Balloon-Assisted Coil Embolization of Intracranial Aneurysms: Incidence, Complications, and Angiography Results

Balloon-Assisted Coil Embolization of Intracranial Aneurysms: Incidence, Complications, and Angiography Results

Sluzewski M, van Rooij WJ, Beute GN, Nijssen PC.
J Neurosurg 2006;105:396–9

Background: Over 10 years, the authors performed coil embolization in a total of 827 intracranial aneurysms. In 71 of these, embolization was performed using the balloon-assisted coil embolization (BACE), whereas in the remaining 756 aneurysms, conventional coil embolization (CE) was applied.

Methods: For both groups, initial occlusion rates, peri-procedural complications and the retreatment rate were recorded.

Results: In the BACE group, significantly more complications leading to death or dependency occurred compared to CE (14.1% vs. 3%). Initial aneurysm occlusion and 6-month control angiography did not differ between both groups, but there was a trend toward a higher retreatment rate in patients treated with BACE.

Conclusion: The authors conclude that “(…) surgical clip application should be considered as a first treatment option in large and wide-necked aneurysms”.

Comment

This is quite a remarkable study. Our own experience and all studies reported in the literature using BACE [1, 2] contradict the high complication rate reported by Sluzewski et al. The authors used noncompliant, stiff balloons (Balt no I, Endeavor, Solstice, Sentry), which were either not intended for neurovascular use or already taken from the market. Since 2003, none of the balloons applied in this series are commercially available any longer. In particular, it is unclear why the authors did not apply new soft and compliant balloons such as the HyperForm (MTI) which has been available in Europe since 2002. This product is specially designed for BACE, CE-marked for neurovascular use, and a substantial improvement in the BACE technique [3]. The authors should state that their high complication rate is based on a series with products which are no longer available and not the technical standard any longer.

Over > 10 years the authors treated 49 aneurysms with BACE which is less than five aneurysms per year. How many numbers are needed to have enough experience with a specific, challenging technique in order to assess to periprocedural complication rate? The authors state that the increased ischemic risk of using a balloon is well known in the literature. However, they do not mention another study reporting no increased incidence of ischemic lesions after BACE on diffusion-weighted MRI [4].

The authors argue that balloon inflation may cause rupture of the aneurysm. This is not substantiated by the data reported in the literature so far [1, 2]. Moreover, they do not mention the potential life-saving effect if a balloon is in place in case of aneurysm rupture: the bleeding can immediately be stopped by inflation of the balloon and the aneurysm can be coiled quickly to prevent rebleeding after deflation of the balloon.

Finally, BACE cannot simply be compared to conventional CE as the aneurysm population is different: while the latter technique is suitable in smaller aneurysms with a defined neck, the first technique is necessary large aneurysms with a wide neck. These aneurysms are a different entity with an inherent higher treatment risk with any technique.

This should be kept in mind even though all data on BACE reported so far did not differ substantially in periprocedural complications from conventional coil embolization [1, 2]. Sluzeswski et al. conclude that “(…) surgical clip application should be considered as a first treatment option in large and wide-necked aneurysms”. In order to substantiate this statement, we would need to have comparative data on the surgical complication rate in these aneurysms. Sluzewski et al. refer to surgical data from the late 1960es and early 1980es. In a recent unselected prospective series of 190 aneurysms operated by one experienced neurosurgeon, the periprocedural rate of hemorrhage and infarction amounted to 17% (33/190). Moreover, there was a 2.6% periprocedural mortality [5]. These numbers would be substantially higher in a population of difficult broad-based and complex aneurysms like in the presented BACE series. Unless numbers are provided to prove a lower complication rate in these aneurysms after surgery, the conclusion by Sluzewski et al. is not acceptable.

References

1. Cottier JP, Pasco A, Gallas S, Gabrillargues J, Cognard C, Drouineau J, Brunereau L, Herbreteau D. Utility of balloon-assisted Guglielmi detachable coiling in the treatment of 49 cerebral aneurysms: a retrospective, multicenter study. AJNR Am J Neuroradiol 2001;22:345–51.
2. Halbach VV, Phatouros CC, Lempert TE, Meyers PM, Dowd CF, Higashida RT. Balloon-assist technique for endovascular coil embolization of geometrically difficult intracranial aneurysms. Neurosurgery 2000; 46:1397–406.
3. Baldi S, Mounayer C, Piotin M, Spelle L, Moret J. Balloon-assisted coil placement in wide-neck bifurcation aneurysms by use of a new, compliant balloon microcatheter. AJNR Am J Neuroradiol 2003;24:1222–5.
4. Albayram S, Selcuk H, Kara B, Bozdaf E, Uzma O, Kocer N and Islak C. Thromboembolic events associated with balloon-assisted coil embolization: evaluation with diffusion-weighted MR imaging. AJNR Am J Neuroradiol 2004;25:1768–77.
5. Lafuente J, Maurice-Williams RS. Ruptured intracranial aneurysms: the outcome of surgical treatment in experienced hands in the period prior to the advent of endovascular coiling. J Neurol Neurosurg Psychiatry 2003;74:1680–4.

(submitted October 25, 2006)

M. Bendszus, Würzburg