From Baptist Health South Florida
8 min. read
Advances in the diagnosis and treatment of brain aneurysms have accelerated in recent years for both the most common type, those that bulge but have not burst, and the uncommon but deadliest type -- ruptured aneurysms.
A brain aneurysm is a weak or thin spot on an artery in the brain that balloons or bulges out and fills with blood. The bulging aneurysm could burst or rupture, spilling blood into the surrounding tissue. A ruptured aneurysm can cause serious health problems, such as hemorrhagic stroke, brain damage, coma -- and death if not treated promptly.
In a recent Baptist Health Talk: Doc-to-Doc podcast, experts at Baptist Health Miami Neuroscience Institute discussed significant advances in diagnosing and treating brain aneurysms. Michael McDermott, M.D.., a neurosurgeon and the chief medical executive at the Institute, interviewed Guilherme Dabus, M.D., co-director of interventional neuroradiology and vice-chief of the department of neuroscience at the Institute.
General public awareness of major risk factors, such as smoking and high blood pressure, combined with advances in diagnosing and treating unruptured aneurysms before they burst, have helped decrease rates of this potentially deadly condition.
“Now, there's very interesting data that is very recent in the literature,” explained Dr. Dabus. “It seems that the number or the incidents of aneurysms that rupture is actually decreasing over the years. And this number was a little bit higher in the 1980s, and now apparently it's a little bit lower, close to the 7 to every 100,000 patients. The reason for this -- we really don't know for sure. It could be related to lifestyle changes, a lot of less smoking for example, and also the increasing number of aneurysms that are found before they rupture that have been treated.”
The minimally invasive procedures, or endovascular, to treat unruptured aneurysms usually involve coils or mesh stents to promote clotting and close off the aneurysm with a very high success rate. The devices are placed via a catheter that snakes through a blood vessel, usually from the groin or from the wrist to the brain.
“Throughout the last 20 years, there have been many advancements in the endovascular coils and other devices,” adds Dr. Dabus. “Now, we have stents that we use to treat aneurysms along with coils. We have balloons that we use to do balloon remodeling and place coils within the aneurysm. We also have flow diverters, which is special type of stent that is placed in the parent vessel, or the artery where the aneurysms arise from, and kind of deviates the blood flow away from the aneurysm and basically cures those aneurysms. And it actually allows us to treat aneurysms that before were not really possible to treat.”
Here are question-and-answer excerpts from the Doc-to-Doc podcast with Drs. McDermott and Dabus.
Dr. McDermott: “First of all, could you tell the audience a little bit about the different types of aneurysms and their frequency in the population?
Dr. Dabus: “When we're talking about intracranial aneurysms, there are basically two types of presentation. An unruptured aneurysm is often an incidental finding. So, the aneurysm was found because you're having an imaging study done for other reasons, such as maybe headaches or dizziness or memory loss. And then you have the type that is really the most dangerous one (ruptured aneurysms), which basically is when the patient presents with what we call a subarachnoid hemorrhage (a type of hemorrhagic stroke). That is when the aneurysm has bled. Basically, blood leaked out of the aneurysm into the brain, or adjacent structures from the brain, and becomes really a medical emergency that needs to be fixed..
“When we're talking about the aneurysms that rupture, the incidence of those is somewhere between six to 12 per 100,000 people. In contrast, the prevalence of brain aneurysms in the population is approximately 2%. In other words, most of the aneurysms will never rupture.
“Of course, when the aneurysms are found incidentally, a lot of times they're not really causing any symptom. And when the aneurysms rupture, which is again the blood leaks outside the aneurysm, a lot of times the patients present with what we call the worst headache of their lives. The patient is experiencing a headache that he or she has never felt before. Even patients with migraines know it's a different type of headache. Sometimes, it can be associated with other neurological symptoms, weakness, problems to speak, somnolence. And some patients, unfortunately, have aneurysms that bleed and will not make it alive to the hospital.
Dr. McDermott: “One of the questions that comes up relates to imaging: Whether or not CT angiography or MR angiography for example, are as good as conventional catheter angiography for defining anatomy and assisting with decisions about treatment for different types of aneurysms. Could you comment on this for some of the patients that might be listening?”
Dr. Dabus: “The noninvasive neuroimaging, particularly CT angiography or MR angiography, which are basically done specifically to look at the blood vessels in the patient's brain, have evolved tremendously over the last 10, 15 years with the noninvasive imaging capability becoming very good. However, I wouldn't say exactly as good as a diagnostic catheter angiography, which is the minimally invasive way and best test to study the blood vessels in the brain. And I'm saying that because there also has been significant advancements in the procedure itself. The catheter-based angiography has also become much safer. We do 3-D rotation to study aneurysms or the blood vessels better. We can do what we call cone beam CTs with contrast angiography, which actually has probably one of the best spatial resolutions that one can have. But there’s no question that CT angiography and MR angiography are playing very important roles when we're talking about intracranial aneurysms and the technology continues to evolve.
“Those (CTA and MRA) are great screening methods. For example, if you're having headaches or if you have a history of aneurysms, that's a very good way to get a first study or follow-up aneurysms. However, the diagnostic cerebral angiography may provide more details regarding some important aspects of the aneurysm. Therefore, sometimes before you're really decide if an aneurysm needs to be treated or not, a lot of times we end up doing diagnostic cerebral angiography to better understand some features of the patient’s aneurysm and cerebral vessels with greater resolution that sometimes the CT angiography and the MR angiography cannot really give us.
Dr. McDermott: “Let's talk about treatment options now, and specifically in your specialty, endovascular therapy. And maybe just tell the audience how endovascular coiling is different than craniotomy for clipping of an aneurysm.”
Dr. Dabus: “Historically, aneurysms have been treated with something that we call craniotomy and microsurgical clipping of the aneurysm, where basically the neurosurgeon does a craniotomy and puts a clip in the aneurysm. He opens the bone, he goes into the spaces of the brain, and he puts a clip that pretty much strangles the neck of the aneurysm and blocks completely the blood flow to the aneurysm using a titanium clip. With the evolution of the devices and techniques, basically endovascular procedures became a very important, and in several centers, the first option for treatment of intracranial aneurysms. Basically, endovascular means that the aneurysm is treated from inside the blood vessel, with a minimally invasive approach. What we do is put a catheter, which is this plastic tube that it goes either through the groin or through the wrist of the patient, and we navigate microcatheters to the aneurysm, and we treat the aneurysms with several different devices that we have available nowadays.
“The first device was a device that we call a coil, which is basically a platinum coil which is inserted through tiny tubes and basically blocks the flow that is going to the aneurysm. And this was initially developed in the early 1990s … was actually approved by the FDA in 1995. So, since 1995, we're treating the aneurysm through endovascular means, which is minimally invasive, less invasive than the open surgery. And that is its main advantage.
“The advancements of the endovascular field over the last 20 to 30 years have been really, really tremendous. And they allow us to treat patients that even 5 or 10 years ago were not being treated or we were not able to treat. That has been really, really marvelous for our patients.”
Urgency of Ruptured Aneurysms
Dr. McDermott: “For our audience, just to let you know how potentially bad a ruptured aneurysm can be. Many patients who experience ruptured aneurysm will experience sudden death and never make it the hospital alive. Another 20 percent will die from re-hemorrhage or complications during the hospital stay; and 20 percent will get something called cerebral vasospasm, narrowing of blood vessels from irritation caused by the subarachnoid blood. And 20 percent will end up with something called hydrocephalus, obstruction of cerebral spinal fluid circulation or drainage requiring a shunt. So, when you have a patient with a ruptured aneurysm, how quickly do you proceed with endovascular treatment following the admission of the patient into the hospital with acute subarachnoid hemorrhage?”
Dr. Dabus: “When you're facing an aneurysm that ruptured (bled inside the skull), the first thing that needs to be taken care of is to make sure the pressure inside the skull is relieved. If the patient has what we call hydrocephalus, usually there's a catheter that needs to be placed through the skull, and it is usually done by neurosurgeon just to relieve the pressure inside the head. And then the aneurysm is usually treated, or what we call secured, as soon as possible, usually within the first 24 hours after the hemorrhage so that the chance of further bleeding is markedly reduced. That's the goal for us.
“Basically, if the patient comes in in the middle of the night, he or she is probably going to be stabilized overnight and then treated first thing in the morning, sometimes depending on the situation, even earlier than that. Most of the time the aneurysm will be secured in the first 24 hours. One of the things that's important too is that a lot of these patients have other risk factors for aneurysm rupture, such as hypertension, smoking, and family history. And that also plays a factor when you're talking about the chances of those patients having a good outcome after the subarachnoid hemorrhage.”
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