MedWire News: Endovascular treatment of very small intracranial aneurysms is feasible and effective in more than 90% of cases, a meta-analysis of seven published studies suggests.
However, the researchers say that endovascular treatment of these aneurysms “should be pursued very selectively” in view of the substantial rates of morbidity and mortality associated with the procedure.
Guiseppe Lanzino (Mayo Clinic, Rochester, Minnesota, USA) and team investigated the safety and efficacy of coil embolization for the treatment of aneurysms measuring 3 mm or less. These lesions tend to have a benign natural history, particularly if unruptured, and their treatment is therefore controversial.
The meta-analysis included seven studies and a total of 422 aneurysms, 271 of which were ruptured at the time of treatment. Adjunctive techniques, such as balloon- or stent-assisted coiling, were used in one-third of cases.
Overall, 95.3% of aneurysms were completely or nearly occluded at immediate postoperative angiographic follow-up whereas 3.8% had failed occlusion, Lanzino et al report in the journal Stroke.
Occlusion rates were similar for ruptured and unruptured aneurysms, they add.
In terms of safety, the intraprocedural rupture rate was 5.0% in unruptured and 10.7% in ruptured aneurysms, with associated morbidity of 1.2% and 1.8%, respectively, and mortality of 1.2% and 3.1%, respectively.
This “relatively high” rupture rate is explained by the technical challenges associated with treating very small aneurysms, say the authors, for which purpose coils are being placed into very confined spaces.
Mortality due to thromboembolism was 1.3% in unruptured and 2.2% in ruptured aneurysms while early postprocedural hemorrhage occurred in 0.9% and 2.4% of cases, respectively.
Long-term follow-up revealed that 93.5% of aneurysms remained completely or nearly occluded, while 5.4% were retreated through either endovascular treatment or surgical clipping.
The authors conclude: “When treating very small intracranial aneurysms, the risk of treatment has to be balanced against the very benign natural history. This meta-analysis has shown that the risk of treating very small, unruptured intracranial aneurysms is not negligible, as it resulted in a combined morbidity and mortality of 4.6%.
“Studies are under way to ascertain whether treatment of small unruptured aneurysms is better than their benign natural history.”
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