Viscous energy loss in the presence of abnormal aortic flow. Issue 3 (2nd October 2013)

• Record Type: Journal Article
• Authors: Barker, Alex J.; van Ooij, Pim; Bandi, Krishna; Garcia, Julio; Albaghdadi, Mazen; McCarthy, Patrick; Bonow, Robert O.; Carr, James; Collins, Jeremy; Malaisrie, S. Chris; Markl, Michael
• Is Part Of: Magnetic resonance in medicine. Volume 72:Issue 3(2014:Sep.)
• Page Start: 620
• Page End: 628
• Publication Date: 2013-10-02
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.24962
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mrm24962-sec-0001" sec-type="section"> <title>Purpose</title> <p>To present a theoretical basis for noninvasively characterizing in vivo fluid‐mechanical energy losses and to apply it in a pilot study of patients known to express abnormal aortic flow patterns.</p> </sec> <sec id="mrm24962-sec-0002" sec-type="section"> <title>Methods</title> <p>Four‐dimensional flow MRI was used to characterize laminar viscous energy losses in the aorta of normal controls (n = 12, age = 37 ± 10 yr), patients with aortic dilation (n = 16, age = 52 ± 8 yr), and patients with aortic valve stenosis matched for age and aortic size (n = 14, age = 46 ± 15 yr), using a relationship between the three‐dimensional velocity field and viscous energy dissipation.</p> </sec> <sec id="mrm24962-sec-0003" sec-type="section"> <title>Results</title> <p>Viscous energy loss was elevated significantly in the thoracic aorta in patients with dilated aorta (3.6 ± 1.3 mW, <italic>P</italic> = 0.024) and patients with aortic stenosis (14.3 ± 8.2 mW, <italic>P</italic> < 0.001) compared with healthy volunteers (2.3 ± 0.9 mW). The same pattern of significant differences was seen in the ascending aorta, where viscous energy losses in patients with dilated aortas (2.2 ± 1.1 mW, <italic>P</italic> = 0.021) and patients with aortic stenosis (10.9 ± 6.8 mW, <italic>P</italic> < 0.001) were elevated compared with healthy volunteers (1.2 ± 0.6 mW).</p> </sec> <sec id="mrm24962-sec-0004" sec-type="section"> <title>Conclusion</title> <p>This technique provides a capability to quantify the contribution of abnormal laminar blood flow to increased ventricular afterload. In this pilot study, viscous energy loss in patient cohorts was significantly elevated and indicates that cardiac afterload is increased due to abnormal flow. Magn Reson Med 72:620–628, 2014. © 2013 Wiley Periodicals, Inc.</p> </sec> </abstract>