A Preclinical Study of the Safety and Efficacy of Occlusin™ 500 Artificial Embolization Device in Sheep

Introduction

This study evaluated the safety, effectiveness, and biodegradation of a new embolic agent, Occlusin? 503 Artificial Embolization Device (OCL 503). The agent consists of biodegradable poly-lactic-co-glycolic acid microspheres (150–212 μm) coated with type I bovine collagen and was compared with Embosphere^® Microspheres (300–500 μm) in this controlled study of uterine artery embolization (UAE) in sheep.

Methods

Unilateral UAE was performed in 32 adult ewes randomly assigned. Vessels were embolized to effective stasis. The cohort was divided into four groups, which were sacrificed at 1, 3, 6, and 12 months.

Results

Both agents were 100% effective in achieving stasis. At 6 months, all OCL 503-treated arteries were occluded, the microspheres degraded with time, and at 12 months all four animals examined demonstrated recanalization. OCL 503 was found in the untreated uterine artery in one animal with no other evidence of non target embolization. In the Embosphere-treated group, all vessels remained occluded and microspheres were detected in the contralateral uterine artery in 6 of 15 examined vessels and in 10 vaginal, 2 ovarian, and 1 vesical artery. No procedural-related complications were seen in either group.

Conclusions

OCL 503 is as effective an embolic agent as Embosphere^® Microspheres when embolizing ovine uterine arteries and resorbs with time, allowing recanalization of the treated arteries. No device-related issues or adverse events were observed.     

Gelatin Microspheres: Correlation between Embolic Effect/Degradability and Cross-linkage/Particle Size

Purpose

To evaluate the embolic effect and degradability of gelatin microspheres (GMS) using various degrees of cross-linkage and particle sizes in rabbit renal artery embolization.

Methods

Four types of GMS were used, as follows: 2 types of cross-linkage and 2 types of particle size. Twenty-four rabbits (6 in each group) were used for the renal artery embolization. Renal angiography was performed before and after embolization of right renal artery. Follow-up renal angiography was performed 2 days (n = 2), 5 days (n = 2), and 15 days (n = 2) after embolization in each group, and then kidneys were removed for histopathological evaluation. Vascular areas of the angiography were measured by Image J software, and the reperfusion rate was calculated. In renal specimens, residual GMS were checked and the degree of degradation was classified according to a 4-point scale.

Results

The mean amounts of large- and small-particle-size GMS injected were 15.0 and 34.3 mg, respectively. Tissue necrosis was confirmed in each group; however, no difference was observed among groups. Renal reperfusion was observed more with small GMS than with large GMS. Renal reperfusion was also observed more with low cross-linked GMS than with high cross-linked GMS. In histopathological specimens, large GMS were confirmed in lobar artery, and small GMS were confirmed in lobular artery. Low cross-linked GMS completely degraded 15 days after embolization. In contrast, high cross-linked GMS were persistent 15 days after embolization.

Conclusion

Degree of cross-linkage and particle size affected degradability and reperfusion.     

Transarterial Embolization of Type II Endoleaks after EVAR: The Role of Ethylene Vinyl Alcohol Copolymer (Onyx)

Purpose

To determine the feasibility and efficacy of transarterial endoleak embolization using the liquid embolic agent ethylene vinyl alcohol copolymer (Onyx).

Methods

Over a 7-year period eleven patients (6 women, 5 men; mean age 68 years, range 37–83 years) underwent transarterial embolization of a type II endoleak after endovascular aortic aneurysm repair using the liquid embolic agent Onyx. Two patients (18 %) had a simple type II endoleak with only one artery in communication with the aneurysm sac, whereas 9 patients (82 %) had a complex type II endoleak with multiple communicating vessels. We retrospectively analyzed the technical and clinical success of transarterial type II endoleak embolization with Onyx. Complete embolization of the nidus was defined as technical success. Embolization was considered clinically successful when volume of the aneurysm sac was stable or decreased on follow-up CT scans.

Result

Mean follow-up time was 26.0 (range 6–50) months. Clinical success was achieved in 8 of 11 patients (73 %). Transarterial nidus embolization with Onyx was technically successful in 6 of 11 patients (55 %). In three cases the nidus was embolized without direct catheterization from a more distal access through the network of collateral vessels.

Conclusion

Onyx is a favorable embolic agent for transarterial endoleak embolization. To achieve the best clinical results, complete occlusion of the nidus is mandatory.     

Multiple Renal Artery Pseudoaneurysms in Patients Undergoing Renal Artery Embolization Following Partial Nephrectomy: Correlation with RENAL Nephrometry Scores

Purpose

To describe the incidence of multiple renal artery pseudoaneurysms (PSA) in patients referred for renal artery embolization following partial nephrectomy and to study its relationship to RENAL nephrometry scores.

Materials and Methods

The medical records of 25 patients referred for renal artery embolization after partial nephrectomy were retrospectively reviewed for the following parameters: size and number of tumors, RENAL nephrometry scores, angiographic abnormalities, technical and clinical outcomes, and estimated glomerular filtration rates (eGFRs) after embolization.

Results

Twenty-four patients had primary renal tumors, while 1 patient had a pancreatic tumor invading the kidney. Multiple tumors were resected in 4 patients. Most patients (92 %) were symptomatic, presenting with gross hematuria, flank pain, or both. Angiography revealed PSA with (n = 5) or without (n = 20) AV fistulae. Sixteen patients (64 %) had multiple PSA involving multiple renal vessels. Higher RENAL nephrometry scores were associated with an increasing likelihood of multiple PSA. Multiple vessels were embolized in 14 patients (56 %). Clinical success was achieved after one (n = 22) or two (n = 3) embolization sessions in all patients. Post-embolization eGFR values at different time points after embolization were not significantly different from the post-operative eGFR.

Conclusion

A majority of patients requiring renal artery embolization following partial nephrectomy have multiple pseudoaneurysms, often requiring selective embolization of multiple vessels. Higher RENAL nephrometry score is associated with an increasing likelihood of multiple pseudoaneurysms. We found transarterial embolization to be a safe and effective treatment option with no long-term adverse effect on renal function in all but one patient with a solitary kidney.

     

Transcatheter embolisation of iatrogenic renal vascular injuries

Purpose

The aim of our study was to review our experience and long-term follow-up in the treatment of iatrogenic renal vascular injuries using transcatheter embolisation.

Materials and methods

Our retrospective analysis of cases collected in two interventional centres consists of a total of 21 patients who underwent renal arterial embolisation (RAE) for iatrogenic arterial kidney bleeding. Biopsy (n = 4), percutaneous nephrolithotomy (n = 4), nephron-sparing surgery (n = 4), guidewire-induced arterial perforation during coronary angiography or renal stenting (n = 3), percutaneous nephrostomy (n = 3), renal endopyelotomy/pyeloplasty (n = 2) and surgical nephrectomy were the iatrogenic causes. Seven patients presented with haemodynamic instability requiring blood transfusion (33.3 %), the remaining were haemodynamically stable (66.7 %). Diagnostic renal angiography revealed 9 actively bleeding vessels, 6 pseudoaneurysms, 4 arteriovenous fistulas and 1 arterio-calyceal fistula. In one patient selective renal arteriography was negative probably because the bleeding observed at CT angiography was self-limited. Twenty-one embolisation procedures were performed in 20 patients; one patient required a second embolisation 3 h after the first one. Embolisation was performed with microcoils, polyvinyl alcohol particles, embospheres, spongostan emulsion and vascular plug.

Results

The technical success rate was 100 %. The overall clinical success rate was 95 %. Apart from a patient who died due to disseminated intravascular coagulation, no major complications requiring intensive care treatment were encountered during or after the procedures. No patient required emergency surgery or subsequent surgical treatment. No statistically significant differences in eGFR or renal function stage appeared after RAE.

Conclusions

Percutaneous treatment can be proposed as a first-line treatment in iatrogenic renal arterial injuries, resulting in a safe and effective procedure.     

Selective transarterial embolization with n-butyl-2-cyanoacrylate for the treatment of arterial hemorrhage after third molar extraction

Introduction

Comprehensive reports concerning selective embolization for arterial bleeding from third molar removal have not been published. We analyzed cases of arterial bleeding from third molar extraction that required transarterial embolization, and we demonstrate representative cases.

Methods

Five consecutive patients (three men and two women, aged 24 to 37 years) who underwent transarterial embolization at our institution were included in this study. Four of them showed postoperative bleeding after lower third molar removal, and one suffered bleeding after upper third molar extraction. The period of time from extraction to embolization varied from 5 h to 5 weeks.

Results

Angiography revealed pseudoaneurysms at the inferior alveolar artery in four cases and at the superior alveolar artery in one case. The pseudoaneurysms were selectively embolized using 25–33 % n-butyl-2-cyanoacrylate (NBCA)–lipiodol. All of the cases showed good results angiographically and clinically. Transit hypoesthesia at the region of the mental nerve was observed in one patient.

Conclusion

Selective transarterial embolization is an effective technique for arterial bleeding from third molar removal when it is difficult to obtain hemostasis by dental procedures. Injection of NBCA can be useful when the alveolar artery is too small to embolize with coils.     

Chemical Renal Denervation by Vincristine: The Role of the Flow Rate of Delivery

Purpose

Vincristine has been proven promising regarding its safety and efficacy for the renal artery denervation both in experimental models and in humans. The aim of the study was to compare in an experimental model the efficacy of constant versus random flow rate delivery of vincristine on renal sympathetic denervation.

Methods

We used 10 juvenile Landrace swine. After the introduction of a 7F sheath into the femoral artery, a guide wire was advanced into the distal part of the renal artery. Then the first delivery balloon catheter, which delivers vincristine in random flow rate, was advanced at the proximal part of the artery, and the balloon was inflated in order to locally deliver vincristine to the media of the renal artery. The process was repeated in the contralateral renal artery, with the use of the double balloon catheter that delivers vincristine with a constant flow rate. Euthanasia of the animals was performed at 28 days. All sections were processed for histological and immunohistochemical analysis.

Results

The delivery of vincristine with both catheters was successful and uncomplicated. Immunohistochemistry showed that the mean number of intact nerves in all sections was significantly lower in the group of vincristine delivered with constant flow catheter compared to the group that the delivery was performed in a random fashion. (1.48 ± 0.37 vs. 1.70 ± 0.41, p = 0.04).

Conclusion

Chemical renal denervation with vincristine by a constant flow rate catheter is more effective compared to the denervation performed by a catheter that delivers vincristine in a random fashion.     

Endovascular coil embolization of middle cerebral artery aneurysms of the proximal (M1) segment

Introduction

Proximal middle cerebral artery (M1 segment) aneurysms have various configurations and are distinct from middle cerebral artery bifurcation aneurysms. We present the clinical and radiological results of coil embolization of the M1 segment aneurysms.

Methods

From a prospective database, we retrieved the data for 59 consecutive patients harboring 60 M1 aneurysms that were treated with endovascular coil embolization from January 2006 to May 2012. We assessed the clinical outcomes of the patients and morphological outcomes of the aneurysms using the Raymond classification.

Results

The aneurysms were located on the superior wall of the M1 segment in 43 and on the inferior wall in 17. Superior-wall aneurysms were related to the frontal cortical artery and the lateral lenticulostriate perforator while inferior-wall aneurysms were to the temporal cortical artery. With coil embolization, complete aneurysmal occlusion or residual neck could be achieved in 52 aneurysms (86.7 %) and residual aneurysm in 8. The microcatheter protection technique was most commonly used for coil embolization (41.7 %) followed by single microcatheter (31.7 %), double microcatheter (23.3 %), and stent protection (3.3 %). There was no procedure-related morbidity or mortality. Follow-up angiography more than 6 months after embolization (n?=?46; mean 12.4 months) demonstrated stable occlusion in 40 (87.0 %), minor recanalization in 4 (8.7 %), and major recanalization in 2 (4.3 %). One patient experienced delayed cerebral infarction without permanent neurologic deficit.

Conclusion

Coil embolization in M1 aneurysms seems to be safe and efficacious, although it may require various technical strategies due to distinct anatomic configurations.     

Intra-arterial Ultra Low Iodine CT Angiography of Renal Transplant Arteries

Purpose

This study was designed to evaluate the technical feasibility and the image quality of intra-arterial 320-row CT angiography (ia-CTA) in the detection of transplant renal artery stenosis (TRAS) using a very low dose of contrast agent.

Methods

Evaluation of ia-CTA using a 4F catheter in ten patients with impaired renal transplant function and suspected TRAS. Average amount of contrast agent applied was 10 ± 3.7 ml standard deviation (SD). Patient serum creatinine levels had been monitored for 72 h. TRAS was detected and graded (1: less than 20 %; 2: 20–49 %; 3: 50–74 %; 4: 75–99 %; 5: total occlusion) and presence of kinking was recorded. Attenuation and vessel delineation were parameters for image quality analysis of the renal arterial supply, divided into four segments. Subjective image quality.

Results

Ia-CTA of the renal transplant was technically successful in all patients, revealing relevant stenoses in 7 of 10 patients. Serum creatinine levels before and after ia-CTA were 2.71 ± 1.46 and 2.56 ± 1.39 mg/dl, respectively. None of the patients developed signs of contrast-induced nephropathy within 72 h. Subjective image quality was excellent in all four segments, rated by two separate readers. No segment was found to be nondiagnostic. Mean attenuation values in the arterial segments ranged between 754 and 987 Hounsfield units.

Conclusions

Wide detector ia-CTA for the diagnosis of TRAS is feasible using very low doses of contrast agent and results in high image quality.     

MRI Assessment of Uterine Artery Patency and Fibroid Infarction Rates 6 Months after Uterine Artery Embolization with Nonspherical Polyvinyl Alcohol

Purpose

We have observed significant rates of uterine artery patency after uterine artery embolization (UAE) with nonspherical polyvinyl alcohol (nsPVA) on 6 month follow-up MR scanning. The study aim was to quantitatively assess uterine artery patency after UAE with nsPVA and to assess the effect of continued uterine artery patency on outcomes.

Methods

A single centre, retrospective study of 50 patients undergoing bilateral UAE for uterine leiomyomata was undertaken. Pelvic MRI was performed before and 6 months after UAE. All embolizations were performed with nsPVA. Outcome measures included uterine artery patency, uterine and dominant fibroid volume, dominant fibroid percentage infarction, presence of ovarian arterial collaterals, and symptom scores assessed by the Uterine Fibroid Symptom and Quality of Life questionnaire (UFS-QOL).

Results

Magnetic resonance angiographic evidence of uterine artery recanalization was demonstrated in 90 % of the patients (64 % bilateral, 26 % unilateral) at 6 months. Eighty percent of all dominant fibroids demonstrated >90 % infarction. The mean percentage reduction in dominant fibroid volume was 35 %. No significant difference was identified between nonpatent, unilateral, and bilateral recanalization of the uterine arteries with regard to percentage dominant fibroid infarction or dominant fibroid volume reduction. The presence of bilaterally or unilaterally patent uterine arteries was not associated with inferior clinical outcomes (symptom score or UFS-QOL scores) at 6 months.

Conclusion

The high rates of uterine artery patency challenge the current paradigm that nsPVA is a permanent embolic agent and that permanent uterine artery occlusion is necessary to optimally treat uterine fibroids. Despite high rates of uterine artery recanalization in this cohort, satisfactory fibroid infarction rates and UFS-QOL scores were achieved.     

Transarterial treatment of direct carotico-cavernous fistulas with coils and Onyx

Introduction

The purpose of this study was to evaluate the role of combination of liquid embolic agent ethylene vinyl alcohol copolymer (Onyx) and detachable coils in the treatment of direct carotico-cavernous fistulas (CCFs).

Methods

We prospectively collected clinical and radiological data of all patients who underwent embolization of direct CCFs at our institution over a period of 21 months. The clinical parameters, angioarchitecture, presence of cortical venous reflux, volume of Onyx used, number of coils used, extent of embolization and complications were recorded.

Results

A total of 21 consecutive patients (18 men and 3 women, 14 to 48 years) with direct CCF underwent embolization with a combination of coils and Onyx. Embolization was done through the arterial route in all cases. Complete obliteration of the fistula was achieved in 19 of 21 cases. Cast embolization in middle cerebral artery occurred in one patient; however, the cast was completely retrieved with Solitaire device, and the patient did not have any neurological deficit. All completely treated patients reported relief of symptoms at varying intervals. At 6-month follow-up, none of the patients with complete occlusion of the fistula showed any recurrence.

Conclusion

The adjuvant use of Onyx with detachable coils in direct CCF through the arterial route is a safe and effective method for embolization with immediate and complete occlusion of the fistula. To the best of our knowledge, this is the first case series of demonstration of arterial use of Onyx with coils in the treatment of direct CCFs.     

Aortic Branch Artery Pseudoaneurysms Associated with Intramural Hematoma: When and How to Do Endovascular Embolization

Purpose

To describe when and how to perform endovascular embolization of aortic branch artery pseudoaneurysms associated with type A and type B intramural hematoma (IMH) involving the descending thoracic and abdominal aorta (DeBakey I and III) that increased significantly in size during follow-up.

Materials and Methods

Sixty-one patients (39 men; mean ± standard deviation age 66.1 ± 11.2 years) with acute IMH undergoing at least two multidetector computed tomographic examinations during follow-up for 12 months or longer were enrolled. Overall, 48 patients (31 men, age 65.9 ± 11.5) had type A and type B IMH involving the descending thoracic and abdominal aorta (DeBakey I and III).

Results

Among the 48 patients, 26 (54 %; 17 men, aged 64.3 ± 11.4 years) had 71 aortic branch artery pseudoaneurysms. Overall, during a mean follow-up of 22.1 ± 9.5 months (range 12–42 months), 31 (44 %) pseudoaneurysms disappeared; 22 (31 %) decreased in size; two (3 %) remained stable; and 16 (22 %) increased in size. Among the 16 pseudoaneurysms with increasing size, five of these (three intercostal arteries, one combined intercostobronchial/intercostal arteries, one renal artery), present in five symptomatic patients, had a significant increase in size (thickness >10 mm; width and length >20 mm). These five patients underwent endovascular embolization with coils and/or Amplatzer Vascular Plug. In all patients, complete thrombosis and exclusion of aortic pseudoaneurysm and relief of back pain were achieved.

Conclusion

Aortic branch artery pseudoaneurysms associated with type A and type B IMH involving the descending thoracic and abdominal aorta (DeBakey I and III) may be considered relatively benign lesions. However, a small number may grow in size or extend longitudinally with clinical symptoms during follow-up, and in these cases, endovascular embolization can be an effective and safe procedure.     

A Pilot Study of Uterine Artery Embolization with Tris-Acryl Gelatin Microspheres in Guinea Pigs

Objective

This study was designed to establish guinea pigs as an animal model for uterine artery embolization (UAE) with tris-acryl gelatin microspheres (TAGM).

Methods

Twenty-five female adult guinea pigs were randomly divided into two groups, including a uterine artery casting mould group (n = 10) and a UAE group (n = 15). Pelvic angiography and vascular casting mould were performed in the first group. The anatomical characters of the pelvic cavity in guinea pigs were described. In the second group, the technical feasibility of performing UAE with TAGM in guinea pigs was investigated. The histopathological slides of the uterus of guinea pigs after UAE were examined to inspect the outcomes of UAE.

Results

The uterine artery springs from the internal iliac artery, ascends tortuously along the cervix, and gives off vertically 8–10 branches to the cervix uteri and uterine horns. The diameters of the trunk of the uterine artery and its first branch were 0.32 ± 0.027 mm and 0.14 ± 0.01 mm, respectively. For UAE animals, the dosages of 40–120 and 100–300 μm TAGM were 0.033 ± 0.003 ml and 0.015 ± 0.002 ml, respectively. On histopathological slides, embosphere particles were found in the first branches of the uterine artery, the subserous arteries, and the intramural arteries. Inflammatory reactions in the uterus were common in guinea pigs after UAE. Local or dispersed areas of necrosis in uterus also were observed in a few guinea pigs.

Conclusions

Guinea pigs are an appropriate and feasible model for UAE with TAGM.     

Modified protection using far proximal portion of self-expandable closed-cell stents for embolization of wide-necked intracranial aneurysms

Introduction

Stent-assisted embolization is sometimes limited in wide-necked aneurysms involving the acute-angled origins of tortuous branching arteries, and occasionally, Y-shaped stenting is required to remedy the sweeping effects of a broad aneurysmal neck on arterial branches. Described herein is a modified stent-assisted coil embolization technique entailing strategic placement of far proximal stent (“distal stenting”) as an alternate approach in such scenarios.

Methods

For this particular technique, stent placement is confined to a branch artery, allowing far proximal stent to cover aneurysmal neck, with no bridge to parent artery. Kinking of stents deployed in tortuous arteries is thereby avoided, and better coverage of aneurysmal neck is achieved, compared with traditional stent protection. Records of 12 consecutive patients with wide-necked aneurysms, all treated by coil embolization with distal stenting between January 2009 and February 2014, were retrieved from a prospective data repository at our institution. Outcomes were analyzed in terms of morphologic features and clinical status.

Results

This modified technique was largely applied to aneurysms of middle cerebral artery, followed by posterior communicating artery and anterior communicating artery sites. With one exception, all aneurysms treated were successfully occluded. There were no complications directly related to distal stenting. At final follow-up (mean interval, 16.8?±?9.7 months), complete aneurysmal occlusion was sustained in 81.8 %. Delayed stent migration was observed in one patient (8.3 %).

Conclusion

Our study suggests that distal stenting in wide-necked aneurysms is a reasonable alternative to traditional stent protection, despite the potential for delayed stent migration.     

Is There a Role for Empiric Gastroduodenal Artery Embolization in the Management of Patients with Active Upper GI Hemorrhage?

Purpose

To assess the relative efficacy of empiric gastroduodenal artery (GDA) embolization in reducing recurrent hemorrhage compared to image-guided targeted embolization.

Methods

Data were retrospectively collected for consecutive patients who had catheter angiography for major upper gastrointestinal hemorrhage from May 2008 to November 2010 (n = 40). The total number of cases were divided into two main groups according to angiographic findings: those that demonstrated a site of hemorrhage on catheter angiography (group 1, n = 13), and those where the site of hemorrhage was not identified on catheter angiography (group 2, n = 27). Group 2 was then further divided into patients who received empiric embolization (group 2a, n = 20) and those who had no embolization performed after angiography (group 2b, n = 7).

Results

The technical and clinical success rates for embolization in groups 1 and 2a were, respectively, 100 vs. 95 %, and 85 vs. 80 %. There was no statistical significance in the recurrent hemorrhage rate, reintervention rate, or 30 day mortality between targeted and empiric embolization groups. There were no complications attributed to embolization within this study cohort.

Conclusion

Cases of duodenal-related major upper gastrointestinal hemorrhage where no embolization is performed have poor outcome. Empiric embolization of the GDA in patients with major upper gastrointestinal hemorrhage refractory to endoscopic treatment appears to be a safe and effective treatment, with low reintervention rates and good clinical outcome comparable to patients where the site of hemorrhage is localized and embolized with computed tomographic angiography or catheter angiography and embolized.     

Determination of the Nonlethal Margin Inside the Visible “Ice-Ball” During Percutaneous Cryoablation of Renal Tissue

Objective

The study was designed to determine the distance between the visible “ice-ball” and the lethal temperature isotherm for normal renal tissue during cryoablation.

Methods

The Animal Care Committee approved the study. Nine adult swine were used: three to determine the optimum tissue stain and six to test the hypotheses. They were anesthetized and the left renal artery was catheterized under fluoroscopy. Under MR guidance, the kidney was ablated and (at end of a complete ablation) the nonfrozen renal tissue (surrounding the “ice-ball”) was stained via renal artery catheter. Kidneys were explanted and sent for slide preparation and examination. From each slide, we measured the maximum, minimum, and an in-between distance from the stained to the lethal tissue boundaries (margin). We examined each slide for evidence of “heat pump” effect.

Results

A total of 126 measurements of the margin (visible “ice-ball”–lethal margin) were made. These measurements were obtained from 29 slides prepared from the 6 test animals. Mean width was 0.75 ± 0.44 mm (maximum 1.15 ± 0.51 mm). It was found to increase adjacent to large blood vessels. No “heat pump” effect was noted within the lethal zone. Data are limited to normal swine renal tissue.

Conclusions

Considering the effects of the “heat pump” phenomenon for normal renal tissue, the margin was measured to be 1.15 ± 0.51 mm. To approximate the efficacy of the “gold standard” (partial nephrectomy, ~98 %), a minimum margin of 3 mm is recommended (3 × SD). Given these assumptions and extrapolating for renal cancer, which reportedly is more cryoresistant with a lethal temperature of ?40 °C, the recommended margin is 6 mm.     

Inferior Mesenteric Artery Embolization Before Endovascular Aortic Aneurysm Repair Using Amplatzer Vascular Plug Type 4

Purpose

This study was designed to evaluate the efficacy and safety of Amplatzer Vascular Plug type 4 (AVP-4) for embolization of the inferior mesenteric artery (IMA) before endovascular aneurysm repair (EVAR) of the abdominal aorta to prevent endoleaks.

Methods

A single-center retrospective review of 31 patients who underwent IMA embolizations before EVAR using the AVP-4 was performed. We analyzed the insertion and detachment procedure, the technical success, and the final position of the plug. Technical success was defined as complete occlusion of the IMA. To compare the incidence of IMA-related type II endoleaks in patients with and without preoperative IMA embolization, we additionally reviewed the course of 43 patients with a preoperatively patent IMA who underwent no IMA embolization.

Results

Plugs with a diameter of 5, 6, and 8 mm were used in 5 (16.1 %), 21 (67.7 %), and 5 (16.1 %) patients, respectively (50–100 % oversizing). In 29 of 31 patients (93.5 %), we observed complete occlusion of the IMA within 10 min (mean 5.1 min). Precise placement of the plug in the proximal segment of the IMA without occlusion of the first IMA branches was achievable in all patients. The distance between the AVP-4 and the first branches was on average 12 (range 2–57) mm. Preoperative IMA embolization with AVP-4 significantly reduced the incidence of complex IMA-lumbar type II endoleaks after EVAR (0/31 vs. 11/43; p = 0.002).

Conclusions

The AVP-4 is a safe, feasible, and technically effective embolization device for IMA embolization before EVAR.     

Coil embolization of intracranial saccular aneurysms using the Low-profile Visualized Intraluminal Support (LVIS™) device

Introduction

The novel Low-profile Visualized Intraluminal Support (LVIS?, LVIS and LVIS Jr.) device was recently introduced for stent-supported coil embolization of intracranial aneurysms. Periprocedural and midterm follow-up results for its use in stent-supported coil embolization of unruptured aneurysms are presented herein.

Methods

In this prospective multicenter study, clinical and radiologic outcomes were analyzed for 55 patients with saccular aneurysms undergoing LVIS-assisted coil embolization between October 2012 and February 2013. Magnetic resonance angiography or digital subtraction angiography was performed to evaluate midterm follow-up results.

Results

The standard LVIS device, deployed in 27 patients, was more often used in internal carotid artery (ICA) aneurysms (n?=?19), whereas the LVIS Jr. (a lower profile stent, n?=?28) was generally reserved for anterior communicating artery (n?=?14) and middle cerebral artery (n?=?8) aneurysms. With LVIS-assisted coil embolization, successful occlusion was achieved in 45 aneurysms (81.8 %). Although no instances of navigation failure or stent malposition occurred, segmentally incomplete stent expansion was seen in five patients where the higher profile LVIS was applied to ICA including carotid siphon. Procedural morbidity was low (2/55, 3.6 %), limited to symptomatic thromboembolism. In the imaging of lesions (54/55, 98.2 %) at 6-month follow-up, only a single instances of major recanalization (1.9 %) occurred. Follow-up angiography of 30 aneurysms (54.5 %) demonstrated in-stent stenosis in 26 (86.7 %), with no instances of stent migration. Only one patient suffered late delayed infarction (modified Rankin Scale 1).

Conclusion

The LVIS device performed acceptably in stent-assisted coil embolization of non-ruptured aneurysms due to easy navigation and precise placement, although segmentally incomplete stent expansion and delayed in-stent stenosis were issues.     

Chemical Renal Denervation in the Rat

Introduction

The recent success of renal denervation in lowering blood pressure in drug-resistant hypertensive patients has stimulated interest in developing novel approaches to renal denervation including local drug/chemical delivery. The purpose of this study was to develop a rat model in which depletion of renal norepinephrine (NE) could be used to determine the efficacy of renal denervation after the delivery of a chemical to the periadventitial space of the renal artery.

Methods

Renal denervation was performed on a single renal artery of 90 rats (n = 6 rats/group). The first study determined the time course of renal denervation after surgical stripping of a renal artery plus the topical application of phenol in alcohol. The second study determined the efficacy of periadventitial delivery of hypertonic saline, guanethidine, and salicylic acid. The final study determined the dose–response relationship for paclitaxel. In all studies, renal NE content was determined by liquid chromatography–mass spectrometry.

Results

Renal NE was depleted 3 and 7 days after surgical denervation. Renal NE was also depleted by periadventitial delivery of all agents tested (hypertonic saline, salicylic acid, guanethidine, and paclitaxel). A dose response was observed after the application of 150 μL of 10^?5 M through 10^?2 M paclitaxel.

Conclusion

We developed a rat model in which depletion of renal NE was used to determine the efficacy of renal denervation after perivascular renal artery drug/chemical delivery. We validated this model by demonstrating the efficacy of the neurotoxic agents hypertonic saline, salicylic acid, and guanethidine and increasing doses of paclitaxel.     

Coil embolization in precommunicating (A1) segment aneurysms of anterior cerebral artery

Introduction

Precommunicating (A1) segment aneurysms of the anterior cerebral artery are rare and often pose technical challenges for coil embolization due to their distinctive configurations. Clinical and radiologic outcomes of treating such aneurysms through endovascular coil embolization are presented herein.

Methods

Data accruing prospectively from May 2002 to August 2013 yielded 48 patients harboring 50 A1 segment aneurysms, each classified as proximal, middle, or distal by location. Clinical outcome of the patients and morphological outcome of the aneurysms were assessed, with emphasis on technical aspects of treatment.

Results

The aneurysms studied occupied either proximal (n?=?39), middle (n?=?6), or distal (n?=?5). Proximal aneurysms were largely directed posteriorly (80 %), and most (97 %) were devoid of branches. Middle and distal aneurysms were associated with the medial lenticulostriate artery, cortical branches, or fenestrations. The preshaped “S” and steam-shaped “S” microcatheters facilitated aneurysm selection in 60 % of lesions. Single-microcatheter technique was most commonly applied for coil embolization (62 %), followed by balloon protection (16 %). Successful aneurysmal occlusion could be achieved in 76 % of the patients, with no procedure-related morbidity and mortality. At final follow-up (mean interval, 29.9 months), stable aneurysmal occlusion was sustained in 93 % of the patients (40/43).

Conclusion

A1 segment aneurysms are amenable to safe and efficacious endovascular coil embolization by adjusting procedural strategy to accommodate distinctive anatomic configurations.