A new study suggests that contrary to popular belief, the actual size of a brain aneurysm has little to do with its risk of rupturing. Instead, researchers believe that smoking is more closely linked to this risk, especially in males.

In a unique study, a team of researchers monitored aneurysm patients over their entire lifetime. They found that nearly one-third of all aneurysms and up to a quarter of all small aneurysms will rupture during a patient’s lifetime, according to the press release. This is more common in female smokers who have aneurysms of 7 millimeters in diameter or larger.

However, in men, although being a smoker also puts them at a higher risk, the size of their aneurysm had little to do with the chances of it rupturing. Those at the lowest risk of rupture are non-smoking males. "This is not to say that aneurysms in non-smoking men never rupture, but that the risk is much lower than we previously thought. This means treating every unruptured aneurysm may be unnecessary if one is discovered in a non-smoking man with low blood pressure," Dr. Seppo Juvela, study researcher, explained in the press release.

Prior studies have only followed patients over the course of one to five years, according to the press release. These much shorter studies had always pointed to the size of the aneurysm as being the most significant risk for rupture. This led to the common practice of leaving larger aneurysms untreated, even though they have been known to also rupture and cause brain hemorrhages. The researchers of this current study believe that past investigations into brain aneurysm have been distorted because there were not enough studies done on the subject. “Now the situation is clearly changing, and clinically reasonable, population-based studies using non-selected data are on the rise again," said Docent Miikka Korja of the HUCS neurosurgery clinic.

A brain aneurysm is a bulge or ballooning in a blood vessel in the brain. According to the Mayo Clinic, when they leak or rupture, bleeding will occur throughout the brain. This bleeding can quickly become life-threatening and require immediate medical attention.

Finland has historically been at the forefront of brain aneurism research and care. The Helsinki University Central Hospital has international recognition for their excellent care of aneurysm patients. The country is also home to some of the most extensive and in-depth brain aneurysm studies.

 

Source: L Korja M, Lehto H, Juvela S. Lifelong Rupture of Intracranial Aneurysms Depends on Risk Factors. Stroke. 2014.