Retrograde aortic blood flow as a mechanism of stroke: MR evaluation of the prevalence in a population-based study

  • Andreas HarloffEmail author
  • Paul Hagenlocher
  • Thomas Lodemann
  • Anja Hennemuth
  • Cornelius Weiller
  • Jürgen Hennig
  • Werner Vach
Magnetic Resonance



Retrograde blood flow from complex atheroma in the descending aorta (DAo) has only recently been described as a potential mechanism of stroke. However, prevalence of this mechanism in the general population and the exact factors influencing stroke risk are unclear.


One hundred twenty-six consecutively recruited inhabitants of Freiburg, Germany, between 20 and 80 years of age prospectively underwent 3-T MRI. Aortic plaque location and thickness were determined by 3D T1 MRI (1 mm3). 4D flow MRI (spatial/temporal resolution 2 mm3/20 ms) and dedicated software were used to determine prevalence and extent of flow reversal and potential embolization from DAo plaques. Flow was correlated with baseline characteristics and echocardiographic and MRI parameters (aortic diameter, wall thickness, and pulse wave velocity).


The maximum length of retrograde blood flow connecting the DAo with the left subclavian artery (LSA) increased from 16.1 ± 8.3 mm in 20–29-year-old to 24.7 ± 11.7 mm in 70–80-year-old subjects, correlated with age (r = 0.37; p < 0.001), and was lower in females (p = 0.003). Age was the only independent predictor of increased flow reversal. Complex DAo plaques ≥ 4-mm thickness were found in eight subjects (6.3%) and were connected with the LSA, left common carotid artery, and brachiocephalic trunk in 8 (100%), 1 (12.5%), and 0 (0%) cases, respectively.


Retrograde blood flow from the DAo was very frequent. However, potential retrograde embolization was rare due to the low incidence of complex DAo plaques. The magnitude of flow reversal and prevalence of complex atheroma increased with age. Thus, older patients with aortic atherosclerosis are especially vulnerable to this stroke mechanism.

Key Points

4D flow MRI allows in vivo visualization and quantification of individual and three-dimensional blood flow patterns within the thoracic aorta including retrograde components.

This population-based study showed that blood flow reversal from the proximal descending aorta to the brain-supplying great arteries is very frequent and able to reach all brain territories. The extent of such flow reversal increases with age and with the extent of aortic atherosclerosis.

The combination of blood flow reversal with plaque rupture in the proximal descending aorta constitutes a potential stroke mechanism that should be considered in future trials and in the management of stroke patients in clinical routine.


Magnetic resonance imaging Angiography Atherosclerosis Embolism Thoracic aorta 



Ascending aorta


Brachiocephalic trunk


Left common carotid artery


Descending aorta


Generalized autocalibrating partial parallel acquisition


Left subclavian artery


Parallel MRI with extended and averaged GRAPPA kernels


Pulse wave velocity


Transthoracic echocardiography



The authors thank Adriana Komancsek for performing MRI examinations and Dr. Konrad Whittaker for proof reading of the manuscript.


Prof. Dr. Andreas Harloff received funding from Deutsche Forschungsgemeinschaft (DFG), Bonn, Germany, grant no. HA5399/3-1.

Compliance with ethical standards


The scientific guarantor of this publication is Prof. Dr. Andreas Harloff.

Conflict of interest

The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article.

Statistics and biometry

One of the authors, Prof. Dr. Werner Vach, has significant statistical expertise and performed statistical analysis.

Informed consent

Written informed consent was obtained from all subjects in this study.

Ethical approval

Institutional Review Board approval was obtained.

Study subjects or cohorts overlap

Data from this population-based study were analyzed and published. In these three articles, aortic pulse wave velocity, hemodynamics of the right heart, and hemodynamics of the pulmonary arteries were investigated.

Accordingly, there is only minimal overlap with the submitted paper focussing on the extent of retrograde blood flow and potential retrograde embolization from the descending aorta:

Harloff A, Mirzaee H, Lodemann T, Hagenlocher P, Wehrum T, Stuplich J, Hennemuth A, Hennig J, Grundmann S, Vach W. Determination of aortic stiffness using 4D flow cardiovascular magnetic resonance - a population-based study. J Cardiovasc Magn Reson. 2018 Jun 21;20(1):43.

Wehrum T, Lodemann T, Hagenlocher P, Stuplich J, Ngo BTT, Grundmann S, Hennemuth A, Hennig J, Harloff A. Age-related changes of right atrial morphology and inflow pattern assessed using 4D flow cardiovascular magnetic resonance: results of a population-based study. J Cardiovasc Magn Reson. 2018 Jun 14;20(1):38.

Wehrum T, Hagenlocher P, Lodemann T, Vach W, Dragonu I, Hennemuth A, von Zur Mühlen C, Stuplich J, Ngo BT, Harloff A. Age dependence of pulmonary artery blood flow measured by 4D flow cardiovascular magnetic resonance: results of a population-based study. J Cardiovasc Magn Reson. 2016 May 31;18(1):31.


• prospective

• cross-sectional study/observational

• performed at one institution

Supplementary material

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  1. 1.
    Tunick PA, Kronzon I (2000) Atheromas of the thoracic aorta: clinical and therapeutic update. J Am Coll Cardiol 35:545–554CrossRefPubMedGoogle Scholar
  2. 2.
    Cui X, Li Y, Liu J, He S, Liu M (2014) Aortic arch atheroma and the risk of stroke: a meta-analysis. J Evid Based Med 7:185–191CrossRefPubMedGoogle Scholar
  3. 3.
    Harloff A, Strecker C, Frydrychowicz AP et al (2007) Plaques in the descending aorta: a new risk factor for stroke? Visualization of potential embolization pathways by 4D MRI. J Magn Reson Imaging 26:1651–1655CrossRefPubMedGoogle Scholar
  4. 4.
    Harloff A, Strecker C, Dudler P et al (2009) Retrograde embolism from the descending aorta: visualization by multidirectional 3D velocity mapping in cryptogenic stroke. Stroke. 40:1505–1508CrossRefPubMedGoogle Scholar
  5. 5.
    Harloff A, Simon J, Brendecke S et al (2010) Complex plaques in the proximal descending aorta: an underestimated embolic source of stroke. Stroke. 41:1145–1150CrossRefPubMedGoogle Scholar
  6. 6.
    Wehrum T, Kams M, Strecker C et al (2014) Prevalence of potential retrograde embolization pathways in the proximal descending aorta in stroke patients and controls. Cerebrovasc Dis 38:410–417CrossRefPubMedGoogle Scholar
  7. 7.
    Wehrum T, Guenther F, Vach W et al (2017) Aortic atherosclerosis determines increased retrograde blood flow as a potential mechanism of retrograde embolic stroke. Cerebrovasc Dis 43:132–138CrossRefPubMedGoogle Scholar
  8. 8.
    Markl M, Semaan E, Stromberg L, Carr J, Prabhakaran S, Collins J (2017) Importance of variants in cerebrovascular anatomy for potential retrograde embolization in cryptogenic stroke. Eur Radiol 27:4145–4152CrossRefPubMedPubMedCentralGoogle Scholar
  9. 9.
    Wehrum T, Dragonu I, Strecker C et al (2017) Aortic atheroma as a source of stroke - assessment of embolization risk using 3D CMR in stroke patients and controls. J Cardiovasc Magn Reson 19:67CrossRefPubMedPubMedCentralGoogle Scholar
  10. 10.
    Hashimoto J, Ito S (2013) Aortic stiffness determines diastolic blood flow reversal in the descending thoracic aorta: potential implication for retrograde embolic stroke in hypertension. Hypertension. 62:542–549CrossRefPubMedGoogle Scholar
  11. 11.
    Shen X, Schnell S, Barker AJ et al (2018) Voxel-by-voxel 4D flow MRI-based assessment of regional reverse flow in the aorta. J Magn Reson Imaging 47:1276–1286CrossRefPubMedGoogle Scholar
  12. 12.
    Yaghi S, Bernstein RA, Passman R, Okin PM, Furie KL (2017) Cryptogenic stroke: research and practice. Circ Res 120:527–540CrossRefPubMedGoogle Scholar
  13. 13.
    Lang RM, Bierig M, Devereux RB et al (2005) Recommendations for chamber quantification: a report from the American Society of Echocardiography's Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology. J Am Soc Echocardiogr 18:1440–1463Google Scholar
  14. 14.
    Macleod MR, Amarenco P, Davis SM, Donnan GA (2004) Atheroma of the aortic arch: an important and poorly recognised factor in the aetiology of stroke. Lancet Neurol 3:408–414CrossRefPubMedGoogle Scholar
  15. 15.
    Markl M, Harloff A, Bley TA et al (2007) Time-resolved 3D MR velocity mapping at 3T: improved navigator-gated assessment of vascular anatomy and blood flow. J Magn Reson Imaging 25:824–831CrossRefPubMedGoogle Scholar
  16. 16.
    Wehrum T, Kams M, Schroeder L, Drexl J, Hennemuth A, Harloff A (2014) Accelerated analysis of three-dimensional blood flow of the thoracic aorta in stroke patients. Int J Cardiovasc Imaging 30:1571–1577CrossRefPubMedGoogle Scholar
  17. 17.
    Tautz L, Chitiboi T, Hennemuth A (2015) Automatic perfusion analysis using phase-based registration and object-based image analysis. In: Camara O, Mansi T, Pop M, Rhode K, Sermesant M, Young A (eds) Statistical Atlases and Computational Models of the Heart - Imaging and Modelling Challenges. STACOM 2014. Lecture Notes in Computer Science, vol 8896. Springer, ChamGoogle Scholar
  18. 18.
    Hennemuth A, Friman O, Schumann C et al (2011) Fast interactive exploration of 4D MRI flow data. Proc. SPIE 7964, Medical Imaging 2011: Visualization, Image-Guided Procedures, and Modeling, 79640E.
  19. 19.
    Harloff A, Mirzaee H, Lodemann T et al (2018) Determination of aortic stiffness using 4D flow cardiovascular magnetic resonance - a population-based study. J Cardiovasc Magn Reson 20:43CrossRefPubMedPubMedCentralGoogle Scholar
  20. 20.
    Bogren HG, Buonocore MH (1994) Blood flow measurements in the aorta and major arteries with MR velocity mapping. J Magn Reson Imaging 4:119–130CrossRefPubMedGoogle Scholar
  21. 21.
    Harloff A, Schlachetzki F (2018) Rivaroxaban for stroke prevention after embolic stroke of undetermined source. N Engl J Med 379:986–987Google Scholar

Copyright information

© European Society of Radiology 2019

Authors and Affiliations

  • Andreas Harloff
    • 1
    • 2
    Email author
  • Paul Hagenlocher
    • 1
    • 2
  • Thomas Lodemann
    • 1
    • 2
  • Anja Hennemuth
    • 3
  • Cornelius Weiller
    • 1
    • 2
  • Jürgen Hennig
    • 2
    • 4
  • Werner Vach
    • 5
    • 6
  1. 1.Department of Neurology and Neurophysiology, Medical CenterUniversity of FreiburgFreiburgGermany
  2. 2.Faculty of MedicineUniversity of FreiburgFreiburgGermany
  3. 3.Institute for Cardiovascular Computer-Assisted MedicineCharité - Universitätsmedizin BerlinBerlinGermany
  4. 4.Department of Diagnostic RadiologyMR Physics, Medical Center - University of FreiburgFreiburgGermany
  5. 5.Institute for Medical Biometry and Statistics, Medical Faculty and Medical CenterUniversity of FreiburgFreiburgGermany
  6. 6.Department of Orthopaedics and TraumatologyUniversity Hospital BaselBaselSwitzerland

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