Study suggests added benefits from proactive treatment of certain unruptured brain aneurysms

July 10, 2003

CHICAGO -- July 10, 2003 -- Data from the International Study of Unruptured Intracranial Aneurysms (ISUIA), published today in The Lancet, provided substantial new evidence showing that aneurysm size, location and a previous history of a ruptured aneurysm are the best predictors of future aneurysmal ruptures. These data provides physicians with new insight regarding the risk-benefit of aneurysm repair versus conservative treatment, such as monitoring the aneurysm and observation of the patient.

"The ISUIA data regarding aneurysm size, location and patient characteristics will help physicians more accurately determine which patients will benefit from proactive treatment," said Charles M. Strother, M.D., president of the American Society of Neuroradiology. "In particular, the data revealed that even smaller aneurysms than previously thought may warrant treatment."

An aneurysm is an area of weakness in a blood vessel, which usually enlarges over time. When a brain aneurysm ruptures, blood flows into the space surrounding the brain (the subarachnoid space), resulting in a subarachnoid hemorrhage (SAH), the deadliest form of stroke. SAH affects approximately 35,000 individuals each year in the U.S. About 50 percent of patients with ruptured brain aneurysms will die within the first 30 days. Of those that survive, about half will suffer from severe neurological injury. It is estimated that up to 17 million people have or will develop unruptured aneurysms.

The primary objective of the ISUIA study was to establish better patient management protocols by better defining the natural history of UIAs and determining which aneurysms are best suited for medical intervention (or repair) versus conservative treatment, and by identifying whether there are any morbidity or mortality differences between surgical clipping (open brain surgery) and minimally invasive endovascular procedures such as coiling.

The ISUIA data also showed that patients with multiple unruptured aneurysms and a previous history of rupture from a separate aneurysm were at greater risk for a second hemorrhage. Some of these individuals may benefit from interventional treatment of even smaller aneurysms depending on their location.

Aneurysms that were repaired during the ISUIA study were either treated surgically or endovascularly. The surgical procedure, called neurosurgical clipping, involved performing a craniotomy (removing a section of the skull) and placing a surgical clip at the neck of the aneurysm. Endovascular treatment, a minimally invasive procedure most commonly performed by interventional neuroradiologists, involves filling (occluding) the aneurysm with detachable platinum coils (such as the Guglielmi Detachable Coil by Target Therapeutics/Boston Scientific Corporation). The coiling procedure entails inserting a catheter into an artery in the patient's leg and navigating it through the vascular system under X-ray guidance, into the head and into the aneurysm. Tiny platinum coils are then threaded through the catheter and deployed into the aneurysm, obstructing blood flow into the aneurysm to prevent rupture.

The study conveyed that outcomes of endovascular treatment appeared to be less affected by factors such as patient age, previous brain hemorrhage and aneurysmal symptoms other than rupture, suggesting additional advantages for patients with these characteristics when compared to open brain surgery. Disability and death rates following endovascular treatment were lower than those for surgery at both one month (9.1% endovascular versus 13.2% surgical) and one year (9.5% endovascular versus 12.2% surgical). The study states that the benefits achieved via endovascular treatment may be even greater than the numbers imply since the endovascular patient group was comprised of older patients.

"Endovascular treatment such as 'coiling' resulted in less death and disability, despite the fact that the endovascular patient group was older and had more extenuating risk factors," explained Charles M. Strother, M.D., president of the American Society of Neuroradiology. "Further, since endovascular treatment is minimally invasive, patients typically experience less overall risk, less pain and shorter recovery times. These are very promising results that add to the accumulating data regarding the benefits of endovascular treatment as compared to open surgical clipping. It is important to continue monitoring these patients to evaluate long-term success as well."

The lifetime healthcare cost of UIA patients in the U.S. is estimated at $522 million annually. When a SAH occurs, the lifetime healthcare costs of patients rise to approximately $1.8 billion each year, according to an article published in The New England Journal of Medicine .

Advances in neuroradiology and medical imaging technology, such as computed tomographic angiography (CTA), computed tomography (CT) and magnetic resonance imaging (MRI), are minimally invasive and highly sensitive imaging techniques that are vital for the detection of intracranial aneurysms. With images generated by these methods, neuroradiologists can assess aneurysms based on the risk factors reported in the ISUIA trial results to determine the potential for aneurysm rupture. These techniques not only enhance accurate detection of brain aneurysms but also provide the information necessary for making the most informed treatment recommendations.

"The data from the ISUIA trial emphasizes the complexity and multifactorial nature of aneurysm development and treatment, and how certain patient subgroups may benefit from referrals to physicians specializing in diagnostic and interventional neuroradiology," added Dr. Strother.
About the American Society of Neuroradiology

The American Society of Neuroradiology (ASNR) is a professional membership society comprised of physicians specializing in the diagnostic radiology of diseases of the central nervous system, brain, head and neck, through the use of x-ray, MRI, CT and angiography. It is practiced in hospital settings, academic/educational institutions, and private practice.

Neuroradiology is an increasingly integral part of the accurate diagnosis and enhanced treatment of stroke, aneurysms, vulnerable plaque, and other disorders. Additionally neuroradiologists are at the forefront of applying advanced radiological techniques, such as fMRI, to research how the brain functions. The ASNR was founded in 1962 and is headquartered in Oak Brook, Illinois. The ASNR publishes the American Journal of Neuroradiology (AJNR), a monthly medical journal, as well as promotes education and research in neuroradiology through support of the Neuroradiology Education and Research Foundation (NER), which provides funding for investigators and research in neuroradiology.

On the Net: ASNR's site:

About the International Study of Unruptured Intracranial Aneurysms (ISUIA)

ISUIA is the world's first study of the natural history/development of unruptured intracranial aneurysms (UIAs) to include prospective (forward-looking) data along with retrospective data (historical). The study's dual design allows for the assessment of follow-up data from the retrospective observations, and the verification of results using the prospective data and vice versa. The ISUIA was approved and supported by the National Institute of Neurologic Disorders and Stroke, National Institute of Health and has to date enrolled 4,060 patients in the prospective arm and 1,449 patients in the retrospective arm at 61 centers in the United States, Canada and Europe. Retrospective data collection dates from 1970 - 1991, with prospective data entered from 1991 - 1997, with follow-up from 1991 - 1998. ISUIA will be continuing the process of analyzing data and releasing findings.

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