Authors: Alice Weatherston
New findings from a study carried out at the University of Virginia Health System (VA, USA) and published recently in Stroke, have suggested that the common decision to leave arteriovenous malformations (AVM) untreated in children and young adults may be a mistake.
AVM are the most common cause of strokes in this age group due to the tendency for leaking within the tangles of blood vessels, however due to the risks associated with the Gamma Knife radiosurgery used to treat the condition, it is commonly left untreated.
The new study, which also involved six other medical centers, discovered that the risk of Gamma Knife radiosurgery are in fact outweighed by the increasing risk of leaving the condition untreated, particularly for individuals diagnosed as teenagers or young adults.
The study followed 509 patients for, on average, more than seven years, who had been diagnosed as having AVM but had not suffered a stroke.
“There’s a real uncertainty about the risk of stroke with these AVMs, but the general risk of stroke is thought to be about 1 [percent]to 3 percent per year,” Sheehan commented. “When you factor that in over a 10-year period of time, you are talking about somewhere in the order of 10 to 30 percent risk of stroke, and that’s just the beginning if you’re diagnosed as a pediatric patient or a young adult.”
For teenagers the risk of death following a rupture is also very high, resulting in death in approximately 10% of cases, in addition to the potential for causing other severe neurological effects such as seizures, weakness or blindness.
Gamma Knife radiosurgery represents one of the least invasive treatment options for AVM’s, closing off AVM’s by utilizing fine beams of concentrated gamma rays rather than invasive surgery. The technique can be used for approximately 80% of AVM’s, however it can take 2–3 years for the malformation to close completely, meaning the risk of stroke remains high for some time.
In the study, results indicated that approximately 70% of participants had a ‘favorable outcome’ following the procedure. Of the remaining patients, 4% died, mainly as a result of stroke prior to full closure of the malformation, and 11% experienced side-effects directly related to the treatment, however these were permanent in only 3% of cases.
“These findings strongly suggest that patients who are younger are going to be far more likely to benefit from treatment than people who may be diagnosed later on in their life,” explained neurosurgeon Jason Sheehan (UVA Health System’s Gamma Knife Center). “If patients have at least a 10-year life expectancy, this new study strongly suggests treatment.”
He went on: “If conservative management meant a risk-free approach for these patients, that is what we would recommend to them. Unfortunately, that is not the case for many AVM patients.”