RSNA: Endovascular treatment (EVT) of intracranial aneurysm is effective in preventing long-term bleeding, but may be followed by aneurysm recurrences in a significant proportion of cases, according to a new magnetic resonance angiography (MRA) study published online in the journal Radiology. Intracranial aneurysm is a weak or thin spot in a blood vessel in the brain that balloons and fills with blood. It can leak or rupture, leading to a potentially fatal cerebral hemorrhage.
EVT with coils was developed in the 1990s and became an established
treatment for intracranial aneurysm in the early 2000s. In EVT, coils
are threaded via a micro-catheter through a blood vessel in the groin to
the location of the aneurysm. The coils expand and cause formation of a
clot in the aneurysm that provides a seal, or occlusion, to prevent
The main drawback of endovascular treatment is recanalization, or a
return of blood flow into the original aneurysm. Previous studies on the
clinical significance of this have followed a limited number of
patients for relatively short periods.
For the new study, researchers looked at the long-term efficacy of
EVT in preventing aneurysm ruptures. They performed clinical examination
and 3-Tesla MRA 10 years after EVT of intracranial aneurysm in a single
institution. In addition, they reviewed results from the medical
literature to identify studies reporting bleeding and/or aneurysm
recurrence rate in patients followed beyond 10 years after EVT.
Among 129 aneurysms followed for more than10 years, 16, or 12.4
percent, demonstrated recanalization between midterm and long-term MRA.
Incomplete occlusion on midterm MRA and retreatment within five years
were risk factors for late recurrence. The literature review of 2,902
aneurysms showed that incomplete occlusion and aneurysm size of greater
than 10 millimeters were risk factors for late recurrence.
"This result is of importance since a large proportion of patients in
the study were young, with a mean age of 47 years," said Olivier N.
Naggara, M.D., Ph.D., from the Centre Hospitalier Sainte-Anne in Paris.
"Consequently, demonstration of the efficacy of prevention of rupture
more than 10 years after treatment is a crucial point."
If supported by additional research, the findings may mean that
longer follow-up protocols are necessary for some intracranial aneurysm
patients who undergo EVT.
"We believe that the subgroup of patients with aneurysm size 10
millimeters or more and patients with incomplete occlusions should be
followed by noninvasive imaging exams for 10 years or more, particularly
young patients," Dr. Naggara said.
EVT can be repeated to prevent a potential angiographic recurrence.
However, more research is needed, Dr. Naggara said, to develop a clearer
picture of the risks and benefits of this approach.
"Retreating a recurrent aneurysm with additional coils may fail in up
to 50 percent of cases," he said. "Adjunctive techniques we add to
standard coiling, such as modified coils, stents and flow diverters,
have demonstrated lower recurrence rate after EVT but may involve more
risks than simple treatment with platinum coils."