Endovascular embolization

Definition

Endovascular embolization is a procedure that utilizes chemical agents or metallic coils to stop bleeding and treat aneurysms or brain tumors.

Purpose

The purpose is either to cut off blood supply or to fill a sac (also creating a thrombus). Endovascular embolization is a procedure used to treat hemorrhage, cranial tumors, or aneurysms. The procedure can be life saving. Bleeding can be stopped in cases of trauma, epistaxis (nosebleed), coughing up blood from the lungs (hemoptysis), gastrointestinal bleeding, hemorrhage to solid organs, and postcesarean, postoperative, or postpartum bleeding in the abdomen or pelvis. Additionally, endovascular embolization is used to cut off the blood supply to cranial tumors which eventually causes tumor cell destruction and tumor mass shrinkage from lack of oxygen and nourishment. The procedure can also be utilized for packing an aneurysm with coils, to prevent rupture and possible death from intracranial hemorrhage.

Precautions

Embolization is an indication for treatment of many clinical entities. The procedure is performed under general anesthesia and elective cases require pre-procedural evaluation with an anesthesiologist. The procedure requires a brief inpatient stay for one to two days. Dietary restrictions and medical work-up are usually indicated before elective surgery (i.e., cranial tumors). If an aneurysm or tumor cannot be safely embolized, the procedure is terminated. For bleeding, the procedure may likely be an emergency.

Description

Embolization is a useful procedure in a broad spectrum of clinical disorders. Typically embolization for any reason begins with a diagnostic angiography procedure to identify the source of the problem. The diagnostic angiography is usually performed in an artery. A catheter is usually inserted into the groin artery and dye is injected into the system. The catheter is wiggled through to the desired location using a television monitor. The target area may be a region where there is bleeding or it may be an aneurysm or cranial tumor. Once at the target area, chemicals or metal coils (for an aneurysm) are introduced by a microcatheter. In the case of an aneurysm, soft metal coils are placed with a microcatheter in the aneurysm until it is packed with about five to six coils. Filling the aneurysm will prevent blood flow into the aneurysm sac, since the sac is filled with coils and a thrombus after the procedure. Endovascular embolization can help to stop bleeding or rebleeding for patients who are hemorrhaging. For cranial tumors the goal is to inject emboli in blood vessels that nourish brain tumors. This causes destruction of the tumor mass due to lack of blood supply. For any reason, when a blood vessel requires embolization, coils are the instrument of choice.

Preparation

Routine blood tests are done one to two days before an elective embolization. For scheduled procedures the patient should not eat or drink liquids after midnight the night before the procedure. The procedure is usually performed in a neuroangiography unit. A nurse will shave the patient's groin area since the catheter is inserted in the groin artery (also called the femoral artery). Emergency preparation may be initiated for persons who are actively bleeding.

Aftercare

After elective embolization, patients are taken to a neurosurgical intensive care unit or a step-down unit for close monitoring and recovery. It is necessary to lie flat for eight hours after the procedure to allow the groin area (where the catheter was inserted) to heal. Usually the next day the patient will be transferred to a regular ward room and discharged to home the following day.

Risks

The risk of embolization is low. Possible complications include weakness in an arm or leg, dysesthesia, speech or visual deficits, and stroke .

Normal results

Normal results depend on the indications for the procedure. For bleeding the desired goal is rapid cessation of bleeding source. Aneurysm will likely develop saccular occlusion (occlusion of the aneurysm sac), reducing the risk of rupture and fatal intracranial hemorrhage. The desired effect for an intracranial tumor is obliteration of tumor vasculature, which eventually causes destruction of the tumor mass, secondary to oxygen deprivation.

Resources

BOOKS

Grainger, Ronald G., and David Allison. Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging, 4th Ed. Churchill Livingstone, Inc.

WEBSITES

Arteriovenous Malformations. The Mayfield Clinic. <http://mayfieldclinic.com/PE/PE-AVM.HTM>.

Endovascular Embolization of Cranial Tumors. University of North Carolina at Chapel Hill. <http://www.cs.unc.edu/Research/intel/brain.html>.

Endovascular Embolization Treatment of Aneurysms. The University of Toronto. <http://nrainavm.uhnres.utoronto.ca/malformations/content/treat_embo_aneurysm.htm>.

ORGANIZATIONS

International Radiosurgery Support Association. PO Box 5186, Harrisburg, PA 17110. (717) 260-9808; Fax: (717) 260-9809. [email protected]. <http://www.irsa.org>.

Laith Farid Gulli, MD

Robert Ramirez, DO