1Department of Neurosurgery, Iwaki City Medical Center, Japan
2Department of Neurosurgery, Tohoku University Graduate School of Medicine, Japan
Submission: October 30,2019;Published: December 11, 2019
*Corresponding author: Yasuhiro Suzuki Department of Neurosurgery, Iwaki City Medical Center, 16 Kusehara, Mimayamachi, Uchigo, Iwaki, Fukushima 973-8555, Japan
How to cite this article: Masahito K, Yasuhiro S, Yoshimichi S, Keisuke S, Ryo M, Shoji M, Teiji T. Number of Coils for Parent Artery Occlusion of
Ruptured Vertebral Artery Dissecting Aneurysm:Delta Coil Case Series and Literature Review. Open Access J Neurol Neurosurg. 2019; 12(3): 555836.
Background: Parent Artery Occlusion (PAO) by simple coiling for Vertebral Artery Dissection (VAD) sometimes needs a large number of coils, increasing both operative time and medical costs. DELTA coils (Johnson and Johnson, USA) provide a homogenous coil distribution and high packing density due to their triangular shape. They have the potential to decrease the number of coils used in PAO. In this study, we retrospectively investigated the number of coils required for PAO using the simple coiling to treat VAD-induced Subarachnoid Hemorrhage (SAH).
Methods: We analyzed 11 of our own SAH patients who underwent PAO for VAD by simple coiling. A literature search was performed using PubMed and Japan Medical Abstracts Society for VAD, endovascular treatment, and coil.
Results: The mean number of coils used in our hospital was 6.8 (3-10); the mean operative time was 77.8 (49-140) minutes. In the literature review, 20 of the 112 acquired reports stated the number of coils used for PAO by simple coiling for VAD-induced SAH. Of the 33 cases in the 20 reports, the mean number of coils used was 10.4 (3-60).
Conclusion: DELTA coils and their characteristic triangular shape have the possibility to save medical costs by reducing the number of coils used for PAO.
Keywords: Vertebral artery dissection Parent artery occlusion Endovascular treatment Coiling; DELTA coils Medical cost Subarachnoid hemorrhage Minimally invasive surgery
Intracranial Vertebral Artery Dissection (VAD) represents an important cause of ischemic and hemorrhagic stroke, especially in young adults. VAD sometimes causes aneurysms; the intracranial aneurysms associated with VAD frequently rupture and result in massive Subarachnoid Hemorrhage (SAH). These aneurysms tend to rerupture, with a rebleeding rate ranging from 30 to 58% within 24 hours of the initial bleed [1-5]. Therefore, early obliteration of VAD aneurysms should be considered. At present, parent artery occlusion (PAO) viaendovascular procedures is more popular than open surgical treatment for SAH due to VAD-associated aneurysm [4-39].
Endovascular therapy offers clear advantages over open surgical treatment, as it has a dramatically reduced operative time and is minimally invasive . However, PAO by endovascular simple coil embolization sometimes requires multiple coils, up to a total of 60,  increasing operative time and medical costs. Rounded and triangular, DELTA coils (Johnson and Johnson, New Jersey, USA) ring precess and establish natural deflection pointsevery quarter millimeter along the initial coil wind, helping
coils change direction more easily. This technology provides a
more homogenous coil distribution and higher packing density
because of the triangular coil shape, increased length, and
softness . We posited that DELTA coils could reduce the
number of coils used for PAO by the simple coiling technique. We
herein report our case series to analyze the number of coils used
and compare our findings to that described in previous reports.
From our hospital’s medical records, we retrieved the data
for patients with spontaneous VAD-induced SAH from 2009 to
2019. We only included those who had undergone PAO by simple
coiling using DELTA coils for more than 70% of all coils. Data
extracted included age, sex, parent artery diameter, dissection
maximum diameter and length, number and the total length of
coils used, and operative time. Operative time was defined as
the period of time from sheath insertion to sheath removal. We
obtained written informed consent from all patients for their
inclusion in this study; the hospital’s research ethics committee
approved this study.
Diagnosis of SAH and spontaneous VAD was based on
clinical history, the presence of SAH on Computed Tomography
(CT), angiographic findings of dissection including a string sign,
tapered stenosis or occlusion or flame-shaped occlusion, intimal
flap, dissecting aneurysm, distal pouch on CT angiography,
magnetic resonance imaging, and Digital Subtraction
Angiography (DSA). Endovascular procedures for VAD weresimilar in all cases; patients underwent DSA under sedation,
including left and right Vertebral Angiography (VAG). Dissection
maximum diameter and length and parent artery diameter were
evaluated. Coil mass was made as tight and small as possible to
avoid rerupture and thrombotic complication. Operations were
deemed finished when PAO was confirmed.
A comprehensive literature review was performed by
searching PubMed and Japan Medical Abstracts Society with the
keyword’s vertebral artery dissection, endovascular treatment,
and coil. Both and OR combinations were used. Inclusion criteria
were as follows: reports in English or Japanese including case
series and case reports published up to May 2019 with clear,
detailed descriptions of VAD-associated SAH pathological
condition and endovascular treatment. If an article described
cases with other endovascular treatments, such as stentassisted
coil embolization, or with other pathological conditions,
including ischemic or asymptomatic VAD, trauma, malignant
tumor, and extracranial vertebral artery dissection, it was
excluded from the analysis. Conference abstracts, review articles,
and guidelines were also excluded. Four investigators selected
literature independently according to the above inclusion
criteria. The initial selection was based on reviewing titles and
abstracts. For the second selection, investigators reviewed the
full text (where available). Investigators then discussed to find
a consensus on which articles to include. From each article,
the following clinical information was extracted: age, sex, and
number and the total length of coils used. We compared these
results to those from our hospital.
From our medical records, we retrieved the data from 11
patients with VAD-induced SAH. These patients had undergone
PAO by simple coiling; DELTA coils made up more than 70%
of the total coils. The mean utilization rate of DELTA coils was90% (ranging from 72% to 100%). Overall, four men and seven
women were included, and the mean values are summarized in
Table 1. The mean number of coils used was 6.8 (3-10); their
mean total length was 72.6 (43-114) centimeters. The mean
operative time was 77.8 (49-140) minutes. One patient had
symptomatic cerebellar infarcts as a perioperative complication;
another had postoperative takotsubo cardiomyopathy. Except for
three patients whose Hunt and Kosnik grade was V and who died
of primary brain injury due to severe SAH, the mean observation
period was 57.5 (1-103) months. No patients had recanalization
A 54-year-old woman presented to our hospital with a
sudden headache and repetitive vomiting. She had a mild
disturbance of consciousness (Figure 1). CT showed massive
SAH in front of the brainstem (Figure 1A). CT angiography
revealed left VAD aneurysm (Figure 1B, arrowhead). We
diagnosed her with SAH (Hunt and Kosnik grade II) due to left
VAD aneurysm rupture. Under general anesthesia, we performed
DSA to evaluate the left VAD aneurysm. The aneurysm had a
7.35-millimeter maximum diameter and was 20.0 millimeters
in length (Figure 1C, arrowhead). The parent artery was 2.73
millimeters in diameter. We decided to perform PAO to prevent
rerupture and to make the coil mass as tight as possible. Through
a six French guiding catheter (Fubuki, Asahi Intecc, Aichi, Japan)
from the right femoral artery, an SL-10 microcatheter (Boston
Scientific, CA, USA) was advanced over a micro guidewire (Chikai
14, Asahi Intecc, Aichi, Japan) and positioned in the distal part of
the dilated portion. Two Presidio 10 coils (Johnson and Johnson,
New Jersey, USA) were advanced and successfully detached.
Five DELTA coils were deployed to occlude the proximal portion
of the lesion (Figure 1D, arrowhead). Postoperative right
VAG showed occlusion of the left vertebral artery (Figure 1E,
arrowhead). Postoperative magnetic resonance imaging did not
show any infarcts in the posterior circulation territory (Figure
1F). The patient was discharged on the 18th postoperative day
without any neurological deficits and has lived independently
PubMed yielded 368 studies, Japan Medical Abstracts 110.
After excluding duplicate studies by reviewing the title, abstracts
were screened. Those that failed to meet the inclusion criteria
were removed; 160 articles remained. Of those, we acquired
112 reports with full text. Of the 112, 20 studies described
the number of coils used and so were eligible for inclusion in
the present study [2,3,6-8,14-21,27,32-35,38]. We performed
a systematic review using the 20 studies, which comprised 33
cases. Overall, 17 men and 15 women (one patient’s sex was
unknown) were included, with a mean age of 51 (33-77) years.
The mean number of coils used was 10.4 (3-60); their mean
total length was 50.8 (20-130) centimeters (Table 2). We did not
know what coil types were used or the operative time.
Open surgical intervention, consisting of proximal ligation of
the dissected vessel and clipping or wrapping of the aneurysm, is
the traditional VAD treatment [5,12]. However, these procedures
need extended operative times and microsurgical techniques
. Consequently, alternative endovascular procedures
have become more popular [4,12,28,31,39,40]. Economic
comparisons between endovascular coiling and clipping for
intracranial aneurysms have been performed [26,37,41]. but
these do not yet exist for VAD. Solitary stenting and stentassisted
coil embolization for ruptured VAD aneurysms reduce
the number of coils and preserve blood flow. However, solitary stenting and stent-assisted coil embolization sometimes result
in rerupture, recanalization, or aneurysm recurrence
. Antithrombotic medications are also generally required
due to the thrombogenicity of a stent, contributing to delayed
aneurysm thrombosis and the possibility of rerupture. In some
cases, sacrificing parent artery flow via the simple coiling
technique is preferable in order to guarantee the prevention
of fatal rebleeding. Therefore, discussion on PAO by the simple
coiling technique is both relevant and valuable.
New hydrogel  or fibered coils  that favor early
thrombosis contribute to a reduction in the total number of coils
required for artery occlusion. However, PAO with hydrogel and
fibred coils for VAD has not got consensus to reduce coil numbers.
Another alternative, a vascular plug, has been developed toreduce the number of coils and costs. The Amplatzer vascular
plug (Abbott, Illinois, USA) is composed of an expandable
nitinol wire mesh and acts as focal coil and embolic material
immobilizer. However, it is porous, so additional coils  or
several plugs  are needed for complete PAO. Therefore, PAO
using the simple coiling technique still has relevance despite the
rise of new technologies.
Tight packing is necessary to avoid recanalization due to
incomplete thrombosis and ischemic complications resulting
from flow obstruction of the many vertebral artery perforating
branches . Coils for neuro-endovascular surgery cost
approximately 144,000 JPY per unit as of 2019. As such, it is
desirable to use as few coils as possible. Furthermore, using
many coils requires a long operative time. Longer operative times
mean patients and medical staff are exposed to more radiation
. Therefore, tight packing and reduced coil numbers are
crucial to avoid ischemic complication, save medical costs, and
shorten the operative time. In our review, several case reports
and case series described the numbers of coils used, but they
did not go into detail. Only Grigoryan reported PAO for nonhemorrhagic
VAD using a single oversized coil as well as the
safety, speed, and cost .
Therefore, our case series is one of the few studies highlighting
the number of coils used in PAO for VAD. It is also the first report
comparing different case and study coil numbers. Of the 160
reports found on PubMed and Japan Medical Abstracts Society
discussing PAO for VAD-induced SAH by the simple coiling
technique, only 20 described the number of coils used. Although
we could not perform further statistical analysis, the mean
number of coils used in our DELTA coil approach, 6.8, appears
fewer than the 10.4 found in the literature review. We could
not clarify whether the reduction of coil numbers contributes
to the shortening the operative time. The patient of case one
took 140 minutes as the operative time, even though the coil
number was seven. This is because she was well aged, so it was
difficult and took a long time to advance the guiding catheter and
microcatheter due to her severe atherosclerosis. The operative
time depends on various factors, so it was uncertain that DELTA
coils shorten it via the reduction of coil numbers
We only investigated the number of coils used. Other factors,
such as radiographic coil density, morphological evaluation,
and rheological effects during the procedure, were not taken
into account. Whether DELTA coils really reduce coil number is
unknown due to a lack of information regarding coil type in the
reviewed reports and no statistical analysis. Neither could we
analyze operative time since previous reports did not describe it.
Accumulation of additional cases detailing this information and
further comparative study are required
Reducing the number of coils is important in PAO with the
simple coiling technique for VAD-associated SAH. DELTA coils
can pack tightly and necessitate smaller coil numbers, therefore
contributing to lower medical costs.
M Katsuki, Y Suzuki, Y Sato, K Sasaki, R Matsuoka and S
Mashiyama contributed to data acquisition. M Katsuki and Y
Suzuki wrote the manuscript. T Tominaga conceived the study.
All authors have read and approved the final manuscript. We
would like to thank Edit age (www.editage.com) for English
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