Systolic flow displacement correlates with future ascending aortic growth in patients with bicuspid aortic valves undergoing magnetic resonance surveillance.
OBJECTIVE
Altered systolic blood flow in the ascending aorta has been correlated with increased aortic growth in patients with bicuspid aortic valves (BAVs). We used conventional, 2-dimensional (2D) phase contrast magnetic resonance imaging (PC-MRI) to assess the relationship between altered flow and future growth in patients with BAV.


METHODS
Aortic MRI data were reviewed for 17 adult patients with BAV with right-left leaflet fusion undergoing surveillance imaging who had 2D PC-MRI through their ascending aortas on an initial study, follow-up studies more than 1 year later, and an initial maximum aortic diameter of less than 4.5 cm. Diameters were measured at standard levels by 2 blinded reviewers. Normalized systolic flow displacement was calculated at peak systole from the PC-MRI data, and correlation with the interval aortic growth was performed, with adjustment for clinical/demographic factors.


RESULTS
The average follow-up interval was 2.9 ± 1.3 years. Systolic flow displacement at the initial study strongly correlated with ascending aortic growth rate (r = 0.71, P < 0.005) with moderate, non-significant correlation between initial diameter and growth (r = 0.45, P = 0.214). Aortic growth was 4 times faster in patients with initial flow displacement of 0.2 or greater (n = 9) compared with those (n = 8) with initial flow displacement less than 0.2 (0.8 ± 0.4 vs 0.2 ± 0.3 mm/y; P = 0.002).


CONCLUSIONS
Systolic flow displacement calculated from conventional 2D PC-MRI in the ascending aorta correlates with future aortic growth in patients undergoing routine surveillance imaging for BAV. With a cutoff valve of 0.2, flow displacement may be used to identify a subset of patients likely to have elevated growth rates and may better risk-stratify patients with BAV for aortic disease progression than vessel diameter alone.
From the *Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA; †CREATIS Laboratory, University of Lyon, Lyon, France; ‡School of Public Health, University of California, Berkeley; and §Department of Cardiothoracic Surgery, University of California, San Francisco, CA.
Nicholas S
NS
Burris
Monica
M
Sigovan
Heather A
HA
Knauer
Elaine E
EE
Tseng
David
D
Saloner
Michael D
MD
Hope
D000293:Adolescent; D000328:Adult; D000368:Aged; D001011:Aorta / Q000254:growth & development* / Q000473:pathology* / Q000503:physiopathology; D001021:Aortic Valve / Q000002:abnormalities* / Q000473:pathology / Q000503:physiopathology; D000082882:Bicuspid Aortic Valve Disease; D001783:Blood Flow Velocity / Q000502:physiology; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D019786:Gadolinium DTPA; D006349:Heart Valve Diseases / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D009929:Organ Size / Q000502:physiology; D012039:Regional Blood Flow / Q000502:physiology; D055815:Young Adult
D003287:Contrast Media; D019786:Gadolinium DTPA