DIRECT MEASUREMENT OF ARTERIOVENOUS ANASTOMOTIC BLOOD-FLOW AFTER LUMBAR SYMPATHECTOMY

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  • 1 January 1977
    • journal article
    • research article
    • Vol. 82  (1) , 82-89
Abstract
[Lumbar sympathectomy has been frequently employed in the treatment of arterial occlusive disease.] Absolute blood flows through hind limb capillaries and arteriovenous anastomoses (AVA) were determined by the radioactive microsphere technique of relative shunt measurement combined with direct (electromagnetic) measurement of femoral artery flow. Hemodynamic parameters were measured before and after laparotomy, after unilateral lumbar sympathectomy, during reactive hyperemia, and during .alpha. adrenergic blockade in normal and sympathectomized hindlimbs of 6 anesthetized dogs. After sympathectomy, arteriovenous (A-V) shunting increased from 3.8 to 32.1% (P < 0.005). AVA flow increased from 4 to 54 (P < 0.01), while capillary flow was unchanged. Nonsympathectomized limbs did not demonstrate these changes. During reactive hyperemia, capillary flow increased more than 100% (P < 0.03) in both normal and sympathectomized limbs, while AVA flow was unchanged. After phentolamine (5 mg, i.v.), AVA flow increased from 2 to 19 ml/min (P < 0.01) only in nonsympathectomized limbs. Phentolamine mimicked surgical sympthectomy effects in nonsympathectomized limbs, with paw temperature, femoral flow, A-V O2 difference, A-V shunting, AVA flow and capillary flow equal to sympathectomized limbs after phentolamine administration. In the acute canine model, increased blood flow after sympathectomy is due to increased non-nutritive AVA flow, with no change in total hindlimb capillary flow, both at rest and during reactive hyperemia.