Infrainguinal arterial bypass procedures may be indicated in patients with ischemic nocturnal rest pain, with impending tissue loss such as occurs with gangrene of the toes or ulceration of the foot or ankle, or with progressive, severe claudication. Compared to bypass procedures using either a synthetic graft or a reversed autogenous saphenous vein, the use of the in situ saphenous vein technique is preferred by some surgeons. Currently, there are no significant differences in patency rates between in situ and reversed vein grafts. Hence, the choice is largely a matter of surgeon preference. Additionally, this technique extends the level of the distal anastomosis especially into the tibial and peroneal arteries. This is possible because the vein size tapers in the correct direction in contrast to reversed vein grafts. The taper results in an easier anastomosis as the sizes are comparable and in improved hemodynamic flow. It is believed that all these factors contribute to the improved results in a biologically living bypass graft whose natural lining is not thrombogenic.
The majority of the patients are older and have generalized arteriosclerotic cardiovascular disease. A general medical assessment is necessary, with special attention being given to associated risk factors like diabetes and smoking. Cardiopulmonary function should be assessed with a chest x-ray, electrocardiography, and additional studies as indicated while the patient's overall condition is optimized.
Segmental Doppler pressures and waveforms are useful in evaluating the extent of the arterial disease and serve as baseline for postoperative studies that document improvement. However, most surgeons believe that the best evaluation is obtained with detailed biplane contrast angiograms. These may require visualization from the aorta to the foot so as to evaluate any possible obstruction of inflow, the levels of occlusion, and the suitability for use of the arteries in the lower leg, ankle, or foot. Venous mapping with duplex ultrasound studies is the preferred method for assessment of the saphenous vein. It demonstrates the patency and anatomy of the saphenous vein, as it is prone to variation, double systems, or unexpectedly large perforating connectors.
Immediately prior to operation, systemic antibiotics are given. Catheters are placed to monitor the urinary output, arterial pressure and blood gases, and central venous pressure. A Swan-Ganz pulmonary artery catheter for measurement of the pulmonary artery wedge pressure and cardiac output may be indicated in high-risk patients. Finally, the course of the saphenous vein is marked with an ...