Exclusion Of A Femoropopliteal Aneurysm Using A Stent Graft.

Case 9 : Dr. Rahul Sheth

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Clinical profile: A 70-year-old man, chronic smoker, presented with pain, swelling, varicose veins of both lower limbs He was referred for colour doppler of both lower limbs to detect deep vein thrombosis, which was normal. However, the Doppler exmination revealed a fusiform dilatation of the right distal superficial femoral artery extending into the proximal popliteal artery, for about 7.5 cms. In addition it showed a curvilinear echogenic thrombus attached to the lateral wall. (Fig. 1.)

Fig 1

The proximal and the distal arteries were normal. There were no concomitant aneurysms in the contralateral popliteal artery, or in the abdominal aorta. The right lower limb angiogram, revealed a large fusiform dilatation of the artery at the junction of the right superficial femoral artery and the popliteal artery measuring 8cm in length and 1.8 cm in its maximum width. (Fig. 2) The distal popliteal artery and the leg branches were normal.

Fig 2

Since the patient was unwilling for surgery, it was decided to treat this aneurysm with a covered stent-graft and, to exclude the aneurysm from the superficial femoral and popliteal artery. An antegrade right transfemoral approach was used for the introduction of a 9F vascular sheath .A HEMOBAHN Endoprosthesis (W.L Gore & Associates, Arizona, USA), which is an expanded polytetrafluoroethylene graft with external nitinol support, measuring 8mm in diameter and 10cm in length was introduced over a 035-inch exchange glide wire. After precise placement of the stent-graft across the aneurysm via road mapping, the stent-graft was deployed. Balloon dilatation of the stent-graft was performed with 8mm x 4 cm and 9mm x 4cm balloon angioplasty catheters (Cordis, Powerflex, Johnson and Johnson Netherlands, Europe). (Fig 3).

Fig 3

Angiography after stent placement revealed complete exclusion of the aneurysm from the native circulation, with normal distal vessels. (Fig. 4)

Fig 4

The patient was anticoagulated with 7500 IU of heparin intraarterially during the procedure and with 5000 IU s.c. three times a day for the next two days. The patient was advised asprin (75mg) life long. Follow up colour Doppler after one month revealed a patent stent, with thrombosis of the aneurysm. The patient was symptom free and complained of no pain during the follow up period.

Discussion:

Popliteal arterial aneurysms are the most common peripheral arterial aneurysms. 50% of these aneurysms are bilateral and they can be associated with abdominal aortic aneurysms, femoral and iliac artery aneurysms. The causes of the most popliteal artery aneuysms is not known, but it may be secondary to atherosclerotic disease or traumatic injury. Clinically these patients are frequently asymptomatic, but they may present with calf claudication, non-healing ulcers, and embolic phenomena of the toes. Popliteal aneurysms frequently develop mural thrombi within the lumen. Such thrombi can potentially cause distal embolization or arterial occlusion.

Treatment of femoro-popliteal arterial aneurysms using non-covered stents has been attempted albeit unsuccessfully, because of long lesion lengths, the smaller arterial diameter, and the exposed nature of the femoropopliteal artery, which may result in the compression of the rigid stents. Stent-grafts have a role in the endoluminal treatment of peripheral aneurysms. Most peripheral stent-grafts can be categorized into two types. The first type involves the implantation of a standard vascular bypass graft constructed of either woven polyester or expanded teflon. These grafts can be fixed in place with a conventional intraluminal stent, such as the Palmaz stent, which can be sewn to each end of the graft material and mounted on a balloon for deployment. The second version involves the use of a fully supported graft with an expandable stent on either the inside or the outside of the graft material. This type of stent was used in the above-mentioned case. These stents appear to effectively exclude aneurysms provided appropriate sizing of the graft to the native circulation is achieved. The complications resulting from stent-graft placement in the femoropopliteal artery include stent-graft migration or dislocation, leakage around the stent-graft and the obstruction of the side branches The advantages of stent-graft placement are that it reduces hospitalization time, obviates the need for additional therapy with warfarin, it can be performed in high-risk surgical candidates because of co morbid surgical conditions.

The uses of stent-grafts in the treatment of femoropopliteal aneurysms are encouraging as the aneurysms are effectively excluded from the native circulation, and also prevent distal emboliazation and its clinical sequelae.