Fig. 52.2 X-ray demonstrates suprarenal vena caval filter in proper position

performedatthelevelofthesaphenofemoraljunction,followedbyprotrusionofalargeamount of acute thrombus. The leg was raised and a tight rubber bandage applied with minimal extrusion of the infrainguinal thrombus. Attempts to pass a catheter from the inguinal ligament distally into the femoral vein and attempts to pass a guidewire distally were unsuccessful.

Question 7

The next appropriate step would be

A.Perform iliofemoral and caval thrombectomy with AV fistula, leaving the infrainguinal thrombus.

B.Abandon thrombectomy and anticoagulate.

C.Perform an infrainguinal venous thrombectomy aided by a cut-down on the left posterior tibial vein.

A cut-down on the posterior tibial vein was performed. Following a posterior tibial venotomy,ano.3Fogartycatheterwaspassedupwardsthroughthethrombosedvenoussystem, exiting the common femoral venotomy. This catheter was used to guide a no. 4 Fogarty catheter distally through the venous valves by placing both catheter tips within a 14-gauge Silastic intravenous catheter sheath after the hub was amputated. Following a mechanical

balloon catheter thrombectomy, the leg was flushed using a bulb syringe with a large volume of heparin/saline solution, which flushed additional thrombus from the common femoral venotomy. After clamping the femoral vein, the deep venous system was then filled with 300 ml of a dilute recombinant tissue plasminogen solution (6 mg rt-PA in 300 ml).

The iliofemoral and vena caval thrombectomy was performed under fluoroscopic guidance, filling the balloon with contrast to ensure that the suprarenal caval filter was not dislodged. After completing the thrombectomy, an operative iliocavagram was performed to assess the adequacy of thrombectomy and to ensure unobstructed venous drainage into the vena cava. An iliac vein stenosis was observed.

Question 8

The appropriate next step is

A.  Close the venotomy and anticoagulate, since a common iliac vein stenosis is frequently observed due to normal vascular anatomy.

B.  Close the venotomy and perform an AV fistula.

C.  Perform angioplasty and insert a self-expanding stent if recoil occurs.

D.  Operatively expose the common iliac vein and perform an endovenectomy and transpose the vein above the right common iliac artery.

A balloon angioplasty catheter was placed into the lesion and an angioplasty performed. The iliac vein was dilated to 14 mm without evidence of recoil (Fig. 52.3).

Question 9

Now that patency has been restored to the infrainguinal and iliofemoral venous systems, are there any additional techniques that can be performed to reduce risk of rethrombus?

A.  An AV fistula, using the end of the proximal saphenous vein sewn to the side of the superficial femoral artery.

B.  The saphenous vein should not be used for AV fistula, since it represents collateral drainage from the leg in the event of recurrent thrombosis.

C.  Placement of a catheter into the posterior tibial vein for anticoagulation with unfractionated heparin.

D.  Elevate the legs and avoid ambulation for the next 4–5 days. E.  Therapeutic anticoagulation.

An arteriovenous fistula (AVF) using the proximal saphenous vein anastomosed to the superficial femoral artery increases flow velocity through the iliofemoral venous system, reducing the risk of rethrombosis. A thrombectomy of the proximal great saphenous vein was required in this patient, as is often the case. Since the goal of the AVF is to increase venous blood flow velocity, the size of the anastomosis is limited to 3.5–4 mm in order to avoid a steal and avoid venous hypertension. A small piece of PTFE is wrapped around the saphenous AVF and looped with a 2-cm piece of O-Prolene, which is left in the subcutaneous tissue (Fig. 52.4). This will serve as a guide should the AVF require closure.

Fig. 52.4  The construction of the arteriovenous fistula (AVF) using a large side branch of the great saphenous vein sutured end-side to the superficial femoral artery. Note sleeve of PTFE wrapped around the AVF and looped with a 2-cm piece of O-monofilament suture. The purpose of this is to assist in operative closure should obliteration of the AVF become necessary

the skin and secured with a sterile button. This is used to occlude the vein after 5–6 days when the catheter is removed following full oral anticoagulation with warfarin. In the case of this pregnant patient, intravenous anticoagulation through the leg veins was maintained for 4 days, after which she was converted to subcutaneous enoxaparin at 1 mg/kg every 12 h. The catheter was removed and the patient discharged. The patient was maintained on subcutaneous enoxaparin 1 mg/kg twice a day until she delivered a healthy baby 6 weeks later.

Question 10

The patient does not wish to breastfeed her baby. What is your best recommendation for ongoing therapy?

A.  Six more weeks of Lovenox.

B.  Oral anticoagulation for 6–12 months.