Peripheral blood flow responses to exercise after successful correction of coarctation of the aorta.
OBJECTIVE
The purpose of this study was to characterize peripheral flow kinetics in response to progressive discontinuous maximal exercise in 10 patients who underwent repair of coarctation of the aorta and 11 age-matched healthy adolescents.


BACKGROUND
An impairment of leg blood flow has been suggested on the basis of exaggerated femoral muscle lactate accumulation in patients with successful repair of coarctation. Few data are available describing blood flow kinetics of the exercising leg in such patients.


METHODS
Duplex ultrasound provided transcutaneous measurements of peak systolic and end-diastolic flow velocities of the femoral, humeral and renal arteries at rest and immediately after mild, moderate and maximal exercise intensities for computation of mean velocity, resistance index and femoral blood flow.


RESULTS
Femoral mean velocity and femoral blood flow increased linearly with exercise intensity in both groups, but the slope of this increase was significantly lower in patients. Similarly, humeral mean velocity increased significantly less in patients than in control subjects. Femoral resistance index sharply decreased from that at rest (patients [mean +/- SE] 1.4 +/- 0.04; control subjects 1.4 +/- 0.03) to mild exercise intensity in both groups (patients 0.69 +/- 0.03; control subjects 0.72 +/- 0.03). A further decrease was observed at maximal exercise in patients (0.60 +/- 0.04, p = 0.08) but not in control subjects (0.69 +/- 0.02).


CONCLUSIONS
These observations suggest that despite a greater exercise-induced femoral vasodilation, patients with successful correction of coarctation of the aorta demonstrate an impaired lower limb blood flow in response to strenuous dynamic exercise. In the absence of stenosis at rest, this alteration could result from exaggerated flow turbulence in the descending aorta distal to the site of correction because of loss of elasticity at the site of the resection of the coarcted segment.
Johnson
D
D
Cardiology and Cardio-Thoracic Surgery Units, Sainte-Justine Hospital, Montreal, Quebec, Canada.
Bonnin
P
P
Perrault
H
H
Marchand
T
T
Vobecky
S J
SJ
Fournier
A
A
Davignon
A
A
D000293:Adolescent; D000328:Adult; D001017:Aortic Coarctation / Q000503:physiopathology* / Q000601:surgery*; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002648:Child; D005121:Extremities / Q000098:blood supply*; D005260:Female; D005263:Femoral Artery / Q000503:physiopathology; D006339:Heart Rate; D006801:Humans; D008297:Male; D005082:Physical Exertion; D012039:Regional Blood Flow; D012077:Renal Artery / Q000503:physiopathology; D014655:Vascular Resistance