The Pipeline Embolization Device is a stent-like option that is delivered endovascularly.
Ticking Time Bombs
New options for interventional brain aneurysm treatment
issue 16 | summer 2012
For patients, being diagnosed with a brain aneurysm can feel like they've been told they have a ticking time bomb in their head. A rupture could occur at any time, and their odds of surviving the resulting subarachnoid hemorrhage with good functionality are approximately 50 percent.
Recent advances in treating intracranial aneurysms and other cerebrovascular conditions have made it possible to defuse many of these "bombs" before they cause irreparable harm. Both open surgical and endovascular approaches, and the neuroimaging to guide them, have improved in the last decade.
But until recently, some patients with especially large, deep or complex aneurysms have still been deemed inoperable. Now, teams at the University of Michigan Health System and other top centers can offer a broad range of approaches to fill aneurysms or divert blood flow from entering them.
MAKING THE INOPERABLE OPERABLE
The newest is a first-of-its-kind stent-like option called the Pipeline Embolization Device.
Delivered via endovascular technique, it is placed within the parent vessel across the aneurysmal opening. But unlike a stent, the fine-mesh Pipeline diverts blood flow away from the aneurysm into the parent vessel. This allows the vessel wall to remodel itself over time and completely clot off the aneurysm. It was approved last year by the FDA for large or giant wide-necked brain aneurysms arising on the internal carotid artery.
"This allows us to treat patients who had no other option," says Aditya Pandey, M.D., a U-M assistant professor of neurosurgery and member of the U-M Cerebrovascular Disease team. "It's a promising new technology, but durability will be determined with long-term usage."
Pandey and his colleagues B. Gregory Thompson, M.D., Joseph Gemmete, M.D., and Neeraj Chaudhary, M.D., M.R.C.S., F.R.C.R., lead an interdisciplinary team of cerebrovascular specialists who evaluate and treat hundreds of patients with aneurysms and cerebrovascular conditions each year.
The team gives referring physicians direct access to one of the four attending physicians 24 hours a day, every day of the year, about both elective management options and emergent cases. They often receive calls about patients who have had an incidental finding of an intact aneurysm on an imaging study performed for another reason, such as trauma or diagnosis of another condition.
A LIQUID CURE
Unruptured intracranial aneurysms usually do not cause symptoms, but in certain circumstances they can cause severe headaches or even stroke-like symptoms (weakness, numbness, speech difficulty and visual disturbance). But once an aneurysm has ruptured, most patients describe their symptom as the worst headache of their life. Many also experience photophobia, blurred or double vision, stiff neck, nausea and vomiting.
Imaging studies such as contrast-enhanced MRI, MRI angiography, CT angiography or catheter-based cerebral angiography can confirm aneurysms. The next challenge is to determine the best treatment approach for the particular patient.
"We truly have an armamentarium at our disposal -- a wide range of options that we can choose from to suit the individual," says Thompson, the J.E. McGillicuddy Professor of Neurosurgery and Radiology, a neurosurgeon trained in both microsurgery and minimally invasive interventional neuroradiology techniques.
One option is a liquid called Onyx HD-500, which can be deployed through a catheter to fill the aneurysm sac. A balloon catheter is first threaded into the vessel that has the aneurysm, and then it is positioned to completely bridge the neck of the bulge. Next, the liquid is delivered into the aneurysm's open space through a second catheter that rides along with the balloon catheter. Onyx HD-500 hardens instantaneously, completely obliterating the aneurysm.
The U-M team also offers both open surgical clipping options and endovascular placement of coils to fill aneurysms and prevent rupture. Specialized stents to support and seal off coil-filled aneurysms have been available for the last six years at U-M.
Onyx HD-500 is a liquid delivered into an aneurysm's open space that hardens on contact, sealing off the aneurysm.
MORE OPTIONS MEAN MORE ACCESS
A specially constructed "hybrid suite" for neurointerventional care at U-M allows the patient to have dual imaging modalities during elective and emergent care. This is especially important for stroke patients who need both an angiogram and a CT of the head to be performed quickly for endovascular intervention.
"While the availability of all these options makes it possible to treat more patients than ever before, we are also conscious of the need to evaluate new technologies fully," says Gemmete, an associate professor of Radiology and Neurosurgery, interventional neuroradiologist and director of U-M's Neurointerventional Radiology fellowship program. He adds, "Outcome studies do show that morbidity and mortality are comparable between open and endovascular approaches, and length of hospital stay is shorter with the ability to send patients directly home within 24 hours of treatment higher with endovascular care."
"Here at U-M, our cerebrovascular team treats the whole spectrum of neurovascular diseases -- in adults and children, and in brains and spinal cords," says Chaudhary, an assistant professor of radiology and neurosurgery at
U-M and a neurointerventional radiologist.