[How can we improve the prognosis of infrapopliteal bypasses?]

Infrapopliteal bypasses are often used for critical ischemia, in patients older than 80, in diabetics patients in 20% of cases, and patients with end-stage renal disease in 10% of cases. The goal of this paper is to analyze the systemic factors, which contribute to the clinical results, the technical aspects, which improve the patency of the bypass, and the role of postoperative follow-up. Postoperative mortality in those patients ranges from 3 to 10%, depending on several factors: age, global cardiovascular diffusion, diabetes mellitus, end-stage renal disease. A complete evaluation of concomitant cardiovascular disease including coronary, renal and carotid disease is necessary to achieve the goal of reducing early and late mortality. Previous treatment of septic lesions of the foot is very important, before revascularisation. Technical aspects of infra-inguinal revascularisations modalities are based on a complete analysis by duplex scan, magnetic resonance imaging and intra-arterial angiography, with asynchronous subtractions and lateral view of the foot. With the duplex scan, the quality and the length of the homolateral or controlateral long saphenous vein can be previewed, allowing an appropriate choice among bypass modalities. A surgically safe portion, free of proximal hemodynamic lesions, must be chosen for the proximal anastomosis: common femoral artery, superficial femoral artery (SFA), popliteal artery or tibial artery. In patients with poor arterial distal run off, and high peripheral resistances (diabetic foot, end-stage renal disease, foot infections) the proximal anastomosis must be made as distal as possible, on the popliteal or tibial artery. In case involving a short lesion of the superficial femoral artery, a combined strategy with angioplasty and distal bypass is a safe therapeutic option. The distal anastomosis must be made on an artery in continuity with the foot, and the plantar arch. In diabetic patients, the best artery is often the pedal artery. The graft is preferentially venous, which is better than prosthetic bypass. The long saphenous vein can be used in situ or reversed, or transposed, reversed after valvular disruption, when the proximal anastomosis is made below the common femoral artery. At 3 years, the primary patency of prosthetic bypasses is between 30 and 50%. Several technical artifices, (external route) or venous artifice at the distal anastomosis site (venous patch, venous cuff) can be useful. A distal arteriovenous fistula improves the flow in the grafts, but increases the distal resistances. Free tissue transfer increases outflow, allowing treatment of major tissue loss of the foot. Postoperative therapy must include a systemic heparinisation, until the patient is able to have a muscular activity. Antiplatelet therapy with aspirin is warranted for venous grafts. For prosthetic by-pass, some studies have shown that coumadin therapy provides a benefit. These bypasses require a duplex scan follow-up at 1, 6, 12 months and then annually to search for stenosis of the venous grafts. If a significant hemodynamic lesion is found, a new procedure, via an endovascular or surgical approach can improve secondary patency. In cases of acute occlusions of the graft, an aggressive approach including thrombectomy, thrombolysis and distal angioplasty, can improve the patency. A global evaluation, with medical therapy, with antiplatelets, statins, diabetes control, annual evaluation of silent myocardial ischemia, and duplex scan follow-up of carotid artery disease, may improve the quality-of-life of these patients.