Abstract
Background and purpose
In our previous study, we established the utility of 8-F balloon guide catheters for anterior circulation aneurysms. This study aims to assess the efficacy of the proximal flow control method using 8-F balloon guide catheters for coil deployment into the aneurysms as a novel adjunctive technique for aneurysmal coil embolisation along with local balloon neck remodeling, stent assist and double catheter techniques.
Materials and methods
We retrospectively analysed patients who underwent endovascular coiling of anterior circulation aneurysms between August 2013 and December 2017.
Results
Of 206 patients enrolled in this study, the balloon of the guiding catheter was inflated to assist coil deployment in 43 patients (20.9%). In addition, the proximal flow control method found utility in cases with small aneurysms and relatively narrow-necked internal carotid artery. We observed no intraprocedural complications in this study.
Conclusion
This technique enabled secure coil deployment without navigating another microcatheter or balloon catheter around the aneurysms.
Keywords: Adjunctive technique, balloon guiding catheter, coil embolisation, intracranial aneurysms
Introduction
Endovascular coil embolisation is rapidly gaining prominence as a treatment option for intracranial aneurysms. This fast-evolving approach comprises three prominent adjunctive techniques as follows: balloon neck remodeling,1 stent assist,2 and double catheter techniques.3 Previously, we established the efficacy of 8-F balloon guide catheters for proximal flow control in patients with anterior circulation aneurysms.4 The primary objective of this technique was to prepare the proximal balloon for intraprocedural premature rupture, and was used for temporary proximal flow reduction during an unexpected rupture. Despite initially being strategic and used for emergency situations, we serendipitously recognised additional advantages of using an 8-F balloon guide catheter. In addition, proximal flow control was advantageous during the construction of the frame. This study aims to assess the efficacy of the proximal balloon flow control method for endovascular coil embolisation as a novel adjunctive technique.
Methods
In this retrospective study, we enrolled patients who underwent endovascular coil embolisation of anterior circulation aneurysms between August 2013 and December 2017. We obtained data of all the patients from Kariya Toyota General Hospital (Kariya, Aichi, Japan) medical records and all images from the picture archiving and communication system. In addition, we assessed the patients and aneurysmal characteristics.
Endovascular procedure
An 8-F balloon guide catheter (8-F Cello; Medtronic, Minneapolis, MN, USA or 8-F Optimo; Tokai Medical Products, Aichi, Japan) was advanced in the cervical internal carotid artery. The proximal balloon was inflated when the framing coil tended to migrate to the parent artery. After the coil was deployed in an aneurysm, the proximal balloon was deflated, and the framing coil was detached if it appeared to be stable against the revival blood flow. Furthermore, in the case of uncertain stabilisation of the coil, the proximal balloon was retained inflated until the insertion of a few additional coils.
Results
In this study, the mean age of participants was 63.3 ± 14.2 years, and 59 of the 206 patients were men (28.6%). The mean aneurysm size was 6.86 ± 4.7 mm. While 76 patients (36.9%) presented with a subarachnoid haemorrhage, it was coincidently or because of mass effects detected in the remaining patients (63.1%). We successfully navigated the 8-F guiding catheter in all patients and encountered no intraprocedural complications. In 177 patients (85.9%), we used a 4-F intermediary catheter and a microcatheter, except for the local balloon assist, double catheter, and stent assist with a jailing technique.
Table 1 summarises the induction results for each adjunctive technique. In this study, 55.3% of the patients received an uncomplicated coil embolisation, and the proximal flow control method using balloon inflation (20.9%) was the leading adjunctive technique. Table 2 presents the characteristics of the aneurysmal locations. No patient in this study had prior experience of using the proximal flow control method for coiling in the distal anterior cerebral artery, anterior communicating artery, or middle cerebral artery aneurysms. Remarkably, the choroidal segment and ophthalmic artery bifurcation constituted the most common locations wherein the proximal flow control method was used. Table 3 summarises the results of the aneurysmal size and dome: neck ratio of each adjunctive technique. Proximal flow control was used in the small-sized and narrow-necked aneurysms compared with the other adjunctive techniques.
Table 1.
Results of patients for each adjunctive technique.
| Number of patients (%) | |
|---|---|
| Total | 206 |
| Simple coil embolisation | 114 (55.3%) |
| Proximal balloon inflation | 43 (20.9%) |
| Local balloon assist for neck remodeling | 6 (2.9%) |
| Stent assist | 30 (14.6%) |
| Double catheter | 13 (6.3%) |
Table 2.
Aneurysmal locations of whole patients and patients with proximal flow control method.
| Number of patients (%) | |
|---|---|
| Total | 206 |
| Aneurysmal location | |
| Distal anterior cerebral artery | 18 |
| Anterior communicating artery | 35 |
| Middle cerebral artery | 17 |
| Internal carotid artery terminus | 9 |
| Choroidal segment | 16 |
| Posterior communicating artery | 50 |
| Superior hypophyseal artery | 27 |
| Ophthalmic artery | 8 |
| Cavernous segment | 22 |
| Others | 4 |
| Proximal flow control method | 43/206 (20.9%) |
| Aneurysmal location | |
| Distal anterior cerebral artery | 0/18 (0%) |
| Anterior communicating artery | 0/35 (0%) |
| Middle cerebral artery | 0/17 (0%) |
| Internal carotid artery terminus | 1/9 (11.1%) |
| Choroidal segment | 10/16 (62.5%) |
| Posterior communicating artery | 18/50 (36.0%) |
| Superior hypophyseal artery | 7/27 (25.9%) |
| Ophthalmic artery | 5/8 (62.5%) |
| Cavernous segment | 2/22 (9.1%) |
| Others | 0/4 (0%) |
Table 3.
Results of aneurysmal size and dome/neck ratio of each adjunctive technique.
| Mean maximum diameter (mm) | Dome: neck ratio | |
|---|---|---|
| All | 6.86 | 1.82 |
| Simple coil embolisation | 6.78 | 1.99 |
| Proximal balloon inflation | 4.82 | 1.79 |
| Local balloon assist for neck remodeling | 8.04 | 1.66 |
| Stent assist | 9.72 | 1.37 |
| Double catheter | 7.2 | 1.53 |
Discussion
We previously demonstrated the utility of 8-F balloon guide catheters for the proximal flow control method in patients with anterior circulation aneurysms,4 which was organised as an insurance for the proximal temporary clip during surgical clipping. Despite initially being strategic and used for emergency situations, we remarkably detected additional advantages of using an 8-F balloon guiding catheter.
Figures 1–4 show that the balloon guiding catheter in this study was inflated for stabilisation during the deployment of the framing coil. In particular, the proximal flow control method was advantageous during the construction of the frame in patients with internal carotid artery aneurysms (Table 2). In this study, several beginning loops of the framing coil tended to migrate to the distal parent artery as a result of the steady blood flow. In our opinion, a few beginning loops of the first coil were stabilised in the aneurysm under the proximal flow control method, and the following coil loops were also stabilised. Thus some patients do not require the local balloon catheter. Despite some authors reporting that the balloon-assist technique was not associated with increased periprocedural complications,5,6 the navigation of the local balloon catheter occasionally poses risks because the proceeding guidewire has to pass through the aneurysmal neck, which could cause an aneurysmal rupture or a vessel perforation at the distal parent artery and eventually cause thromboembolic complications. We recommend the proximal flow control method before any other adjunctive techniques because this technique is the safest among the four mentioned techniques.
Figure 1.
(a) Preoperative digital subtracted angiography revealing the left internal carotid artery aneurysm. White arrow indicates the anterior choroidal artery. (b) Three-dimensional angiogram showing irregularly shaped aneurysm with blebs.
Figure 2.
A roadmap image showing the migration of several loops of the framing coil to the distal parent vessel (white arrowhead). White arrow, the tip of the microcatheter.
Figure 3.
The proximal balloon (white arrowhead) is inflated to reduce intra-aneurysmal flow and to stabilise the frame.
Figure 4.
Postoperative angiography showing complete obliteration of the blebs.
The results of this study established the utility of the proximal flow control method for small-sized and narrow-necked internal carotid artery aneurysms. Although the other three adjunctive techniques were preferred for large-sized and broad-necked aneurysms, the proximal flow control method proved to be the primary choice. The microcatheter remains free during the proximal flow control method compared with using an independent balloon catheter. Therefore, the microcatheter can be controlled with delicate handling by the operator.
Nevertheless, the proximal flow control method during coil embolisation and this study have certain limitations. First, this is a retrospective study conducted at a single centre with a small sample size. Hence, further worldwide accumulation of data is imperative to validate this method. Second, Nguyen et al.7 reported that the incidence of balloon guide catheter-related ischaemic events was higher in patients with acute ischaemic stroke compared with those treated using the conventional guiding catheter. However, no significant complications were observed in this study. Additional anticoagulation therapy for proximal balloon occlusion may affect haemorrhagic complications during the procedures. Third, as stated above, the balloon-assist technique has established the utility and efficacy of coil embolisation. Therefore, the proximal flow control method should only be performed when the balloon-assist technique poses complications such as tortuous parent vessels. Finally, this method requires a more extensive calibre arterial sheath than the conventional approach. Thus careful and secure haemostasis of the puncture site is required.
Conclusions
This study establishes the efficacy of the proximal flow control method in cases of small-sized and relatively narrow-necked internal carotid artery aneurysms. In addition, we recommend this method as the safest adjunctive technique among local balloon neck remodeling, stent assist coiling and double catheter techniques. Nevertheless, some of the limitations of this method need to be addressed to enhance its efficacy.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
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