Reversed Vein Bypass Graft to Popliteal, Tibial, and Peroneal Arteries

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Robyn A. Macsata

Byron Faler

Anton N. Sidawy

As the average population age keeps increasing, atherosclerosis, in particular lower extremity occlusive disease, is on the rise. Patients presenting with rest pain, nonhealing ulcers, or gangrene are candidates for infrainguinal distal bypass for limb salvage. There are multiple ways to perform an infrainguinal vein bypass, including reversed, in situ, and translocated configurations. In this chapter, we will focus on reverse vein bypass advantages and disadvantages, techniques, and outcomes.

We find the reverse vein bypass technique to be most advantageous in patients requiring short bypasses. There are multiple benefits to this technique, most importantly, maintaining venous endothelial integrity. Because the vein is reversed, there is no need for valvulotomies, with the potential for endothelial damage and long-term consequences of intimal hyperplasia leading to graft thrombosis at these sites. Another benefit, seen in short bypasses, the best portion of the available vein may be used and relocated to the bypass site. For example, in a popliteal-to-tibial bypass, the larger thigh greater saphenous vein may be removed and placed in the distal leg for bypass. This also avoids long skin incisions in the distal aspect of the leg where the skin is often tenuous or even broken down and at risk for poor wound healing and infection secondary to ischemia.

There are two main disadvantages of the reverse vein bypass. First and most importantly, there is a size discrepancy between the inflow and outflow arteries and the ends of the vein used as conduit. This can create a problem at the proximal anastomosis, between the large arterial inflow vessel and the distal smaller aspect of the vein. In small-caliber veins, a postanastomotic stenosis may develop in the vein conduit, which leads to intimal hyperplasia. A second problem with reverse vein bypass is difficulty in treatment of an acute perioperative thrombosis. Secondary to the valves still being in place, passing of thrombectomy catheters is extremely difficult, and usually results in valvular endothelial injury, leaving the graft at risk for recurrent thrombosis.

Preoperative Planning

Many patients with lower extremity ischemia present with foot infections including abscesses and wet gangrene. These patients need to have thorough irrigation and debridement of their abscesses and infected tissue followed by a course of intravenous antibiotics before proceeding with revascularization. Only when these foot infections have completely cleared and the foot is believed to be salvageable does treatment for arterial ischemia proceed.

Adequate visualization of inflow and outflow vessels through high-quality preoperative arteriogram is essential in distal bypasses. To improve quality, arteriograms are obtained in an appropriate radiology suite using digital subtraction imaging. Selective catheterization to at least the external iliac artery is imperative to adequately visualize outflow vessels. Intra-arterial injections of papaverine or nitroglycerin help to vasodilate and better visualize outflow vessels. Lower extremity arteriograms are only complete once adequate visualization of the inflow and outflow vessels is achieved.

Preoperative venous mapping performed in the noninvasive vascular laboratory is not routinely performed; however, this can be particularly useful in a subgroup of patients. Vein is often in limited supply in patients who have had multiple venous harvests for cardiac or other peripheral bypass procedures, and vein mapping can identify the longest lengths of vein left available. Also, in patients requiring a long distal bypass, such as a common femoral artery to dorsalis pedis bypass, an adequate length vein may be identified preoperatively and help avoid the need for multiple harvests and venovenostomies. When preoperative vein mapping is done, all harvest sites are marked in the vascular laboratory, which decreases the need for multiple skin incisions and helps avoid large skin flaps at harvest sites, improving wound healing.

Arterial Inflow

Shorter bypasses require less vein conduit, which allows the surgeon to choose the best segment of the vein available, as well as decreasing the need for venovenostomies. Therefore, the inflow of venous bypasses is taken as distally as possible in the lower extremity. The common femoral artery is used when necessary; however, the profunda femoris, the superficial femoral artery, and the popliteal artery are all adequate sources of inflow and are used when available. Also, in secondary procedures, the common femoral artery may be previously dissected and used for bypass, making repeat dissection difficult. By using distal sources of inflow this challenging and often tedious dissection may be avoided.

Arterial Outflow

The most important determining factor for adequate distal outflow is the preoperative arteriogram. As mentioned previously, this makes high-quality arteriograms with adequate visualization of outflow vessels imperative. To decrease the length of our vein conduit, we choose the most proximal popliteal or tibial artery with the best runoff to the foot as our distal target vessel.

Venous Conduit

When deciding on portions of vein to harvest, the best available vein of appropriate length is used at all times. Multiple pieces of vein require venovenostomies to be performed and decreases long-term graft patency rates overall. This situation can be avoided by using shorter bypasses.

Our choices for venous conduit in order include ipsilateral greater saphenous vein, contralateral greater saphenous vein, arm vein, and lesser saphenous vein. Use of the contralateral greater saphenous vein is rarely associated with limb loss on the contralateral side; therefore, we do not hesitate to use this vein.

Surgical Technique

Arterial Dissection

The common femoral as well as proximal superficial and profunda femoral arteries

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are exposed through a vertical groin incision made halfway between the pubic tubercle and anterior superior iliac spine. When necessary, after exposing the common femoral artery, the dissection is taken superiorly to the inguinal ligament, which is incised for 1 to 2 cm to further expose the proximal common femoral artery and the distal external iliac artery. Distally, the vessel is dissected to the bifurcation, exposing the superficial and profunda femoral arteries. By retracting the sartorius muscle laterally, the superficial femoral artery may be dissected further distally. The profunda artery is posterior and lateral; proximal control can be obtained at the origin with a vessel loop. However, if distal dissection of the profunda is required, the superficial femoral artery is exposed distally first, and retracted medially. There are multiple crossing veins between the superficial and profunda femoral arteries, which are ligated before exposing the distal profunda femoris (Fig. 1).

The distal superficial femoral and above-the-knee popliteal artery are exposed through a medial thigh incision. After incision of the subcutaneous tissue and fascia, the sartorius muscle is exposed and retracted posteromedially, while the adductor magnus muscle and tendon are retracted anteriorly. This tendon may be cut if necessary for adequate exposure. The popliteal fossa is entered and the neurovascular bundle is identified. Careful dissection of the vessel is necessary because the vein usually is attached laterally and could easily be injured (Fig. 2).

The below–the-knee popliteal as well as the posterior tibial and peroneal arteries are best exposed through a lower leg medial incision made approximately 1 cm below the medial border of the tibia. In the upper third of the lower leg, the medial head of the gastrocnemius muscle is exposed and retracted posteromedially; the popliteal fossa is entered and the popliteal neurovascular bundle is identified. The popliteal artery may be dissected proximally to the knee joint and distally to the orgin of the anterior tibial artery. The tibioperoneal trunk is also exposed and dissected through this incision. In the middle third of the lower leg, the medial head of the gastrocnemius as well as the soleus muscle are identified and retracted posteromedially, exposing the posterior tibial neurovascular bundle. In the distal third of the lower leg, the soleus muscle is retracted posteromedially and the flexor digitorum longus muscle is retracted anterolaterally to expose the posterior tibial neurovascular bundle at this level. The peroneal artery

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is also best dissected through these medial skin incisions. In this dissection, the posterior tibial neurovascular bundle is retracted posteromedially, exposing the peroneal neurovascular bundle just medial to the fibula (Fig. 3).

Fig. 1. A: Incision for approach to common femoral, deep femoral, and upper superficial femoral arteries. B: Exposure of common femoral, deep femoral, and proximal superficial femoral arteries.

Fig. 2. A: Medial view of left thigh and calf, with incisions for approach to lower superficial and upper popliteal arteries. The transverse line indicates level of C. B: Exposure of lower superficial femoral and upper popliteal arteries. C: Open cross section through lower thigh at level marked in A, showing exposure of lower femoral or upper popliteal artery. v.m., vastus medialis; v.l., vastus lateralis; b.f., biceps femoris; sm. semimembranosus; g., gracilis; s., sartorius muscle.

The anterior tibial artery is exposed through a lateral skin incision made halfway between the lateral edge of the tibia and the fibula. The subcutaneous tissue and fascia are incised and the intramuscular septum between the tibialis anterior muscle medially and the extensor digitorum longus muscle laterally is located and incised. With retraction of these two muscles, the anterior tibial neurovascular bundle is identified and exposed. The dorsalis pedis artery is exposed through a dorsal foot skin incision directly overlying the vessel (Fig. 4).

Venous Dissection

The main principles of appropriate venous harvest include gentle dissection with minimal manipulation of the vein, minimizing skin flaps, and continuous dilation of the harvested vein with appropriate vein solution. The importance of minimizing skin flaps needs to be stressed to improve postoperative wound healing. Large skin flaps create ischemic areas of tissue that are prone to wound necrosis and infection. As mentioned previously, appropriate skin incisions may be guided with the help of preoperative venous mapping and marking of the appropriate vein. In order to provide continuous dilation of the vein, we begin our dissection in the distal aspect of the vein, cannulating the vein, after we assure ourselves of appropriate length. Throughout the dissection, vein solution consisting of 1 000 mL of normal saline, 10,000 units of heparin, and 120 units of papaverine is continuously instilled. This aids in dissection by dilating the vein, helping with identification of the main trunk and side branches as well as prevention of vasospasm.

Once the vein is completely harvested it is taken to the back table and reassessed,

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checking for missed side branches and any areas of stenosis. Missed side branches are ligated with 4–0 silk ties or 7–0 prolene and any area of stenosis is addressed. If multiple segments of the vein have been harvested, venovenostomies are performed. After reversing each vein individually, the ends of the vein to be anastomosed are cut on a bevel, increasing the diameter of the venous anastomosis. The anastomosis is sewn using an end-to-end technique with 7–0 prolene interrupting at least half of the anastomosis to prevent narrowing of the lumen. When the anastomosis is complete, the vein is redilated with vein solution to check for patency and anastomotic integrity.

Fig. 3. A: Medial view of left calf, with incision for approach to lower popliteal artery and the posterior tibial artery. B: Exposure of lower popliteal artery.

Fig. 4. A: Anterior view of left calf, with incision for approach to anterior tibial artery lateral to the tibia. The transverse line refers to C. B: Exposure of anterior tibial artery. C: Open cross section of calf with incision as shown in A. t.a., tibialis anterior; t.p., tibialis posterior; e.d.l., extensor digitorum longus; e.h., extensor hallucis muscle; f., fibula; t, tibia.

Tunneling

Tunnels may be made either superficially through the subcutaneous tissue or deep along the anatomic route. We prefer subcutaneous tunnels secondary to their technical simplicity and ability to leave the vein easily accessible if repeat access is required for further procedures along the vein. The tunnel is performed before heparinization and an umbilical tape is left in the tunnel as a guide for later passage of the vein. After the proximal anastomosis is complete, the distal end of the vein is tied with a 2–0 silk tie to the tunneling device and passed back through the previously made tunnel. Occasionally, in a long bypass, a second skin incision is required midway between the proximal and distal incisions, requiring the

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tunneler to be passed a second time. Of note, in bypasses to the anterior tibial artery, the graft may be tunneled medially or laterally. We prefer a lateral tunnel when the reversed vein is used to avoid a sharp turn and possible kinking of the vein at the distal anastomosis (Fig. 5).

Fig. 5. A: Medial tunnel from common femoral artery to posterior tibial artery B: Lateral tunnel from common femoral artery to anterior tibial artery.

Anastomosis

Proximal and distal control of the inflow vessel is obtained with appropriately sized vascular clamps. A soft portion of the artery with a good pulse is chosen and an arteriotomy approximately 2 to 3 cm in length is made. A venotomy is performed in the distal aspect of the vein and the proximal anastomosis is sewn with two running 6–0 prolene sutures, beginning in the heel and toe of the arteriotomy using a parachute technique.

As mentioned previously, secondary to a size discrepancy between the large inflow vessel and the small end of the venous conduit, a postanastomotic stenosis may develop in the venous conduit. This is usually avoided by incorporating a side branch of the vein into the proximal anastomosis, which enlarges this area. If this cannot be done and a significant stenosis is noted after the anastomosis is complete, a patch angioplasty with a small piece of vein is performed to relieve this stenosis (Figs. 6 and 7).

Proximal and distal control of the outflow vessel is obtained with vessel loops to minimize vasospasm. Distal vessels can be extremely calcified, and if control cannot be obtained with vessel loops a tourniquet is used to interrupt blood flow to the distal leg. An arteriotomy approximately 2 to 3 cm in length is made and the distal anastomosis is sewn with two 7–0 prolene sutures beginning at the proximal and distal end of the arteriotomy using a parachute technique for best visualization of the vessels. In particularly small arteries, we prefer to place interrupted sutures at the toe of the anastomosis. This helps in two ways: first, it avoids purse stringing of the arterial outflow, and second, if the need arises to open the hood of the vein, this will avoid unraveling of the entire anastomosis (Fig. 8).

Intraoperative Assessment

After the bypass is complete, the adequacy is assessed with evaluation of distal pulses and Doppler flow. However, secondary to vasospasm, pulses may not always be present immediately. Completion arteriograms assessing the proximal and distal anastomosis,

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conduit, and distal runoff are performed routinely. This is done by percutaneous cannulation of the proximal hood of the graft with a 20-gauge butterfly needle. The arteriogram is completed with intraoperative fluoroscopy using digital subtraction imaging and hand injection of contrast mixed half and half with saline. If distal visualization is not adequate, the butterfly needle is moved further distally in the graft, just above the distal anastomosis, and imaging is completed.

Fig. 6. Technique of proximal anastomosis. A: Conventional anastomosis is prone to narrowing in proximal portion of graft. B: Incorporation of side branch into anastomosis. C. Narrowing prevented. (Reproduced from

Taylor LM Jr, Edwards JM, Philley ES, Porter JM. Reversed vein bypass to infrapopliteal arteries. Ann Surg 1987;205:90

, with permission.)

Fig. 7. Technique of patching proximal anastomosis. A: Conventional anastomosis is prone to narrowing in proximal portion of graft. B: Venotomy through area of narrowing. C: Narrowing alleviated with proximal venous patch.

Fig. 8. Technique of distal anastomosis. A: Standard technique of running anastomosis leaves toe of anastomosis prone to purse stringing. B: Interrupted sutures placed at toe of anastomosis prevents purse stringing. C: Interrupted sutures allow for opening of hood of anastomosis without unraveling of suture line.

Skin Closure and Wound Management

Wounds are closed in as many layers as possible with interrupted or continuous 3–0 Vicryl sutures for subcutaneous tissue, taking care not to injure or compress the graft. In the femoral incision, we do not close the deep fascia secondary to possible graft compression. Distally, the deep compartments are also left open because of inevitable postbypass lower extremity edema and concern of compartment syndrome. The proximal skin is closed with staples and any distal tenuous skin is closed with interrupted vertical mattress sutures of 3–0 nylon. Dry dressings are placed and are removed 2 days postoperatively and left open to air, except for groin incisions, which are always covered with a dry dressing until healed. These groin wounds, especially in patients with a large pannus, are prone to breakdown and infection. All staples and sutures are removed 2 weeks later.

Postoperative Management

Rarely are any foot procedures done at the time of distal bypass. All infected foot wounds are thoroughly irrigated and debrided and left open prior to revascularization. These open wounds are closed secondarily approximately 1 week after revascularization. Any amputations of dry gangrene are also completed approximately 1 to 2 weeks after revascularization, when lines of demarcation are clear.

Early ambulation with the assistance of physical therapy staff is encouraged as soon as the 1st postoperative day. Weight-bearing status is determined by any foot procedures required in the perioperative period.

We do not prescribe anticoagulation therapy to patients when autogenous vein is used, except low-dose aspirin. If patients have previously been taking Plavix or Coumadin, this is resumed on postoperative

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day 1 as long as no significant wound bleeding is noted.

Grafts are monitored closely during the perioperative period by evaluating distal pulses, graft pulse, or ankle brachial indices. If a graft is believed to be thrombosed clinically or if confirmed by duplex evaluation, the patient is immediately brought back to the operating room for re-evaluation. As discussed previously, one of the main drawbacks of the reverse bypass is difficulty with thrombectomy secondary to competent valves left behind. This makes passing of a thrombectomy catheter complicated, with the potential of endothelial injury at patent valve sites. In our practice, we have used the following technique for thrombectomy of reversed vein. A thrombectomy catheter is passed from the proximal to distal anastomosis in the direction of the blood flow, opening the competent valves. Next, distally, a second thrombectomy catheter is tied to the first, and the two catheters are fed distally to proximally, through the previously opened valves. The first thrombectomy catheter is untied and removed. The second thrombectomy catheter is then inflated and passed proximally to distally, performing the thrombectomy in the direction of the valves and therefore not injuring the competent valves.

Once the patient is discharged, routine long-term follow-up is scheduled for graft surveillance at 6 weeks postoperatively and then biannually. Any stenosis in the graft or at the anastomotic sites is further evaluated with arteriogram and treated to prevent graft thrombosis, either with endovascular angioplasty or open patch angioplasty.

Patency Rates

Several studies have evaluated the patency rates of reverse vein and in situ vein bypasses. In a review of the current literature, 2-year patency rates for reverse vein bypasses range from 69% to 82%, and 2-year patency rates for in situ vein bypasses are similar at 69% to 80%. Also, there is no difference in limb salvage rates between these two groups of patients. In both groups, the most significant determining factor in patency rates and limb salvage is the distal target vessel; those patients with infrapopliteal bypasses have significantly lower patency and limb salvage rates than both above-the-knee and below-the-knee popliteal bypasses. Also noted in the literature, the most common cause of graft failure in reverse vein bypasses is vein stenosis just adjacent to the proximal anastomosis. As we have discussed, this is secondary to the small diameter of the vein just distal to the proximal anastomosis, and this area should be thoroughly evaluated and treated, if necessary, at the time of reverse vein bypass placement. This size discrepancy is probably the best argument favoring in situ or transpositional vein configurations over reversed vein.

Conclusion

Using the preoperative planning, surgical techniques, and postoperative care described in this chapter, we find reverse vein distal bypasses to be a satisfactory technique for limb salvage in patients presenting with rest pain or gangrene. In our practice, we find this technique to be ideally suited for patients requiring short bypasses below the knee, allowing for the best segments of vein to be used while minimizing incisions in the distal aspect of the leg.

Editor’s Comment

Despite a proliferation of endovascular procedures for infrainguinal occlusive disease, vein femoral-popliteal and distal tibial bypass will remain common and important operations for saving limbs in the increasing population of elderly patients with peripheral arterial disease. Many of these individuals, especially those in their 80s and 90s, do not have the classic atherosclerotic risk factors of smoking, dyslipidemia, hypertension, diabetes mellitus, and family history (genetic predisposition). They appear to have only age-related deterioration of their peripheral vasculature.

The operation described by Dr. Sidawy and his colleagues is the classic approach and is sound and effective. The differences that I point out are more differences of style rather than of substance. The first difference is that I prefer the nonreversed, translocated vein bypass. This avoids the discrepancy in size between the inflow and outflow arteries and the ends of the vein graft. As pointed out, the size discrepancy at the proximal anastomosis can lead to a stenotic area in the vein graft just distal to the “hood” of the vein graft that may need remedial patching as described by the authors. In addition, I think that fear of acute thrombosis from instrumenting the vein graft to disrupt venous valves and associated endothelial damage is more theoretical than real, and is probably outweighed by the superior hemodynamics of a conduit with valves rendered incompetent. (Walsh DB, et al. J Surg Res 1987;42:39; Chin AK, et al. J Vasc Surg 1988;8:316). However, I must admit that this is also a largely theoretical advantage and is not proven. Bottom line: both techniques are valid and it is impossible to argue that one approach is superior to another.

In this day and age, I don’t think that it is necessary to obtain digital subtraction arteriography on all patients. High-resolution computed tomographic angiography (CTA) from multidetector row systems (Ouwendijk R, et al. Radiology 2005;236:1094), magnetic resonance angiography (Swan JS, et al. Radiology 2002;225:43), and even duplex ultrasonagraphy (Staffa, R, et al. J Vasc Surg 2006, in press) have been used by many to find distal “targets.” All of these imaging modalities are less invasive than digital subtraction arteriography, and some are less expensive. Our approach has evolved to using CTA coupled with prebypass angiography in the operating room when CTA doesn’t adequately image distal arteries. CTA is rapidly improving and may replace conventional arteriography for most imaging needs.

As for tunneling, I prefer an anatomic approach rather than routing the vein bypass through the subcutaneum. The anatomic passage may require more dissection, but the deeply placed vein graft is less likely to get infected if there are wound complications. Wound infections are quite common in this population, and the subcutaneous vein bypass may disrupt if it becomes infected by contiguous wound sepsis that may be only a few millimeters away. This is rare, but it is a life-threatening problem when it occurs. The anatomic placement also makes the vein graft less vulnerable to kinking.

Wound complications may be avoided by harvesting the vein through carefully placed interrupted or “skip” incisions over the course of the vein. This technique is particularly useful in obese patients. The long “slash” to harvest vein is, in my opinion, to be avoided. Another approach that has some merit is the endoscopic harvest technique. This also reduces the incidence of wound complications from vein harvest but may be associated with increased trauma to the vein graft, has a bit of a learning curve, and may be cost-ineffective.

The final issue worthy of discussion is the role of antithrombotic therapy in the postoperative period and on long-term follow-up. A large, randomized trial from the Netherlands (the Dutch BOA Study) showed superiority of warfarin anticoagulation with a rather high INR (3.0–4.0) over aspirin therapy in maintaining patency (Dutch Bypass Oral Anticoagulants or Aspirin (BOA) Study Group, Lancet 2000;355:346; Tangelder MJD, et al. J Vasc Surg 2001;33:522). However, the benefit was marginal and a there was a significant and disturbing increase in the incidence of major hemorrhage in patients on warfarin therapy. In addition, a Veterans Affairs Cooperative randomized study showed an excessive incidence of bleeding complications in patients receiving warfarin (INR 2.0–3.0) plus aspirin versus aspirin alone, and no significant improvement in patency or any other outcomes (Johnson WC, Williford WO. J Vasc Surg 202;35:413). Thus, I prefer aspirin treatment for the majority of patients undergoing infrainguinal bypass unless the quality of the runoff or the bypass conduit is poor. In the latter group of patients I will use warfarin plus aspirin, particularly for reoperative bypasses. This strategy is based on a small, randomized trial that showed superior patency and limb salvage in patients with severely “disadvantaged” infrainguinal bypasses treated with this regimen (Sarac TP, et al. J Vasc Surg 1998;28:446). Patients treated with warfarin plus aspirin must be thoroughly reliable and monitored closely.

G. P. C.

	Mastery of Surgery 5th Edition
	© 2007 Lippincott Williams & Wilkins

Mastery of Surgery5th Edition

Mastery of Surgery
5th Edition