SMART coils for intracranial aneurysm embolization: Follow-up outcomes

Technical Success and Early Efficacy in 851 Patients with Saccular Intracranial Aneurysms: A Subset Analysis of SMART, a Prospective, Multicenter Registry Assessing the Embolization of Neurovascular Lesions using the Penumbra SMART COIL System

OBJECTIVE

The Prospective, Multicenter Registry Assessing the Embolization of Neurovascular Lesions Using the Penumbra SMART COIL® System (SMART) is the largest prospective, multicenter, postmarket registry established to gather real-world experience on Penumbra (Alameda, USA) SMART COIL System, PC400, and POD embolization coils. The goal of this study is to report the technical success and efficacy of SMART COIL System coils in treating saccular intracranial aneurysms.

METHODS

This subgroup analysis from the SMART registry included patients with saccular intracranial aneurysms treated using ≥75% SMART COIL System or PC400 coils. Baseline and procedural data, angiographic data, and clinical outcomes were collected. Predictors of catheter kickout, packing density, and postprocedural angiographic outcome were analyzed using multivariable regression models in saccular aneurysm cases.

RESULTS

Between June 2016 and August 2018, the SMART registry enrolled 995 patients at 68 sites, of which 851 of 995 (85.5%) were treated for saccular aneurysms (mean age, 59.9 years). Aneurysms had a mean size of 6.8 mm, were wide neck in 63.1%, and ruptured in 31.0% of patients. Mean aneurysm packing density was 32.3%. Postprocedural Raymond-Roy Occlusion Classification (RROC) I-II was achieved in 80.3% of patients; smaller aneurysms, non-wide-neck aneurysms, and high packing density were predictive of RROC I-II. Overall, mean fluoroscopic time was 43.4 minutes, rate of reaccess attempts because of catheter kickout was 6.2%, and mean procedure time was 83.2 minutes.

CONCLUSIONS

SMART COIL System coils achieved good technical success and adequate occlusion in treating saccular intracranial aneurysms in a real-world setting.

An Efficient Method for Aneurysm Volume Quantification Applicable in Any Shape and Modalities

Objective

Aneurysm volume quantification (AVQ) using the equation of ellipsoid volume is widely used although it is inaccurate. Furthermore, AVQ with 3-dimensional (3D) rendered data has limitations in general use. A novel universal method for AVQ is introduced for any diagnostic modality and application to any shape of aneurysms.

Methods

Relevant AVQ studies published from January 1997 to June 2019 were identified to determine common methods of AVQ. The basic idea is to eliminate the normal artery volume from 3D model with the aneurysm. After Digital Imaging and Communications in Medicine (DICOM) data is converted and exported to stereolithography (STL) file format, the 3D STL model is modified to remove the aneurysm and the volume difference between the 3D model with/without the aneurysm is defined as the aneurysm volume. Fifty randomly selected aneurysms from DICOM database were used to validate the different AVQ methods.

Results

We reviewed and categorized AVQ methods in 121 studies. Approximately 60% used the ellipsoid method, while 24% used the 3D model. For 50 randomly selected aneurysms, volumes were measured using 3D Slicer, RadiAnt, and ellipsoid method. Using 3D Slicer as the reference, the ratios of mean difference to mean volume obtained by RadiAnt and ellipsoid method were -1.21±7.46% and 4.04±30.54%, respectively. The deviations between RadiAnt and 3D Slicer were small despite of aneurysm shapes, but those of ellipsoid method and 3D Slicer were large.

Conclusion

In spite of inaccuracy, ellipsoid method is still mostly used. We propose a novel universal method for AVQ that is valid, low cost, and easy to use.

The SMART Registry: Long-Term Results on the Utility of the Penumbra SMART COIL System for Treatment of Intracranial Aneurysms and Other Malformations

Introduction: Penumbra SMART COIL® (SMART) System is a novel generation embolic coil with varying stiffness. The study purpose was to report real-world usage of the SMART System in patients with intracranial aneurysms (ICA) and non-aneurysm vascular lesions.

Materials and Methods: The SMART Registry is a post-market, prospective, multicenter registry requiring ≥75% Penumbra Coils, including SMART, PC400, and/or POD coils. The primary efficacy endpoint was retreatment rate at 1-year and the primary safety endpoint was the procedural device-related serious adverse event rate.

Results: Between June 2016 and August 2018, 995 patients (mean age 59.6 years, 72.1% female) were enrolled at 68 sites in the U.S. and Canada. Target lesions were intracranial aneurysms in 91.0% of patients; 63.5% were wide-neck and 31.8% were ruptured. Adjunctive devices were used in 55.2% of patients. Mean packing density was 32.3%. Procedural device-related serious adverse events occurred in 2.6% of patients. The rate of immediate post-procedure adequate occlusion was 97.1% in aneurysms and the rate of complete occlusion was 85.2% in non-aneurysms. At 1-year, the retreatment rate was 6.8%, Raymond Roy Occlusion Classification (RROC) I or II was 90.0% for aneurysms, and Modified Rankin Scale (mRS) 0-2 was achieved in 83.1% of all patients. Predictors of 1-year for RROC III or retreatment (incomplete occlusion) were rupture status (P < 0.0001), balloon-assisted coiling (P = 0.0354), aneurysm size (P = 0.0071), and RROC III immediate post-procedure (P = 0.0086) in a model that also included bifurcation aneurysm (P = 0.7788). Predictors of aneurysm retreatment at 1-year was rupture status (P < 0.0001).

Conclusions: Lesions treated with SMART System coils achieved low long-term retreatment rates.

Clinical Trial Registration:https://www.clinicaltrials.gov/, identifier NCT02729740.

Periprocedural safety of saccular aneurysm embolization with the Penumbra SMART Coil System: a SMART registry subset analysis

Background

Using data from the SMART registry, we report on periprocedural safety of the Penumbra SMART Coil System for endovascular coil embolization of saccular intracranial aneurysms.

Methods

The SMART registry was a prospective, multi-center registry of site standard of care endovascular coiling procedures performed using at least 75% Penumbra SMART Coil, PC400, and/or POD coils. This subset analysis reports on the periprocedural safety outcomes of the saccular intracranial aneurysm cohort. Predictors of rupture/re-rupture or perforation (RRP), thromboembolic complications, and device- or procedure-related adverse events (AEs) were determined in univariate and multivariate analysis.

Results

Between June 2016 and August 2018, 851 saccular aneurysm patients (31.0%, 264/851 ruptured) were enrolled across 66 North American centers. Clinically significant (ie, a serious adverse event) RRP occurred in 2.0% (17/851) of cases – 1.9% (5/264) for the ruptured cohort and 2.0% (12/587) for the un-ruptured cohort. Clinically significant thromboembolic events occurred in 3.1% (26/851) of cases – 5.3% (14/264) for the ruptured cohort and 2.0% (12/587) for the un-ruptured cohort. Multivariate predictors of periprocedural RRP were increased packing density and adjunctive treatment with a balloon. For periprocedural thromboembolic events, multivariate predictors were bifurcation location and ruptured status. For device- or procedure-related AEs, multivariate predictors were bifurcation location and adjunctive treatment with stent or balloon.

Conclusion

The low rates of thromboembolic complications and RRP events demonstrate the adequate safety profile of the SMART Coil System to treat cerebral aneurysms in routine clinical practice.

Trial registration number

NCT02729740.

Long-term follow-up results of the SMART coil in the endovascular treatment of intracranial aneurysms

BACKGROUND

The Penumbra SMART coil is a novel device that becomes progressively softer from its distal to proximal end to maximize coil packing and prevent microcatheter prolapse or coil migration. Here, we report a large series of patients detailing the long-term experience of a single institution using the SMART coil among patients with intracranial aneurysms (IAs).

METHODS

Prospective data of 105 consecutive patients with 106 IAs treated using SMART coils was collected between March 2015 and July 2018. Clinical and angiographic data were analyzed.

RESULTS

Forty-nine patients (46.7%) presented with subarachnoid hemorrhage and 16 (14.2%) had recurrent aneurysms. Two patients had minor intraprocedural ruptures and remained neurologically stable. One patient had a thromboembolic complication with progressive neurologic decline. There was only one case microcatheter prolapse related to placement of a stent before coiling. An initial post-treatment modified Raymond-Roy Occlusion Classification (mRROC) I or II closure was achieved in 56 (52.8%) aneurysms. The average time to last follow-up was 8.4 months at which 70 (81.4%) aneurysms had mRROC I or II occlusion and a major recurrence was seen in 5 (5.8%) patients. Thirteen (12.3%) aneurysms required re-treatment of which one aneurysm was clipped.

CONCLUSIONS

The Penumbra SMART coil is safe and effective for the endovascular treatment of appropriately selected IAs. Additional studies at multiple centers comparing safety and efficacy profile over long-term periods to other mainstream coils are necessary.

SMART coils for intracranial aneurysm repair - a single center experience

Background

Due to uniform stiffness of standard platinum coils, dense packing of intracranial aneurysms can be difficult to achieve, since stiffer coils can cause microcatheter prolapse or coil migration. SMART coils have a varying softness along the length of the coils to improve deliverability. We report our initial 2 year experience with the SMART coil system, including direct and follow-up results.

Methods

We performed a retrospective study of all patients who underwent coil embolization of an intracranial aneurysm with SMART coils between July 2016 and August 2018 at our institution. We analyzed clinical and angiographic data before and directly after treatment as well as at 6 months follow-up.

Results

A total of 49 patients harboring 49 aneurysms were treated; 23 (47%) were ruptured aneurysms. Most aneurysms (57%) were located in the anterior circulation. Median patient age was 55 (31–88), 63% were female. Mean aneurysm size was: neck 3.4 (±1.5), height 6.3 (±2.9) and width 5.2 (±2.3) mm. SMART coils were solely used in 96% of cases. Initial favorable angiographic results were achieved in 45 (92%) of 49 cases, which were stable at 6 months in 26/29 (90%). Thromboembolic complications occurred in 4 (8%) cases without clinical sequelae; microcatheter prolapse occurred in 1 case. No aneurysm rupture or device malfunction was observed.

Conclusion

The treatment of ruptured and unruptured intracranial aneurysms with SMART Coils was safe and efficacious in our cohort.