Safety and efficacy of Surpass Evolve Flow diverter for intracranial aneurysms: A study of 116 patients

Abstract

Background and purpose

Flow diverter embolization is a recognized method for treating intracranial aneurysms. This study evaluates the safety and efficacy of the Surpass Evolve flow diverter in treating intracranial aneurysm.

Material and methods

From May 2019 to June 2022, our center prospectively enrolled patients presenting with both ruptured and unruptured intracranial aneurysms. We assessed aneurysm occlusion, along with the occurrence of ischemic and hemorrhagic complications, and mortality at 6-months. The 3-month occlusion rate was determined using MR angiography, while the 6-month occlusion rate employed the O’Kelly–Marotta (OKM) grading scale on DSA.

Results

A total of 116 patients with 120 aneurysms received treatment with the Surpass Evolve device. The average aneurysm size was 6.6 mm (range: 2-30 mm). All patients were administered two loading doses of ticagrelor (180 mg) one day before the procedure and 2 h pre-embolization. A procedural complication occurred in one case, involving wire-related perforation of an M3 branch distant from the giant aneurysm; however, this evolved favorably. There were no reported deaths linked to the treatment. Permanent neurological deficits were observed in 3 (2.5%) patients, primarily due to early in-stent thrombosis. MR angiography results at 3 months indicated complete occlusion for 87 out of 115 (75.6%) monitored aneurysms. The 6-month DSA showed neck remnant or complete occlusion (OKM grade C or D) in 86 out of the 107 (80.4%) patients who underwent follow-up.

Conclusion

The Surpass Evolve stands out as a reliable and effective flow diverter for the management of intracranial aneurysms.

Introduction

Intracranial aneurysm is a relatively common condition in the adult population with an overall prevalence estimated as 3.2%. ¹ The risk of subarachnoid hemorrhage due to aneurysm rupture is low, however, if it occurs, the morbidity and mortality are high. ² Therefore, preventive aneurysm treatment is commonly offered to patients with unruptured aneurysm to reduce this risk. Endovascular embolization using flow diverters (FD) has become a cornerstone in the treatment of unruptured intracranial aneurysms, especially those that are large, complex, or have a wide neck. Previous research has validated the safety and efficacy of FDs for such aneurysms.^3–5

Following the Food and Drug Administration (FDA) approval for FDs in humans in 2011, ⁴ technological advances in the device have occurred, broadening the indications for their application. ⁶ Today, even blister-like and distal aneurysms can be addressed safely with FDs.^7,8

Surpass Evolve diverter (Stryker, Neurovascular, Fremont, CA) is a new generation flow diverter which received FDA approval in 2018. It is a 48- or 64-wire self-expanding flow diverter with constant mesh density across diverse vascular anatomy. Notably, its enhanced braid angle and slender wires grant the Surpass Evolve superior flexibility and adaptability over its predecessor, the Surpass Streamline, all while preserving the same radial force. Few studies have assessed the safety and efficacy of Surpass Evolve and found promising results. However, these studies suffered from several shortcomings including small sample sizes, short follow-up periods, and the exclusion of ruptured aneurysms.^9–13

In this study, we present the safety and efficacy results of 116 consecutive patients harboring unruptured or ruptured intracranial aneurysms treated in our center with the Surpass Evolve device.

Methods

Patient population

Between May 2019 and June 2022, we enrolled adult patients with either unruptured or ruptured intracranial aneurysms who underwent endovascular treatment of their aneurysm in a prospective registry. This study included patients with intracranial aneurysm treated using the Surpass Evolve flow diverter. All treatment decisions, made jointly, followed thorough discussions involving interventional neuroradiologists and vascular neurosurgeons. All cases were approved by the ethics board of our institution and all patients gave informed consent before the study.

Surpass Evolve flow diverter

The Surpass Evolve is a cobalt–chromium device, approved for aneurysm embolization in both Europe and the USA, comes in diameters ranging from 2.5 to 5.0 mm and lengths between 12 and 40 mm. It possesses either 48 (for the 2.5 mm diameter) or 64 wires and is delivered through a 0.027-inch microcatheter.

Pre-embolization preparation

Patients with unruptured aneurysms consulted with a neurointerventionist ahead of the procedure to understand the procedure’s benefits and risks and to provide informed consent. These patients received a loading dose of ticagrelor (180 mg, 2 tablets of 90 mg) the day before the procedure and then 2 h before the embolization. Cases involving ruptured aneurysms were discussed among neurointerventionists, vascular neurosurgeons, and neurointensivists to evaluate the embolization risks and benefits using a flow diverter. For such cases, external ventricular drainage was established, and ticagrelor was administered on the procedure day.

Intervention

The endovascular procedure was conducted on a GE Innova biplane angiosuite under general anesthesia (GE Healthcare, Chicago, IL). After achieving femoral access, a 0.088” long sheath was positioned in the cervical segment of the internal carotid or vertebral artery. Utilizing a 5F intermediate catheter, a 0.027” XT-27 microcatheter was advanced past the aneurysm for flow diverter deployment under fluoroscopic guidance using the best working projections (Figure 1). Should adjunctive coiling be necessary, an SL-10 (Stryker) or Echelon 10 (Medtronic) microcatheter was jailed within the aneurysm. In our facility, large aneurysms (typically >15 mm) often undergo coiling to minimize the risk of recanalization and delayed rupture. ¹⁴

Figure 1.

Pre-embolization 2D and 3D imaging of a right carotid-ophthalmic segment saccular aneurysm (white arrow, a, b). High-resolution cone beam CT after Surpass Evolve (4.5 × 20 mm) deployment showing a good wall apposition of the flow diverter (c). Volume rendered 3D DSA images depicting the neck coverage of the flow diverter.

The device's diameter and length selections followed manufacturer guidelines, ensuring at least 4 mm coverage both proximally and distally to the aneurysm neck. Throughout the intervention, patients were administered intravenous heparin (50 UI/kg or 35 UI/kg, operator-dependent) and 250 mg intravenous aspirin post-placement of the long sheath. After deployment of the flow diverter, a high-resolution cone beam CT was performed to assess the positioning and the wall apposition of the device. Post-procedure, patients continued taking ticagrelor (90 mg twice daily) for 3 months and aspirin (160 mg/day) for 1 year.

Study outcomes

All patients underwent neurological evaluations immediately post-procedure, 3–5 h afterward, and daily until discharge. The operating physician documented procedural complications like perforation and wall apposition, with subsequent validation by a second reader. Board-certified neuroradiologists or surgeons gauged functional outcomes at the 3 and 6-months marks using the modified Rankin Scale score during face-to-face consultations. Two independent readers assessed efficacy outcomes at 3 months post-intervention through MRA (3D time of flight) using the Raymond–Roy occlusion classification (RR1, complete occlusion; RR2, residual neck; RR3, residual aneurysm) ¹⁵ and at 6 months via DSA employing the O’Kelly–Marotta (OKM) grading scale for residual intra-aneurysmal flow (A, complete filling; B, incomplete filling; C, neck remnant; D, no filling; 1, no stasis; 2, moderate stasis; 3, significant stasis). ¹⁶ For the study results, we refer to the aneurysm embolization procedure as a case to avoid confusion with a subject.

Results

Aneurysm and patient baseline characteristics

In this study, we included 116 patients who underwent treatment for 120 aneurysms using the Surpass Evolve. The median age was 55 (range: 47–63) years, and the majority (80.2%) were women. Of the included aneurysms, 7 (5.8%) were ruptured, and 113 (94.2%) were unruptured. The internal carotid artery (ICA) was the most prevalent aneurysm location at 76%, trailed by the posterior circulation at 15%, and the anterior communicating artery at 8%. Aneurysms had diameters spanning 2 to 30 mm, with an average size of 6.6 (SD: 4.2) mm and an average neck size of 4.2 (SD: 2.4) mm. Prior treatments, including coiling or other devices were noted in 21.7% of the cases (refer to Table 1). The sizes of Surpass Evolve utilized ranged from 2.5 × 15/20 mm to 5 × 15/40 mm.

Table 1.

Summary of demographics, aneurysms characteristics, and procedure details.

Patient characteristics (N = 116)
Age, median (IQR)	55 (47-63)
Female sex	93 (80.2)
History of ruptured aneurysm	11 (9.2)
Previous ischemic stroke	4 (3.3)
Initial mRS score (n = 105)
• 0	98 (87.5)
• 1	6 (5.4)
• 2	1 (0.9)
• ≥ 3	0 (0)
History of hypertension	27 (23.2)
Smoking	38 (32.7)
Aneurysm features (N = 120)
Clinical presentation
• Ruptured	7 (5.8)
• Unruptured	113 (94.2)
Incidental	79 (65.8)
Sentinel headache	7 (5.8)
Neurovascular compression	3 (2.5)
History of SAH	21 (17.5)
Familial screening	2 (1.7)
Polycystic kidney disease	1 (0.8)
Localization (anterior vs posterior)
• Anterior circulation	102 (85.0)
• Posterior circulation	18 (15.0)
Detailed localization
• Cavernous	8 (6.7)
• Carotido-ophtalmic	40 (33.3)
• ICA (communicating segment)	39 (32.5)
• ICA (other)	4 (3.3)
• MCA	1 (0.8)
• ACom	10 (8.3)
• Basilar	7 (5.8)
• Posterior circulation (other)	11 (9.2)
Aneurysm form
• Saccular	116 (96.7)
• Fusiform	3 (2.5)
• Blister	1 (0.8)
Aneurysm (largest diameter), mean (SD)	6.6 (4.2)
Aneurysm (neck), mean (SD)	4.2 (2.4)
Multiples aneurysms	35 (29.9)
Treatment details
Treatment type
• First endovascular treatment	94 (78.3)
• Retreatment of initial treatment with coils	23 (19.2)
• Retreatment of initial treatment with non-FD stent	2 (1.7)
• Retreatment of initial treatment with WEB	1 (0.8)
Number of FD
• 1	108 (90.0)
• 2	12 (10.0)
Additional material a
• None	109 (90.8)
• Coils	11 (9.2)
• Non-flow diverting stent	12 (10.0)
Aspirin duration (160 mg)
• ≤ 3	2 (1.6)
• 12	115 (96.6)
• 24	1 (0.8)
Ticagrelor duration
• 3	116 (96.7)
• 9	1 (0.8)
• 12	2 (1.7)
Perprocedural GP II2/IIIa antagonist	2 (1.7)
Perprocedural heparin
• 50 UI/kg	102 (85.7)
• 35 UI/kg	17 (14.3)

Data are n (%), mean (SD) or median (IQR).

^aNumbers do not add up as some aneurysms were treated with more than one material.

Efficacy outcomes

In every instance, the deployment of the Surpass Evolve device was feasible in the artery harboring the aneurysm. There were reasons for using two Surpass Evolve devices in 12 (10.0%) cases: (a) inadequate neck coverage (n = 7), (b) poor wall apposition (n = 2), (c) significant vertebrobasilar dissecting aneurysm in the vertebral artery (two devices deployed via a Leo stent, n = 2), and (d) multiple aneurysms in the carotid artery (n = 1). Concurrent coiling was performed in 11 (9.2%) cases.

Optimal wall apposition was evident in all but 12 (10.0%) instances. In these, 2 cases required a second Surpass Evolve device, while 10 cases saw the deployment of a Neuroform Atlas Stent in the proximal third of the Surpass Evolve to achieve optimal expansion (Figure 2).

Figure 2.

A posterior communicating artery aneurysm in a 50-years woman with a history of fatal ruptured brain aneurysm in father. Pre-embolization lateral view of right ICA demonstrating the wide-necked aneurysm (arrow) (a). Lateral view of ICA acquisition during (b) and after (c) deployment of the Surpass Evolve (4 × 17 mm) (arrows). High-resolution cone beam CT after Surpass Evolve Deployment demonstrating a poor wall apposition of the proximal end of the flow diverter (arrow) (d). A Neuroform Atlas stent (dotted arrow: Atlas marker) was used to ensure a good wall apposition of the proximal end of Surpass Evolve (arrow) (e). A single shot acquisition demonstrating the Atlas stent within the proximal end of the Surpass Evolve (f).

Three-month MR angiography data were available for 115 of the 120 (95.8%) cases, revealing complete occlusion (RR 1) in 87 (75.6%) cases. Six-month DSA data was available for 107 of the 120 (89.2%) cases. Complete occlusion (OKM D) was noted in 79 (73.8%) cases, neck remnant (OKM C) in 7 (6.5%) cases, subtotal filling (OKM B) in 20 (18.7%) cases, and total filling (OKM A) in one (0.9%) case (see Table 2).

Table 2.

Outcome and follow-up data.

Complications
Hemorrhagic stroke	1 (0.8)
Focal neurological deficit
• Transient	1 (0)
• Permanent	3 (2.5)
Arterial access pseudoaneurysm	2 (1.7)
Death within 6 months
• Procedure-related	0 (0)
• Not linked to procedure	2 (1.7)
3-months Follow-up
Aneurysm occlusion on MRA (n = 115)
• Complete occlusion	87 (75.6)
• Persistent intrasaccular flow	28 (24.3)
3m mRS (n = 114/116)
• 0	100 (87.7)
• 1	9 (7.9)
• 2	0 (0)
• 3	3 (2.6)
• 4	0 (0)
• 5	1 (0.9)
• 6	1 (0.9)
6-months Follow-up
Aneurysm occlusion on DSA (n = 107)
• No filing (D)	79 (73.8)
• Neck remnant <5% (C)	7 (6.5)
• Subtotal filing 5%–95% (B)	20 (18.7)
• Total filing >95% (A)	1 (0.9)
6 m Intimal hyperplasia (n = 107)	17 (15.9)
• <25% stenosis	14 (13.1)
• 25%–49% stenosis	2 (1.9)
• ≥50% stenosis	1 (0.9)
6 m fish Mouthing	3 (2.8)
6 m mRS (n = 105/116)
• 0	92 (87.6)
• 1	10 (9.5)
• 2	0 (0)
• 3	0 (0)
• 4	0 (0)
• 5	1 (0.9)
• 6	2 (1.9)

Data are n (%).

mRS: modified Rankin Scale.

Functional outcomes

Data for 3-month and 6-month mRS were available for 114 of 116 (98.3%) and 105 of 116 (90.5%) patients, respectively. An mRS score of 0–1 was achieved in 109 of 114 (95.6%) patients at 3 months and in 102 of 105 (97.1%) patients at 6 months (see Table 2).

Safety outcomes

In one instance, a patient with a large saccular ophthalmic aneurysm experienced intraprocedural bleeding during a looping technique. The bleeding, originating from an M3-MCA branch perforation, was halted by loose coiling. This patient exhibited no functional disability after 90 days (mRS 0). Acute focal neurological deficits arose in 4 cases, with 3 being permanent and 1 transient. In-stent thrombosis was a complication during the procedure in one case with a wide-neck communicating artery aneurysm, which was treated with tirofiban administration. In two other cases, in-stent thrombosis occurred post-procedure due to missed ticagrelor doses. The transient neurological deficit, resulting from a missed ticagrelor dose, was resolved without extra intervention.

Arterial access complications involving pseudo-aneurysms occurred in two (1.7%) cases, managed surgically in one and via endovascular stenting in another.

At the 6-month DSA follow-up, endothelial hyperplasia was observed in 17 of the 107 (15.9%) cases. Of these, severe narrowing (greater than 50%) within the stent was found in only one (0.9%) case, addressed with prolonged dual-antiplatelet therapy. All cases were asymptomatic and required no further intervention. “Fish mouthing” was observed in 3 of 107 (2.8%) cases without significant stenosis. One case needed prolonged dual-antiplatelet therapy. None needed endovascular intervention since they remained asymptomatic, and distal cerebral perfusion was unaffected.

Within 6 months, 2 of the 116 (1.7%) patients had passed away and the cause of death was not linked to the Surpass Evolve device. Both had ruptured aneurysms: one with a blister-like aneurysm died at 2.5 months due to multiple organ system failure, while the other succumbed at 3 months from refractory hydrocephalus.

Discussion

In this study, we found that aneurysm embolization using the Surpass Evolve FD is safe and efficacious in treating intracranial aneurysms. Occlusion rates, safety, and functional outcomes were comparable to previous studies on Surpass Evolve and other flow diverters.

Subtotal occlusion (total occlusion or neck remnant) at 6 months was observed in 80.4% in this study. Similar rates were observed in the DIVERSION cohort study of 477 aneurysms (near-complete and complete occlusion in 79.9% at 12 months) ⁵ and in the meta-analysis of 29 studies (complete occlusion in 76% at 6 months). ¹⁷ Prior studies assessing Surpass Evolve found rates of near-complete to complete occlusion on follow-up imaging, ranging between 21/27 (78%) and 31/36 (86%).^9,13

Acute neurological deficit was seen in 4 cases (3.3%), with three instances resulting in permanent deficit, and death within 6 months occurred only in 2 patients (1.7%) (both with ruptured aneurysms) and were not related to the aneurysm embolization device. Previous Surpass Evolve studies reported varying rates of neurological deficit ranging from 0 to 20% (Table 3). In the DIVERSION study, the rate of neurological deficit at 12 months was 2.3%. ⁵

Table 3.

Characteristics of published studies on the use of Surpass Evolve in treatment of intracranial aneurysms.

Study			Aneurysm details			Procedural outcomes		Follow-up data
Author	Study period	Study type	No. aneurysms, no. patients	Mean aneurysm size	Ruptured aneurysms	Acute neurological deficit	Intracranial bleeding	Median follow-up, days	Complete or near-complete occlusion	Any intrastent stenosis	Mortality
Bibi et al.	05/2019 to 06/2022	Monocentric retrospective	120, 116	6.6	7 (6%)	4/116 (3%)	1 (0.8%)	180	86/107 (80%)	17/107 (16%)	2/116 (2%)
Orru et al. 12	04/2019 to 10/2019	Bicentric retrospective	26, 25	11	0	5/25 (20%)	0	120	13/23 (57%) a	NR	0
Mauss et al. 9	05/2019 to 06/2020	Bicentric retrospective	46, 42	7.6	6 (13%)	4 (10%)	0	116	31/36 (86%)	4/34 (12%)	1 (2%) b
Rautio et al. 13	05/2019 to 01/2020	Bicentric retrospective	30, 29	8.5	5 (17%)	0	1 (3%) c	180	21/27 (78%)	11/27 (41%)	3/29 (10%)
Jee et al. 11	06/2019 to 12/2020	Monocentric retrospective	31, 31	18	0	1 (3%)	1 (3%) c	180	11/31 (35%) a	NR	1 (3%)

NR: not reported.

^aonly complete occlusion rate was reported.

^bmortality at discharge.

^cdelayed aneurysmal rupture.

A distinct 10% of the treated aneurysms in this study manifested a proximal FD diverter malapposition, necessitating the employment of an auxiliary device. Techniques varying from the use of an open-cell stent within a FD to balloon-angioplasty have been suggested in literature to enhance FD wall alignment. Our study utilized telescoping stenting with Neuroform Atlas for malapposition rectification, which showed successful outcomes. ¹⁸ Telescoping stent technique using an open-cell stent inside a FD might be a safe and feasible alternative to balloon-angioplasty. The latter technique was associated with a higher risk of recurrence and serious complication.^19,20 In our study, all cases with malapposition undergoing telescoping stenting using Neuroform Atlas were successfully remedied.

Our antiplatelet protocol comprises the combination of aspirin and ticagrelor for 3 months and then aspirin alone for an additional 9 months. Ticagrelor has few advantages over clopidogrel: (1) reversible antiplatelet effect, (2) faster and greater platelet inhibition, (3) low incidence of drug resistance, and was associated with a lower risk of ischemic events and death compared with clopidogrel in the Platelet Inhibition and Patient Outcomes (PLATO) trial for patients with acute coronary syndromes. ²¹ As a result, ticagrelor associated with aspirin has become the first-line antiplatelet regimen for endovascular treatment procedures in our center for several years. ²² Intracranial bleeding and arterial access complications occurred in one (0.8%) and two (1.7%) cases, respectively, in this study. These rates are lower than those reported in the DIVERSION study: 3.7% for intracranial bleeding and 4.9% for noncerebral hemorrhage. ⁵

Intrastent stenosis at 6-month follow-up DSA due to endothelial hyperplasia was seen in 17 (15.9%) cases in our study, however, only one case was >50% in diameter. One study reported a similar rate with the Pipeline Embolization Device (15.8%), however, the rate of severe stenosis (>50%) was lower in our study (0.9% vs 7.9%). ²³ The DIVERSION study reported a rate of 3.5% at 12-month follow-up imaging (mainly assessed on DSA). ⁵ Several factors may partially explain this difference, including the type follow-up imaging modality and time from treatment to follow-up. Difference in antiplatelet therapy regimen between previous studies using the association of aspirin–clopidogrel and our study may have may also contributed to this difference.

We acknowledge several limitations. First, this study is monocentric and retrospective with a relatively small sample size, however, it is the largest study to date reporting outcomes of intracranial aneurysms treated with the Surpass Evolve device. Second, longer follow-up data were not available at this time for all patients. Third, the study lacks a control group and therefore, we were not able to compare the safety and efficacy profile to other FD available on the market.

Conclusion

In this monocentric study of 120 intracranial aneurysms treated with Surpass Evolve with clinical and angiographic follow-ups at 6 months, the safety and efficacy outcomes were satisfactory and comparable to the existing literature on Surpass Evolve and other flow diverters. Studies with longer follow-up are warranted.

ORCID iDs

Nourou Dine Adeniran Bankole https://orcid.org/0000-0002-4277-9767

Fouzi Bala https://orcid.org/0000-0001-6748-2081