Role of precapillary arteriovenous shunting in the pathogenesis of varicose veins and its therapeutic implications.

The conventional pathogenesis of varicose veins and their subsequent development is essentially based on primary valvular insufficiency of the main saphenous trunk and incompetence of the perforating veins. In contrast, the concept of the pathogenesis of varicose veins presented in this review is based on the presence of arteriovenous (AV) shunting that occurs primarily in the venous tributaries and rarely in the main trunks of the saphenous system. Identification of arteriovenous communications (AVCs) with varicose veins has been documented by visual observation during surgery and especially by use of high-powered microscopes or magnifying lenses. The AVCs have been found consistently to originate subfascially and to terminate in tributaries extrafascially, thus bypassing the capillary network. By means of serial arteriography it was shown that in more than 80% of varicose veins there is premature venous opacification. By means of Doppler ultrasonography, it was demonstrated that AV shunting was present in 80% of the cases. A correlative study of these parameters has shown that the initial significant pathology in varicose veins is mostly confined to the tributaries, although at an advanced stage the main trunk may also be subsequently affected to a lesser degree. In terms of management, these data strongly imply that sclerotherapy or surgical treatment (ligation or excision) should be confined to the tributaries and that high saphenofemoral ligation and stripping should be avoided except in cases where evidence shows valvular involvement and incompetency of the latter. As a result, this study strongly suggests that one could most often spare the main trunk of the saphenous vein for eventual use as a vascular graft.