1. Catheter angiography

2. Ultrasound (US)

3. Computed tomography (CT)

4. Magnetic resonance imaging (MRI).

1. The patient will need admission to hospital. Careful preparation before the procedure and observation after are required. With the introduction of smaller-diameter catheters, day-case admission may be appropriate for routine peripheral angiography and some angioplasty cases.

2. If the patient is on anticoagulant treatment, blood clotting should be within an acceptable therapeutic ‘window’.

3. The radiologist or a suitably trained person should see the patient, preferably several days prior to the procedure, in order to:

1. Femoral artery – most frequently used

2. Brachial artery

3. Axillary artery

4. Radial artery.

Needles

The technique of catheter insertion via double-wall needle puncture and guidewire is known as the Seldinger technique. The original Seldinger needle consisted of three parts:

Many radiologists now prefer to use modified needles:

Guidewires

Basic guidewires consist of two central cores of straight wire around which is a tightly wound coiled wire spring (Fig. 9.1). The ends are sealed with solder. One of the central core wires is secured at both ends – a safety feature in case of fracturing. The other is anchored in solder at one end, but terminates 5 cm from the other end, leaving a soft flexible tip. Some guidewires have a movable central core so the tip can be flexible or stiff. Others have a J-shaped tip which is useful for negotiating vessels with irregular walls. The size of the J-curve is denoted by its radius in mm. Guidewires are polyethylene coated but may be coated with a thin film of Teflon to reduce friction. Teflon, however, also increases the thrombogenicity, which can be countered by using heparin-bonded Teflon. The most common sizes are 0.035 and 0.038 inch diameter. More recently hydrophilic guidewires have been developed. These frequently have a metal mandrel as their core. They are very slippery with excellent torque and are useful in negotiating narrow tortuous vessels. They require constant lubrication with saline.

Catheters

Most catheters are manufactured commercially, complete with end hole, side holes, preformed curves and Luer lock connection. They are made of polyurethane or polyethylene. Details of the specific catheter types are given with the appropriate technique.

Some straight catheters may be shaped by immersion in hot sterile water until they become malleable, forming the desired shape and then fixing the shape by cooling in cold sterile water. For the average adult a 100-cm catheter with a 145-cm guidewire is suitable for reaching the thoracic aortic branches from a femoral puncture. If abdominal aortography or peripheral arteriography of the legs is to be performed shorter catheters may be used.

The introduction of a catheter over a guidewire may be facilitated by dilation of the track with a dilator (short length of tapered diameter tubing). If the patient has a large amount of subcutaneous fat in the puncture area, catheter control will be better if it is manipulated through an introducer sheath. This is also indicated where it is anticipated that frequent catheter exchanges may be required.

Taps and connectors

These should have a large internal diameter that will not increase resistance to flow. Taps should be removed during high-pressure injections.

1. Blood dyscrasias

2. Femoral artery aneurysm or pseudoaneurysm

3. Local soft-tissue infection

4. Severe hypertension

5. Ehlers–Danlos syndrome (due to the vessel wall being easily torn).

1. The patient lies supine on the X-ray table. Both femoral arteries are palpated and if pulsations are of similar strength the side opposite the symptomatic leg may be chosen, which gives the option to proceed to angioplasty by crossing over the aortic bifurcation. If all else is equal, then the right side is technically easier (for right-handed operators).

2. The appropriate catheter and guidewire are selected and their compatibility checked by passing the guidewire through the catheter and needle.

3. The location and point of puncture of the femoral artery must be considered. The external iliac artery arches anteriorly and laterally as it passes under the inguinal ligament and continues as the femoral artery. Attempts to puncture the artery cephalad to the ligament may result in a puncture deep in the pelvis at a point where haemostasis is difficult to achieve by manual compression and where peri-catheter and post-procedure bleeding may be obscured by preferential passage of blood into the retroperitoneum. Brief preliminary fluoroscopy of the groin can identify the centre of the femoral head with the intention of puncturing the artery at this point. This increases the likelihood of hitting the common femoral artery and facilitates haemostasis post procedure by allowing the artery to be compressed against bone. The inguinal skin fold does not reliably correlate with the position of the inguinal ligament. The entire common femoral artery lies above the skin fold in more than 75% of Western European subjects.¹ Direct US guidance is increasingly routinely used for vascular puncture.

4. Using aseptic technique, local anaesthetic is infiltrated either side of the artery down to the periosteum. A 3–5-mm stab incision is made over the artery to reduce binding of soft tissues on the catheter. In thin patients the artery may be very superficial and the skin may need to be pinched-up or deflected laterally, to avoid cutting the artery.

5. The artery is immobilized by placing the index and middle fingers of the left hand on either side of the artery, and the needle is held in the right hand. The needle is advanced through the soft tissues until transmitted pulsations are felt. Either both walls of the artery are punctured through-and-through or a single wall puncture is performed depending on the needle used. If present, the stilette is removed and the needle hub is depressed so that it runs more parallel to the skin and is then withdrawn until pulsatile blood flow indicates a satisfactory puncture. Poor flow may be due to:

6. When good flow is obtained the guidewire is introduced through the needle and advanced gently along the artery using intermittent fluoroscopy to avoid engaging the vessel wall. When the wire is in the descending thoracic aorta the needle is withdrawn over the guidewire, keeping firm pressure on the puncture site to reduce bleeding. The free portion of guidewire is then wiped clean with a wet sponge and the catheter threaded over it. For 5F or greater diameter catheters, particularly those which are curved, a dilator is recommended matched to catheter size. The catheter is advanced up the descending aorta, under fluoroscopic control, and when in a satisfactory position the guidewire is withdrawn.

7. Catheter patency can be maintained by continuous flushing from a pressurized bag of heparinized saline (2500 units in 500 ml of 0.9% saline) attached through a three-way tap, or by intermittent manual flushing throughout the procedure. Flushing should be done rapidly otherwise the more distal catheter holes will remain unflushed.

8. At the end of the procedure the catheter is withdrawn and manual compression of the puncture site should be maintained for 5–10 min.

1. Bed rest – typically for 4 h, but longer at the discretion of the operator. Larger catheters, antiplatelet therapy and anticoagulation require longer observation

2. Careful observation of the puncture site for haemorrhage

3. Pulse and blood pressure observation, e.g. half-hourly for 4 h and then 4-hourly for the remainder of 24 h, if the larger catheter systems are used.

1. Atherosclerosis of the axillary or subclavian arteries

2. Subclavian artery aneurysm.

1. The patient lies on the X-ray table with his arm in supination. The peripheral pulses are palpated and the brachial artery localized approximately 10 cm above the elbow.

2. A small incision is made in the skin, 1–2 cm distal to the selected point of arterial puncture.

3. A single-wall puncture needle is used, with an acute angle of entry into the artery.

4. A straight, soft-tipped guidewire is introduced when good pulsatile flow is obtained.

5. A 5F pigtail catheter is introduced over the guidewire and its pigtail formed in the aorta.

6. At the end of the procedure the catheter tip is straightened using the guidewire and then removed. This reduces the risk of intimal damage and flap formation during withdrawal of the catheter.

1. Atherosclerosis of the axillary or subclavian arteries

2. Subclavian artery aneurysm.

1. The patient lies supine on the X-ray table with the arm fully abducted. The puncture point is just distal to the axillary fold. It is infiltrated with local anaesthetic.

2. A small incision is made in the skin 1–2 cm distal to the point of the arterial puncture.

3. The needle is directed more horizontally than the femoral approach and along the line of the humerus.

4. Following satisfactory puncture the remainder of the technique is as for femoral artery catheterization.

1. Haemorrhage/haematoma – the commonest complication. Small haematomas occur in up to 20% of examinations and large haematomas in up to 4%. The SCIR threshold for haematomas requiring transfusion, surgery or delayed discharge after diagnostic angiography is 0.5%. Haematoma formation is greater with larger catheters, more frequent catheter exchanges and heparin, antiplatelet or thrombolytic agents. Haematoma formation is also greater when the femoral artery is punctured high because of inadequate compression of the artery following catheter removal.

2. Arterial thrombus may be due to:

Factors implicated in increased thrombus formation are:

The incidence is decreased by the use of:

3. Infection at the puncture site.

4. Damage to local structures; especially the brachial plexus during axillary artery puncture. Femoral nerve palsy can result from inadvertent infiltration of the nerve with local anaesthetic. It is short-lived but should prompt very cautious subsequent mobilization of the patient in case the leg ‘gives way’. More protracted femoral nerve damage can be due to excessive haematoma or pseudoaneurysm formation in the groin.

5. Pseudoaneurysm. The SIR threshold for diagnostic angiography is 0.2%. It presents as a pulsatile mass at the puncture site any time after arteriography and is due to communication between the lumen of the artery and a cavity within semi-solid or organized haematoma. Arterial puncture below the common femoral artery bifurcation increases the risk of this complication. Some may require surgical or interventional radiological repair.

6. Arteriovenous fistula – rare. SIR threshold is 0.1%. More common when puncture is below the common femoral artery bifurcation, because at this level the vein lies posterior to the artery and both are punctured in the standard double-wall technique.

1. Peripheral embolus – from stripped catheter thrombus. Emboli to small digital arteries will resolve spontaneously; emboli to large arteries may need aspiration thrombectomy through a catheter or surgical embolectomy. The SCVIR threshold is 0.5%.

2. Atheroembolism – more likely in older subjects. J-shaped guidewires are less likely to dislodge atheromatous plaques.

3. Air embolus. May be fatal in coronary or cerebral arteries. It is prevented by:

4. Cotton fibre embolus. Occurs when syringes are filled from a bowl containing swabs or when a guidewire is wiped with a dry gauze pad. This very bad practice is prevented by:

5. Artery dissection – due to entry of the catheter, guidewire or contrast medium into the subintimal space. It is recognized by resistance to passage of the guidewire or catheter, poor back-bleeding from the catheter hub, increased resistance to injection of contrast medium or subintimal contrast medium on fluoroscopy. The risk of serious dissection is reduced by:

6. Catheter knotting – more likely during the investigation of complex congenital heart disease. Non-surgical reduction of catheter knots is discussed by Thomas and Sievers.² Withdrawal of the knotted end to the groin followed by surgical removal may be the only solution in some cases.

7. Catheter impaction:

8. Guidewire breakage – less common with modern guidewires and tended to occur 5 cm from the tip, where a single central core terminates.

9. Bacteraemia – rarely of clinical significance.

1. Aortic aneurysm, trauma or dissection

2. Atheroma at the origin of the major vessels

3. Aortic regurgitation (echocardiography is more sensitive and less invasive if available)

4. Congenital heart disease – particularly the demonstration of congenital or iatrogenic aorto-pulmonary shunts and coarctation

5. As a preliminary to endovascular intervention, e.g. aneurysm repair.

1. Digital fluoroscopy unit with C-arm capable of 20–30 frames s^–1

2. Pump injector

3. Catheter:

1. The catheter is introduced using the Seldinger technique via the femoral artery, and its tip sited 1–3 cm above the aortic valve.

2. The C-arm is positioned 45° left anterior oblique (LAO) to open out the aortic arch, and to show the aortic valve and the left ventricle to best advantage.

3. A test injection is performed to ensure that:

1. Arterial ischaemia

2. Trauma

3. Arteriovenous malformation.

Both lower limbs

One lower limb

If thin 4F catheters are used, only day-case admission is necessary.

1. Dilation of localized vascular stenoses, mainly of the renal, iliac, lower limb and coronary arteries.

2. Recanalization of occluded segments of vessels in selected cases.

1. Digital fluoroscopy unit with C-arm capable of angiography and preferably with ‘road mapping’ facilities

2. Arterial pressure measuring equipment (optional)

3. Catheters:

4. Guidewires:

5. Thrombolytic agents may be infused into recently thrombosed vessels, prior to angioplasty.

Principles

Renal arteries

Iliac arteries

Femoral arteries (common, and origins of superficial femoral and profunda femoris arteries)

Superficial femoral and popliteal arteries

Catheter-directed arterial thrombolysis

It is an important tool in the management of thrombosed haemodialysis access.

1. The pulses distal to the artery that has been dilated and the colour of the toes should be observed half-hourly for 4 h

2. Aspirin 150 mg daily (for life, unless there is a contraindication)

3. Reinforcement of the need to stop smoking.

Due to technique

1. To control bleeding – from the gastrointestinal and genitourinary tracts, from the lungs and after trauma

2. To infarct or reduce the blood supply to tumours or organs

3. To reduce or stop blood flow through arteriovenous malformations, aneurysms, fistulae or varicoceles

4. To reduce the blood flow in high-flow priapism

5. As treatment for uterine fibroids.

1. Digital fluoroscopy unit with C-arm capable of angiography and preferably with ‘road mapping’ facilities.

2. Pre-shaped femoro-visceral catheters. These should not have side holes since their presence promotes clumping of particles and fibres at the catheter tip leading to blockage of the lumen. Size and shape will depend on the particular problem. Balloon occlusion catheters and co-axial catheters may also be useful.

3. Embolic materials:

1. As for arteriography

2. Some procedures are painful and sedo-analgaesia may be needed (see Chapter 18).

Principles

1. Observation of temperature pulse and blood pressure for signs of sepsis or bleeding

2. Observation of the tissues distal to the occluded vessel should be maintained for 24 h

3. Analgesia as required (patient-controlled administration).

1. Misplacement of embolic material: this may occur without the operator being aware that it has happened.

2. There may be propagation of thrombus, with embolization to the lungs or elsewhere.

3. Post-embolization syndrome results from infarcted tissue releasing toxins into the circulation. It comprises pain, fever, malaise, raised white cell count and inflammatory indices and transient impairment of renal function. Infarcted tissue can cause fever for up to 10 days. However, this tissue can become infected, and antibiotics may be required.

1. Lower-limb ischaemia

2. Arterio-venous malformation

3. Trauma.

1. Contrast: 100–150 ml LOCM 300 mg I ml^–1 (volume determined by scanner and scan protocol)

2. Contrast injection rate: 4 ml s^–1 via a peripheral vein

3. Range: lower abdominal aorta to heel, or extended as upper abdominal aorta to heel

4. Slice thickness: 3 mm or less

5. Reconstruction increment: 0.6 mm

6. Delay: