A 62-year-old overweight postal worker presented with complaints of cramps in his right calf. He stated that this reproducible pain occurred each time he walked 50 yards and resolved upon sitting down. He denied tissue loss or rest pain. His past medical history was significant for hypertension, hypercholesterolemia and tobacco use, as well as coronary revascularization.

On physical examination, he had bilateral carotid bruits, normal heart examination, and a strong right femoral pulse, but absent popliteal and pedal pulses. His left lower extremity had a saphenectomy scar. Both extremities had shiny, hairless skin without ulcerations or gangrene.

Question 1

Which of the following is not an indication for a bypass to the popliteal artery?

A.  Mild to moderate intermittent claudication.

B.  Non-healing toe ulcer with an ankle brachial index (ABI) of 0.30. C.  Rest pain.

D.  Symptomatic popliteal aneurysm, entrapment syndrome, or adventitial cystic degeneration­.

Thepatient´sbloodpressureandcholesterollevelswerecontrolledwellbymedication.Helost excess weight, quit smoking, and initiated cilostazol therapy, but to no avail. His symptoms persisted and he was so incapacitated that he was unable to continue delivering the mail.

Arteriography was performed, demonstrating patency of the right iliac arteries but severe occlusive disease of the superficial femoral artery. There was reconstitution of the popliteal artery with two-vessel run-off. The patient consented to a femoropopliteal bypass procedure.

K.D. Calligaro ( )

Section of Vascular Surgery and Endovascular Therapy, Vascular Surgery Fellowship, Pennsylvania Hospital, Clinical Professor of Surgery,

University of Pennsylvania School of Medicine,

700 Spruce St - Suite 101, Philadelphia, PA 19106 e-mail: kcalligaro@aol.com

Question 2

The conduit yielding the best long-term patency for this bypass is:

A.  Dacron

C.  Autologous vein

C.  PTFE

D.  Umbilical vein

E.  Cryograft vein

Question 3

A distal cuff or patch is most likely worthwhile for which type of bypass?

A.  Femoropopliteal above-knee reversed vein graft. B.  Femorotibial in situ vein graft.

C.  Femoropopliteal above-knee PTFE. D.  Femorotibial PTFE.

E.  Femoral-femoral PTFE cross-over graft.

Femoropopliteal bypass was performed with in situ greater saphenous vein to the belowknee popliteal artery. There was resolution of the patient´s claudication, and he was able to return to work. Unfortunately, he became lost to follow-up, and 2 years later he returned with complaints of recurrent claudication in his right lower extremity. Neither popliteal nor pedal pulses were palpable. Duplex ultrasonography and arteriography demonstrated several sites with elevated velocities, suggestive of two moderate focal stenoses in the proximal half of his bypass graft as well as a severe narrowing at the distal anastomosis.

Question 4

What are the treatment options for a failing graft?

A.  Aspirin therapy

B.  Percutaneous transluminal angioplasty (PTA) C.  Laser-assisted angioplasty and atherectomy D.  Amputation

The patient was taken to the operating room, where a longitudinal incision was made through the distal portion of his vein graft and popliteal artery. Under fluoroscopy, balloon angioplasty of the proximal moderate stenoses was performed, with excellent results. Using a small segment of autologous saphenous vein, patch angioplasty of the distal anastomosis was performed. Completion angiography revealed a widely patent graft, and his distal pulses were again appreciated on palpation. He was able to resume his usual activities and was seen routinely in the vascular clinic.

Question 5

The most useful serial postoperative test to assess graft patency and a possible failing graft is:

A.  Arteriography

B.  Pulse volume recordings C.  Duplex ultrasonography D.  Ankle brachial index

E.  Magnetic resonance angiography (MRA)

21.1  Commentary

Mild to moderate intermittent claudication is not an indication for surgical bypass. Most (approximately 75%) patients presenting with only intermittent claudication have a benign course, remaining stable or improving with conservative measures, such as smoking cessation, weight loss and alteration in diet, graduated exercise programs, and medical treatment of risk factors (e.g. hypertension, hypercholesterolemia, diabetes). Claudication is a strong and independent predictor of mortality, however, and thus concomitant identification of comorbidities such as coronary and cerebrovascular atherosclerotic disease may have significant impact on survival.

Pharmacological therapy may be initiated with rheological agents such as pentoxifylline or cilostazol with variable effect. Antiplatelet therapy is frequently started to prevent cardiac or cerebrovascular complications. Only a minority (10–20%) of patients require

surgical reconstruction, and few (3–6%) ultimately progress to major amputation.1 Revascularization is reserved for patients with disabling claudication or evidence of

critical ischemia manifest as acute motor or sensory loss, chronic tissue loss or rest pain. Other less common etiologies for lower-extremity ischemia may cause femoropopliteal occlusion and are occasionally indications for surgical revascularization. [Q1: A]

Long-term patency rates are highest when autologous vein is used as conduit. If the greater saphenous vein is not available, then lesser saphenous vein, femoropopliteal vein, or upper-extremity veins may be acceptable alternatives. The advantages of in situ vein bypass grafting include the preservation of the vein´s nutrient supply and the better size match of the proximal and distal artery to the proximal and distal vein. Using reversed vein grafts, however, avoids the endothelial trauma of valve lysis. Although at times somewhat conflicting, the literature does not support the superiority of one technique over the other for femoropopliteal bypasses.

The use of human umbilical vein2 or cryopreserved vein has also been described with varying success. The latter may be a potential alternative to prosthetic grafts if autologous vein is unavailable, but in below-knee revascularization, cryopreserved vein has demonstrated the tendency for aneurysmal degeneration and poor long-term patency.3

Prosthetic grafts in the suprageniculate bypass have demonstrated patency rates that are comparable with those for autologous vein.4 The type of prosthetic graft is less important than the age of the patient or the size of the conduit.5 The patency of prosthetic grafts to infrageniculate arteries, however, is significantly worse than that of autologous vein. Further, the use of composite prosthetic and autologous vein does not seem to improve long-term patency compared with pure prosthetic grafts.6

Finally, there have been reports of endovascular treatment of femoropopliteal atherosclerotic disease, including percutaneously inserted covered stents7 and prosthetic grafts introduced through a femoral arteriotomy and anchored distally with stent deployment.8 Long-term patency with these techniques remains to be evaluated. [Q2: B]

Intimal hyperplasia occurs frequently at the distal anastomosis when a prosthetic graft is used for an infrainguinal bypass and compromises its survival. Modifications to improve long-term patency include various vein cuffs and patches. Using these techniques theoretically improves compliance match between the prosthetic material and the artery at the distal anastomosis. The reduction in turbulence minimizes the trauma to the arterial endothelium and decreases its proliferative response.

The Miller cuff was studied in a prospective randomized study to determine its potential benefit in improving the patency rate of distal supraand infrageniculate femoropopliteal polytetrafluoroethylene (PTFE) grafts. Although no difference was noted in above-knee bypasses with or without vein cuff, a statistically significant improvement in patency was observed in below-knee procedures.9 Similarly, the Taylor patch has been reported to improve patency of infrageniculate bypasses.10 [Q3: D]

Salvage of a bypass graft in the early postoperative period may include strategies such asthrombectomyandrevisionoftechnicalerrors.Theseerrorsincludegraftkinks,retained valve leaflets, intimal flaps, and residual arteriovenous fistulas in an in situ graft.

Recently, percutaneous endovascular techniques such as balloon angioplasty have been utilized with increasing frequency but with equivocal results. Focal lesions (less than 20 mm) are more amenable to catheter-based techniques than are more diffuse stenoses, but even these favorable lesions may recur. Laser angioplasty and atherectomy, however, have not been shown to be beneficial in the preservation of failing grafts.

Thrombolysis may be considered for patients who present with sudden and recent onset of symptoms attributable to bypass graft occlusions. For patients with chronic graft occlusion, a new bypass graft provides improved clinical outcome, but in acute graft occlusion, thrombolysis may improve limb salvage and reduce the magnitude of the subsequent surgical procedure.11

For short-segment stenoses, patch angioplasty or interposition within an existing vein graft with autologous or prosthetic material may be performed to preserve a bypass to the popliteal artery. Although technically simpler and requiring less autologous material, patch angioplasty has inferior results when compared with interposition.12 Longer-segment stenosesarepreferablytreatedwithinterpositionorjumpgraftaroundtheareaofnarrowing. Failing these strategies, however, the creation of an entirely new bypass may be required.

Amputation is reserved for tissue loss or ischemic pain without possible vascular reconstruction. Long-term survival of patients requiring major amputation is poor. [Q4: B]

Early graft failure (i.e. within the first 30 postoperative days) is most likely the result of a technical error, hypercoagulability, poor distal run-off, or postoperative hypotension. In