Hydrogels in endovascular embolization. V. Antitumour agent methotrexate-containing p(HEMA)

Advances in Biomaterials and Technologies for Vascular Embolization

Minimally invasive transcatheter embolization is a common nonsurgical procedure in interventional radiology used for the deliberate occlusion of blood vessels for the treatment of diseased or injured vasculature. A wide variety of embolic agents including metallic coils, calibrated microspheres, and liquids are available for clinical practice. Additionally, advances in biomaterials, such as shape-memory foams, biodegradable polymers, and in situ gelling solutions have led to the development of novel preclinical embolic agents. The aim here is to provide a comprehensive overview of current and emerging technologies in endovascular embolization with respect to devices, materials, mechanisms, and design guidelines. Limitations and challenges in embolic materials are also discussed to promote advancement in the field.

Radiopaque nano and polymeric materials for atherosclerosis imaging, embolization and other catheterization procedures

A review of radiopaque nano and polymeric materials for atherosclerosis imaging and catheterization procedures is presented in this paper. Cardiovascular diseases (CVDs) are the leading cause of death in the US with atherosclerosis as a significant contributor for mortality and morbidity. In this review paper, we discussed the physics of radiopacity and X-ray/CT, clinically used contrast agents, and the recent progress in the development of radiopaque imaging agents and devices for the diagnosis and treatment of CVDs. We focused on radiopaque imaging agents for atherosclerosis, radiopaque embolic agents and drug eluting beads, and other radiopaque medical devices related to catheterization procedures to treat CVDs. Common strategies of introducing radiopacity in the polymers, together with examples of their applications in imaging and medical devices, are also presented.

Targeted chemoembolization of tumors with poly(2-hydroxyethyl methacrylate) particles

Thirty-four patients suffering from various kinds of tumors, including metastasis, were treated by selective embolization with both spherical and cylindrical poly(2-hydroxyethyl methacrylate) [poly(HEMA)] particles and topical chemotherapy. Treatment of a patient with carcinoid metastases in the liver is discussed. Immediately after embolization, 5-fluorouracil, and later, doxorubicin and Lipiodol, were selectively infused into the tumorous tissue for approximately 1 week. Patient received four cycles of this infusion. Chemoembolization proceeded against the background of anticoagulant therapy using small doses of heparin or its low-molecular-weight analogue, dalteparin. This was followed by transcutaneous transhepatic portography and embolization. Finally, the tumor-feeding artery and portal vein were sealed by a hydrogel. After 1.5 months, the affected liver lobe was resected. Although 4 years from the beginning of treatment, the patient is still alive. Embolization with poly(HEMA) hydrogel particles in conjunction with an anticancer drug infusion via catheter is recommended as an efficient method of tumor treatment. The therapeutic effect has been shown to be a function of ischemia and slow local infusion of drug into the tumor, and systemic drug levels can be kept low.

Tubal sterilization by means of selective catheterization: comparison of a hydrogel and a collagen glue

PURPOSE

To test, in an animal model, two potentially suitable materials for nonsurgical selective tubal sterilization.

MATERIALS AND METHODS

A hydrogel that forms an in situ plug by phase inversion of a polymer solution was placed in four rabbit fallopian tubes, and a proprietary collagen glue was placed into three rabbit fallopian tubes by means of transvaginal fluoroscopic fallopian tube catheterization. As controls, 11 tubes were catheterized without sterilization material injection. The rabbits were bred, and the presence of embryos was confirmed with palpation and at autopsy. Histologic analysis was performed.

RESULTS

The short-term contraception rate was 100% in the hydrogel group, 33% in the collagen glue group, and 0% in the control group (P < .001 hydrogel group, P not significant in collagen group). Inflammation was minimal in the three groups (P not significant).

CONCLUSION

The collagen glue had an insufficient contraceptive effect and should be abandoned. The hydrogel used proved effective and biocompatible, and long-term studies of this compound are warranted.