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June 10, 2005
Dr. Philippe Gailloud is an assistant professor at the Johns Hopkins Department of Radiology. Although he treats many adults, his focus now is on pediatric interventional neuroradiology.
How did you start at Hopkins?
Dr. Gailloud: I am originally from Switzerland, and did my medical training in Geneva in diagnostic and interventional radiology. At one point, my mentor decided I should see something else, something different from what I was doing there, and there were a few options. I chose Hopkins almost by chance for my fellowship. The person who hired me wanted me for here 3 years, but I thought it would be too much time for me, so I agreed to stay for 2 years. This was 7 years ago…
Although the majority of your patients are adults, your main interest is in children. Why is that?
Dr. Gailloud: For some reason, not many people are interested in treating cerebrovascular diseases in children. Probably because they are infrequent and usually challenging cases. The emotional investment with children is usually heavier and that may also play a role. In the Division of Interventional Neuroradiology, we obviously see more adult patients than children. That is the reason I treat mostly adults. We currently perform around two or three pediatric angiograms per week, and one or 2 pediatric interventions per month, while we have 5 or 6 angiograms per day for adults and around 10 to 15 interventions every week.
This is not surprising because we are dealing with a smaller population, but we have seen a constant increase in the number of pediatric cases over the last 2 years, even from within the institution.
In fact, I think Hopkins is an ideal place to treat children with cerebrovascular disorders. Since the number of cases nationwide is relatively limited, we need to concentrate them in a few specialized centers, and Hopkins is certainly good to be considered a major one. We have dedicated pediatric neurosurgery, pediatric and neonatal ICUs, pediatric vascular neurology, pediatric anesthesiology, everything to take optimal care of these kids.
What are the most common cases you see?
Dr. Gailloud: In adults, we see basically everything. Cerebral vascular malformations, brain aneurysms and blockage of neck or brain vessels are among the most common conditions we treat. We in fact deal with every possible vascular abnormality of the brain and spinal cord. We also tend to deal with more difficult cases because Hopkins is often considered the last resort for many patients who have been traveling to many places before coming to us.
The distribution of cerebrovascular diseases in children is different. For example, although we do treat them occasionally with detachable microcoils, brain aneurysms are infrequent, while other lesions such as vein of Galen aneurysmal malformations are almost specific to children. AVMs (Arteriovenous Malformations) are among the most common lesions we treat, by embolization with a special liquid agent we call “glue”, sometimes as a definitive cure, but most often as a preparation to either surgery or radiosurgery. We use the same glue for brain arteriovenous fistulas, while arteriovenous fistulas of the dural venous sinuses can be treated, depending on each specific patient, by any combination of glue, detachable coils, and stents. We also treat spinal cord arteriovenous malformations and fistulas, and embolize many vascular tumors to shut down their blood supply, and render the subsequent surgical resection safer.
What is a Vein of Galen Aneurysmal Malformation?
Dr. Gailloud: Vein of Galen Aneurysmal Malformations (we usually just say VGAM) is a disease considered typical of children, but we begin to see it more often in adults as a result of the wider availability of noninvasive brain imaging techniques such as MRI. Today, if you have a persistent headache, your doctor will order an MRI, and most of the adult cases of Vein of Galen Aneurysmal Malformation we see are discovered during such MRI studies. We call these incidental findings, because they are most often not the cause of the symptoms that led to the MRI request.
The symptomatic form of Vein of Galen Aneurysmal Malformation is seen almost only in children. These lesions can present in many ways, but the most dramatic ones are involving newborn babies with large and complex arteriovenous fistulas (a fistula is an abnormal connection between an artery and a vein). Many of these lesions are now detected by prenatal ultrasonography. Once detected, we can better characterize them with fetal MRI (that is, MRI of the baby while still in his mother’s womb), and have them followed by a specialized high-risk pregnancy unit. This way, we are ready to intervene as soon as the baby needs it, sometimes immediately after delivery.
These babies usually come to life with major cardiovascular problems. They have to pump so much blood into their heads to feed their vascular malformation that the heart cannot follow. This quickly results in severe cardiac and respiratory issues, which in the past most often resulted in death from cardiorespiratory distress. When the cardiovascular problems are lighter, we face the risk of delayed diagnosis, with children suffering from seizures and mental retardation.
How do you treat Vein of Galen Aneurysmal Malformations?
Dr. Gailloud: Because these babies are born in a lot of distress, treatment must in most cases be offered emergently. Usually, there are numerous connections feeding the fistula, so we close just a few of them in order to keep the vital functions of the baby stable, helping the heart and the respiratory function, and keep them going as long as we can with minimum intervention. We are of course ready to go back and close more connections on an “as needed basis”. This approach, which requires a close relationship with the neonatal ICU and pediatric anesthesiology teams, proves very rewarding in terms of outcome. Sometimes it is all these babies need. They go through, the fistula shrinks, and they go on developing normally. Unfortunately, there are still babies born with such devastating brain or cardiac damage that they are beyond therapeutic reaches.
If closing a few arteriovenous connections is not sufficient, for example if there is a bigger malformation that persists or even enlarges, we perform a new intervention around the fifth month of life, this time aiming towards definitive treatment. It is still important, however, to proceed carefully. By this, I mean that trying to close too many connections in a single procedure may result in a rapid redistribution of the blood flow, which may cause hemorrhages in the brain tissue surrounding the vascular malformation. This is why we usually like to stage the treatment by performing several procedures separated by a 5 to 6-week intervals. We use the same approach for the treatment of children who present later in life, for example, when they are investigated for seizures or developmental delay.
Do you have an estimate of how many children are born with a Vein of Galen Aneurysmal Malformation?
Well, it is difficult to obtain precise numbers with an infrequent disorder. Some babies who die before or immediately after they are born from the cardiorespiratory distress are probably not diagnosed. It is estimated that the Vein of Galen Aneurysmal Malformation represents a third of the vascular malformations in children.
If the disease is detected in uterus, will the future bring a treatment in uterus?
Dr. Gailloud: We need to use the baby’s vascular system to get to the lesion, and the blood vessels of the fetus are well protected by the mother through the placenta. I am not saying it is not possible, it is a challenge that may be addressed in the future.
Do you think that a neuroradiologist should see the ultrasounds to detect this kind of malformation?
Dr. Gailloud: The ultrasonographic diagnosis of most Vein of Galen Aneurysmal Malformations is relatively straightforward for an experienced sonographer. It is important to emphasize how crucial the ultrasound of the 3rd trimester is. Any doctor who diagnoses one of these malformations should know that there are a few centers in the country that are very well equipped to monitor the pregnancy and have the ability to treat the baby immediately after birth.
That’s the way we do it at Hopkins. When a mother is carrying a baby known to have a Vein of Galen Aneurysmal Malformation, she is closely followed all the way through by our High Risk Pregnancy Unit, and our team is available on a 24-hour basis to treat the baby if an emergent procedure is needed.
Do you “help” other specialties get their work done?
Dr. Gailloud: We certainly do. We obviously work very closely with the Departments of Neurological Surgery, Neurology and Pediatrics concerning all aspects of pediatric cerebrovascular disorders. We also have a close relation with the Department of Otolaryngology-Head & Neck Surgery to treat children with vascular tumors of the nasal fossa and skull base. In spite of being most often benign, these tumors are highly vascularized and represent significant therapeutic challenges. We can prepare a safer surgery by closing feeding arteries prior to the surgery, thus helping to reduce the loss of blood during the surgical resection. We work in a similar way with the Department of Orthopedic Surgery, embolizing vascular tumors of the spine before surgery.
One of the main new developments in the near future lies in the recognition of pediatric stroke. It has been assumed for a long time that stroke was exceptional in children. When kids come with a stroke, they are often marginalized, and lose the possibility of being treated with the tools that are available and used for adults. We have now at Hopkins a pediatric neurologist (Lori Jordan, MD) sub specializing in the field of pediatric stroke.
Do children have strokes?
Dr. Gailloud: Contrary to what is often assumed, stroke involves a fair number of children and, as with adults, you only have a limited time to try to fix it. There is a disorder called Moyamoya, for instance, that typically causes strokes in children. Although it may be associated with sickle cell disease, the origin of this disease remains in most cases unknown, and there is no currently available cure. However, neurosurgical options do exist that have an excellent result on the risk of stroke in these children, such as the extracranial-intracranial bypasses and transplantation of blood vessels from the scalp to the brain performed by Hopkins vascular neurosurgeon Rafael Tamargo. In selected situations, it is also possible to reopen a narrowed intracranial artery by inflating a small balloon inside the diseased segment of the vessel.
Healthy children can also have strokes, for example after a trauma that damaged a main blood vessel. Such damaged blood vessels, if diagnosed and referred quickly enough, can often be fixed before they result in a devastating stroke. Children with abnormalities in their blood coagulation system are also more prone to develop stroke, either from an occluded brain artery, or from more diffuse thrombosis of the cerebral venous system. In both situations, rapid diagnosis can lead to brain-saving endovascular therapy.
As a matter of fact, it is generally not appreciated that arterial strokes (which represents only one half of all strokes) are as frequent in children as brain tumors.
What kind of treatment is used in children?
Dr. Gailloud: Today, it is difficult to understand why the stroke treatments successfully applied to adult patients are only rarely offered to children. An adult patient presenting to the ER within 3 hours of stroke onset and without contraindications can be treated with various intravenous thrombolytics aiming at dissolving the clot and save as much brain tissue as possible. After this 3-hour window, a small microcatheter is advanced into the diseased artery itself, and the thrombolytics are delivered at the contact of the clot. This treatment, called intra-arterial thrombolysis, is used with success in adults. It is at this stage almost never considered in children.
Why not?
Dr. Gailloud: I don’t know. We are prepared to offer this option to parents that bring their child to Hopkins, but I think it is usually not considered in other places around the country because, again, children are marginalized, and doctors don’t really expect to be able to treat a child with a stroke.
I should mention, however, another factor that may play a role: a stroke in an adult can be quickly recognized by symptoms such as numbness, weakness, loss of language, etc. In children, stroke often present as a seizure, and people think “it’s just a seizure”, and miss the window of opportunity for treatment. It is certainly important to increase the public awareness of stroke symptoms and treatment in children.
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