Materials used for embolization

According to whether the resulting devascularization is permanent or temporary, the embolic agents can be classified as:

1. Temporary agents: autologous blood clot, gelfoam powder and microfibrillar collagen
2. Permanent agents:

• Particles: polyvinyl alcohol particles, trisacryl gelatin particles
• Coils (steel, tungsten or platinum) and balloons ( latex or silicone)
• Liquid includes sclerosants,adhesives and soluble plastics: ethanol, sodium tetradecyl sulphate,NBCA ( n butyl 2 cyanoacrylate),ethyl vinyl alcohol copolymer

RELATED QUESTIONS

HOW DOES PVA OR GELATIN PARTICLES WORK AS AN EMBOLIZATION AGENT?

• They cause an initial acute inflammatory response which is followed by a chronic foreign body reaction within weeks.
• Devascularization causes ischaemia and necrosis within hours which leads to swelling of tumours and may cause pain.

WHAT ARE THE VARIOUS SIZE OF PVA OR GELATIN MICROSPHERES?

• 40 to 800 microns in diameter

WHEN IS EMBOLIZATION BEST PERFORMED?

• Preoperative embolization is best performed the day before or immediately prior to operation.

WHAT ARE THE DISADVANTAGES OF SMALLER PARTICLES AND LARGE PARTICLES?

• Smaller particles will penetrate to smaller vessels, they are more likely to pass through arteriovenous shunts and reach the lungs. They also may cause ischaemic damage to normal tissues.
• Larger particles occlude proximal arteries and achieve less reliable tumour devascularization.

WHAT ARE THE DIFFERENT METHODS TO USE BALLOONS DURING EMBOLIZATION?

• Used for temporary test occlusion fixed to a catheter tip or
• Used for vessel occlusion by detaching and inflation using radiographic contrast media.

WHICH EMBOLIC AGENT IS CONSIDERED THE MOST PERMANENT FORM OF EMBOLIZATION?

• Liquid namely NBCA and copolymer ethylene vinyl alcohol.