Studies of pathologic vasoconstriction (vasospasm) in microvascular surgery

Characterization and resolution of microvascular spasm were investigated in 170 studies with the use of tail or femoral arteries of the rat. Topical epinephrine reliably produced vasospasm and topical vasodilators which included 2% and 20% lidocaine (Xylocaine) and 0.75% bupivacaine (Marcaine) were applied to resolve the vasoconstriction. Extensive vessel dissection was necessary to obtain significant resolution of vasospasm, and adventitial stripping was associated with even more impressive results. Local anesthetics appear to have a concentration dependent ability to resolve vasospasm, and 20% Xylocaine is the most effective agent yet studied.