Embolic agents and their use in therapeutic vascular occlusion have advanced considerably since the emergence of these procedures in the mid-1960s. The earliest embolic agents included muscle tissue and Gelfoam used for the treatment of traumatic carotid-cavernous fistula in 1965 and 1966, respectively.[1] [2] Other early embolizations employed permanent agents such as 1.5- and 3-mm stainless steel pellets administered for the treatment of arteriovenous malformation[3] and lead pellets for the treatment of spinal cord hemangioma, both in 1968.[4]

Pharmacologic agents such as epinephrine and propranolol were also being investigated for their occlusive effects by Czech radiologist, Dr. Josef Rösch in 1970.[5] These embolization procedures differed in that they capitalized on image guidance to identify and occlude distant vessels, specifically for the treatment of gastrointestinal hemorrhage. Rösch's ground-breaking publication prompted an editorial note in Gastroenterology titled “Turned Off Bleeders” which cautioned against unchecked enthusiasm for minimally invasive procedures,[6] [7] but early interventionalists were not swayed.

With influence from Rösch, American radiologist Dr. Charles Dotter administered an autologous clot to treat gastrointestinal hemorrhage shortly thereafter.[8] In the coming years, embolic agents for gastrointestinal hemorrhage were further explored in canine models with physical agents, like Gelfoam, outperforming pharmacologic vasoconstrictors.[9] By the 1980s, Gelfoam became the favored agent for temporary occlusion in gynecologic hemorrhage, presurgical devascularization, and hemoptysis.[10] [11] Other temporary embolic agents studied in animal models included Oxycel and Surgicel,[12] with polyvinyl alcohol (Ivalon), silicone, and cyanoacrylates rounding out the permanent embolic agents. As the application of therapeutic embolization grew, so did the arsenal of embolic agents, each with unique advantages and drawbacks. One of the major distinguishing factors for embolic agents is whether they provide temporary or permanent occlusion.

This review article will focus on the temporary embolic agents in use today, namely: Gelfoam, autologous blood clots (ABCs), and Avitene. Their preparation, indication, and specific limitations will be discussed in addition to advances in embolic bioengineering with the emergence of on-demand degradation, shape memory polymers (SMP), and drug-eluting beads.

Article published online:
10 July 2024

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