32P-oligodeoxynucleotide-coated coils to prevent arterial recanalization after embolization

Endovascular treatment of aneurysms with coils, a less invasive alternative to surgery, is too often associated with recurrences. In a canine model, recanalization after coil embolization can be inhibited by in situ beta radiation.

Radioactive platinum coils were produced by immersion in a (32)P-oligodeoxynucleotide solution. In vitro and in vivo (32)P-oligodeoxynucleotide elution profiles were assessed after incubation or arterial implantation for 14 days or less. Activities within arteries, thrombi, and coils were measured by scintillation counting. Angiographic and pathologic results no more than 12 weeks after standard platinum and radioactive coil embolization of canine maxillary, cervical, and vertebral arteries were compared among 17 animals.

Exposure to (32)P-oligodeoxynucleotide solution at 65 degrees C yielded coils with an average activity of 0.3 microCi/cm. Elution profiles in vitro and in vivo showed that 50% of total activities eluted from coils within 24 hours at first, but coil activities then paralleled the natural decay of (32)P. Radioactivity was present in the thrombi and arterial wall throughout the 14-day observation period. Arteries that were embolized with standard coils recanalized at 2 weeks. Implantation of (32)P-oligodeoxynucleotide-coated coils produced total occlusions in 78.6% of arteries throughout the 12-week observation period. Most arteries that were implanted with radioactive coils were filled with fibrous tissue at 3 months.

Radioactive coils can be produced by using the binding properties of a (32)P-oligodeoxynucleotide to platinum. Use of these coils in an animal model was effective in preventing recanalization. This method could be performed on site to provide coils tailored to each intervention.