Plate 167

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 indelible pen on the overlying skin using a Doppler instrument.

General or continuous epidural anesthesia may be used while hemodynamic parameters are monitored carefully.

The patient is placed supine on the operating table.

The lower abdomen and entire leg are prepared with the usual antiseptic solutions. The sterile drapes are applied so as to allow access to the entire leg. Gangrenous toes or a foot ulcer should be enclosed in a sterile, impervious plastic wrap or bag.

Most surgeons prefer a long, continuous incision beginning at the level of the inguinal ligament. It is placed just medial or posterior to the marked course of the saphenous vein, and it continues beyond the anticipated level for the distal anastomosis (Figure 1). Alternatively, several isolated incisions with intervening skin bridges may be created, but this makes isolation of the saphenous branches and disruption of the venous valves more difficult. A two-team approach may be used to prepare both ends of the incision simultaneously, but a single-team procedure will be presented. Several intraluminal valve cutters are now commercially available. They allow the use of small distal incisions and have been associated with fewer incisional site problems. Direct visualization with intraluminal endoscopy may soon improve upon this technique.

The entire course of the saphenous vein is exposed with the dissection approaching the anterior medial aspect of the vein (Figure 2). A special effort is made to expose only this surface of the saphenous vein such that its delicate blood supply is maintained over the greatest possible area for the entire length of the vein. All venous branches are searched for diligently and then doubly looped with 00 silk ligatures that are not tied. This technique allows any of these side branches to be used as an entrance site for the retrograde valvulotome.

The proximal incision is deepened to expose the common femoral, superficial femoral, and profunda femoris arteries. The region for proximal arterial takeoff of the graft is chosen, and elastic loops are placed about each artery (Figure 3). The proximal saphenous vein is exposed, and 00 silk ligatures are tied about each branch, including the fairly large and constant superficial epigastric, superficial external pudendal, medial and lateral superficial circumflex iliac, and the medial superficial femoral cutaneous veins (see Plate 169, Figure 2). The superficial or Scarpa's fascia of the fossa ovalis is incised to allow complete exposure of the saphenofemoral venous junction. This junction is usually just at the level of the profunda artery. Additional venous length may be needed if the anastomosis is to be proximal on the common femoral artery. This length can be obtained by excising a portion of the anterior common femoral vein in continuity with the saphenous bulb. This technique can also be used to create a larger inflow anastomosis. The common femoral vein is then repaired with a monofilament 6-0 vascular continuous suture. Ordinarily, however, the Satinsky curved vascular clamp is applied to the saphenous side of the junction. A small cuff of saphenous vein is left above the clamp for closure with a running 6-0 monofilament vascular suture such that there will be no constriction of the common femoral vein when the vascular clamp is removed (Figure 4).

The proximal 5 to 7 cm of the saphenous vein is mobilized as its major tributaries are ligated and divided. Using Potts scissors, the first valve, about 1 cm into the saphenous bulb, is excised in the translucent central portion of each valve under direct vision (Figure 5). The second valve is typically 3 to 5 cm farther distal. The remainder of the saphenous vein valves are cut and rendered incompetent using either the in situ valve cutter instrument for large thigh valves only or the retrograde valvulotome for all of the valves.

If a good single saphenous vein of 3 mm or greater in diameter is present, some surgeons prefer to use a valve cutting instrument (see Plate 168, Figure 10). A guide catheter is introduced into the cut end of the saphenous vein at the ankle. It is passed cephalad and through the open proximal saphenous bulb. The system is attached to a heparinized saline solution delivery system and an elastic loop is snugged about the saphenous bulb. Infusion of the heparinized solution inflates the proximal vein and delineates the next valve assuming all side branches have been occluded with the simple silk loops. The valve cutter should float freely within the larger vein. It is rotated such that the cutting edges are at 90 degrees to the plane of the valve leaflets. That is to say, the blades should be perpendicular to the skin as the leaflets lie parallel to it. The cutter catheter assembly is slowly pulled distally. Resistance is felt as the cutter engages each valve. A “popping” sensation is noted or felt as the leaflets are cut and the vein immediately distends downward to the level of the next valve.

Alternatively, some surgeons prefer to make several small incisions for division of the saphenous branches rather than the long continuous incision illustrated. In these cases, an on-the-table venogram beginning at the ankle site will show the major side branches. Individual incisions are made after the branches are located precisely with a Doppler. The branches are then ligated or clipped. The same Doppler search is performed again after the arterial anastomoses are completed. Any missed branches are found with the Doppler and ligated.

Alternatively, the valves may be divided using a retrograde valvulotome. In this technique the proximal saphenous vein may be inflated with heparinized saline via the cut open bulb (proximal) end. However, the usual method is to inflate the saphenous vein with the patient's own heparinized blood. The patient is given systemic heparin, and several minutes later the proximal arterial inflow site is isolated and opened at about the level of the profunda branch (Figure 6). This allows inspection of the profunda stoma and possible endarterectomy.

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