Arterial stenosis or occlusion
Cause and effect
Arterial stenosis or occlusion is commonly caused by atherosclerosis, but can occur acutely as a result of emboli or trauma. Stenosis or occlusion produces symptoms related to the organ which is supplied by the artery: e.g. lower limb — claudication, rest pain and gangrene; brain — transient ischaemic attacks and hemiplegia; myocardium — angina and myocardial infarction; kidney — hypertension or infarction ; intestine —abdominal pain and infarction. The severity of the symptoms is related to the size of the vessel occluded and the alternative routes (collaterals) available .
Symptoms and signs of lower limb arterial stenosis or occlusion
Intermittent claudication is a cramp-like pain felt in the muscles that:
• is brought on by walking;
•is not present on taking the first step (contrast osteoarthrosis);
•is relieved by standing still (contrast lumbar intervertebral disc nerve compression).
The distance walked is called the claudication distance. It is a very subjective distance which varies only slightly from day to day in the same patient. It is altered by walking up hill or against a wind, the speed of walking, or by changes in general health such as anaemia or heart failure.
The pain of claudication is most commonly felt in the calf, but can affect the thigh or buttock. Pain in the buttock occurring on exercise (walking) and associated sexual impotence, which result from arterial ischaemia, are given the eponymous title ‘Leriche syndrome’. Claudication less commonly occurs in the upper limb in subclavian, axillary or brachial artery obstruction, the pain being brought on by such activities as writing or manual labour.
Rest pain is severe pain felt in the foot at rest, made worse by lying down or elevation of the foot. Characteristically, the pain is worse at night; it may be somewhat relieved by hanging the foot out of bed or by sleeping in a chair. Night cramps, which are short, severe muscle cramps of unknown origin, should not be confused with rest pain.
Coldness, numbness and paraesthesia
Coldness, numbness and paraesthesia are common in moderate as well as severe ischaemia but, in the absence of colour changes, it is essential to exclude a neurological cause.
Moderate or severely ischaemic limbs become blanched on elevation and develop a purple discoloration on dependency. Any bright red speckling is due to the extravasation of red cells through capillary walls. The angle of elevation at which blanching first occurs gives a rough guide to the degree of ischaemia.
Ulceration and gangrene
Ulceration occurs with severe arterial insufficiency and often presents as a painful, superficial erosion between toes. Alternatively, small, shallow, indolent nonhealing ulcers may occur on the dorsum of the feet, on the shins and especially around the malleoli. The blackened mummified skin and tissues of frank gangrene are unmistakable to the observer,but it must be remembered that in acute ischaemia a dead, white limb which becomes mottled means impending gangrene and not an improvement in the circulation.
The combination of rest pain, colour changes, oedema and hyperaesthesia, with or without ischaemic ulceration, is frequently referred to as pregangrene.
A severely ischaemic foot is usually cold but sometimes paradoxically may feel warmer than the noninvolved foot. The acutely ischaemic limb tends to take on the temperature of its surroundings and may feel quite warm under the bedclothes.
Sensation and movement
Acutely ischaemic limbs are frequently paralysed and without sensation. These are ominous physical signs and such a limb has a poor prognosis in the absence of active treatment. Severe chronic ischaemia does not produce paralysis, but hyperaesthesia is common, especially in those areas of skin on the borderline of gangrene. Gentle handling of such limbs is essential.
Arterial pulsations below an occlusion in a main artery are usually absent or, in the presence of good collaterals, diminished. In patients with vascular symptoms, it is standard practice to feel the pulsations in the radial arteries, the carotid arteries, the abdominal aorta, the femoral arteries in the groins, the popliteal arteries behind the knees (an easily palpable popliteal artery may be aneurysmal), the posterior tibial arteries behind the medial malleoli and the dorsalis pedis arteries on the dorsum of the feet. Diminution of a pulse can best be appreciated by comparing it with the pulse in the other limb, provided that the latter is normal. Expansile arterial pulsation with a mass may indicate an aneurysm. In arterial occlusion with a highly developed collateral circulation, or in main artery stenosis, the distal pulses may be normal to palpation. The following physical sign is then useful.
The ‘disappearing pulse’
Where peripheral pulses are apparently normal, exercising the patient to the point of claudication may unmask the effect of an arterial obstruction by causing the previously palpable pulse to disappear. After a minute or two of rest the disappearing pulse reappears. The explanation is that exercise produces vasodilatation below the obstructing lesion and the arterial inflow reduced by the lesion, cannot keep pace with the increasing vascular space; arterial pressure falls and the pulse disappears.
A vascular examination should include auscultation of the subclavian arteries in the supraclavicular fossas, the carotid arteries behind the angle of the mandibles, the abdominal aorta and the femoral arteries in the groins and over the adductor (subsartorial) canals. A systolic bruit over an artery is due to turbulence and indicates a stenosis of the artery.
Systolic bruits are conducted distally. Thus a bruit in the neck at the level of the angle of the mandible without any supraclavicular bruit frequently means a carotid artery stenosis. Where, however, a bruit is heard at both sites, its origin may be more proximal, e.g. sortie valve, sortie arch, brachiocephalic or subclavian arteries. Under these circumstances the carotid artery may prove quite normal. The patient with renal artery stenosis shown in had a bruit over the renal artery. A continuous ‘machinery’ murmur over an artery usually indicates the presence of an arteriovenous fistula.
The limb should be elevated for 30 s and then laid flat on the bed. Normal refilling occurs within seconds. Reduced venous filling is often present in the severer forms of arterial insufficiency, but is also common in vasospastic disease and in cold weather.
If the two index fingers are placed firmly side by side on a vein and the finger nearer the heart is moved so as to empty a short length of vein, the release of the distal finger will allow the speed of venous refilling to be observed. Increased venous return and varicosities of veins are associated with arteriovenous fistulas.
Impotence from failure to achieve an erection is often a feature in male patients with an occlusion in the region of the bifurcation of the aorta and the internal iliac arteries (Leriche’s syndrome).
Relationship of clinical findings to the site of disease
By associating the symptoms and signs found in a case of arterial disease, the site of the major arterial obstruction can be determined.
The presence of another (secondary) obstruction can usually be inferred. For example, a patient with signs of iliac artery obstruction, but with rest pain and pregangrene of the foot, must have a secondary obstruction as collateral circulation around an isolated iliac artery obstruction is usually excellent. The severe symptoms indicate a secondary obstruction, probably in the femoral or popliteal arteries.
Investigation of arterial stenosis or occlusion
Many patients with symptoms due to arterial disease without stenosis or occlusion do not need active treatment. This decision can often be made without submitting the patient to a series of special investigations. Active treatment includes angioplasty and surgical reconstruction.
Patients with arterial disease tend to be elderly and atherosclerosis is a generalised disease. If surgery is indicated, a full assessment is essential.
Investigations relevant to diabetes, abnormalities of lipid metabolism, anaemia, conditions causing high blood viscosity, e.g. polycythaemia and thrombocythaemia (in small-vessel disease), include a full blood count (including erythrocyte sedimentation rate and platelets), plasma fibrinogen, protein electrophoresis, blood and urine glucose and blood lipid profile. A plain radiograph of the abdomen will show the presence of arterial calcification and flecks of calcium may outline an aneurysm . Heart failure, myocardial ischaemia, hypertension and age-related diseases such as bronchial problems and neoplasia should also be excluded.
Although a normal ECG does not exclude severe coronary artery disease, a grossly abnormal ECG may influence the decision for surgery in patients with lower limb disease.
Exercise ECG gives a more accurate cardiac assessment, although many of the patients are severely limited in their ability to exercise.
This is an isotope technique measuring left ventricular ejection fraction which correlates well with cardiac function.
This noninvasive technique is often useful in assessing left ventricular function.
Doppler ultrasound blood flow detection
A continuous wave ultrasound signal is beamed at an artery and the reflected beam picked up by a receiver. The change in frequency in the reflected beam compared with that of the transmitted beam is due to the Doppler shift, resulting from the reflection of the beam by moving blood cells. The frequency change may be converted into an audio signal and, in arteries, a pulsatile sound typically results. Doppler ultrasound equipment can, therefore, be used as a very sensitive type of stethoscope in conjunction with a sphygmomanometer to assess the systolic pressure in relatively small vessels. This is often possible even at sites where the arterial pulse cannot be palpated.
The ankle:brachial pressure index (ABPI) is the ratio of systolic pressure at the ankle to that in the arm. Generally, the higher of the recordings of pressure in the dorsalis pedis and posterior tibial arteries serves as the numerator, with the higher systolic pressure between the brachials serving as the denominator. The resting ABPI is normally about 1.0; values below 0.9 indicate some degree of arterial obstruction. A value of less than 0.3 suggests imminent necrosis. It must be appreciated, however, that values approaching normality at rest may still be associated with intermittent claudication. Retesting after exercise is useful in this context: in normality ABPI will rise while occlusive disease may result in a depression of ABPI.
A Doppler ultrasound probe can also be used to assess differences in arterial blood pressure between segments of a limb, thereby giving an indication of the site of a stenosis. In the leg, the cuff is commonly placed above the ankle, at midcalf and midthigh, to provide ‘segmental pressures’. Artifacts are due especially to calcified arteries, which may be incompressible and lead to a falsely high limb pressure or ABPI result. This is particularly the case in diabetics.
This is an investigative technique of major importance in vascular disease. A duplex scanner uses B-mode ultrasound to provide an image of vessels . This image is created through the different ability of different tissues to reflect the ultrasound beam. A second type of ultrasound, namely Doppler ultrasound, is then used to insonate the imaged vessels and the Doppler shift obtained is analysed by a dedicated computer in the duplex scanner. Such shifts can give detailed knowledge of vessel blood flow turbulence, etc. Some scanners have the added sophistication of colour coding which allows visualisation of blood flow on the image. The various colours indicate change in direction and velocity of flow; points of high flow generally indicate a stenosis. It should be appreciated that modern duplex scanning is at least as accurate as angiography in certain circumstances. In terms of cost-effectiveness and safety, duplex scanning is generally to be preferred to angiography if they are considered to be equally useful in any given clinical context.
Plethysmography assesses changes in volume of a limb or digit over the cardiac cycle. Air-filled cuffs or mercury in rubber strain gauges have typically been used. For most clinical purposes the test has been superseded by duplex scanning, although plethysmography may still have certain research uses.
Oculoplethysmography (OPG) uses fluid- or air-filled cups attached to the eye by suction to investigate carotid artery disease. Once again, the technique has largely been superseded by duplex scanning.
A treadmill with a slight incline is a useful diagnostic apparatus in the assessment of walking distance in claudicants. Patients are known to be very poor assessors of walking ability in terms of distance; objective measurement using the treadmill is recommended.
Arteriography (syn. angiography)
In lower limb disease it is symptoms and their severity which decide whether intervention is needed. An arteriogram is done only after a decision has been taken that intervention is appropriate. Even then, it may be advisable in some circumstances to precede the arteriogram with a duplex scan. This is so especially in the field of carotid artery disease where arteriography is associated with a stroke rate of between 1 and 2 per cent. Many surgeons are content to operate on carotid artery disease solely on the results of a duplex scan without arteriography.
Arteriography involves the injection of a radio-opaque solution into the arterial tree, generally by a retrograde percutaneous method usually involving the femoral (occasionally the brachial or axillary) artery. This retrograde method is known as the Seldinger technique. Direct arteriography, by puncturing, for example, the carotid artery or aorta, is more hazardous; it is outdated and no longer in use. Hazards include thrombosis, arterial dissection, haematoma, neurological dysfunction and anaphylaxis. Anaphylactic reactions can occur even with a trial injection and informed consent should always be obtained for this form of imaging.
Digital subtraction angiography (DSA)
This technique, which is in widespread use, employs a computer system to digitise the angiographic information . It allows the image before contrast injection to be subtracted from the contrast image, yielding great clarity. DSA may be carried out by arterial or venous injection. The former allows the use of finer catheters and less contrast agent than conventional angiography.
The latter avoids the need for arterial puncture completely, although rather high volumes of contrast agent must be injected into a large vein.
Management of arterial stenosis or occlusion
Explanation and advice
Patients are worried by the presence of pain on walking. Once told that walking is not doing harm, many are content to live within the limitations imposed by their claudication. Spontaneous improvement occurs in some patients over the first 6 months after an occlusive episode as collateral vessels are developed.
Adjustment of lifestyle
Adjustments to everyday habits of transport can increase mobility within the claudication distance, e.g. the use of a bicycle or a car.
Particularly for patients with Buerger’s disease (see later in this chapter). Progression of the disease and graft failure after surgery are more common in any patient who continues to smoke.
Taking regular exercise
Within the limits of the pain.
To reduce weight in the obese and, more specifically, in the treatment of hyperlipidaemia.
Vasodilator drugs are ineffective in the management of arteriosclerotic disease.
• Praxilene (naftidrofuryl oxalate) may alter tissue metabolism, increasing the claudicating distance by allowing a greater oxygen debt to be incurred.
• Trental (oxpentifylline) has some effect on whole blood viscosity.
• Prostacyclin is currently being evaluated and may have a role in the management of the critically ischaemic limb.
The first line of treatment is dietary to reduce weight (if necessary) and to reduce fat intake. Patients who have no primary metabolic disease and who achieve an ideal weight but remain lipaemic should be considered for drug treatment.
Diabetes and hypertension
These should be treated by standard methods. In hypertension, the overzealous reduction of blood pressure by the use of beta-adrenoceptor blocking drugs can worsen claudication.
Care of the feet
This includes avoiding socks with holes and amateur chiropody, which can spark off gangrene in the toes and heels, particularly in diabetic patients.
Claudication distance may be increased by raising the heels of shoes by 1 cm. The work of the calf muscles is reduced thereby.
Analgesics and position
Rest pain can be relieved to some extent in some patients by the use of analgesics and elevation of the head of the bed (Buerger’s position).
In dispersible form this may be prescribed for its anti-adhesive effect on platelets. A dose of 150 mg/day is usual.
Sympathectomy is not effective in claudication but occasionally it may relieve ischaemic rest pain and ulceration. However, it must be recognised that the results of sympathectomy are very much poorer than those of bypass surgery or percutaneous transluminal angioplasty. Sympathectomy can only be justified when it is not technically possible to operate or employ balloon angioplasty. The details of lumbar sympathectomy (operative and chemical) are given at the end of this chapter.
Arterial occlusive disease may be treated by inserting a balloon catheter into an artery and inflating it within a narrowed area. This may be done at the same time as an operation but, more usually, it is carried out percutaneously in the radiology department . Percutaneous transluminal angioplasty (PTA) may be used for stenoses or short occlusions; in the latter case the occlusion must first be traversed by a guidewire. Balloon angioplasty has had its major success in dilating the iliac vessels. To a lesser extent the vessels of the leg itself may be dilated with a good outcome.
Technique. A femoral arteriogram is performed and a guidewire inserted through any stenosis to be treated. The balloon catheter is then inserted over the guidewire. The balloon is positioned within the stenosis (confirmed by angiography). The balloon is then inflated for approximately 1 minute and then deflated. This is repeated before withdrawal of the catheter.
A variety of new devices is available to allow the percutaneous removal of atheroma from within the vessel in the radiology department. These cutting catheters have several styles and their use in certain circumstances, e.g. eccentric plaque, may be efficacious.
In certain circumstances after balloon dilatation, the vessel fails to stay adequately dilated and it may then be possible to hold the lumen open using a metal stent. Such a device may be introduced on a balloon catheter; the balloon itself when inflated expanding the stent, which acts as a rigid skeleton for the vessel, keeping it widely patent. The catheter balloon is deflated and the catheter removed. An alternative type of self-expanding stent is held compressed by a sheath of plastic in a delivery system. When the stent has been positioned at the appropriate arterial site the sheath is withdrawn and the stent self-expands to hold the lumen open. The results of stenting have not been fully assessed but early results suggest that the technique has considerable promise.
Operations for arterial stenosis or occlusion
Site of disease and type of operation
Aortoiliac occlusion with good calibre vessels below the site of disease responds well to aortofemoral bypass . If the disease is limited in extent, an iliac endarterectomy might be considered, but PTA with or without a stent is probably a better alternative if technically possible. In the patient who is unable to withstand major abdominal surgery and who has pronounced ischaemia due to aortoiliac occlusion, a femoro—femoral or ilio—femoral crossover bypass may be considered (if only one iliac system is involved with disease) or an axillo—bifemoral bypass may be done (if both iliac segments are diseased).
Superficial femoral and profunda femoris artery occlusive disease often produce unilateral symptoms. For long-distance claudication, conservative treatment is usually suitable. For more severe disease a supervised exercise programme may be appropriate. In certain circumstances, when the occlusive appearance on angiography is favourable and the patient fully understands the risks and benefits of intervention, angioplasty or bypass may be considered. A femoropopliteal bypass graft is the most usual operation (to overcome a blocked superficial femoral artery). Long-term graft patency is related to the inflow and outflow from the graft. It is also related to the material used for the bypass. The patient’s own saphenous vein gives the best results when used either as a reversed conduit or in situ after valve disruption. In some patients a profunda femoris origin stenosis is noted and this situation can be helped by a small patch angioplasty to relieve the diseased site.
Occlusive disease below the popliteal artery used to be
widely regarded as unreconstructable but it is increasingly recognised that bypass to the tibial vessels, even down to ankle level, can be met with reasonable success. The most usual and successful conduit is the long saphenous vein used in the in situ fashion after disrupting the valves with a valvulotome. If the saphenous vein is not available from either leg, it may still be realistic to carry out the surgery with a polytetrafluoroethylene (PTFE) graft; many surgeons construct the lower anastomosis using a small collar of vein between the PTFE and the recipient artery. This technique (Miller cuff) may give prolonged patency.
For bypass of the aortoiliac segment the favoured material is Dacron . Prostheses come in two types: woven and knitted. Woven grafts tend to leak less when first exposed to blood flow during surgery, but newer knitted prostheses may be sealed with gelatin or collagen by the manufacturer and may leak even less than their woven counterparts. In the final analysis, there is probably little to choose between any of the styles of Dacron graft; all achieve satisfactory results. For bypass in the femoropopliteal region, if autogenous long saphenous vein (or other veins such as the short saphenous or arm vein) is not available, PTFE or glutaraldehyde-tanned, Dacron-supported, human umbilical vein may be employed. In general, any vein used requires a diameter of at least 3.5mm. For profundaplasty, a small piece of vein may be used or, alternatively, PTFE or Dacron.
Suture materials for vascular surgery are usually monofilament in nature; polypropylene has been particularly popular. In the aorta it is
usual to use 2/0 or 3/0 polypropylene. In the femoral artery at the groin it is usual to use 4/0 or 5/0 polypropylene. Finer sutures, up to 7/0, may be needed further down the limb. PTFE may (alternatively) be stitched using a suture of the same material. PTFE sutures tend to cause less bleeding through stitch holes in the graft substance.
Aortofemoral bypass graft. The aorta is approached through a midline or transverse abdominal incision. The common femoral arteries and their branches are exposed through vertical groin incisions. The small bowel is retracted to the right and the posterior peritoneum opened. Retroperitoneal tunnels are made from the aorta to the groins. Heparin (5000 units) is given intravenously and the vessels are clamped. A vertical incision is made in the anterior aspect of the aorta to which an obliquely cut, bifurcated Dacron graft is sutured. The graft limbs are then fed down to the groins where they are in turn anastomosed to the common femoral arteries or, if there is evidence of profunda stenosis, to an arteriotomy running from the common femoral vessel down into the profunda. The posterior peritoneum is closed carefully over the Dacron to prevent adhesion of the graft to bowel. The abdomen and groin wounds are closed without drainage.
Femoropopliteal bypass. The popliteal artery above or below the knee is exposed through a medial incision. The femoral artery is exposed at groin level. The long saphenous vein may be treated in two different ways. First, it may be excised, its tributaries tied, reversed and sutured into the limb as a bypass. Second, it may be left in place (in situ) and the valves disrupted with a valvulotome, either blindly or using an angioscope. The graft is then sutured to the femoral artery proximally and to the popliteal vessel distally. Suction drains are rarely necessary.
Femorodistal bypass. This surgery is usually carried out using long saphenous vein in the in situ mode. Great care must be taken at the conclusion of the procedure to assess the conduit and the lower anastomosis. This may be done using completion angiography or angioscopy.
Profundaplasty.The common femoral artery and its branches are exposed through a vertical incision. After giving intravenous heparin and clamping the vessels, an incision is made into the common femoral artery and carried down into the profunda, effectively dividing the stenotic profunda origin. The arteriotomy is then closed with a vein, Dacron or PTFE patch to widen the narrowed segment.
Other arterial operations and salvage procedures
Femorofemoral crossover graft is useful for relieving an iliac artery occlusion when the other iliac artery is patent with a strong femoral pulse. An 8-mm Dacron or PTFE graft is tunnelled subcutaneously above the pubis and anastomosed end-to-side to the common femoral arteries on each side. Blood from the patent iliac system is then carried through this graft to vascularise the ischaemic limb.
Axillofemoral graft is useful for salvaging a pregangrenous limb in a poor-risk patient with bilateral iliac obstruction. A long 8-mm PTFE graft is tunnelled subcutaneously, from an end-to-side anastomosis with the axillary artery proximally, to reach the femoral artery of the involved limb in the groin where the distal anastomosis is made. The axillary artery will carry a sufficient volume of blood to maintain the circulation in the arm and revascularise the lower limb. The short-term results are usually good and in these patients with their poor general condition, the poorer, long-term result is usually less important. An axillobifemoral bypass carries twice as much bloodflow through its long limb as does an axillo(uni)femoral bypass; the former has a correspondingly improved patency rate. Salvage operations should not be performed for intermittent claudication alone. Gangrene and loss of limb may result if the operation should fail.
Adjuncts to direct arterial surgery. Blood-flow estimations (by Doppler ultrasonography or electromagnetic flowmeter) or on-table arteriography at the completion of the operation are useful techniques for ensuring that there have been no errors of surgical technique before the wound is closed.
Results of operation
The long-term results of aortoiliac reconstructive surgery are good; they are usually only marred by progressive disease producing femoropopliteal occlusions at a later date. Femoropopliteal surgery is less successful. The immediate postoperative success rate for vein bypass exceeds 90 per cent but many cases fail in the first 18 months after operation and, at the end of 5 years, the success rate is usually only between 50 and 60 per cent. The results of femoropopliteal endarterectomy are less good in both the short and long term. Dacron or PTFE bypass also gives a poorer result than vein, with 5-year success rates of less than 50 per cent. The rather poor long-term results of femoropopliteal surgery emphasise that these operations should only be used for clear indications.
Other sites of atherosclerotic obstruction
The principles of arterial surgery as stated above can be applied to other arteries which are stenosed by the disease.
Carotid stenosis may cause transient ischaemic attacks (TIAs). These are recurrent and, by definition, short-lived mini-strokes. Resolution occurs within 24 hours (usually within a few minutes) but TIAs are a warning of impending major stroke. Patients with TIAs should have a duplex scan (not an angiogram) in the first instance. If the scan confirms carotid occlusive disease at an appropriate site, then formal angiography may be considered desirable. Some surgeons operate frequently on duplex scan evidence alone, without angiographic confirmation of disease.
Carotid atheroma classically affects the internal carotid artery origin.The usual procedure is a carotid endarterectomy which involves clamping the vessels, an arteriotomy in the common carotid artery continued up into the internal carotid artery through the diseased segment, removal of the occlusive disease (endarterectomy) and closure of the arteriotomy, often with a patch (vein, PTFE or Dacron). During clamping, some patients will have inadequate cerebral blood flow (especially if the contralateral carotid vessels are compromised). Such a situation may be recognised by recording a low pressure in the distal internal carotid artery above the level of the clamp. It may be necessary in such Circumstances to insert a temporary silicone shunt over the arterial field being worked upon.
Subclavian artery stenosis may cause claudication and (rarely) frank ischaemia of an arm. The subclavian lesion may also have an effect by causing artery-to-artery embolisation. This may lead to loss of digits. The condition may be treated by endarterectomy or bypass but nowadays percutaneous transluminal balloon angioplasty is the treatment of choice. It must be noted, however, that some subclavian artery lesions are associated with neck pathology such as cervical rib. Any underlying pathology must he corrected at the time of arterial repair.
Subclavian steal syndrome. If the first part of the subclavian artery is obstructed, the vertebral artery may provide a collateral circulation into the arm by reversing its direction of flow. This may cause periods of cerebral ischaemia. The classic syndrome of syncopal attack and visual disturbance associated with arm exercise and a diminished blood pressure in the affected limb is rather rare. Asymptomatic reversal of flow in the vertebral artery, recognised by either duplex scanning or angiography, is much commoner. In symptomatic patients, percutaneous transluminal angioplasty may relieve the problem, or the situation may be corrected by endarterectomy or a bypass from the ipsilateral common carotid artery to the third part of the subclavian artery.
Enteric artery occlusive disease. Pain after eating that has no obvious diagnosis in a patient with known atheromatous disease and weight loss may be due to coterie artery occlusion. In general, two of the three coterie vessels (coeliac axis, superior mesenteric artery, inferior mesenteric artery) must be occluded to produce ‘intestinal claudication’. Great care must be taken to exclude all other diagnoses before contemplating surgical endarterectomy or bypass.
Renal artery stenosis may be responsible for hypertension and, eventually, loss of renal function. In general it is possible to control hypertension using drugs. When this pathology is associated with loss of renal tissue, however, arterial intervention is indicated. Both percutaneous transluminal angioplasty and arterial surgery have their specific place in this disease. A variety of operations is available ranging from endarterectomy, aortorenal bypass, renal artery revascularisation using another vessel (such as the splenic artery), to renal autotransplantation.