Reductions in basal limb blood flow and lumen diameter after short-term leg casting.
OBJECTIVE
We tested the hypotheses that short-term casting immobilization of a leg would reduce basal blood flow and vascular conductance and induces structural alterations in femoral artery.


METHODS
Right knee and ankle joints of eight healthy young men were immobilized with casting for 7 d. Before and immediately after casting, and 14 d after the cast was removed, femoral artery hemodynamics and structure were measured using a high-resolution ultrasound.


RESULTS
Femoral artery lumen diameter in the immobilized leg decreased after the immobilization (P < 0.05) and returned to baseline during the recovery period, in which the subjects did not receive any special rehabilitation treatment. Femoral artery intima-media thickness (IMT) and IMT/lumen ratio in both legs did not show significant changes throughout the interventions. In the immobilized leg, femoral artery blood flow and vascular conductance decreased (-23 to 24%) after the immobilization (all P < 0.05). These parameters returned to the baseline during the recovery period, and there were no significant differences between the baseline and recovery values. In the control leg, femoral blood flow and vascular conductance did not change throughout the investigation. After 7 d of casting, femoral arterial distension, an index of arterial distensibility, tended to decrease in the immobilized leg but not in the control leg.


CONCLUSIONS
We concluded that a short-term immobilization of lower limb decreases basal limb blood flow and arterial lumen diameter. These results suggest that basal limb blood flow and lumen diameter decrease rapidly upon the cessation of muscular weight bearing and locomotor activity, and may be modulated by an ordinary level of physical activity.
Sugawara
Jun
J
Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan. jun.sugawara@aist.go.jp
Hayashi
Koichiro
K
Kaneko
Fuminari
F
Yamada
Hiroshi
H
Kizuka
Tomohiro
T
Tanaka
Hirofumi
H
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D002370:Casts, Surgical; D005263:Femoral Artery / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D007103:Immobilization; D007866:Leg / Q000098:blood supply*; D008297:Male; D020127:Recovery of Function / Q000502:physiology; D014655:Vascular Resistance / Q000502:physiology