Background Balloon-assisted mechanical angioplasty for cerebral vasospasm following aneurysmal subarachnoid hemorrhage (aSAH) has a number of limitations, including transient occlusion of the spastic blood vessel. Comaneci is an FDA-approved device for temporary coil embolization assistance which has recently also been approved for the treatment of distal symptomatic refractory vasospasm. We aimed to report the feasibility, efficacy and safety of our experience with Comaneci angioplasty for refractory distal vasospasm (up to the second segment of the cerebral arteries) following aSAH.
Methods This is a retrospective analysis of a prospective series of 18 patients included between April 2019 and June 2021 with aSAH and symptomatic vasospasm refractory to medical therapy, who were treated using Comaneci-17-asssisted mechanical distal angioplasty. Immediate angiographic results, procedure-related complications, and clinical outcomes were assessed. Inter-rater reliability of the scores was determined using the intraclass correlation coefficient.
Results Comaneci-assisted distal angioplasty was performed in 18 patients, corresponding to 31 target arteries. All distal anterior segments were easily accessible with the Comaneci-17 device. Vasospasm improvement after Comaneci mechanical angioplasty was seen in 22 distal arteries (71%) (weighted Cohen’s kappa (κw) 0.73, 95% CI 0.69 to 0.93). Vasospasm recurrence occurred in three patients (16.67%) and delayed cerebral infarction in three patients (16.67%), with a mean±SD delay between onset of symptoms and imaging follow-up (MRI/CT) of 32.61±8.93 days (κw 0.98, 95% CI 0.88 to 1).
Conclusion This initial experience suggests that distal mechanical angioplasty performed with the Comaneci-17 device for refractory vasospasm following aSAH seems to be safe, with good feasibility and efficacy.
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Cerebral vasospasm is a frequent and severe complication of aneurysmal subarachnoid hemorrhage (aSAH); it is responsible for significant morbidity and mortality1 and is the most important determinant of delayed cerebral infarction (DCI).2 Cerebral vasospasm is broadly managed with chemical and mechanical angioplasty. Most physicians perform angioplasty with two approaches, alone or combined: (1) proximal mechanical angioplasty (up to the end of the first segment)3 4 or (2) chemical angioplasty with IA vasodilator infusion.5 6
These approaches have been shown to be effective in reducing the severity of arterial narrowing but, to date, they have not been shown to reduce the rates of DCI or clinical outcomes.7 8 As a consequence, mechanical and chemical angioplasties for cerebral vasospasm following aSAH are reported to be supported by weak (Class IIb, Level B) evidence according to the American Heart Association guidelines,9 10 with no update since 2012, prompting the need for new approaches to vasospasm management.
The feasibility of distal balloon angioplasty (up to the end of the second segment of the cerebral arteries) using an extracompliant balloon has recently been reported,11 with data suggesting that distal management is safe and decreases the risk of DCI and the recurrence of vasospasm compared with conventional angioplasty.12
The Comaneci device (Rapid Medical, Yokneam, Israël) was initially designed for aneurysms as a temporary bridging device to perform the remodeling embolization technique. Recently, one feasibility case of distal mechanical angioplasty for cerebral vasospasm has been reported with the Comaneci.
We aimed to report the feasibility, efficacy, and safety of our experience with Comaneci angioplasty for distal vasospasm refractory to medical therapy in patients with aSAH.
We retrospectively searched our prospectively-maintained database to identify all patients admitted to our Comprehensive Stroke Center with aSAH between April 2019 and January 2021 who underwent Comaneci distal angioplasty. The National Institutional Review Board provided approval for the use of patient data for this retrospective analysis. Written informed consent for patient information and images to be published was provided by the patients or a legally authorized representative.
All patients were monitored in the neurovascular intensive care unit for at least 15 days due to aSAH with aneurysms treated by embolization or clipping within 24 hours of admission. Standard intensive care included: (1) primary prevention with 60 mg enteral nimodipine every 4 hours for 21 days or IV if not possible; (2) mean blood pressure goal maintenance between 90 and 100 mmHg with use of pressors if necessary; (3) acute hydrocephalus and other neuroprotective measures according to current guidelines10; and (4) daily transcranial doppler tests.
Inclusion criteria were: (1) modified Fisher grade ≥1; (2) symptomatic distal vasospasm (associated or not with proximal vasospasm); (3) initially suspected clinically (fever, neurological deficit) with ultrasound and confirmed with CT perfusion10; (4) patients underwent CT or MRI imaging within 6 weeks of onset of SAH in order to evaluate whether DCI had occurred.
Distal vasospasm diagnosed by CT perfusion was defined as arterial narrowing involving the arteries, downstream of their first segment (M2, M3, A2, A3, P2), associated with CT perfusion imaging showing a mean transit time of 5.9 s in the corresponding territory.13
Patients who died within the first 4 days after aSAH without distal vasospasm or with distal vasospasm treated using a device other than the Comaneci were excluded.
Comaneci distal angioplasty
All angioplasty procedures were performed using the Comaneci-17 device under general anesthesia and efficient anticoagulation using a single bolus (50 IU/kg) with reversion at the end of the procedure.
Comaneci angioplasty was performed according to a previously reported technique14 using a 0.014-inch Chikai microwire (Asahi Inter, Aichi, Japan). A 0.017-inch Headway microcatheter (Microvention, California, USA) was navigated through a 6F Chaperon guide catheter. The Headway 17 was then navigated over the microwire into the detail target vessel segment and the Comaneci-17 was deployed.
The Comaneci-17 was cautiously and slowly opened under live fluoroscopy. A contrast injection was given when the supposed normal diameter of the artery was obtained and/or when the lateral border of the Comaneci became parallel. The Comaneci-17 was left at that diameter for approximately 30 s after which it was closed.
When a severe stenosis persisted after the first dilation, a second dilation was performed by taking care that the Comaneci diameter did not exceed the supposed normal diameter. Hypoplastic segments were not treated based on pre-vasospasm angio-CT. Segments with obvious collateral supply through the circle of Willis were usually not treated.
According to our local protocol using both types of angioplasty management (mechanical and chemical), after distal mechanical angioplasty a chemical angioplasty was performed using 4 mg in situ milrinone with 2 mg in situ nimodipine slowly injected over 30 min through the guide catheter. Kwon et al 15 reported less recurrence of vasospasm when a vasodilator is injected after the deployment of the stent.
In cases of more than two failed attempts at Comaneci-assisted mechanical distal angioplasty, the procedure was switched to further mechanical angioplasty (eg, balloon angioplasty, more than two attempts at Comaneci deployment), or the procedure was stopped according to the discretion of the neurointerventionalist. In cases of associated proximal vasospasm, a proximal balloon angioplasty was performed using a 4–10 mm Hyperglide balloon (ev3/Covidien, Dublin, Ireland).
All patients underwent CT or MRI within 6 weeks of onset of SAH to evaluate whether DCI had occurred in comparison with the admission imaging.
DCI is defined as any cerebral infarction visualized either (a) on the brain CT and/or MRI within <6 weeks after aSAH, or (b) on the latest CT and/or MRI performed before death within 6 weeks, or (c) proven at autopsy. This cerebral infarction must not be present on the CT and/or MRI 24–48 hours after an early aneurysm occlusion and must not be explained by other causes such as surgical clipping or endovascular treatment.8 16
Efficacy of Comaneci angioplasty
Clinical and imaging data were blindly reviewed by two neuroradiologists, both of whom were independent of the procedures, and had 7 (JFH) and 4 years (LT) of experience.
Using admission diagnostic DSA and/or aneurysm embolization procedure imaging, each distal spastic segment was graded before Comaneci dilatation as none/mild (luminal narrowing ≤25%), moderate (25–50%), severe (50–75%), or very severe (≥75%) vasospasm, according to the diameter of the most spastic point in each segment compared with the normal diameter at admission.
Using angioplasty procedure imaging, two methods were assessed to evaluate stenosis improvement after angioplasty procedures (before any in situ chemical angioplasty):
binary: improvement/no improvement of the stenosis; or
post-Comaneci target point angioplasty diameter compared with admission imaging to evaluate residual stenosis classified as none/mild (luminal narrowing ≤25%), moderate (25–50%), severe (50–75%), or very severe (≥75%).
Safety of Comaneci angioplasty
To evaluate the safety of the procedures, embolism, dissection, perforation, vasospasm worsening, and occlusion of the target artery were assessed using vascular imaging from the angioplasty procedures and on vascular imaging follow-up at 3 months.
Baseline characteristics were explored using descriptive statistics as appropriate for the nature of each variable. Data are presented as absolute numbers (percentage), mean (SD), or median (IQR). Inter-reader reliability was evaluated between the two readers using weighted Cohen’s kappa (κw)17 for: (1) initial distal vasospasm grading; (2) the binary method of evaluating Comaneci efficacy; (3) evaluation of residual stenosis after Comaneci angioplasty; and (4) evaluation of DCI within 6 weeks of onset of SAH. Analysis was performed using RStudio version 1.2.5033 (R Foundation for Statistical Computing, Vienna, Austria), with the use of the Detrended Fluctuation Analysis package.
A total of 182 aneurysms were treated at our center during the study period. Of these, 75 developed symptomatic refractory cerebral vasospasm and 32 were diagnosed as distal refractory cerebral vasospasm. Twenty patients were treated with distal mechanical angioplasty and 18 with the Comaneci-17 device (figure 1). Clinical, imaging and follow-up MRI or CT imaging data were available for all patients.
The baseline characteristics of the population are shown in table 1.
Efficacy of distal Comaneci angioplasty and follow-up
Before any angioplasty procedure and in comparison with baseline imaging (diagnostic DSA before aneurysm clipping or embolization procedure), symptomatic distal vasospasm (n=31) was evaluated as very severe in 16 vessels (51.6%) and as severe in 15 patients (48.4%) (κw=0.876, 95% CI 0.705 to 0.951). No mild or moderate distal vasospasm was seen in this cohort. Proximal vasospasm was seen in 15 patients (83.33%).
Vasospasm improvement after Comaneci mechanical angioplasty was seen in 22 distal arteries (70.97%) (κw=0.73, 95% CI 0.69 to 0.93). Among these cases, one Comaneci deployment was enough for vasospasm improvement in 14 (63.64%) and two Comaneci deployments were needed for vasospasm improvement in six patients (36.36%). Severe stenosis persisted after the first Comaneci dilatation in 14 distal arteries (45.16%). An example of Comaneci-assisted A1–A2 left distal mechanical angioplasty is shown in figure 2 and an example of Comaneci-assisted left M2 angioplasty is shown in figure 3. No Comaneci navigation failures were reported across all of the target distal arteries (n=31).
Table 2 summarizes arterial narrowing before and after mechanical treatment in the 18 patients.
After distal mechanical angioplasty (without in situ chemical angioplasty), residual stenosis was evaluated as very severe for one vessel (3.2%), severe for seven vessels (22.6%), moderate for seven vessels (22.6%), and none/mild for 16 vessels (51.2%) (κw=0.93, 95% CI 0.82 to 0.99). According to our local protocol, all mechanical angioplasties were followed by chemical angioplasty.
Recurrence of vasospasm occurred in three patients (16.67%), with a mean±SD delay of 7±3.46 days after the first vasospasm angioplasty procedure. DCI also occurred in three patients (16.67%), with a mean±SD delay between onset of symptoms and imaging follow-up (MRI/CT) of 32.61±8.93 days, (κw=0.98, 95% CI 0.88 to 1.00). The DCI all occurred in the territories treated without any infarcts already present at the time of mechanical Comaneci distal angioplasty. With a mean±SD last follow-up of 6.17±2.57 months, the mean±SD modified Rankin Scale score was 1.89±2.08.
Safety of distal Comaneci angioplasty
Vasospasm worsening was observed in one (5.56%) of the 18 patients after distal Comaneci angioplasty. Intracranial hemorrhages were not observed during this procedure. However, in one case from this cohort a target distal artery was perforated after one distal balloon angioplasty using an extracompliant remodeling balloon HyperForm 4–7 (ev3, Irvine, California, USA), after two previous Comaneci angioplasty failures. This perforation was supported by coiling, but the patient died 2 days later.
No cerebral embolism, dissection, reperfusion syndrome or occlusion of the target artery was observed when using the Comaneci device. No incidents were reported relating to the distal tip of the device.
In this preliminary study we have demonstrated the efficacy and safety of the Comaneci device for the treatment of distal refractory vasospasm. Vasospasm improvement after Comaneci mechanical angioplasty was seen in 71% of target arteries and no cerebral embolism, dissection, perforation or occlusion of a target artery was observed using the Comaneci device.
One distal artery did rupture when a Comaneci-assisted angioplasty failed and was then converted to an extracompliant balloon remodeling-assisted angioplasty. This serious complication may be explained by too many mechanical angioplasty attempts using different devices, or it may be attributed to the balloon. Stent retrievers exert less radial force against the vessel wall than balloons, which can prevent vessel rupture. On the other hand, balloons can exert an outward radial pressure of up to 300 kPa,18 19 which is greater than that needed to treat a spastic vessel and is orders of magnitude higher than the radial force exerted by a stent. Arterial rupture rates range from 1% to 5% with balloon-assisted angioplasty.20 21 Even if recommendations to prevent rupture often require that balloon expansion during angioplasty is limited to 85% inflation, inflation is very user-dependent and difficult to assess.2
On the one hand, balloon angioplasty in distal and smaller vessels is expectedly associated with a higher rate of arterial rupture when using compliant balloons. On the other, non-compliant balloons can be used to prevent overdilation. Using a non-compliant balloon, Patel et al 22 reported an improvement in angiographic vasospasm (80%) and neurologic function (79%), but these results were associated with a higher rate of recurrence of vasospasm and 18% of the patients required a second treatment. Bhogal et al showed that stent-assisted angioplasty was associated with a lower and self-limiting radial force compared with the use of balloons.19
Our series adds to the one case report previously published14 on the use of the Comaneci device in the Comaneci-assisted angioplasty procedure. Ten days after aSAH the patient developed acute left-sided hemiparesis with proximal and distal vasospasm. A Comaneci-17 device was deployed in the right internal carotid artery terminus, M1, M2, A1, and A2 segments, resulting in improvement in angiographic vasospasm without recurrence of vasospasm the day after. The patient had complete return of neurologic function at last follow-up.
Kwon et al 15 reported stent-assisted proximal mechanical angioplasty following aSAH using an array of devices such as the Solitaire (4×20 mm or 4×30 mm), Trevo (4×20 mm or 6×25 mm), and Revive (4.5×22 mm). Recently, Su et al 23 reported the safety and technical feasibility of the Solitaire (6×40 mm) for mechanical distal angioplasty in patients with distal vasospasm following aSAH. They suggested that, compared with balloon angioplasty, stent retrievers provide a passive self-limiting expansion of blood vessels, with the added possibility of simultaneously injecting IA vasodilators, limiting contact and damage to the vessel wall, and allowing a non-occlusive expansion with technical ease. The Comaneci device is in line with these suggestions as it is the first adjustable remodeling mesh device designed to temporarily support vessels in the brain without occluding blood flow. Since December 2020 the device has received the CE and FDA mark of approval for the expanded indication to treat cerebral vasospasm. To our knowledge, this work reports the largest cohort of Comaneci-assisted distal angioplasty.
More recently, Labeyrie et al 12 reported that distal balloon-assisted mechanical distal angioplasty using a HyperForm 4–7 or a Scepter XC 412 (MicroVention, Tustin, California, USA) was safe and decreased the risk of DCI and the recurrence of vasospasm compared with conventional angioplasty.
According to Sul et al,23 one of the most significant advantages of stent-assisted mechanical distal angioplasty is its ease in reaching distal internal cerebral arteries such as A2 and M2. Balloon angioplasty is limited in terms of its access, which can be confined to proximal large vessels. Thus, balloon access can be technically challenging with tortuosity toward the distal distribution, although it is feasible in experienced hands.24
In their cohort of balloon-assisted angioplasties, Labeyrie et al 12 reported failure of catheterization in 21/187 (11%) because of an excess angulation between the first and second segments of the cerebral arteries. For these segments or for those without distal vasospasm, only proximal balloon angioplasty was performed. Besides, stent-assisted angioplasty is non-occlusive in contrast to balloon angioplasty, allowing continuous blood flow during the period of deployment. It has already been shown that lack of blood flow during balloon-assisted angioplasty contributes to a poor outcome in patients.25 26
We found the Comaneci device easy to maneuver, safe to deploy, and simple to retrieve. As such, according to our experience, Comaneci-assisted mechanical distal angioplasty has several benefits over balloon angioplasty for the treatment of vasospasm.
Limitations of study
This is a limited series involving only 18 patients with 31 distal target arteries from one center. Even when accounting for the number of procedures performed, we lack the power to provide statistical analysis on the clinical benefit and durability of Comaneci-assisted mechanical distal angioplasty. However, this study demonstrates the technical feasibility of Comaneci-assisted mechanical distal angioplasty.
According to our experience, distal severe refractory vasospasm following aSAH performed with the Comaneci-17 seems to be safe, with good feasibility, navigability and efficacy.
Patient consent for publication
This study involves human participants and was approved by Comité d’éthique de la recherche en imagerie médicale - CERIMCRM-2111-211 Vascular emergencies.
Twitter @LouisT, @gboulouis
Contributors LT, XC, J-FH were responsible for the conception of the study. LT, XC, BT, GB, PH, FT, AR, PL, PD-L, J-PS, NG, HB, J-FH collected the data, had full access to data and take responsibility for the accuracy of the data analysis. LT, XC, J-FH drafted the initial version of the manuscript. All authors, contributed to data acquisition, analysis, and interpretation, and revised and approved the final version of the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests XC and J-FH are consultants for educational work with Rapid Medical.
Provenance and peer review Not commissioned; externally peer reviewed.
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