Interventional Vascular Radiology Techniques

Contraindications

Very few absolute contra-indications – caution with patients on anticoagulants / systemic hypertension / prolonged steroid treatment / connective tissue disorders

The right common femoral arterial approach is preferred (other sites include the axillary, brachial or radial artery) this allows good access with well defined puncture landmarks and a low complication rate

• Arterial puncture technique: can use a single (anterior artery wall) or double puncture (anterior and posterior arterial walls) technique, followed by guidewire insertion and then exchange with dilators / catheters, and a heparinized saline flush injection ▸ the most common problem with antegrade femoral artery puncture is catheterisation of the profunda femoris

• Landmarks for a fluoroscopic guided puncture: the skin entry point is at the inferior margin of the femoral head ▸ the arterial entry point is at the mid-femoral head level ▸ puncture is usually achieved under direct US guidance

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    Puncturing too high (above the inguinal ligament): this increases the risk of bleeding and also means that direct pressure to maintain haemostasis is difficult

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    Puncturing too low (e.g. into the superficial femoral artery): this increases the risk of false aneurysm and arteriovenous fistula formation

• The guidewire should never be advanced without fluoroscopic guidance and never against resistance

Potential complications

• Haemorrhage: retroperitoneal bleeding may occur if the puncture site is above the inguinal ligament – it can also occur if a normal puncture penetrates the femoral sheath (downward extension of pelvic fascia around the femoral vessels, allowing bleeding to enter the retroperitoneum / abdominal wall) ▸ peritoneal bleeding occasionally with punctures above the inguinal ligament

• Local vascular complications: late stenosis or occlusion ▸ local sepsis / local nerve damage

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    False aneurysm formation: this occurs where there has been inadequate haemostasis and is more likely to occur with a low CFA puncture where the artery cannot be compressed against the femoral head ▸ the treatment options include US guided compression, thrombin injection and surgical repair

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    Arteriovenous fistula formation: this is uncommon with a CFA puncture but is more likely with a SFA puncture (as the femoral vein lies deep to it)

• Thrombosis: due to severe vessel trauma during puncture or thrombus wiped off the outside of the arterial catheter during extraction acts as a nidus ▸ this is more likely if the artery is severely diseased at the puncture site

• Arterial dissection following angioplasty: this usually occurs with an antegrade approach ▸ retrograde dissections are usually self limiting

• Distal microembolization: this follows thrombus or atheroma breaking off from the vessel wall

• Perivascular contrast injection: pain ▸ possible to dissect and occlude a vessel with a subintimal injection

• Catheter complications: thrombi in or on a catheter and entering the vascular system ▸ vascular injuries (commonly dissection of the tunica intima forming a flap that can occlude a vessel) ▸ organ injuries (following ischaemia during arteriographic procedures) ▸ guidewire fracture

Vascular sheath

• This provides an atraumatic access route (e.g. preventing the wings of a deflated angioplasty balloon creating an arteriotomy as it is removed)

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    It consists of a hollow tube connected to a haemostatic valve (through which catheters are inserted) and a side arm for flushing

Haemostasis

As well as direct pressure applied to the puncture site, other alternatives are available:

• Suture mediated closure devices (e.g. Perclose): the technique relies on a complex mechanism whereby 2 needles pass through the vessel wall adjacent to the puncture site and then retrieve a suture loop ▸ the suture loop is then pulled through and out of the skin (it closes the puncture site as it is tightened and a slipknot is formed)

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    It allows immediate haemostasis and repuncture (if required)

• Collagen plug and anchor (e.g. Angioseal): a collagen footplate is deployed within the arterial lumen ▸ this is attached to an anchor on the external side of the arterial lumen (this has collagen wadding which forms a plug at the puncture site) ▸ the collagen footplate dissolves after approximately 10 weeks

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    Unlike the suture mediated method a repuncture should not happen within 3 months as there is a risk of dislodging the anchor plate

Catheter outer diameter

This determines the catheter size

• ‘French’ (Fr) size: the outer circumference in millimeters (the French size divided by 3 gives the approximate outer diameter)

Catheter inner diameter

this is measured in 1/1000 of an inch

Catheter length

This is commonly 65 cm (abdominal work) or 100 cm (aortic arch and carotid work)

Non selective catheters

• Pigtail catheter: this is used within the aorta ▸ it has a large endhole and smaller sideholes with a pigtail loop and measures approximately 15 mm in diameter