Velocity-encoded magnetic resonance image assessment of regional aortic flow in coarctation patients.
BACKGROUND
During primary coarctation repair, collateral blood vessels contribute significantly to distal perfusion. We sought to determine if velocity-encoded cine magnetic resonance imaging (VENC-MRI) could provide insight into anatomy and hemodynamics of collateral flow in patients with unrepaired coarctation.


METHODS
Sixteen patients (median age, 6.2 years; range, 1 to 18) with discrete coarctation (65% severe, 29% mild-moderate) and 10 controls (median age, 12.0 years; range, 9 to 15) without left-sided heart lesions were referred for cardiac MRI. Flow volumes were calculated from VENC-MRI images at the coarctation (proximal), diaphragm (distal), and midway between the two points (midpoint). A means model, repeated-measure analysis, was performed for volumes.


RESULTS
In coarctation patients, flow volumes increased by 59% (p = 0.0002) from coarctation to diaphragm, primarily between the proximal and midpoint sites (by 77%, p < 0.0001). In controls, flow volumes decreased by 11% along the entire aortic study length. Coarctation volumes were lower than controls by 54% (p = 0.0003) at the proximal site but showed no statistical difference at the midpoint or diaphragm.


CONCLUSIONS
Coarctation flow volumes maximally increase in the upper thoracic aorta, but approach normal flow volumes in the lower thoracic region. Arteries arising from mid and lower thoracic level, such as those supplying the anterior spinal cord, may have nearly normal flow if collaterals are present. Velocity-encoded MRI can evaluate flow in patients who have poor collateral circulation to improve surgical planning and decrease neurologic complications of coarctation repair.
Emory University School of Medicine, Atlanta, Georgia, USA.
Tiffany J
TJ
Riehle
John N
JN
Oshinski
Marijn E
ME
Brummer
Jennifer
J
Favaloro-Sabatier
William T
WT
Mahle
Derek A
DA
Fyfe
Kirk R
KR
Kanter
W James
WJ
Parks
D000293:Adolescent; D001013:Aorta, Thoracic / Q000473:pathology*; D001017:Aortic Coarctation / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D012189:Retrospective Studies