (A.P.), Pediatric and Adult Cardiology (A.D., J.P.), Department of Radiology (D.T., J.C., M.M.), and Department of Biomedical Engineering (M.M.), Northwestern University, Chicago, IL. , R.A. De FreitasR.A. De Freitas From the Feinberg School of Medicine (S.G.), Medical Imaging, Children's Memorial Hospital (A.P.), Pediatric and Adult Cardiology (A.D., J.P.), Department of Radiology (D.T., J.C., M.M.), and Department of Biomedical Engineering (M.M.), Northwestern University, Chicago, IL. , D. ThakrarD. Thakrar From the Feinberg School of Medicine (S.G.), Medical Imaging, Children's Memorial Hospital (A.P.), Pediatric and Adult Cardiology (A.D., J.P.), Department of Radiology (D.T., J.C., M.M.), and Department of Biomedical Engineering (M.M.), Northwestern University, Chicago, IL. , J. PuthumanaJ. Puthumana From the Feinberg School of Medicine (S.G.), Medical Imaging, Children's Memorial Hospital (A.P.), Pediatric and Adult Cardiology (A.D., J.P.), Department of Radiology (D.T., J.C., M.M.), and Department of Biomedical Engineering (M.M.), Northwestern University, Chicago, IL. , J. CarrJ. Carr From the Feinberg School of Medicine (S.G.), Medical Imaging, Children's Memorial Hospital (A.P.), Pediatric and Adult Cardiology (A.D., J.P.), Department of Radiology (D.T., J.C., M.M.), and Department of Biomedical Engineering (M.M.), Northwestern University, Chicago, IL. and M. MarklM. Markl From the Feinberg School of Medicine (S.G.), Medical Imaging, Children's Memorial Hospital (A.P.), Pediatric and Adult Cardiology (A.D., J.P.), Department of Radiology (D.T., J.C., M.M.), and Department of Biomedical Engineering (M.M.), Northwestern University, Chicago, IL. Originally published14 Feb 2012https://doi.org/10.1161/CIRCULATIONAHA.111.064634Circulation. 2012;125:e347–e349We present the case of a 39-year-old physically active male amateur hockey player with a history of preductal coarctation of the aorta repaired at the age of 10 years with an ascending-to-descending aortic conduit. He presented with neurological symptoms, which were present at rest but paradoxically resolved with physical exertion, including left upper extremity weakness, dizziness, visual changes, and facial tingling.A 2008 echocardiogram demonstrated a bicuspid aortic valve with moderate regurgitation and a mildly to moderately dilated and hypertrophied left ventricle with ejection fraction of 50%. A 2009 carotid Doppler ultrasound examination demonstrated high-velocity retrograde flow in the left vertebral artery, which reduced on exertion. Stenosis of the subclavian artery, and thus subclavian steal, which has been shown to cause neurological symptoms, was ruled out by a 2010 arteriogram.1 A recent magnetic resonance imaging (MRI) evaluation (in 2011) demonstrated worsening (moderate to severe) aortic insufficiency with a clearly visible asymmetrical diastolic flow jet (Figure 1, white arrows), mild decrease of left ventricular ejection fraction, and a patent aortic bypass conduit.Download figureDownload PowerPointFigure 1. Cardiac magnetic resonance angiography demonstrating aortic valve insufficiency and a clearly visible asymmetrical flow jet (white arrows, regions with signal void in the left ventricle). The individual images represent sagittal (left) and coronal (right) reformats of a 3D respiratory and ECG-gated magnetic resonance angiography acquisition. AAo indicates ascending aorta; LV, left ventricle; and RV, right ventricle.To further interrogate the paradoxical reversal of neurological symptoms on exertion, we performed flow-sensitive 4D MRI.2 The aim was to evaluate time-resolved 3D blood flow during rest and exertion with full volumetric coverage of the entire aorta, bypass conduit, and supra-aortic vessels (1.5-Tesla MRI; Siemens, Erlangen, Germany; velocity sensitivity=150 cm/s, spatial resolution 2.6×2.6×3.2 mm3, temporal resolution=38 ms, ECG gating, respiratory navigator gating, scan time=20 minutes). Flow-sensitive 4D MRI was performed after administration of intravascular gadolinium contrast agent (Ablavar; Lantheus Medical Imaging, North Billerica, MA; dose=0.03 mmol/kg) at rest. Imaging was repeated after administration of 1.5 mg of atropine intravenously in an attempt to evaluate the effect of exercise on aortic hemodynamics. A moderate increase in heart rate was achieved (from 45 bpm to 67–71 bpm). The study was approved by the institutional review board, and informed consent was obtained from the patient.To visualize blood flow in 3D, we calculated time-resolved path lines depicting the direction and temporal evolution of flow through the entire thoracic aorta, conduit, and 3 supra-aortic branches.3 4D flow data were also used to retrospectively quantify retrograde fraction (retrograde flow divided by antegrade flow) at several locations in the vessels.3D flow visualization demonstrated high flow in both the native aorta and bypass graft (Figure 2), with substantial diastolic retrograde flow throughout the system (Figure 3). The complex dynamics of 3D blood flow are best appreciated in the online-only Data Supplement Movie. Specifically, the retrograde fractions in the conduit, innominate, left common carotid, and left subclavian arteries were consistently reduced after administration of atropine, as summarized in Figure 2.Download figureDownload PowerPointFigure 2. 3D blood flow visualization in the thoracic aorta, bypass conduit, and supra-aortic vessels. For improved anatomic orientation, a 3D phase-contrast angiogram was derived from the flow-sensitive MRI data and displayed as gray isosurface. Systolic path lines illustrate 3D flow characteristics in the aorta, the native hypoplastic descending aorta (DAo), the bypass conduit, and the supra-aortic branches. The complex aortic geometry and high systolic velocities (red) in the small-diameter DAo and conduit can clearly be appreciated. Note that retrograde flow was reduced during simulated exertion (after atropine). Quantification of preatropine and postatropine retrograde fraction clearly revealed reduced retrograde flow in the supra-aortic vessels. See also online-only Data Supplement Movie. AAo indicates ascending aorta; TBC, brachiocephalic trunk; LLCA, left common carotid artery; and LSA, left subclavian artery.Download figureDownload PowerPointFigure 3. Temporal evolution of 3D path lines over the cardiac cycle (before atropine). The individual images represent selected systolic (top row) and diastolic (bottom row) cardiac time frames. High systolic velocities and thus earlier wave reflection at the periphery in combination with aortic valve insufficiency resulted in substantial retrograde flow throughout the entire thoracic aorta, even reaching the distal descending aorta (DAo). Retrograde flow clearly extended into the supra-aortic branches, which offers a potential explanation for neurological symptoms due to insufficient delivery of blood to the cranial circulation. See also online-only Data Supplement Movie. AAo indicates ascending aorta.Our patient's symptoms closely mimicked those of subclavian steal, which occurs when stenosis of the left subclavian artery induces retrograde flow in the left vertebral artery and causes symptoms of vertebrobasilar insufficiency.4 Although ultrasound examination demonstrated retrograde flow in the left vertebral artery, angiography ruled out subclavian stenosis and thus subclavian steal.4D flow analysis demonstrated high flow velocities through the bypass conduit and native hypoplastic descending aorta and, most noticeably, enhanced diastolic retrograde flow throughout the system, likely exacerbated by the severe aortic regurgitation. The worsening of aortic insufficiency, demonstrated on serial imaging examinations, correlates well with the progression of symptoms and provides an explanation for the absence of neurological symptoms during the first 25 years after repair.Interestingly, the patient's symptoms resolved with exertion. We attempted to recreate this effect during 4D flow analysis with the administration of atropine. Although the patient only achieved a modest increase in heart rate, the retrograde flow fraction in the system noticeably decreased, especially in the left common carotid and subclavian arteries.As evident in Figure 3, retrograde flow in the supra-aortic vessels was present even in late diastole. As a result, the low resting heart rate (45–50 bpm) of this physically fit patient (a hockey player) may have contributed to the neurological impact of the retrograde flow. Shorting of diastole associated with an increase in heart rate may thus offer a potential explanation for the reduction of retrograde flow and neurological improvement during exercise.Flow-sensitive 4D MRI analysis helped to elucidate the complex flow dynamics and offered an explanation for the paradoxical resolution of symptoms with exertion and helped guide management. The patient is scheduled for aortic valve replacement.DisclosuresNone.FootnotesThe online-only Data Supplement is available with this article at http://circ.ahajournals.org/lookup/suppl/doi:10.1161/CIRCULATIONAHA.111.064634/-/DC1.Correspondence to Andrada R. Popescu, MD, Medical Imaging, Children's Memorial Hospital, 2300 N Children's Plaza, Box 9, Chicago, IL 60614. E-mail apopescu@childrensmemorial.orgReferences1. Taylor CL, Selman WR, Ratcheson RA. Steal affecting the central nervous system. Neurosurgery. 2002; 50:679–689.CrossrefMedlineGoogle Scholar2. Markl M, Harloff A, Bley TA, Zaitsev M, Jung B, Weigang E, Langer M, Hennig J, Frydrychowicz A. Time-resolved 3D MR velocity mapping at 3T: improved navigator-gated assessment of vascular anatomy and blood flow. J Magn Reson Imaging. 2007; 25:824–831.CrossrefMedlineGoogle Scholar3. Buonocore MH. Visualizing blood flow patterns using streamlines, arrows, and particle paths. Magn Reson Med. 1998; 40:210–226.CrossrefMedlineGoogle Scholar4. Symon L. The concept of intracerebral steal. Int Anesthesiol Clin. 1969; 7:597–615.CrossrefMedlineGoogle Scholar eLetters(0)eLetters should relate to an article recently published in the journal and are not a forum for providing unpublished data. Comments are reviewed for appropriate use of tone and language. Comments are not peer-reviewed. Acceptable comments are posted to the journal website only. Comments are not published in an issue and are not indexed in PubMed. Comments should be no longer than 500 words and will only be posted online. References are limited to 10. Authors of the article cited in the comment will be invited to reply, as appropriate.Comments and feedback on AHA/ASA Scientific Statements and Guidelines should be directed to the AHA/ASA Manuscript Oversight Committee via its Correspondence page.Sign In to Submit a Response to This Article Previous Back to top Next FiguresReferencesRelatedDetailsCited By Xu H, Baroli D, Di Massimo F, Quaini A and Veneziani A (2020) Backflow stabilization by deconvolution-based large eddy simulation modeling, Journal of Computational Physics, 10.1016/j.jcp.2019.109103, 404, (109103), Online publication date: 1-Mar-2020. Tanaka T, Asami R, Kawabata K, Hashiba K, Okada T and Nishiyama T (2017) A posteriori accuracy estimation of ultrasonic vector-flow mapping (VFM), Journal of Visualization, 10.1007/s12650-016-0413-3, 20:3, (607-623), Online publication date: 1-Aug-2017. February 14, 2012Vol 125, Issue 6 Advertisement Article InformationMetrics © 2012 American Heart Association, Inc.https://doi.org/10.1161/CIRCULATIONAHA.111.064634PMID: 22331925 Originally publishedFebruary 14, 2012 PDF download Advertisement SubjectsCardiovascular SurgeryComputerized Tomography (CT)Congenital Heart DiseaseImaging
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