Lowering the risk in patients with arteriovenous malformations through innovative, effective treatment
Embolization of arteriovenous malformations is a treatment that comprises interventions alone or in combination: surgery, stereotactic radiosurgery and embolization. Over the last 10 to 15 years, endovascular surgery has progressed to the point where AVM arterial feeders can be blocked with embolic glue, which then allows the neurosurgeon to excise the AVM with lowered risk to patients and improved outcomes.
A congenital disorder, an AVM is an abnormal tangle of vessels with arteries directly connected to the veins. Since the capillary bed is missing, high pressure blood flows directly from the arteries into the veins. Over time, the center of the AVM can become fragile and prone to bleeding due to the constant pounding circulation. AVMs can occur anywhere in the body. The majority are asymptomatic until they rupture or leak. When located in the brain, a bleeding AVM can produce seizures, headaches, hemorrhage, stroke or severe neurological disability – depending upon both its location and the amount of bleeding – and can even lead to death.
Aided by fluoroscopy, the neurosurgeon carefully threads a micro-catheter via the femoral artery into the center of the AVM. Once the micro-catheter tip is in the desired position, the embolic glue, in liquid form, is slowly injected through the catheter to the targeted malformation. When the liquid comes into contact with the blood, it changes into solid material, sealing off the blood vessels, shutting down the blood flow and reducing the risk of rupture during resection.
Preoperative embolization gives the brain time to quiet down after spending years shunting high-powered blood to the AVM. In some patients, it can reduce the size and vasculature of the AVM and eliminate surgically inaccessible vessels. This dramatically decreases intraoperative blood loss. This results in an easier and safer surgical resection.
Until recently, many rapidly acting embolic glues hardened too quickly and did not always penetrate smaller diametric vessels. At NYU Winthrop, a newer agent called ONYX is used for embolization of AVMs, representing an important, relatively new intracranial AVM treatment option with its ability to facilitate a slower, more deliberate and controlled procedure. ONYX takes longer to harden, allowing for more precise management of its delivery.