Table 1.

Technical Pearls for Coil Embolization

Issue	Pearl
PAVM, pulmonary arteriovenous malformations.
Scaffolding	Adequate scaffolding can be obtained by initially deploying a larger coil, followed by smaller ones.
	An Amplatzer Vascular Obstruction Device may be used for vessels that do not taper; it has legs that penetrate the walls of the vessel, and it acts as a cone into which coils may be placed.
	Coils can be used as a scaffold in combination with Gelfoam when patient is coagulopathic (trauma/shock); such a “coil-Gelfoam sandwich” causes a complete, permanent mechanical occlusion.
	Stiffer coils are generally deployed first and are used as a “backstop.” Softer and pliable coils with unpredictable coil shapes that tend to conform to vessel anatomy, such as the Nestor coil (Cook, Inc., Bloomington, IN), may be deployed following a stiffer “backstop” coil deployment.
Microcoils	Microcatheters should be used when the coil is <0.018 inches (microcoil) to prevent catheter occlusion; care should be taken to be certain that “high-flow” catheters are used with caution when deploying coils, as the larger inner lumen may allow the coils to partially form in the catheter, leading to catheter blockage.
Undersizing	Undersizing may lead to distal embolization and must be avoided especially in cases of PAVM; as a rule of thumb, the coil should be ∼20% larger than the vessel diameter.
Oversizing	Too much oversizing will prevent the coil from achieving its shape; this leads to inadequate occlusions, as well as a markedly longer coil (which may in turn lead to proximal coil malposition).
Deployment	When deployment precision is required (i.e., intracranial procedures, PAVM), coils may be deployed using the floppy end of a “pusher wire”; when precision of deployment is not a concern (i.e., filling a pseudoaneurysm), the coil may be deployed using a saline bolus.
Retrievable coils	Retrievable coils allow the coil to be pulled back in the delivery catheter just before deployment; this technique is also helpful when precise placement is essential.
Composition	As a rule of thumb, steel coils tend to be stiffer while platinum coils tend to be softer.