Autogenous arterial grafts for coronary bypass surgery: current status and future perspectives

Anatomical bases of the bypass-flap: study of the thoracodorsal axis

Cutaneous tissue loss in patients with lesions on the arterial axes remains difficult to treat. Currently, combined surgery associating distal bypass and free flap seems to be the technique that yields the best results. The hemodynamic advantages of this technique, recently demonstrated, are the distal resistance and the increase in bypass flow. Nevertheless, it is complex and its indications limited. Two major drawbacks can be noted: The increasing risk of thrombosis due to the multiplication of anastomoses on the same arterial axis and the deterioration in venous autograft. To overcome these inconveniences we propose a new technique that we call bypass-flap (BF): the graft of an anatomical entity comprised of one artery and one flap. This graft secures the cover of tissue loss and the revascularization of the limb. Apart from its combined nature this technique presents three major advantages. The arterial autograft is superior to the venous graft, the gradually decreasing diameter of the artery secures the congruence of the anastaomoses, and the arterial flow of the graft is higher than a simple bypass due to the joint vascularization of the flap. The arterial graft includes the subscapular and the thoracodorsal arteries. The free flap is composed of serratus anterior muscle supplied by branches of the graft. This investigation studied the feasibility of the bypass flap and determined the length and diameter of the arterial graft and its muscular branch. Forty anatomical preparations were performed on 20 cadavers. The dissections were performed after injection of Rhodorsil. The anatomical feasibility of the bypass flap was confirmed in 37 cases. The total length of the arterial graft that preserved an external diameter above 2 mm was measured at 13 cm (8.5-15.5). This includes the subscapular artery and the thoracodorsal artery with its intramuscular part (if external diameter of that part always above 2 mm). The length of the pedicle of the serratus anterior flap was measured at 7.5 cm (3.0-12.5 cm).

The Bypass Flap: An Innovative Technique of Distal Revascularization—Anatomical Study and Clinical Application

Combined surgery for placement of a distal venous bypass and a free flap enables successful treatment of tissue loss caused by ischemia. This complex surgery has limited indications. The multiple anastomoses on the same arterial axis increase the risk of thrombosis and a certain number of venous grafts are likely to undergo mid-term deterioration. Because of these difficulties, we propose a new concept: the bypass flap (BF), which is based on the harvesting of an arterial axis to provide an arterial graft and a free flap supplied by a collateral branch of the graft. The aim of the anatomic part of this study was to evaluate the length and diameter of the arterial graft and its tissue branch and to study the feasibility of the BF. Thirty-two anatomic preparations were made by intraarterial injection of Rhodosil in 16 cadavers. The arterial graft included the subscapular artery and the thoracodorsal artery. The flap consisted of the anterior serrate muscle supplied by the branch of that graft. The distribution, length, and diameter of the arteries were examined. The mean length of the arterial graft line maintaining diameter above 2 mm was 12.5 cm (8.5-15.5). Three clinical applications of the BF based on the thoracodorsal artery axis were performed on three patients with tissue loss caused by severe ischemia of the lower limb. No occlusion of the BF occurred and healing of the tissue loss was achieved after 4, 7, and 10 months, respectively. This technique has the advantage of decreasing vascular distal resistance, which may contribute to improvement of vessel reconstruction patency. It is simpler because the anastomoses are fewer and it presents the advantage of requiring only autologous arterial material of an appropriate diameter.

Arterial grafts in microscope-assisted pedal bypass for limb salvage

Leg amputations are associated with marked morbidity and mortality in the atherosclerotic population. The survival in patients undergoing lower extremity amputations is 50% at 3 years and 30% at 5 years. Despite excellent reported results with pedal bypass, some patients are "nonbypassable" with traditional techniques because of very small, short target vessels in the pedal arch. The authors report six cases of microscope-assisted inframalleolar bypass using autogenous artery in 5 patients presenting with threatened limb loss, with 83% graft patency at 52 months average follow-up. They hypothesize that the success in these patients is the result of less surgical trauma and less compliance mismatch at the distal anastomosis, and perhaps the result of vasoactive substances secreted by the arterial grafts. Microscope-assisted pedal bypass with autogenous artery should be considered for "nonbypassable" patients with tissue necrosis or rest pain who do not appear to have sufficient inflow to heal a forefoot amputation.