Posts tagged aneurysm

Johns Hopkins researchers, working with mice, say they have identified a chemical compound that reduces the risk of dangerous, potentially stroke-causing blood vessel spasms that often occur after the rupture of a bulging vessel in the brain.

They say their findings offer clues about the biological mechanisms that cause vasospasm, or constriction of blood vessels that reduces oxygen flow to the brain, as well as potential means of treating the serious condition in humans.

When an aneurysm — essentially a blister-like bulge in the wall of a blood vessel — bursts, blood spills into the fluid-filled space that cushions the brain inside the skull. If a patient survives a ruptured aneurysm, between 20 and 40 percent of the time, this brain bleed, called a subarachnoid hemorrhage, will lead to an ischemic stroke within four to 21 days, even when the aneurysm is surgically clipped.

“We’re a long way from applying this to humans, but it’s a good start,” says Johns Hopkins neurosurgery resident Tomas Garzon-Muvdi, M.D., M.Sc., one of the authors of the study led by Rafael J. Tamargo, M.D., and described in the October issue of the journal Neurosurgery.

To conduct their experiments, Garzon-Muvdi and his colleagues took blood from mouse leg arteries and injected it behind their necks to mimic what happens in a subarachnoid hemorrhage. Then they gave the mice a compound called (S)-4-carboxyphenylglycine (S-4-CPG), a placebo or nothing at all. The mice given S-4-CPG developed less vasospasm, looked better and were more active than those in the other two groups.

The scientists also found concentrations of the drug in the brains of the mice, showing that it was able to cross the often impermeable blood-brain barrier. The researchers chose the compound because it is similar to drugs that have been used in stroke research in rodents. It is not approved for any use in humans.

Garzon-Muvdi explains that when blood vessels break anywhere but the brain, the body’s immune cells easily clear the blood cells and their remnants from the area. This is what happens with a bruise, when immune cells rush to the area, and a chemical cascade scavenges and disperses the remnants of excess blood components.

When a blood vessel bursts in the space around the brain, however, the blood is trapped. A subsequent inflammatory response brings key immune system cells into the space, where they secrete the neurotransmitter glutamate outside of the blood vessels where it shouldn’t be, promoting dangerous vasospasm in those blood vessels. This can lead to ischemic stroke, the most common type of stroke, caused by a blockage of a blood vessel in the brain. Death or serious disability may result.

The Johns Hopkins researchers say S-4-CPG keeps glutamate “in check,” prevents or reduces vasospasm and allows oxygen-filled blood to continue flowing into the brain.

According to the National Institutes of Health, subarachnoid hemorrhage caused by a cerebral aneurysm that breaks open occurs in about 40 to 50 out of 100,000 people over age 30. Patients may die immediately, but those who survive are still at elevated risk for developing an ischemic stroke in the days afterward. These patients are often watched very carefully in the intensive care unit for one to two weeks to search for early signs of vasospasm so that doctors can take steps to prevent or limit damage from a stroke.

In the ICU, doctors can order regular angiograms or ultrasounds to measure blood flow in vessels. If need be, they can increase blood pressure to send blood through vessels faster in the hopes of counteracting the constriction.

A drug to prevent stroke after a serious subarachnoid hemorrhage that follows the rupture of an aneurysm would improve quality of life for patients, Garzon-Muvdi says, and could potentially save millions of dollars in health care costs if patients don’t have to endure extensive hospital stays to monitor for a delayed stroke.

(Source: hopkinsmedicine.org)

Subarachnoid haemorrhage (SAH) is one of the most devastating cerebrovascular catastrophes causing death in 40 to 50% of the cases. The most common cause of SAH is a rupture of an intracranial aneurysm. If the aneurysm is found, it can be treated before the possible rupture. However, some intracranial aneurysms will never rupture – the problem is that the doctors don’t know which aneurysms will and which will not. So, they don’t know which patients should be treated and who can safely be left untreated.

(Image: This picture shows: A middle cerebral artery bifurcation aneurysm. Credit: Miikka Korja)

A long-term, population-based Finnish study on SAH, which is based on the FINRISK health examination surveys, and published in PLOS ONE on 9th September, shows that the risk of SAH depends strongly on the combination of certain risk factors. The SAH incidence was shown to vary from 8 up to 171 per 100 000 person-years, depending on whether people had multiple risk factors for SAH – such as smoking, hypertension and female sex – or not.

Such an extreme risk factor -dependent variation in the incidence of any cardiovascular disease is exceptional, and may have significant clinical implications, says one of the main authors, Associate Professor Miikka Korja from the Helsinki University Central Hospital and Australian School of Advanced Medicine.

If smoking women with high systolic blood pressure values have 20 times higher rate of these brain bleeds than never-smoking men with low blood pressure values, it may very well be that these women diagnosed with unruptured intracranial aneurysms should be treated. On the other hand, never-smoking men with low blood pressure values and intracranial aneurysms may not need to be treated at all.

In this largest SAH risk factor study ever, the study group also identified three new risk factors for SAH: previous myocardial infarction, history of stroke in mother, and elevated cholesterol levels in men. The results revise the understanding of the epidemiology of SAH and indicate that the risk factors for SAH appear to be similar to those for other cardiovascular diseases.

We have previously shown that lifestyle risk factors affect significantly the life expectancy of SAH survivors, and now we have shown that the same risk factors also affect dramatically the risk of SAH itself. Thus, it appears quite clear that especially smoking cessation and hypertension treatment are important in preventing SAH and increasing life expectancy after SAH, clarifies one of the study group members, Academy Professor Jaakko Kaprio, from the University of Helsinki and National Institute for Health and Welfare, referring to their previous publication on cause-specific mortality on SAH survivors (Korja et al., Neurology, 2013).

The study group members have previously published also the largest twin study to date, confirming that heritability for SAH is very low (Korja et al., Stroke, 2010), and the first study on the incidence of SAH in type 1 diabetes, showing that the rate of non-aneurysmal SAHs in type 1 diabetes is unusually high (Korja et al., Diabetes Care, 2013).

Many of the previous studies on the epidemiology of SAH have relied on retrospective and single-center databases, which are unfortunately not very reliable data sources. Due to the unique health care system and common academic interest among doctors in Nordic countries, it has been possible to conduct high-quality and unbiased studies on SAH. We hope that our studies truly help doctors and patients, and are not only of interest in coffee tables on university campuses, says neurosurgeon Korja, and rushes to continue his working day in the operation room in Macquarie University Hospital, Sydney, which is one of his current appointments.

(Source: eurekalert.org)

A multi-center study supports the effectiveness of the newest technology available for the treatment of difficult, life-threatening brain aneurysms. The technology, the Pipeline embolization device, is a flow diverter that redirects blood flow away from wide-necked or giant aneurysms that cannot be treated in more conventional ways.

Andrew Ringer, MD, director of the division of cerebrovascular surgery and professor of neurosurgery and radiology at the University of Cincinnati (UC) College of Medicine, led the Cincinnati portion of the study, which was published in the December issue of Neurosurgery.

"The study showed that the Pipeline device is a safe and effective tool for patients and surgeons," says Ringer, a Mayfield Clinic neurosurgeon who has treated 11 patients with the device. "This expands our ability to safely treat aneurysms that were very difficult to treat before."

(Source: sciencedaily.com)

June 11, 2012

The younger a woman is when she goes through the menopause, the greater may be her risk of having a brain (cerebral) aneurysm, suggests research published online first in the Journal of NeuroInterventional Surgery.

A cerebral aneurysm refers to an abnormal bulging of one of the arteries in the brain, which is often only discovered when it ruptures, causing a potentially fatal and/or disabling bleed.

Women are more prone to cerebral aneurysms than men. And fluctuations in the female hormone oestrogen have been implicated in the development of aneurysms, the incidence of which, along with cardiovascular disease, rises sharply after menopause.

The authors base their findings on 76 postmenopausal women who had had a cerebral aneurysm, which, in most cases had not ruptured, and who were subsequently quizzed about their medical and reproductive histories.

Conditions, such as high blood pressure, diabetes, high cholesterol and an underactive thyroid gland (hypothyroidism) can all boost the risk of a stroke, while the number of pregnancies and the age at which periods start and stop determine lifetime exposure to oestrogen.

This information was then compared with that taken from more than 4,500 women participants of the 2002 National Institute of Child Health and Human Development Contraceptive and Reproductive Experiences Study, and matched for age and educational attainment.

The average age at which women in both groups had started the menopause was similar, and analysis of the results showed that later menopause and use of hormone replacement therapy (HRT) protected against the risk of a cerebral aneurysm, lessening the risk by 21% and 77%, respectively.

Premature menopause - before the age of 40 - had occurred in one in four (26%) of the women who had had an aneurysm compared with around one in five (19%) of those in the comparison group.

And each successive four year increase in the age at which a woman went through the menopause lessened the likelihood of a cerebral aneurysm by around 21%.

Smoking did not seem to be linked to an increase in risk, while alcohol consumption was of borderline significance.

The outcomes for ruptured cerebral aneurysms are poor, with around one in two people who have one likely to die. One in 10 people die before they reach hospital and of those who survive, one in five is severely disabled, say the authors, so finding a potential marker may help to detect the condition earlier.

"Loss of oestrogen earlier in a woman’s life may contribute to the [development] of cerebral aneurysm," conclude the authors, adding that HRT may protect against this. And they suggest: "These data may identify a risk factor for [the development of this condition] and also a potential target for future therapies."

Provided by British Medical Journal

Source: medicalxpress.com