Reduction of the veno-arteriolar reflex induced arteriolar constriction in forearm subcutaneous tissue after surgical repair of aortic coarctation.

Arteriolar constriction in subcutaneous tissue elicited by the local sympathetic veno-arteriolar axon reflex was studied in subcutaneous tissue of forearm and leg in 4 patients before and after correction of aortic coarctation. Before the operation the local axon reflex induced an average increase of 154% in vascular resistance in the "hypertensive" forearm and of 76% in the leg. Following coarctectomy the local axon reflex induced increase in vascular resistance decreased in the forearm within 6 months in all patients. Now average increase in vascular resistance was only 109% 3 months after the operation and 45% 6 months after. Minimal vascular resistance in the papaverine relaxed vascular bed was reduced, whereas no systemic changes were seen in the distensibility of the vascular bed. The results indicate that adaptive vascular changes underlying the augmented arteriolar constriction during lowering as well as the increased "minimal vascular resistance" in the forearm are at least partly reversible following coarctectomy.