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Post-Op Information

Endovascular Surgery

Angiogram
Endovascular surgery includes all procedures done in an Angiogram room using minimally invasive techniques and X-Ray imaging to treat diseased arteries or veins. The basic technique is a diagnostic Angiogram under local anaesthetic, possibly with intravenous sedation. A needle is placed through a small skin puncture into an artery, typically the common femoral artery in the groin. Through the needle a wire is inserted into the artery. The needle can then be withdrawn leaving the wire in place as a guide. A hollow plastic tube (“sheath”) can then be “railroaded” over the wire. When the wire is withdrawn there is then a tube in the artery. Through this tube contrast can be injected or devices can be implanted. This is called the “Seldinger Technique”. Injection of “contrast liquid” (which is visible under x-ray because it contains iodine) provides an outline of the lining of the vessel. This is a very accurate technique and exceeds at the moment the accuracy of ultrasound and of CT Angiography. It is particularly suitable for calcified arteries that diabetics often have, and to small arteries which are those below the knee in most patients. Angiography is also used by cardiologists to examine the coronary arteries and by interventional radiologists to examine the cerebral arteries.

Angioplasty and Stenting
After the diagnostic angiogram the procedure may be terminated if there is need to discuss the case or obtain specific equipment. More commonly these days, there is an opportunity to proceed to treat the lesion which has been identified, at the same time. A fine wire can be gently passed through the narrowed artery. Over this a catheter, with a collapsed balloon at the end, is passed. The balloon is then inflated and this pushes the narrowing of the arteries back against the artery wall where it will remain in most cases. If the narrowing is severe or calcified then an additional manoeuvre is to insert a balloon mounted stent or a self expanding stent. Stents are a metal lattice looking like a spring but with a specific laser cut shape allowing blood to flow but holding back the arterial intimal debris. Different stents are rigid, self-expanding, stainless steel stents or flexible self-expanding Nitinol stents. Some stents are combined with a plastic covering i.e. covered stents. The covering is usually some form of Gore-Tex which might be treated on occasions with surface materials to minimise the risk of blood clot formation in the stent e.g. Heparin bonding.

Stenting is widely established in iliac disease and has led to the near elimination of iliac artery open surgery. Angioplasty is more effective below the groin region. Stenting below the groin region is reserved for occlusion or severe disease because the flexibility of the artery leads to fatigue of even the most flexible stent. Compliance mis-matches between the bendability of the stent and that of the artery cause intimal damage at the end of each stent, thus precipitating recurrent disease. It is important to realise that because the stents are expanded inside the artery and press against the wall there is no mechanism to retrieve them. Stent infection is rare but well recognised. Angioplasty and stenting can lead to particles of the lesion running with the blood flow distally. This is called distal embolisation and can cause impaired blood supply to arteries further down the patient e.g. in the toes if there is embolisation from the thigh or into the brain if there is embolisation from the carotid arteries.

Stent Grafts
Stent Grafts are specific devices which started out as metal stents and dacron grafts sewn tighter by very patient and skilled technicians.

The combined device is then sterilised usually with ethylene oxide and packed into a sleeve the diameter of a large pen. Through a small incision or cut down in the groin these will be placed in the femoral artery and be inserted up into the aorta in the abdomen. The delivery sleeve is pulled back and the stent graft will expand and line the artery. This is the specific treatment for Abdominal Aortic Aneurysms (AAA) which are dilations of the aorta that are liable to burst with catastrophic consequences. Lining these leads to exclusion of them from the blood supply and avoidance of rupture. Key points are:

Endovascular Overview
The aim of all endovascular procedures is to treat symptomatic or limb or life threatening arterial vascular disease without the need for open vascular surgery. Endovascular procedures are generally safer than open surgery, although some may be less durable. That may not be such an issue in an older sicker patient if it is remembered that vascular disease is a generalised disease of which the management is primarily preventative or medical. The decision for open versus endovascular surgery depends very much on the procedure and very much on the patient. It may actually depend on the patient’s co-morbidities especially cardiac disease.

Angiography, angioplasty and endovascular procedures are performed by vascular surgeons, interventional radiologists, and a few cardiologists. Input from a vascular surgeon is desirable to provide surgical opinion which is the first step in selection and management of all endovascular procedures.