Safety and Feasibility of Combining On-Demand Selective Locoregional Treatment with First-Line Atezolizumab Plus Bevacizumab for Patients with Unresectable Hepatocellular Carcinoma.

Various locoregional treatments for localized hepatocellular carcinoma (HCC) have been developed. This retrospective study investigated the safety and feasibility of combining on-demand selective locoregional treatment for residual lesions after tumor shrinkage (complete response [CR] oriented) or for solitary or few drug-resistant lesions (progressive disease (PD) salvage) with first-line atezolizumab plus bevacizumab (atezo/bev) for unresectable HCC. Twenty-nine patients with unresectable HCC were included. Fourteen locoregional treatments were performed (CR oriented, 7; PD salvage, 7) in ten patients in the combination-therapy group. All patients in the combination-therapy group successfully achieved a CR or PD salvage status after the planned locoregional treatment. The objective response rate of the combination-therapy group (80.0%) was higher than that of the atezo/bev alone group (21.1%; p = 0.005). Progression-free survival (PFS) and overall survival (OS) were longer in the combination group (medians for PFS and OS not reached) than in the atezo/bev alone group (median PFS, 7.4 months; median OS, 19.8 months) (PFS, p = 0.004; OS, p < 0.001). The albumin-bilirubin score did not change, and no severe complications occurred after locoregional treatment. When performed in a minimally invasive manner, on-demand selective locoregional treatment combined with first-line atezo/bev could be safe and feasible for unresectable HCC.

Successful endovascular embolization of the common hepatic artery for pseudoaneurysm associated with pancreatic fistula after liver transplantation: a case report.

BACKGROUND: After orthotopic liver transplantation (OLT), complications such as hepatic artery stenosis, thrombosis, and bleeding are possible. Hepatic artery pseudoaneurysms (HAP) are prone to rupture, rupture hemorrhage, and increased mortality risk. Endovascular treatment of HAP may result in recurrence, even after successful embolization with thrombin. Formation of a HAP in the common hepatic artery (CHA) is challenging because the CHA is the only artery in the liver graft after OLT. Therefore, CHA embolization in HAP is not an initial option. We report a case of HAP at the CHA after OLT that was treated with endovascular therapy, resulting in the occlusion of the CHA with coil embolization, achieving a radical cure. CASE PRESENTATION: A 59-year-old man with decompensated hepatitis C virus cirrhosis underwent deceased donor whole-liver transplantation after graft failure of a living donor liver transplantation. After the second transplantation, the patient developed infectious narrow-necked HAP at the CHA associated with postoperative pancreatic fistula. Repeated transcatheter arterial embolization with thrombin and n-butyl-2-cyanoacrylate was unsuccessful, as confirmed by postprocedure angiography, which revealed recanalization and regrowth of the HAP. Eight months after the first transcatheter arterial embolization, the patient presented with a chief complaint of abdominal pain due to an enlarged HAP. Angiography of the superior mesenteric artery (SMA) revealed a collateral bypass around the bile duct from the SMA to the liver graft. Coil embolization of the HAP in the CHA completely occluded the HAP without complications. More than 2 years after coil embolization, the liver graft function test results remained within normal limits without HAP recurrence. CONCLUSIONS: HAP at the CHA after liver transplantation can be fatal if ruptured. Because the liver is a highly angiogenic organ, even if initial treatment is not successful, radical treatment to occlude the CHA with HAP is possible if sufficient collateral vessels are developed.

A Retrospective Analysis of Venographic Images of a Central Venous Port without Blood Return and Its Usable Period.

Objective In routine practice, central venous ports without blood return (CVPWBRs) are common. However, very few studies have reported on the viable period of CVPWBR use. We therefore investigated this period by retrospectively analyzing the venographic images of CVPWBRs. Methods We examined patients' venography through the CVPs at the point when they became CVPWBRs for the first time and analyzed the reasons for becoming CVPWBRs. For patients with minor complications of CVPs or normal venographic findings, we used the Kaplan-Meier method to evaluate the period for which such CVPWBRs could be used. Patients Eighty-four patients with malignancy whose CVPs became CVPWBRs for the first time between July 31, 2015, and March 12, 2020, were included. Results Nine (10.7%) patients had major complications that made the CVPs unusable. Thirty-three (39.3%) patients had minor complications, and the remaining 42 (50.0%) had normal venographic findings. For the 75 patients with minor complications or normal venographic findings who continued to use their CVPWBRs, the Kaplan-Meier method estimated that 25% of complications that might make it unusable would occur within 1,273 days. Conclusion There are two learning points in our study. First, venography is needed when the CVP becomes a CVPWBR for the first time due to the high risk, and second, CVPWBRs can be used for a relatively long period in patients without major complications. It is necessary to develop an appropriate follow-up management method for CVPWBRs in prospective studies.

Nonbrain metastases seen on magnetic resonance imaging during metastatic brain tumor screening.

Although metastases found during head magnetic resonance imaging (MRI) are not limited to metastatic brain tumors, the MRI is a very common method for "brain metastasis screening," a modality that is being increasingly performed. In this review, we describe MRI findings of nonbrain metastases and discuss ways to avoid missing these lesions. Metastatic cranial bone tumors are among the most common nonbrain metastatic lesions found on head MRI, followed by leptomeningeal carcinomatosis. The other less-frequent metastatic lesions include those in the ventricle/choroid plexus, the pituitary gland and stalk, and the pineal gland. Metastases in the head and neck area, as well as cranial and intracranial lesions, should be carefully evaluated. Furthermore, direct geographical invasion, perineural spread, and double cancers should also be considered. While it is important to recognize these metastatic lesions on MRI, because they may necessitate a change in treatment strategy that could lead to an improvement in prognosis due to early introduction of therapy, nonbrain lesions should also be given greater attention, given the increasing survival of patients with cancer and advances in MRI technology, such as contrast-enhanced-3D T1-weighted imaging.

Rabbit VX2 Liver Tumor Model: A Review of Clinical, Biology, Histology, and Tumor Microenvironment Characteristics.

The rabbit VX2 is a large animal model of cancer used for decades by interventional radiologists to demonstrate the efficacy of various locoregional treatments against liver tumors. What do we know about this tumor in the new era of targeted therapy and immune-oncology? The present paper describes the current knowledge on the clinics, biology, histopathology, and tumor microenvironment of VX2 based on a literature review of 741 publications in the liver and in other organs. It reveals the resemblance with human cancer (anatomy, vascularity, angiogenic profile, drug sensitivity, immune microenvironment), the differences (etiology, growth rate, histology), and the questions still poorly explored (serum and tissue biomarkers, genomic alterations, immune checkpoint inhibitors efficacy).

Comparison of sampling methods for next generation sequencing for patients with lung cancer.

INTRODUCTION: Success of next generation sequencing (NGS) analysis is becoming indispensable in the treatment of advanced lung cancer. However, the advantages and disadvantages of each sampling method in the NGS analysis have not yet been clarified. METHODS: We compared the success rates of NGS analysis, and DNA and RNA yields for transbronchial biopsy (TBB), endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), computed tomography (CT)-guided biopsy, fluid sample, and surgical biopsy for NGS analysis in patients through the lung cancer genomic screening project for individualized medicine (LC-SCRUM)-Asia, a nationwide NGS screening project. In case, sufficient samples could not be collected by TBB and EBUS-TBNA, re-biopsy (genome re-biopsy) was performed. RESULTS: A total of 223 patients were enrolled and success rates of NGS analysis were not different between samples obtained through TBB, EBUS-TBNA, and CT-guided biopsy; however, success rates for fluid samples and surgical biopsy samples were significantly higher than those of other methods. The risk of genome re-biopsy was higher with TBB for centrally located lesions. CT-guided biopsy yielded more samples but had a lower success rate for analysis of RNA-based NGS than TBB. CONCLUSIONS: TBB is the mainstay of sampling methods, but for centrally located lesions, EBUS-TBNA may be a better strategy. For CT-guided biopsy, the success rate of RNA-based NGS analysis is low. Fluid samples are expected to yield successful results as surgical biopsy samples, but the latter are better for sample preservation. Determining the optimal method for genome biopsy for each case is important.

Whole-body MRI: detecting bone metastases from prostate cancer.

Whole-body magnetic resonance imaging (WB-MRI) is currently used worldwide for detecting bone metastases from prostate cancer. The 5-year survival rate for prostate cancer is > 95%. However, an increase in survival time may increase the incidence of bone metastasis. Therefore, detecting bone metastases is of great clinical interest. Bone metastases are commonly located in the spine, pelvis, shoulder, and distal femur. Bone metastases from prostate cancer are well-known representatives of osteoblastic metastases. However, other types of bone metastases, such as mixed or inter-trabecular type, have also been detected using MRI. MRI does not involve radiation exposure and has good sensitivity and specificity for detecting bone metastases. WB-MRI has undergone gradual developments since the last century, and in 2004, Takahara et al., developed diffusion-weighted Imaging (DWI) with background body signal suppression (DWIBS). Since then, WB-MRI, including DWI, has continued to play an important role in detecting bone metastases and monitoring therapeutic effects. An imaging protocol that allows complete examination within approximately 30 min has been established. This review focuses on WB-MRI standardization and the automatic calculation of tumor total diffusion volume (tDV) and mean apparent diffusion coefficient (ADC) value. In the future, artificial intelligence (AI) will enable shorter imaging times and easier automatic segmentation.

Number of Nodules but not Size of Hepatocellular Carcinoma Can Predict Refractoriness to Transarterial Chemoembolization and Poor Prognosis.

BACKGROUND: To determine whether response to transarterial chemoembolization (TACE) predicts survival and to identify pretreatment factors associated with TACE response and prognosis. METHODS: Between April and September 2010, 50 patients underwent TACE for hepatocellular carcinoma. Response to TACE was assessed using post-treatment computed tomography (CT) and magnetic resonance imaging (MRI) scans and tumor marker levels and classified as Response Poor (P) and Non-poor (NP). Time zero was set to September 30, 2010, and survival rates were analyzed by landmarking. Cumulative survival rates were calculated using the Kaplan-Meier method and compared according to grades using the log-rank test; contributing factors to survival were analyzed using a Cox proportional hazards model. Pretreatment factors were analyzed for 109 TACE sessions performed until October 2017, using a multiple logistic regression model. Receiver operating characteristic (ROC) curves were generated to determine the best tumor number for predicting response P. RESULTS: Response P patients showed significantly lower cumulative survival rates than Response NP patients (P < 0.001). On multivariate analysis, tumor number (hazard ratio (HR), 1.475), protein-induced vitamin-K absence-II (HR, 4.539), and the number of previous TACE sessions (HR, 1.472) were identified as pretreatment factors contributing to Response P. Further, pre-treatment platelet count (HR, 0.876) and tumor number (HR, 1.330) were factors contributing to survival in multivariate analysis. ROC curve analysis revealed that the optimal cut-off value to discriminate Response P was 7.5. CONCLUSIONS: Response to TACE can predict survival. Pretreatment tumor number is a useful factor for predicting both TACE response and prognosis.

Magnetic compression anastomosis for postoperative biliary atresia.

We report a case of successful magnetic compression anastomosis (MCA) for obstructed cyst-jejunostomy in a young woman who had undergone surgery for type 1 biliary atresia (BA) on day 78 of life. A 16-year-old girl was admitted with obstructive jaundice. Jaundice resolved with percutaneous trans-hepatic cholangiodrainage (PTCD) but contrast medium injected from the PTCD tube did not flow through the anastomosis. Magnets were placed on each side of the anastomosis, in the cyst and the jejunum, to compress the partition. On postoperative day (POD) 6, the anastomosis was recanalized and the PTCD tube placed trans-anastomotically until POD 245. The patient remained free from jaundice after removal of the PTCD tube. MCA can be a useful and less invasive procedure for treating biliary tract anastomotic obstruction in patients with BA.

Efficacies of uterine artery embolization for symptomatic uterine fibroids using gelatin sponge: a single-center experience and literature review.

AIM: The aim of this study was to retrospectively analyze the efficacies of uterine artery embolization (UAE) using gelatin sponge for symptomatic uterine fibroids. METHODS: A series of 60 consecutive premenopausal women underwent UAE using gelatin sponge particles or porous gelatin particles. Patients were routinely followed up at 1, 3, 6, and 12 months after the procedure and asked to report any procedure-related complications. At each follow-up, an original clinical questionnaire was completed by the patients to evaluate changes in fibroid-related symptoms. Pelvic magnetic resonance imaging was performed before and at 3 and 12 months after the procedure, and the changes in volume of the dominant fibroid were calculated. RESULTS: Bilateral UAE was successfully performed in all the patients. Median age was 45 years (range 34-53 years), and median follow-up period was 25.2 months (range 1-116 months). At the 3- and 12-month follow-up, the dominant fibroid volumes were found to be significantly decreased by 33.4% (95% confidence interval [CI]: 24.9-41.1) and 48.4% (95% CI: 40.7-56.1) compared to baseline volumes, respectively. Excluding patients not having menorrhagia or bulk-related symptoms, at 12 months 49 of 50 (98%) women showed improvement in menorrhagia, and 45 of 47 (95.7%) women showed improvement in bulk-related symptoms. During the follow-up period, ten patients (16.7%) required further interventions including two patients who had undergone hysterectomy. No sequelae were experienced by any of the patients. CONCLUSION: UAE using gelatin sponge was associated with a high clinical success rate and good fibroid volume reduction compared to UAE using other embolic agents.

Safety and efficacy compared between irinotecan-loaded microspheres HepaSphere and DC bead in a model of VX2 liver metastases in the rabbit.

PURPOSE: To compare irinotecan-eluting HepaSphere (BioSphere Medical, Roissy-en-France, France) and DC Bead (Biocompatibles UK Ltd, London, United Kingdom) embolization microspheres for distribution in tumors, release properties, tolerance, and antitumor effects in a model of liver metastases in the rabbit. MATERIALS AND METHODS: Multiple liver tumors were created by injection of a VX2 cell suspension in the portal vein of rabbits. After 2 weeks, embolization of the proper hepatic artery was performed with a fixed volume of bland HepaSphere (n = 5), irinotecan-loaded HepaSphere (n = 6), or irinotecan-loaded DC Bead (n = 5) microspheres. Untreated animals injected with VX2 cells served as control animals (n = 5). Plasma pharmacokinetics of irinotecan and its metabolite SN38 were assessed. Histopathology and gene expression analysis were performed 3 days after treatment. RESULTS: Among all treated groups, there was no significant difference in liver enzymes or liver damage on histology. Irinotecan-loaded HepaSphere microspheres showed a faster release of drug than DC Bead microspheres leading to a twofold higher concentration of drug in plasma for HepaSphere microspheres. HepaSphere microspheres were less frequently found inside tumor nodules on histology than DC Bead microspheres (11% vs 48%, P < .001) because of their larger size. Tumor necrosis was significantly greater for rabbits given irinotecan-loaded HepaSphere microspheres (69% of total tumor surface) and rabbits given DC Bead microspheres (50% of total tumor surface) compared with control animals (24% of total tumor surface, P = .006 and P = .047). CONCLUSIONS: HepaSphere and DC Bead microspheres loaded with irinotecan caused significant necrosis of tumor nodules in a model of VX2 liver metastases. This outcome was mostly due to irinotecan delivery rather than vascular occlusion by the microspheres and was greater for HepaSphere microspheres compared with DC Bead microspheres.

Chylothorax after esophagectomy cured by intranodal lymphangiography: a case report.

This is a case report of chylothorax after esophagectomy for esophageal cancer cured by intranodal lymphangiography in the groin. A 62-year-old man was admitted to our Hospital with dysphagia. The diagnosis was made of advanced esophageal cancer (T3N1M0, stage IIIA). After neoadjuvant chemotherapy, radical surgery was performed. On postoperative day (POD) 9, left pleural effusion drainage increased sharply and changed to a milky white color, leading to a diagnosis of chylothorax. Although chylothorax was managed with conservative treatment, there was an inadequate response to it. On POD 15, lymphangiography was performed. Inguinal nodes were directly accessed under ultrasound guidance and lipiodol was injected into nodes. After the lymphangiography, the left pleural effusion drainage immediately decreased. On POD 40, the patient was discharged. To the best of our knowledge, this is the first report of a chylothorax after esophagectomy for esophageal cancer to be cured by ultrasound-guided intranodal lymphangiography in the groin.

The assessment of collateral communication after hybrid repair for Crawford extent II thoraco-abdominal aortic aneurysms.

OBJECTIVES: The repair of extensive thoraco-abdominal aortic aneurysms (TAAAs) is invasive and carries a high risk for spinal cord injury (SCI). The aim of this study was to assess the early results and collateral circulation to the spinal cord after hybrid repair for Crawford extent II aortic aneurysms. METHODS: Between 1997 and 2013, we performed 128 thoracic endovascular aortic repair (TEVAR) procedures for TAAAs. This study reviews 12 patients who underwent hybrid TEVAR for a Crawford extent II aortic aneurysm (mean age: 56 years, 6 men, chronic dissection: 10). Aortic arch repair was performed to create a proximal landing zone and visceral debranching bypass was performed to create a distal landing zone at separate stages prior to TEVAR. Subsequently, a stent graft was deployed to cover the residual downstream aorta. TEVAR was generally performed the day after the final debranching procedure. Cerebrospinal fluid drainage was performed, and the mean blood pressure was maintained at >90 mmHg in all cases. RESULTS: The median operation time for TEVAR was 94 min (range: 71-421 min) and the mean blood loss was 300 ml (range: 130-1350 ml). No SCI or in-hospital death was observed after TEVAR. Multidetector computed tomography identified three arteries (subclavian artery, external iliac artery and internal iliac artery) providing collateral circulation to spinal segmental arteries (SAs). In all cases, mid-thoracic SAs (Th5-8) and low lumbar SAs (L2-5) were fed by the subclavian artery and the internal iliac artery, respectively. Additionally, low thoracic to high lumbar SAs (Th9-L1) communicated with the subclavian artery via the lateral thoracic wall and/or the external iliac artery via the abdominal wall. CONCLUSIONS: We achieved satisfactory early and mid-term outcomes with hybrid repair for Crawford extent II TAAAs. Furthermore, collateral circulation to SAs was maintained during and after TEVAR regardless of the extent of the aortic repair.

Percutaneous sclerotherapy for venous malformations in the extremities: clinical outcomes and predictors of patient satisfaction.

The purpose of this study is to retrospectively evaluate the clinical outcomes and to identify the predictors ofpatient satisfaction after percutaneous sclerotherapy for venous malformations (VMs) in the extremities. A totalof 48 patients with VMs in the extremities over 10 years of age underwent sclerotherapy to relieve symptoms, such as pain, swelling, functional limitations, and cosmetic problems. Self-assessment questionnaires were sentto rate the degree of symptom improvement and level of satisfaction. Clinical and imaging data from medicalrecords were analyzed to obtain information about VMs and sclerotherapy. The predictors for patientsatisfaction were determined by univariate and multivariate analysis of clinical variables. Forty patients (meanage, 28.2 years; range, 11-69 years) responded to the survey. Sixteen patients had VMs in the upper extremities, and 24 patients had VMs in the lower extremities. In 12 patients (30%), adjacent bone change was seen. After amean of 2.6 (range 1-10) sclerotherapy sessions, good response to pain, swelling, dysfunction, and cosmeticproblems was obtained in 83%, 74%, 79%, and 50% of patients, respectively. Thirty-two patients (80%) weresatisfied with their outcomes. On univariate analysis, absence of adjacent bone change, maximum diameter (<6.7 cm), and number of sclerotherapy sessions (<3) were significantly associated with patient satisfaction.Multivariate analysis revealed absence of adjacent bone change (odds ratio, 7.56; 95% confidence interval, 1.02-55.8) as an independent predictor for satisfaction. Thus, adjacent bone change significantly portended adissatisfied patient. In conclusion, percutaneous sclerotherapy was effective to relieve symptoms of VMs in theextremities, and most patients were satisfied with the outcomes. However, adjacent bone change was asignificant predictor of patient dissatisfaction.

In vivo evaluation of irinotecan-loaded QuadraSphere microspheres for use in chemoembolization of VX2 liver tumors.

PURPOSE: To investigate the pharmacokinetics and chemoembolization efficacy of irinotecan-loaded QuadraSphere microspheres (QSMs) in a rabbit VX2 liver tumor model. MATERIALS AND METHODS: Fourteen rabbits with VX2 liver tumors were divided into two groups. In the irinotecan-loaded QSM group (n = 7), 3 mg of QSMs (30-60 µm) containing 12 mg of irinotecan (0.6 mL; 20 mg/mL) were injected into the left hepatic artery. In the control group (hepatic arterial infusion [HAI] and QSMs; n = 7), 3 mg of QSMs suspended in ioxaglic acid were injected following a bolus injection of 0.6 mL of irinotecan solution (20 mg/mL). Sequential irinotecan, SN-38, and SN-38G concentration changes were measured in plasma within 24 hours and at 1 week and in tissues at 1 week. The VX2 tumor growth rates at 1 and 2 weeks were calculated from computed tomographic images. RESULTS: All rabbits underwent successful embolization. Plasma irinotecan, SN-38, and SN-38G concentrations in the irinotecan-loaded QSM group showed significantly sustained release compared with the control group (P = .01). Compared with the control group, the irinotecan-loaded QSM group had significantly higher irinotecan concentration in liver tumors (P = .03) and a tendency toward higher SN-38 concentration in liver tumors (P = .29). The SN-38G tissue concentrations were below the limits of quantification. The tumor growth rate was significantly lower and the tumor necrosis rate significantly higher in the irinotecan-loaded QSM group (P = .02 and P = .01, respectively). CONCLUSION: Chemoembolization via irinotecan-loaded QSMs more effectively suppresses tumor growth than chemoembolization with unloaded QSMs after HAI. A clinical feasibility study is warranted.

Embolic effects of transcatheter mesenteric arterial embolization with microspheres on the small bowel in a dog model.

PURPOSE: To determine the arterial distribution and ischemic effects of various particle sizes after transcatheter embolization of the small bowel in a dog model. MATERIALS AND METHODS: In 10 dogs, selective microsphere embolization was performed in six branches of the superior mesenteric artery. Microspheres were allocated into three size ranges (100-300 µm, 300-500 µm, and 500-700 µm) and four volume concentrations (0.625%, 1.25%, 2.5%, and 5%). For each size and volume concentration, embolization was performed of five branches at the origin of the last arcade. The distribution of microspheres and the range of ischemic changes of mucosa were evaluated histologically. Angiograms were categorized into two groups: group A, only the vasa recta nonopacified; group B, the last arcade or more proximal branches nonopacified. RESULTS: Microspheres sized 100-300 µm penetrated into intramural arteries and 500-700 µm microspheres mainly blocked arteries in the mesentery. There was a significant difference among three sizes in terms of the locations within the vasculature (P < .0001). The larger volume and the smaller size resulted in more ischemia. The range of ischemic changes among three sizes and among four volume concentrations was significantly different (P = .004 and P < .0001, respectively). The range of ischemic changes with 500-700 µm microspheres in group B was significantly greater than in group A (0% in group A vs 83% in group B, P = .001). CONCLUSIONS: In a dog model, embolization of the small bowel limited to the vasa recta with the use if 500-700 µm microspheres reduced the range of ischemic changes.

Initial experience with use of hydrogel microcoils in embolization of pulmonary arteriovenous malformations.

The purpose of this study is to describe our initial experience with embolization of pulmonary arteriovenous malformations (PAVMs) using hydrogel microcoils. The technical and radiological outcomes were retrospectively reviewed in seven patients with nine simple-type PAVMs (median feeder size 4 mm, range 3-6 mm) who underwent embolization. Hydrogel microcoils were mainly used, and detachable bare microcoils were combined as needed to occlude the terminal feeding artery just before the sac. Of a total of 43 microcoils, 30 (69.8%) hydrogel microcoils were deployed in eight PAVMs with the median number 3.5 (range 2 to 6) per lesion. All hydrogel microcoils were successfully deployed without microcatheter stuck or malposition. In the remaining one small PAVM, only soft bare microcoils were used, however, resulting in recanalization requiring additional coils in the second session. The venous sac was substantially shrunk in all lesions treated with hydrogel microcoils with the median size reduction rate 95.0% (range 81.8% to 99.0%) during the median follow-up period 10 months (range 6 to 18 months). In conclusion, hydrogel microcoils were safely and effectively applied for occluding PAVMs with relatively small feeders.

Long-term outcomes of coil packing for visceral aneurysms: correlation between packing density and incidence of coil compaction or recanalization.

PURPOSE: To evaluate the correlation between packing density and the incidence of coil compaction or recanalization of visceral artery aneurysms (VAAs) after coil packing. MATERIALS AND METHODS: Between July 2004 and April 2012, coil packing was performed for 46 true visceral aneurysms (16 splenic, 11 pancreaticoduodenal, eight renal, six hepatic, three superior mesenteric, one right gastric, and one gastroepiploic) in 42 patients. The size and volume of the aneurysm, packing density, and the incidences of compaction and recanalization were evaluated retrospectively. RESULTS: The mean follow-up period was 37 months ± 8 (range, 11-80 mo). The mean packing density was 19% ± 8 (range, 5%-42%), mean aneurysm size was 19 mm ± 8 (range, 5-40 mm), and mean volume was 4,108 mm(3) ± 5,435 (range, 72-26,235 mm(3)). Compaction and recanalization occurred in two (4%) and 12 aneurysms (26%), respectively. The mean packing density was significantly lower in aneurysms with compaction or recanalization than in unaffected aneurysms (12% vs 22%; P = .00014). There was a significant difference in mean packing density between small (< 20 mm; 22%) and large (≥ 20 mm) aneurysms (15%; P = .0045). The mean size and volume were significantly larger for coil-compacted or recanalized aneurysms than for unaffected aneurysms (P < .05). In aneurysms with a packing density of at least 24%, no compaction or recanalization occurred. CONCLUSIONS: Coil compaction or recanalization after coil packing for VAAs more often occurs after insufficient embolization with low packing density and in patients with large aneurysms.

Targeting and recanalization after embolization with calibrated resorbable microspheres versus hand-cut gelatin sponge particles in a porcine kidney model.

PURPOSE: To report on polyethylene glycol hydrogel-based resorbable embolization microspheres (REM) that were synthesized to resorb in < 24 hours, before inflammation and vascular remodeling, to achieve a complete arterial recanalization and to compare targeting and recanalization of REM of 300-500 µm, 500-700 µm, and 700-900 µm with hand-cut gelatin sponge particles (GSP). MATERIALS AND METHODS: Eight pigs underwent polar renal artery embolization with REM or GSP. Angiograms were obtained before embolization and 10 minutes and 7 days after embolization before pigs were sacrificed to determine the occlusion level, the percentage of occlusion, and the recanalization rate for each product. The distribution of embolic material was assessed in pathology, and infarction rate of the kidneys was measured. RESULTS: REM of 300-500 µm occluded more distal vessels than REM of 500-700 µm and 700-900 µm. At day 7, the recanalization rate was complete for the larger REM, whereas it was about 60% for the two smaller sizes. REM were completely degraded, with no residual material or inflammation. GSP occluded more proximal arteries than REM of 700-900 µm, were partly degraded at day 7, and were accompanied by a foreign body reaction in proximal and distal arteries. GSP recanalized at 79%. The infarction rate was higher with the two smaller sizes of REM and with GSP than with the largest REM. CONCLUSIONS: REM of different sizes targeted different occlusion levels in kidney arteries. GSP provided an extended occlusion level without actual targeting. Regardless of embolic material used, angiographic recanalization of renal arteries depended on the extent of necrosis. REM of 700-900 µm demonstrated the lowest infarction rate and the best recanalization rate.