title: Three-dimensional haemodynamics in patients with obstructive and non-obstructive hypertrophic cardiomyopathy assessed by cardiac magnetic resonance.
abstract: OBJECTIVE
  The left ventricular outflow tract (LVOT) peak pressure gradient is an important haemodynamic descriptor in patients with hypertrophic cardiomyopathy (HCM); however, secondary alterations in aortic blood flow have not been well described in these patients. Aortic flow derangement is not easily assessed by traditional imaging methods, but may provide unique characterization of this disease. In this study, we demonstrated how four-dimensional (4D) flow MRI can assess LVOT peak pressure gradients in HCM patients and also evaluated the ascending aorta (AAo) haemodynamic derangement associated with HCM.
  
  
  RESULTS
  Obstructive (n = 12) and non-obstructive (n = 18) HCM patients were included in the study along with 10 normal volunteers. 4D flow MRI was used to visualize three-dimensional (3D) blood flow patterns within the LVOT and AAo, which were graded for the presence of helical flow as a marker of flow derangement (absent = 0, mild/moderate = 1, and severe = 2). MRI-estimated pressure gradient (ΔPMRI) was calculated from the peak systolic 3D blood velocity profile within the LVOT. There was higher grade helical flow in obstructive HCM patients compared with non-obstructive patients (P = 0.04) and volunteers (P < 0.001). Non-obstructive patients also had higher helix grade than volunteers (P = 0.002). There was a significant correlation between helical grade and increasing ΔPMRI (rS = 0.69, P < 0.001). Systolic anterior motion (SAM) of the mitral valve was associated with both increasing helix grade (P < 0.001) and ΔPMRI (P = 0.006).
  
  
  CONCLUSIONS
  Ascending aorta flow derangement occurs in both obstructive and non-obstructive HCM patients and can be identified using 4D flow MRI. The degree of flow derangement correlates with LVOT gradient, SAM, and outflow tract geometry.
authors.affiliation: Department of Radiology, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL 60611, USA bdallen@fsm.northwestern.edu.
authors.forename: Bradley D
authors.initials: BD
authors.lastname: Allen
authors.affiliation: Department of Medicine-Cardiology, Northwestern University, Chicago, IL, USA.
authors.forename: Lubna
authors.initials: L
authors.lastname: Choudhury
authors.affiliation: Department of Radiology, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL 60611, USA.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Barker
authors.affiliation: Department of Radiology, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL 60611, USA.
authors.forename: Pim
authors.initials: P
authors.lastname: van Ooij
authors.affiliation: Department of Radiology, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL 60611, USA.
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Collins
authors.affiliation: Department of Medicine-Cardiology, Northwestern University, Chicago, IL, USA.
authors.forename: Robert O
authors.initials: RO
authors.lastname: Bonow
authors.affiliation: Department of Radiology, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL 60611, USA.
authors.forename: James C
authors.initials: JC
authors.lastname: Carr
authors.affiliation: Department of Radiology, Northwestern University, 737 N. Michigan Ave., Suite 1600, Chicago, IL 60611, USA Department of Biomedical Engineering, Northwestern University, Chicago, IL, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Markl
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001783:Blood Flow Velocity; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis*; D016022:Case-Control Studies; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012720:Severity of Illness Index; D014694:Ventricular Outflow Obstruction / Q000175:diagnosis*
keywords: Cardiac magnetic resonance imaging; Flow imaging; Hypertrophic cardiomyopathy
references.citation: J Am Coll Cardiol. 2011 Nov 22;58(22):2313-21
references.pmid: 22093509
references.citation: Eur Radiol. 2011 Aug;21(8):1651-7
references.pmid: 21720942
references.citation: Eur J Echocardiogr. 2009 Dec;10(8):iii9-14
references.pmid: 19889657
references.citation: J Am Coll Cardiol. 2009 Jul 14;54(3):191-200
references.pmid: 19589431
references.citation: Cardiol Rev. 1998 May;6(3):135-145
references.pmid: 10348935
references.citation: Magn Reson Med. 2014 Apr;71(4):1542-53
references.pmid: 23716466
references.citation: J Am Coll Cardiol. 2009 Jul 14;54(3):220-8
references.pmid: 19589434
references.citation: J Am Coll Cardiol. 2002 Dec 18;40(12):2156-64
references.pmid: 12505229
references.citation: JAMA. 2002 Mar 13;287(10):1308-20
references.pmid: 11886323
references.citation: J Cardiovasc Magn Reson. 2011 Jan 14;13:7
references.pmid: 21235751
references.citation: Ann Thorac Surg. 2003 Feb;75(2):620-32
references.pmid: 12607696
references.citation: J Cardiovasc Magn Reson. 2012 Dec 13;14:84
references.pmid: 23237187
references.citation: J Am Coll Cardiol. 2008 Aug 12;52(7):559-66
references.pmid: 18687251
references.citation: J Magn Reson Imaging. 2012 Sep;36(3):598-603
references.pmid: 22549972
references.citation: J Am Coll Cardiol. 2004 Nov 16;44(10):2044-53
references.pmid: 15542290
references.citation: JACC Cardiovasc Interv. 2011 Jun;4(6):704-9
references.pmid: 21700258
references.citation: J Am Coll Cardiol. 2009 Jul 14;54(3):255-62
references.pmid: 19589439
references.citation: J Magn Reson Imaging. 1999 Nov;10(5):861-9
references.pmid: 10548800
references.citation: Circulation. 2011 Dec 13;124(24):2761-96
references.pmid: 22068435
references.citation: Am J Cardiovasc Dis. 2013 Jun 10;3(2):79-84
references.pmid: 23785585
references.citation: J Magn Reson Imaging. 2012 Nov;36(5):1015-36
references.pmid: 23090914
references.citation: Radiology. 2010 Apr;255(1):53-61
references.pmid: 20308444
references.citation: Magn Reson Med. 2014 Sep;72(3):620-8
references.pmid: 24122967
references.citation: Am Heart J. 1988 Nov;116(5 Pt 1):1253-61
references.pmid: 3189142
references.citation: Radiol Med. 2011 Mar;116(2):197-210
references.pmid: 20981502
references.citation: J Magn Reson Imaging. 2013 Jan;37(1):208-16
references.pmid: 22976284
references.citation: J Am Coll Cardiol. 2003 May 7;41(9):1561-7
references.pmid: 12742298
references.citation: Circ Cardiovasc Imaging. 2012 Jul;5(4):457-66
references.pmid: 22730420
references.citation: Circulation. 1995 Aug 15;92(4):785-9
references.pmid: 7641357
references.citation: Am J Cardiol. 2010 Nov 1;106(9):1301-6
references.pmid: 21029828
references.citation: Circulation. 2014 Feb 11;129(6):673-82
references.pmid: 24345403
references.citation: Int J Cardiovasc Imaging. 2009 Jun;25(5):511-8
references.pmid: 19234870
references.citation: J Magn Reson Imaging. 2007 Dec;26(6):1471-9
references.pmid: 17968892
references.citation: N Engl J Med. 2003 Jan 23;348(4):295-303
references.pmid: 12540642
references.citation: Circ Heart Fail. 2008 Sep;1(3):184-91
references.pmid: 19808288