Aortic Function's Adaptation in Response to Exercise-Induced Stress Assessing by 1.5T MRI: A Pilot Study in Healthy Volunteers.
OBJECTIVE
Evaluation of the aortic "elastic reserve" might be a relevant marker to assess the risk of aortic event. Our aim was to compare regional aortic elasticity at rest and during supine bicycle exercise at 1.5 T MRI in healthy individuals.


METHODS
Fifteen volunteers (8 men), with a mean age of 29 (23-41) years, completed the entire protocol. Images were acquired immediately following maximal exercise. Retrospective cine sequences were acquired to assess compliance, distensibility, maximum rates of systolic distension and diastolic recoil at four different locations: ascending aorta, proximal descending aorta, distal descending aorta and aorta above the coeliac trunk level. Segmental aortic pulse wave velocity (PWV) was assessed by through plane velocity-encoded MRI.


RESULTS
Exercise induced a significant decrease of aortic compliance and distensibility, and a significant increase of the absolute values of maximum rates of systolic distension and diastolic recoil at all sites (p<10-3). At rest and during stress, ascending aortic compliance was statistically higher compared to the whole descending aorta (p≤0.0007). We found a strong correlation between the rate pressure product and aortic distensibility at all sites (r = - 0.6 to -0.75 according to the site, p<10-4). PWV measured at the proximal and distal descending aorta increased significantly during stress (p = 0.02 and p = 0.008, respectively).


CONCLUSIONS
Assessment of regional aortic function during exercise is feasible using MRI. During stress, aortic elasticity decreases significantly in correlation with an increase of the PWV. Further studies are required to create thresholds for ascending aorta dysfunction among patients with aneurysms, and to monitor the impact of medication on aortic remodeling.
CRMBM-CEMEREM, UMR 7339 CNRS, Aix-Marseille University, Marseille, France.|Department of Vascular Surgery and Vascular Medecine, La Timone Hospital, Marseille, France.|Aortic Center, La Timone Hospital, Marseille, France.
Laurence
L
Bal-Theoleyre
LE2I, UMR 6306 CNRS, University of Burgundy, Dijon, France.|MRI Department, University Hospital of Dijon, Dijon, France.
Alain
A
Lalande
CRMBM-CEMEREM, UMR 7339 CNRS, Aix-Marseille University, Marseille, France.
Frank
F
Kober
SESSTIM, UMR_S 912 INSERM, Aix-Marseille University, Marseille, France.|Department of Biostatistic and ICT, La Timone Hospital, Marseille, France.
Roch
R
Giorgi
Department of Cardiac Surgery, La Timone Hospital, Marseille, France.|Aortic Center, La Timone Hospital, Marseille, France.
Frederic
F
Collart
Department of Vascular Surgery and Vascular Medecine, La Timone Hospital, Marseille, France.|Aortic Center, La Timone Hospital, Marseille, France.
Philippe
P
Piquet
Aortic Center, La Timone Hospital, Marseille, France.|Cardiology Department, La Timone Hospital, Marseille, France.
Gilbert
G
Habib
Aortic Center, La Timone Hospital, Marseille, France.|Cardiology Department, La Timone Hospital, Marseille, France.
Jean-François
JF
Avierinos
CRMBM-CEMEREM, UMR 7339 CNRS, Aix-Marseille University, Marseille, France.
Monique
M
Bernard
CRMBM-CEMEREM, UMR 7339 CNRS, Aix-Marseille University, Marseille, France.
Maxime
M
Guye
CRMBM-CEMEREM, UMR 7339 CNRS, Aix-Marseille University, Marseille, France.|Department of Radiology and Cardiovascular Imaging, La Timone Hospital, Marseille, France.|Aortic Center, La Timone Hospital, Marseille, France.
Alexis
A
Jacquier
D000222:Adaptation, Physiological; D000328:Adult; D001011:Aorta / Q000000981:diagnostic imaging / Q000502:physiology*; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging / Q000502:physiology*; D003971:Diastole / Q000502:physiology; D004548:Elasticity; D015444:Exercise; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010865:Pilot Projects; D063177:Pulse Wave Analysis; D013312:Stress, Physiological; D016683:Supine Position; D013599:Systole / Q000502:physiology; D059289:Vascular Stiffness / Q000502:physiology*