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1. Peripheral Arterial Disease [PAD]

2. 2- Doppler ultrasound blood fow detection A hand-held Doppler ultrasound probe is very useful in the assessment of steno-occlusive arterial disease. A cont. wave ultrasound signal is transmitted from the probe at an artery and a receiver within the probe itself picks up the refected beam. The change in frequency in the refected beam compared with that of the transmitted beam is due to the Doppler shift, which results from the refection of the beam by moving blood cells. A normal artery has a triphasic signal whereas a diseased artery may have a biphasic or monophasic signal depending on the extent of disease . 3- Duplex Doppler ultrasound This major non-invasive technique uses B-mode ultrasound to provide an image of vessels . The image is created because of the varying ability of diferent tissues to refect the ultrasound beam. A second ultrasound beam is then used to insonate the imaged vessel and the Doppler shift obtained is analysedr. Most scanners now have colour coding, which allows detailed visualisation of blood fow, turbulence, etc. Diferent colours indicate changes in direction and velocity of fow with areas of high fow usually indicating a stenosis.

3. 4. Computed tomography angiography The use of CTA as a minimally invasive alternative to DSA has increased as availability has improved. CTA has become an invaluable tool when planning revascularisation procedures, enabling the surgeon to visualise and measure diseased arterial segments prior to intervention. The major concern with CTA, in addition to the exposure to ionising radiation, is the use of iodinated contrast. A substantial proportion of patients presenting with PAD have concomitant renal dysfunction, which may be acutely exacerbated by iodinated contrast, causing contrast-induced nephropathy. 5. Magnetic resonance angiography (MRA) is a non-invasive test that avoids the need for ionising radiation and iodinated contrast, thereby having advantages over CTA. It is becoming more widely utilised MRA has the ability to separate out contrast from vessel wall calcifcation and has become the preferred imaging modality in many institutions.

4. MANAGEMENT-

5. Transluminal angioplasty and stenting Arterial occlusive disease may be treated by inserting a balloon catheter into an artery and infating it within a stenosed or occluded segment .This technique is suitable for patients with claudication, rest pain or tissue necrosis . Following percutaneous femoral artery puncture under local anaesthetic a guidewire is inserted and negotiated through the stenosis or occlusion under fuoroscopic control. A balloon catheter is positioned within the lesion over the guidewire and infated at high pressure for approximately 30 seconds. Satisfactory dilatation of the lesion is confirmed by performing an angiogram. Percutaneous transluminal angioplasty (PTA) has proved very successful in dilating the iliac and femoropopliteal segments; the results below the knee are less successful but improving. Long occlusions may be treated by the technique of subintimal angioplasty , in which the guidewire crosses the lesion in the subintimal space (in the arterial wall) and a new lumen is created by infation of the balloon.

6. Operations for arterial stenosis or occlusion Site of disease and type of operation Surgical operations are usually reserved for patients with severe symptoms (CLTI or lifestyle-limiting claudication) where angioplasty has failed or is not possible. Aortoiliac occlusion responds well to aortobifemoral bypass using a Dacron graft , although the operation carries a perioperative mortality and systemic morbidity (stroke, cardiorespiratory failure, renal injury) rate of about 5% and 15%, respectively. Superfcial femoral artery disease can be treated by femoropopliteal bypass ; long-term graft patency is determined by the quality of infow and outfow, graft length (whether the distal anastomosis is above or below the knee) and the conduit used for the bypass. Autologous great saphenous vein (GSV) gives the best results and can be used reversed or in situ after valve disruption. If the GSV is not available from either leg, the lesser saphenous or arm veins may be used. If no vein is available, a prosthetic polytetrafuoroethylene (PTFE) graft may be employed although patency rates are less; many surgeons construct the lower anastomosis using a small collar of vein (Miller cuf or St Mary’s boot) between the PTFE and the recipient artery, which may improve patency. Isolated CFA or profunda disease can be treated with endarterectomy and patch (vein or prosthetic) or a short bypass in the groin.

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