Hydrogel Coils Research Articles

Deconstructive vs. reconstructive endovascular treatment paradigms in acute carotid blowout.

Carotid Blowout (CBO), a neuro-oncological emergency characterized by the rupture of the carotid artery, has been predominantly reported in patients with head and neck cancer who have undergone radiation therapy. In this study, our objective is to share our experience with deconstructive and reconstructive endovascular treatments for CBO. This study includes 17 patients who experienced intractable acute CBO, presenting with ear, oral, or nasal bleeding, between 2003 and 2022. We employed deconstructive embolization using vascular plugs, expanding hydrogel coils, glue, and balloons. If vascular anatomy and pathology permitted, we opted for reconstructive treatment using a covered stent. All patients underwent clini-cal follow-up visits, and we used the modified Rankin Scale to evaluate the clinical success of the procedures. We compared outcomes in terms of complications between the deconstructive and reconstructive treatment methods using the Chi-square test. The patient cohort had an age range of 20-64 years (mean 50.9), including three females (18%) and 14 males (82%). We conducted 15 endovascular procedures on 14 patients during 19 angiography sessions. All 15 treatments achieved immediate hemo-stasis, resulting in complete technical success (p=1.0). Six patients (35%) underwent reconstructive treatments with covered stents in the internal carotid artery, while nine patients (65%) underwent deconstructive embolization in either the external or internal carotid artery. We found no significant association between the treatment paradigms (deconstructive vs. reconstructive) and the development of complications using a Chi-square test of independence X² (2, n=15)=0.07, p=0.79. Recent advancements in endovascular treatments have shown promising results in managing life-threatening acute CBO cases. Our study found no significant difference in outcomes between deconstructive and reconstructive endovascular paradigms in such patients. However, it is important to note that the available data, including ours, is heterogeneous and scarce, necessitating higher levels of evidence to draw more definitive conclusions.

Efficacy and Safety of Different Bioactive Coils in Intracranial Aneurysm Interventional Treatment, a Systematic Review and Bayesian Network Meta-Analysis.

Background: Bioactive coils have been used for nearly 20 years to improve aneurysm treatments. Previous studies are inadequate for comparing the efficacy and safety between different coils. The aim of this study was to investigate the safety and efficacy of different coils by comparing the percentage of people with different modified Raymond scale grades, re-rupture rates, and mortality in patients with intracranial aneurysms embolized with different coils. Method: Randomized controlled trials (RCTs) containing coils for aneurysm interventional treatment were collected from Web of Science, PubMed, and the Cochrane Library up to December 2021. Bayesian network meta-analysis with a randomized or fixed model was performed to compare the efficacy and safety among different bioactive coils and bare platinum coils. Results: We pooled 3362 patients from eight RCTs. No significant differences were found between coils in the proportion of patients with a three-grade classification assessed with the modified Raymond scale immediately after surgery. Hydrogel coils did not show a significant difference in the percentage of patients with a modified Raymond scale grade I postoperatively compared with bare platinum coils (OR, −0.1080; 95% CI, −0.4201–0.2423), but at follow-up, the percentage of patients with modified Raymond scale grade I was significantly higher with hydrogel coils than with bare platinum coils (OR, 0.4957; 95% CI, 0.0060–0.9442). There were no statistical differences between these four coils in terms of aneurysm rupture or re-rupture rate and mortality. Conclusion: Though there was no significant difference in the embolization effect between the several coils in the postoperative period, complete embolization was more likely to be achieved with hydrogel coils compared to bare platinum coils at follow-up. There were no significant differences in safety between the several coil materials.

Low profile visualized intraluminal support stent-assisted Hydrocoil embolization for acutely ruptured wide-necked intracranial aneurysms: A propensity score-matched cohort study

PurposeTo compare the safety and efficacy of low profile visualized intraluminal support (LVIS) stent-assisted hydrogel coil embolization and LVIS stent-assisted bare platinum coil embolization for acutely ruptured wide-necked intracranial. Methods89 patients who underwent LVIS stent-assisted hydrogel coil embolization (hydrogel coil group) and 145 patients who underwent LVIS stent-assisted bare platinum coil embolization (platinum coil group) were retrospectively reviewed after 1:2 propensity score matching (PSM). Procedure-related complications, clinical and angiographic follow-up outcomes were compared between the two groups. ResultsAll baseline characteristics were equivalent between hydrogel coil group and platinum coil group after PSM. There were no statistical differences in immediate postoperative embolization results, clinical and angiographic follow-up outcomes between the two groups (P = 0.514, P = 0.323 and P = 0.949, respectively). Intraprocedural aneurysm rupture, intraprocedural thrombosis and postprocedural thrombosis occurred in 2 patients (2.2%, 2/89), 1 patient (1.1%, 1/89) and 1 patient (1.1%, 1/89) of the hydrogel coil group compared with 1 patient (0.7%, 1/145), 1 patient (0.7%, 1/145) and 2 patients (1.4%, 2/145) of the platinum coil group, respectively (P = 0.559, P = 1.000 and P = 1.000). Nevertheless, the rate of postprocedural aneurysm early rebleeding in the hydrogel coil group was significantly lower than that in the platinum coil group (0.0% vs 4.8%, P = 0.046). ConclusionLVIS stent-assisted hydrogel coil embolization may reduce the risk of aneurysm early rebleeding compared with LVIS stent-assisted bare platinum coil embolization for the treatment of acutely ruptured wide-necked intracranial aneurysms, which implies that hydrogel coil may improve the safety of stent placement for ruptured intracranial aneurysms.

Vascular occlusion with 0.035-inch hydrogel expandable coils in congenital heart diseases and vascular anomalies

BackgroundWe present our experience with transcatheter vascular occlusion using 0.035-inch hydrogel expandable coils, which has been reported only in a few cases in the pediatric cardiology fields. MethodsThis study is a retrospective analysis of all patients who underwent transcatheter embolization with 0.035-inch hydrogel coils at the Department of Pediatrics, Okayama University Hospital, between October 2018 and September 2020. ResultsTwenty patients with a median age of 5.1 years (0.05–26.0 years) and a median weight of 13.8 kg (3.0–56.8 kg) were included. A total of fifty-four 0.035-inch hydrogel coils, including 35 Azur 35 and nineteen Azur CX 35 coils (Terumo, Tokyo, Japan), were successfully deployed in 22 target vessels. The target vessels consisted of 10 aortopulmonary collaterals, 8 veno-venous collaterals, and 4 pulmonary arteriovenous malformations. We achieved technical success in all the target vessels. In total, the mean target vessel diameter was 4.4 mm, the mean number of 0.035-inch hydrogel coils was 2.5 per vessel. The mean device to vessel ratio was 1.6 for the anchor coil and 1.2 for the additional coil. Post-implantation angiograms revealed that the primary occlusion rate was 18/22 (82%). There were no periprocedural complications. ConclusionsThe 0.035-inch hydrogel expandable coils are effective and safe in patients with congenital heart disease and vascular anomalies. These occlusion devices could be valuable options for interventional pediatric cardiologists.

Clinical outcomes of first- and second-generation hydrogel coils compared with bare platinum coils: a systematic literature review.

Endovascular coiling has revolutionized intracranial aneurysm treatment; however, recurrence continues to represent a major limitation. The hydrogel coil was developed to increase packing density and improve neck healing and therefore decrease recurrence rates. In this paper, we review treatment outcomes of first- (1HCs) and second-generation (2HCs) hydrogel coils and compare them to those of bare platinum coils (BPC). A query of multiple databases was performed. Articles with at least 10 aneurysms treated with either 1HC or 2HC were selected for analysis. Collected data included aneurysm size, rupture status, initial occlusion, initial residual neck/aneurysm, packing density, mortality, morbidity, recurrence, and retreatment rates. The primary endpoint was recurrence at final follow-up. Secondary endpoints included residual neck and dome rates as well as procedure-related complications and functional dependence at final follow-up. Studies that compared 1HC to BPC showed significant lower recurrence (24% vs. 30.8%, p = 0.02) and higher packing density (58.5% vs. 24.1%, p < 0.001) in 1HC but no significant difference in initial occlusion rate (p = 0.08). Studies that compared 2HC to BPC showed lower recurrence (6.3% vs. 14.3%, p = 0.007) and retreatment rates (3.4% vs. 7.7%, p = 0.010) as well as higher packing density (36.4% vs. 29.2%, p = 0.002) in 2HC, with similar initial occlusion rate (p = 0.86). The rate of complications was not statistically different between HC (25.5%) and BPC (22.6%, p = 0.06). Based on our review, the 1HC and 2HC achieved higher packing density and lower recurrence rates compared to BPC. The safety profile was similar between both groups.

Comparison of hydrogel coils versus bare platinum coils for the treatment of anterior communicating artery aneurysms.

INTRODUCTION:While endovascular coiling has been shown to be a safe treatment option for intracranial aneurysms, there remains concern regarding increased recurrence and retreatment rates. Preliminary studies evaluating hydrogel coated coils have demonstrated decreased recurrence rates compared to bare metal coils.METHODS:A retrospective chart review was done on all patients with anterior communicating artery aneurysms (ACoAAs) treated with endovascular coiling between 2014 and 2018. Treatment groups were divided into hydrogel coated coils or bare metal coils. Patients were categorized into the hydrogel group when ≥ 70% of the coil length was hydrogel coated.RESULTS:Eighty-four ACoAAs were treated with coil embolization between 2014 and 2018. Postoperative imaging was available for 68 patients. Twenty-six patients were categorized into the hydrogel treatment group. Aneurysm recurrence was seen in 7.7% (2/26) of patients treated with hydrogel coated coils compared to 33.3% (14/42) of those treated with bare metal coils (P = 0.03). Subanalysis of patients with ruptured aneurysms revealed decreased recurrence rates in patients treated with hydrogel coated coils at 5.9% (1/17) compared to patients treated with bare metal coils at 39.4% (13/33) (P = 0.01).CONCLUSIONS:Hydrogel-coated coils may reduce recurrence rates in the treatment of both ruptured and unruptured ACoAAs.

Transduction between magnets and ions.

A time-varying magnetic field generates an electric field in an electrolyte, in which ions move. This magnetoionic transduction is studied here in several arrangements. The electrolyte is a hydrogel containing mobile ions, and is in contact with two metallic electrodes. An alternating electric current applied to a metal coil generates a time-varying magnetic field. In response, ions in the hydrogel move. The two hydrogel/electrode interfaces are non-faradaic and accumulate excess ions of opposite signs, which attract and repel electrons in the two electrodes. When the two electrodes are connected to a voltmeter of internal resistance much larger than that of the hydrogel, an open-circuit voltage is measured, linear in the alternating current applied to the metal coil. A metal coil and a hydrogel coil form an ionotronic transformer, in which an alternating electric current in the metal coil induces an alternating ionic current in the hydrogel coil. Such a transformer can be used for noncontact power transmission, with a voltage high enough to turn on many light-emitting diodes in series. The hydrogel is soft, and readily conforms to a curved surface, such as a glove on a human hand. Motion of the hand can be detected by noncontact magnetoionic transduction.

Quality of Life of Patients with Unruptured Intracranial Aneurysms Before and After Endovascular Coiling: A HEAT Trial Secondary Study and Systematic Review of the Literature

The study of quality of life (QOL) in patients with asymptomatic diseases receiving interventional treatment provides an essential metric for the assessment of procedural benefits in the surgical patient population. In this study, we analyzed QOL data collected from patients with unruptured intracranial aneurysms (UIAs) before and after endovascular coiling in the HEAT Trial, alongside a systematic review on QOL in unruptured brain aneurysms. HEAT was a randomized controlled trial comparing recurrence rates in aneurysms treated with either bare platinum coils or hydrogel coils. Patients enrolled in this trial completed a short form-36 (SF-36) QOL questionnaire before treatment and at the 3- to 12- and 18- to 24-month follow-ups. The change in QOL before and after treatment was assessed. Regression analysis evaluated the effect of select baseline characteristics on QOL change. A total of 270 patients were eligible for analysis. There was an increase in the role physical (P= 0.043), vitality (P= 0.022), and emotional well-being (P < 0.001) QOL components at the 18- to 24-month follow-up compared with baseline scores. Regression analysis showed that age younger than 60 and absence of serious adverse events were associated with improved social functioning and vitality. The literature review showed a mixed effect of intervention on QOL in patients with UIAs. Our analysis has revealed that patients with 3- to 14-mm UIAs had improvements in some physical and emotional components of QOL at 18-24 months following aneurysm coiling in the HEAT study. The literature remains indeterminate on this issue. Further studies are needed to better understand the effects of the diagnosis of UIAs and their treatment on QOL.

Development of annulus fibrosus tissue construct with hydrogel coils containing pre-conditioned mesenchymal stem cell

Low back pain associated with degenerative disc diseases has been a major health concern that brings suffering to the patients physically and economically. Many existing therapeutic strategies provide short-term relief of symptoms rather than treatment of the underlying cause. Development of an engineered tissue for disc regeneration is still in its infancy due to the limited autologous healthy disc cell source from the patients. It is also challenging to mimic the complexity of micro-architecture in the native disc tissue that determine their unique structural properties. To date, simple tissue models that mimic the annulus fibrosus (AF) micro-environment for understanding the potential of mesenchymal stem cells (MSCs) in AF tissue engineering are still lacking. In this study, the assembly of a coiled hydrogel microfiber has shown its capability to encapsulate MSCs and create an engineered tissue model that mimics the multiple lamellae of native AF. Using this model, we investigated the potential of MSCs that were previously induced by ascorbic acid (AA). Compared to non-induced MSCs, AA-induced MSCs exhibited significant increase in AF-associated biomarkers during later development in the engineered AF tissue model and also encouraged collagen accumulation through the down-regulated catabolic gene MMP1 and upregulated anti-catabolic gene TIMP1. Furthermore, AA-induced MSCs exhibited a Col2/Col1 ratio closer to that of a native AF tissue. These results suggested that AA-induced MSCs could be a potential cell source for AF tissue engineering and this established tissue model may provide a simple tool for successful AF tissue engineering strategies in the future.

The Hydrogel Endovascular Aneurysm Treatment Trial (HEAT): A Randomized Controlled Trial of the Second-Generation Hydrogel Coil.

BACKGROUNDAneurysm recurrence after coiling has been associated with aneurysm growth, (re)hemorrhage, and a greater need for follow-up. The second-generation HydroCoil Embolic System (HES; MicroVention, Inc) consists of a platinum core with integrated hydrogel and was developed to reduce recurrence through enhancing packing density and healing within the aneurysm.OBJECTIVETo compare recurrence between the second-generation HES and bare platinum coil (BPC) in the new-generation Hydrogel Endovascular Aneurysm Treatment Trial (HEAT).METHODSHEAT is a randomized, controlled trial that enrolled subjects with ruptured or unruptured 3- to 14-mm intracranial aneurysms amenable to coiling. The primary endpoint was aneurysm recurrence using the Raymond-Roy scale. Secondary endpoints included minor and major recurrence, packing density, adverse events related to the procedure and/or device, mortality, initial complete occlusion, aneurysm retreatment, hemorrhage from target aneurysm during follow-up, aneurysm occlusion stability, and clinical outcome at final follow-up.RESULTSA total of 600 patients were randomized (HES, n = 297 and BPC, n = 303), including 28% with ruptured aneurysms. Recurrence occurred in 11 (4.4%) subjects in the HES arm and 44 (15.4%) subjects in the BPC arm (P = .002). While the initial occlusion rate was higher with BPC, the packing density and both major and minor recurrence rates were in favor of HES. Secondary endpoints including adverse events, retreatment, hemorrhage, mortality, and clinical outcome did not differ between arms.CONCLUSIONCoiling of small-to-medium aneurysms with second-generation HES resulted in less recurrence when compared to BPC, without increased harm. These data further support the use of the second-generation HES for the embolization of intracranial aneurysms.

Hydrogel Actuator with a Built‐In Stimulator Using Liquid Metal for Local Control

Hydrogel actuators, comprising gels that convert external stimuli into mechanical motion for actuation, are attracting attention for their promising applications, such as in robotics. The driving force is the absorption or release of water or another solvent, which results in swelling and shrinking motions, leading in turn to more complex functionalities. However, practical hydrogel actuators that can be controlled locally, such as ones that allow local actuation around the joints in rigid‐bodied robots, do not exist. Herein, the driving target of a thermo‐responsive hydrogel, poly(N‐isopropyl acrylamide), is integrated with the stimulation module using a liquid metal. The stimulation module provides heat as an external stimulus to the hydrogel actuator. The motion of the actuator is triggered by the heat supplied by an ultrasoft hydrogel coil, with liquid metal surrounding the driving target. The heat generated by current flowing through the liquid metal changes the temperature only around the desired part of the actuator, which enables the electrical control of an individual part of the hydrogel actuator. The concept of integrating the driving target and stimulator is expected to facilitate functional movement of actuators and expand the range of potential applications of hydrogels.

Stiffness Self‐Tuned Shape Memory Hydrogels for Embolization of Aneurysms

AbstractAn aneurysm is a life‐threatening vascular disease. Embolization with shape memory (SM) hydrogel coils is promising for the treatment of the intractable aneurysms. However, single temperature‐triggered SM is softened in a catheter, and delivery of multiple coils is required, which may clog the catheter and complicate operation procedure. Here, a radiopaque temperature/pH dual responsive shape memory hydrogel with self‐tuned stiffness is fabricated by copolymerizing acrylonitrile (AN, dipole–dipole interaction monomer), N‐acryloyl 2‐glycine (ACG, pH‐sensitive H‐bonding monomer), and polyethylene glycol diacrylate. Under slightly acidic conditions without eliciting cytotoxicity, additional supramolecular PACG hydrogen bonds combined with cyano dipole–dipole pairings contribute to the body temperature‐triggered SM effect with an unprecedented high 430 MPa (10 °C) and 16 MPa (37 °C) Young's modulus. A carotid aneurysm is created in a dog to test the embolization of this SM hydrogel. At 37 °C, the hydrogel's high stiffness ensures its smooth delivery through a catheter. After being transported into the aneurysm sac, secondary swelling occurs concurrent with appropriate decrease of stiffness upon contacting neutral blood, thus enhancing the packing density and reducing recanalization rate and delivery times. This stiffness adaptive SM hydrogel holds its great potential as permanent embolic agents for treating a variety of aneurysms.

Histological and Transmission Electron Microscopy Results after Embolization with HydroSoft/HydroFrame Coils in Experimental Swine Aneurysm.

Coiling and clipping are standard treatment strategies for cerebral aneurysms. Regardless of the strategy used, recanalization may affect the patient's prognosis. The aim of this study was to histologically and morphologically compare the tissue proliferation after coil embolization using bare platinum coils versus second-generation hydrogel coils (HydroSoft/HydroFrame; MicroVention, Inc., Aliso Viejo, CA, USA). Endothelial-like cell proliferation was seen in both groups at 2 weeks after surgery. Macroscopic findings showed a tighter layer at 4 weeks in the hydrogel coil group, and histological and immunohistochemical findings revealed endothelial cell proliferation. This layer became much thicker and tighter at 4 weeks after surgery. Aneurysms treated with second-generation hydrogel coils may be more stable and have a lower incidence of recanalization than those treated with bare platinum coils because of the tight endothelial layer proliferation.

Polymer Embolism from Bioactive and Hydrogel Coil Embolization Technology: Considerations for Product Development

Modified (bioactive and hydrogel) coil embolization technologies were introduced to reduce aneurysm recurrence rates. The addition of bioactive polymers to bare platinum coils is designed to induce a tissue response and promote neoendothelialization. Hydrogel polymers on platinum coils swell in

Hydrogel coils versus bare platinum coils for the endovascular treatment of intracranial aneurysms: a meta-analysis of randomized controlled trials

BackgroundRecent studies have shown conflicting results regarding the effect of hydrogel coils for treating intracranial aneurysm compared to bare platinum coils. We implemented a meta-analysis to assess the value of hydrogel coils in intracranial aneurysm treatment.MethodsThe MEDLINE, EMBASE, and Cochrane Library databases were searched for randomized controlled trials (RCTs) which had evaluated hydrogel coils versus bare platinum coils for intracranial aneurysms.ResultsWe pooled 1526 patients from 4 RCTs with the mean follow-up time of more than 16 months. Hydrogel coils had reductions on mid-term recurrence (RR 0.78, 95% CI 0.65 to 0.94, P = 0.008) and residual aneurysm (RR 0.71, 95% CI 0.57 to 0.88, P = 0.002), but didn’t show any significant differences in other favorable outcomes such as functional recovery, mortality and so on. In the subgroup analysis, we found that second-generation hydrogel coils might exhibit potential impacts on increasing mid-term complete occlusion (RR 1.26, 95% CI 1.07 to 1.48, P = 0.005) and decreasing residual aneurysm neck. (RR 0.54, 95% CI 0.34 to 0.86, P = 0.010).ConclusionsHydrogel coils showed no significant efficacy on functional recovery but exhibited a lower rate of recurrences and residual aneurysms in patients with intracranial aneurysms.

New generation Hydrogel Endovascular Aneurysm Treatment Trial (HEAT): a study protocol for a multicenter randomized controlled trial.

Aneurysm recanalization constitutes a limitation in the endovascular treatment of intracranial aneurysms using conventional bare platinum coils. The development of platinum coils coupled with hydrogel polymers aimed at decreasing the rates of recurrence by way of enhanced coil packing density and biological healing within the aneurysm. While enhanced occlusion and durability has been shown for the first generation hydrogel coils, their use was limited by technical challenges. Less data is available regarding the second-generation hydrogel coils which have been designed to perform like bare platinum coils. The new generation Hydrogel Endovascular Aneurysm Treatment Trial (HEAT) is a multicenter, randomized controlled trial that compares the health outcomes of the second-generation HydroCoil Embolic System with bare platinum coils in the endovascular intracranial aneurysms. The primary endpoint is aneurysm recurrence, defined as any progression on the Raymond aneurysm scale, over a 24-month follow-up period. Secondary endpoints include packing density, functional independence, procedural adverse events, mortality rate, initial complete occlusion, aneurysm retreatment, hemorrhage from treated aneurysm, and any aneurysm recurrence. Patient recruitment initiated in June 2011 and ended in January 2016 in 46 centers. Six hundred eligible patients diagnosed with an intracranial aneurysm, ruptured or unruptured were randomly assigned to one of the two treatment arms. The HEAT trial compares the durability, imaging, and clinical outcomes of the second-generation hydrogel versus bare platinum coils in the endovascular treatment of ruptured or unruptured intracranial aneurysms. The results of this trial may further inform current endovascular treatment guidelines based on observed long-term outcomes.

Long-Term Outcomes of Selective Renal Artery Embolization for Renal Arteriovenous Fistulae with Dilated Venous Sac

PurposeTo retrospectively evaluate the role of selective renal artery embolization for renal arteriovenous fistulae (AVFs) with dilated venous sac. Materials and MethodsBetween 2002 and 2015, 14 patients (7 men and 7 women; mean age, 60 years) with a single renal AVF with dilated venous sac underwent selective renal artery embolization. Three patients presented with gross hematuria, 4 presented with occult blood in urine, and 1 presented with chronic heart failure. Five patients had a history of renal biopsy or partial nephrectomy. Embolic agents used included pushable fibered coils, detachable microcoils, hydrogel coils, N-butyl 2-cyanoactylate, and/or absolute ethanol. Technical success was defined as complete angiographic occlusion of the renal AVF without visualization of the venous sac. Clinical success was defined as the disappearance of the AVF on ultrasound and contrast-enhanced computed tomography, without any symptoms. ResultsFifteen sessions of selective renal artery embolization were performed. Technical success was achieved in 13 sessions (86.7%). Clinical success was achieved in 13 patients (92.9%) after a mean follow-up of 48 months (range, 6-155 months). Two major complications occurred—renal vein thrombosis (n = 1) and renovascular hypertension (n = 1)—and were successfully managed with warfarin and an angiotensin-II receptor blocker, respectively. The former patient required re-embolization because of recanalization. No significant changes were observed in the mean serum creatinine level (.86 mg/dL vs .85 mg/dL; P = .67) and the mean estimated glomerular filtration rate (66.0 mL/min/1.73m2 vs 67.4 mL/min/1.73m2; P = .4) after 6 months. ConclusionsSelective renal artery embolization is a safe and effective treatment for renal AVFs with dilated venous sac.

3:18 PM Abstract No. 304 How peripheral embolic coil design differences affect embolic efficacy

Embolic coils have been used for peripheral embolization since the 1970s with many commercially available designs. However, coil design differences relating to embolization efficacy is not well understood. We aim to test some of the variables used in commercially available coils, including coil size, fiber, fiber material, and expanding gel and compare how these differences affect embolic efficacy using a swine model. Paired arteries were selected and embolized utilizing 2 protocols. Standard clinical embolization practice and flow scoring (TIMI grading) was employed across the study. The first protocol contained two groups; Dacron fiber coil (Interlock 18 Bos. Sci.) vs. nylon/PGLA coil (Concerto Covidien) and Dacron fiber coil (Interlock 18) vs. hydrogel coil (Azur Terumo). Selected arteries fit predetermined size and configuration criteria. The second protocol contained a single group comparing fibered 0.018 coils vs. nonfibered (fibered & nonfibered interlock 18) and compared the effect on coil diameter (Interlock 18 vs. Interlock 35); similar single arteries were selected with three treatment areas. Paired arteries (3) were occluded in each animal and 6 sets were occluded for each group. Occlusion efficiency was assessed by the number of coils used, unit length of coils and the amount of time required for complete embolization. Average occlusion time was quickest for the Interlock 18 and 35, both at mean time of 10.7 min. The Interlock 18 used less coils (mean # of coils 2.9 vs 3.5) and unit length of coil (50.3 and 65.0 cm). The longest mean occlusion time was for the Azur at 19.4 mins and utilizing an average of 4.8 coils and 95.2 cm unit length. Most efficacious was Interlock 18, which was 47% better in embolization time and 48% better in mean coil length for complete embolization, than the least, the Azur. On average, coils with fiber had shorter occlusion time than those without (10.7 vs. 15.3 mins) and utilized less coils (2.9 vs. 4.2). Fibered coils, specifically Dacron fibers, have an improved embolization efficacy over those without fiber (and hydrogel) as measured by embolization time, number of coils, and unit length of coil used in an animal model.

Second-Generation Hydrogel Coils for the Endovascular Treatment of Intracranial Aneurysms: A Randomized Controlled Trial.

Endovascular embolization of intracranial aneurysms with hydrogel-coated coils lowers the risk of major recurrence, but technical limitations (coil stiffness and time restriction for placement) have prevented their wider clinical use. We aimed to assess the efficacy of softer, second-generation hydrogel coils. A randomized controlled trial was conducted at 22 centers in France and Germany. Patients aged 18 to 75 years with untreated ruptured or unruptured intracranial aneurysms measuring 4 to 12 mm in diameter were eligible and randomized (1:1 using a web-based system, stratified by rupture status) to coiling with either second-generation hydrogel coils or bare platinum coils. Assist devices were allowed as clinically required. Independent imaging core laboratory was masked to allocation. Primary end point was a composite outcome measure including major aneurysm recurrence, aneurysm retreatment, morbidity that prevented angiographic controls, and any death during treatment and follow-up. Data were analyzed as randomized. Randomization began on October 15, 2009, and stopped on January 31, 2014, after 513 patients (hydrogel, n=256; bare platinum, n=257); 20 patients were excluded for missing informed consent and 9 for treatment-related criteria. Four hundred eighty-four patients (hydrogel, n=243; bare platinum, n=241) were included in the analysis; 208 (43%) were treated for ruptured aneurysms. Final end point data were available for 456 patients. Forty-five out of 226 (19.9%) patients in the hydrogel group and 66/230 (28.7%) in the control group had an unfavorable composite primary outcome, giving a statistically significant reduction in the proportion of an unfavorable composite primary outcome with hydrogel coils-adjusted for rupture status-of 8.4% (95% confidence interval, 0.5-16.2; P=0.036). Adverse and serious adverse events were evenly distributed between groups. Our results suggest that endovascular coil embolization with second-generation hydrogel coils may reduce the rate of unfavorable outcome events in patients with small- and medium-sized intracranial aneurysms. URL: https://www.drks.de/drks_web/. Unique identifier: DRKS00003132.

Evaluation of Endovascular Embolization of Cerebral Aneurysms by Hydrogel Coils.

SummaryBackgroundHydrogel coils were created to improve the chances of an effective endovascular treatment of cerebral aneurysms. Achieving a high packing density of coils in the lumen of aneurysms can decrease the risk of recurrence. The aim of the present study is to report our initial experience on the effectiveness and safety of endovascular treatment of intracranial aneurysms with the use hydrogel coils.Material/MethodsSixty patients (age: 28–72 years) (45 women, 15 men) were treated. In 18 patients (30%), subarachnoid hemorrhage was present. Digital subtraction angiography (DSA) of cerebral vessels with rotational scanning was performed. Image analysis was performed by the Philips Integris 3D RA device,which is a specialized workstation (Three-Dimensional Rotational Angiography). 3D reconstructions of cerebral arteries were created based on the data. Sixty-six cerebral aneurysms were embolized with hydrogel coils, which expand in contact with blood. reaching the maximum diameter in about 20 minutes. In 29 aneurysms (43.9%), the effect of the procedure was confirmed on a follow-up DSA after 8.0±4.1 months from the initial treatment.ResultsA complete embolization was performed in 55 aneurysms (83.3%), and partial embolization in 11 aneurysms (16.7%). In 6 aneurysms (9.1%), re-embolization was necessary and it resulted in a complete embolization of 5 aneurysms. On a follow-up DSA, complete embolization was present in 25 aneurysms (86.2%), and partial embolization in 4 aneurysms (13.8%), respectively.ConclusionsEndovascular embolization with hydrogel coils is an effective and safe treatment method for cerebral aneurysms, although it carries the risk of some complications.