Calibrated Bioresorbable Microspheres: A Preliminary Study on the Level of Occlusion and Arterial Distribution in a Rabbit Kidney Model

PurposeTo assess the level of occlusion and arterial distribution of calibrated bioresorbable microspheres (BRMS-I and BRMS-II) compared with tris-acryl gelatin microspheres (TGMS) after renal embolization.Materials and MethodsSix rabbits underwent renal embolization with 100–300 µm BRMS-I and TGMS; three rabbits received partial occlusion (group 1, n = 3), and three rabbits received total occlusion (group 2, n = 3). Four other rabbits received 100–300 µm BRMS-II (with higher cross-linking density than BRMS-I) in the left kidneys reaching total occlusion (group 3, n = 4). Coronal sections of the kidneys were histologically analyzed. Ease of injection, microsphere deformation, vessel sizes, and arterial distribution were assessed.ResultsThe injection of BRMS-I, BRMS-II, and TGMS through microcatheters went smoothly without any clogging. In group 1, BRMS identification was easier than TGMS. In group 2, both BRMS-I and TGMS were observed in all three arterial levels (interlobar, arcuate, and interlobular arteries) without a significant difference (P = .84). BRMS-I were not significantly different from TGMS in the mean diameter of vessels occluded (197 µm ± 23 vs 158 µm ± 21, P = .25) or the microsphere deformation (8.85% ± 0.53% vs 11.80% ± 0.64%, P = .071). In group 3, the arterial distribution of BRMS-II was significantly different from BRMS-I and TGMS (P < .0001).ConclusionsIn occluding arteries, 100–300 µm BRMS-I were not significantly different from 100–300 µm TGMS. Arterial distribution of BRMS can be influenced by their cross-linking density.     

Comparison of Polyvinyl Alcohol Microspheres and Tris-Acryl Gelatin Microspheres for Uterine Fibroid Embolization: Results of a Single-Center Randomized Study

PurposeTo assess the efficacy of two embolic agents in the treatment of symptomatic uterine leiomyomas.Materials and MethodsA randomized, prospective, single-center study enrolled 60 women with symptomatic uterine leiomyomas. Uterine artery embolization (UAE) with spherical polyvinyl alcohol (SPVA) microspheres (n = 30; 700–900 μm and 900–1,200 μm; near-stasis or stasis endpoint) and tris-acryl gelatin (TAG) microspheres (n = 30; 500–700 μm; “pruned-tree” endpoint) was performed. Infarction rates were calculated for the dominant tumor and for small (< 2 cm) and large (> 2 cm) nondominant tumors. The primary endpoint was tumor infarction at 24 hours measured by contrast-enhanced magnetic resonance imaging assessed by a blinded reviewer.ResultsBaseline characteristics were similar between groups. The primary endpoint was similar in both treatments (≥ 91% dominant tumor infarction; SPVA. 86.2%; TAG, 93.3%, P = .35). Complete infarction (100%) was also similar between arms at 24 hours and 3 months. Symptom severity was reduced and quality of life improved equally at 3 and 12 months in each treatment group. Complications were minor in both groups.ConclusionsUterine leiomyoma infarction at 24 hours and 3 months after treatment with SPVA or TAG microspheres was comparable when using near-stasis as a procedural endpoint with SPVA microspheres. Symptom relief was maintained for as long as 12 months for both embolic agents.     

Embolic Effects of Transcatheter Mesenteric Arterial Embolization with Microspheres on the Small Bowel in a Dog Model

PurposeTo determine the arterial distribution and ischemic effects of various particle sizes after transcatheter embolization of the small bowel in a dog model.Materials and MethodsIn 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.ResultsMicrospheres 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).ConclusionsIn 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.     

Drug-Eluting Beads Loaded with Antiangiogenic Agents for Chemoembolization: In Vitro Sunitinib Loading and Release and In Vivo Pharmacokinetics in an Animal Model

PurposeThe combination of embolic beads with a multitargeted tyrosine kinase inhibitor that inhibits tumor vessel growth is suggested as an alternative and improvement to the current standard doxorubicin-eluting beads for use in transarterial chemoembolization. This study demonstrates the in vitro loading and release kinetics of sunitinib using commercially available embolization microspheres and evaluates the in vitro biologic efficacy on cell cultures and the resulting in vivo pharmacokinetics profiles in an animal model.Materials and MethodsDC Bead microspheres, 70–150 µm and 100–300 µm (Biocompatibles Ltd., Farnham, United Kingdom), were loaded by immersion in sunitinib solution. Drug release was measured in saline in a USP-approved flow-through apparatus and quantified by spectrophotometry. Activity after release was confirmed in cell culture. For pharmacokinetics and in vivo toxicity evaluation, New Zealand white rabbits received sunitinib either by intraarterial injection of 100–300 µm sized beads or per os. Plasma and liver tissue drug concentrations were assessed by liquid chromatography–tandem mass spectroscopy.ResultsSunitinib loading on beads was close to complete and homogeneous. A total release of 80% in saline was measured, with similar fast-release profiles for both sphere sizes. After embolization, drug plasma levels remained below the therapeutic threshold (< 50 ng/mL), but high concentrations at 6 hours (14.9 µg/g) and 24 hours (3.4 µg/g) were found in the liver tissue.ConclusionsDC Bead microspheres of two sizes were efficiently loaded with sunitinib and displayed a fast and almost complete release in saline. High liver drug concentrations and low systemic levels indicated the potential of sunitinib-eluting beads for use in embolization.     

A Novel Resorbable Embolization Microsphere for Transient Uterine Artery Occlusion: A Comparative Study with Trisacryl-Gelatin Microspheres in the Sheep Model

PurposeTo evaluate angiographic recanalization, inflammatory reaction, and uterine damage after sheep uterine artery embolization (UAE) with a novel calibrated resorbable embolization microsphere (REM) and compare the results with control nonresorbable microspheres.Materials and MethodsSix hormonally artificially cycled sheep underwent bilateral UAE until stasis with either REM or trisacryl-gelatin microspheres (TGMS). At 7 days, control angiograms were obtained to assess the residual vascularization at arterial and parenchymal phases. The animals were then sacrificed for analysis of the presence of microspheres, inflammatory foreign body reaction, and surface areas of uterine damage.ResultsMean volume of microspheres injected per uterine artery (UA) or per animal did not differ between groups. At day 7, the flow was normal for six of six UAs that received embolization with REM versus only three of six UAs with TGMS (P = .0455, χ² test). Uterine parenchymography showed no defects in six UAs in the REM group versus five defects in six UAs in the TGMS group (P = .0060, χ² test). No REM or residual fragments of microspheres were observed on histologic analysis. TGMS were observed in tissues and accompanied by a mild inflammatory response. Necrosis rates were not significantly different between the two products, either in endometrium (REM 23.5% ± 28.8% [median 8.1%] vs TGMS 21.8% ± 23.7% [median 14.6%]) or in myometrium (REM 8.2% ± 22.7% [median 0.0%] vs TGMS 8.8% ± 20.8% [median 0.9%]). Endometrium alteration rate was lower with REM than with TGMS (39.7% ± 25.7% [median 34%] vs 60.6% ± 27.1% [median 71%]; P = .0060, Mann-Whitney test). Myometrium alteration rates were not significantly different between REM (45.7% ± 37.1% [median 63.0%]) and TGMS (37.8% ± 34.0% [median 19.1%]).ConclusionsAt 1 week after sheep UAE with REM, the recanalization was complete, the microspheres were completely degraded, and there was no remnant inflammatory response.     

Feasibility of Time-Resolved MR Angiography for Detecting Recanalization of Pulmonary Arteriovenous Malformations Treated with Embolization with Platinum Coils

PurposeTo assess the feasibility of time-resolved magnetic resonance (MR) angiography as a follow-up method after embolization for pulmonary arteriovenous malformations (PAVMs).Materials and MethodsEvaluation of 28 PAVMs in 10 patients previously treated with embolization with platinum coils was performed. The mean observation period after embolization was 49 months. All patients underwent unenhanced chest computed tomography (CT) and time-resolved MR angiography followed by transcatheter digital subtraction angiography within 5 weeks for a definite diagnosis. Two radiologists reviewed the CT and time-resolved MR angiography findings using a blinded method. On CT, the draining veins of the PAVMs were measured before and after embolization, and shrinkage rates were calculated. On time-resolved MR angiography, recanalization was diagnosed when the draining vein or aneurysmal sac or both were enhanced in the pulmonary arterial phase. Correlations between recanalization, the shrinkage rate of the draining vein, and the diagnostic accuracies of CT and time-resolved MR angiography were assessed and compared with digital subtraction angiography.ResultsFive lesions could not be measured on CT because of metallic artifacts. The mean shrinkage rates of the draining vein for recanalized and occluded PAVMs were 23% ± 19 (SD) for recanalized PAVMs and 47% ± 21 for occluded PAVMs (P = .001). The sensitivity and specificity were 93% and 53%, respectively, when the shrinkage rate threshold was set to 50%. On time-resolved MR angiography, the sensitivity and specificity were 93% and 100%, respectively, for Reader 1 and 100% and 93%, respectively, for Reader 2. The κ coefficient was 0.86.ConclusionsTime-resolved MR angiography appears to be a feasible method for PAVM follow-up examinations and to provide a more accurate diagnosis of recanalization compared with unenhanced CT.     

Combined Antegrade Femoral Artery and Retrograde Popliteal Artery Recanalization for Chronic Occlusions of the Superficial Femoral Artery

PurposeTo evaluate the efficacy and safety of a dual femoral–popliteal approach in the supine position after failed antegrade recanalization attempts in chronic total occlusion (CTO) of the superficial femoral artery (SFA).Materials and MethodsFrom May 2011 to October 2012, 21 patients underwent dual femoral–popliteal recanalization for CTO of the SFA, with a mean lesion length of 87.4 mm ± 5.8. When contralateral antegrade recanalization of SFA occlusions via the common femoral artery could not be achieved, the occlusions were intrainterventionally accessed by retrograde approach via the popliteal artery, which was punctured anteriorly with gently flexed knee and crus extorsion. When the SFA had been recanalized, further angioplasty and stent placement procedures were completed via the femoral artery.ResultsA technical success rate of 100% (entailing puncture of the popliteal artery and SFA recanalization) was achieved, and no hemorrhage, hematoma, pseudoaneurysm, arteriovenous fistula, or other complications developed. During a mean follow-up of 9.8 months ± 1.5, claudication severity, rest pain, and toe ulcers improved significantly. The pulse of the distal arteries, as well as the filling of the veins, could be distinctly felt. Ankle-brachial index changed from 0.48 ± 0.17 to 0.84 ± 0.11 at 1 year after intervention (P < .001), and patency rates at 1, 6, and 12 months after interventions were 100%, 80%, and 42%, respectively.ConclusionsA dual femoral–popliteal approach in the supine position is an alternative backup option after failed attempts at the antegrade approach for patients with proximal barriers in CTO or lesions with major extending collateral vessels.     

Does Polyvinyl Alcohol Particle Size Change the Outcome of Prostatic Arterial Embolization for Benign Prostatic Hyperplasia? Results from a Single-Center Randomized Prospective Study

PurposeTo evaluate whether different polyvinyl alcohol (PVA) particle sizes change the outcome of prostatic arterial embolization (PAE) for benign prostatic hyperplasia (BPH).Materials and MethodsA randomized prospective study was undertaken in 80 patients (mean age, 63.9 y; range, 48–81 y) with symptomatic BPH undergoing PAE between May and December 2011. Forty patients underwent PAE with 100-µm (group A) and 200-µm PVA particles (group B). Visual analog scales were used to measure pain, and rates of adverse events were recorded. PAE outcomes were evaluated based on International Prostate Symptom Score (IPSS) and quality-of-life (QoL) questionnaires, prostate volume (PV), prostate-specific antigen (PSA) levels, and peak flow rate measurements at baseline and 6 months.ResultsNo differences between groups regarding baseline data, procedural details, or adverse events were noted. Mean pain scores were as follows: during embolization, 3.2 ± 2.97 (group A) versus 2.93 ± 3.28 (group B); after embolization, 0.10 ± 0.50 (group A) versus 0 (group B; P = .20); and the week after PAE, 0.85 ± 1.65 (group A) versus 0.87 ± 1.35 (group B; P = .96). Patients in group B had greater decreases in IPSS (3.64 points; P = .052) and QoL (0.57 points; P = .07). Patients in group A had a greater decrease in PV (8.75 cm³; P = .13) and PSA level (2.09 ng/mL; P < .001).ConclusionsNo significant differences were found in pain scores and adverse events between groups. Whereas PSA level and PV showed greater reductions after PAE with 100-µm PVA particles, clinical outcome was better with 200-µm particles.     

Acute Combined Revascularization in Acute Ischemic Stroke with Intracranial Arterial Occlusion: Self-expanding Solitaire Stent during Intravenous Thrombolysis

PurposeTo investigate the safety and efficacy of the self-expanding Solitaire stent used during intravenous thrombolysis (IVT) for intracranial arterial occlusion (IAO) in acute ischemic stroke (AIS).Materials and MethodsConsecutive nonselected patients with AIS with IAO documented on computed tomographic angiography or magnetic resonance angiography and treated with IVT were included in this prospective study. Stent intervention was initiated and performed during administration of IVT without waiting for any clinical or radiologic signs of potential recanalization. Stroke severity was assessed by National Institutes of Health Stroke Scale (NIHSS), and 90-day clinical outcome was assessed by modified Rankin scale (mRS), with a good outcome defined as an mRS score of 0–2. Recanalization was rated by thrombolysis in cerebral infarction (TICI) scale.ResultsFifty patients (mean age, 66.8 y ± 14.6) had a baseline median NIHSS score of 18.0. Overall recanalization was achieved in 94% of patients, and complete recanalization (ie, TICI 3 flow) was achieved in 72% of patients. The mean time from stroke onset to maximal recanalization was 244.2 minutes ± 87.9, with a median of 232.5 minutes. The average number of device passes was 1.5, with a mean procedure time to maximal recanalization of 49.5 minutes ± 13.0. Symptomatic intracerebral hemorrhage occurred in 6% of patients. The median mRS score at 90 days was 1, and 60% of patients had a good outcome (ie, mRS score 0–2). The overall 3-month mortality rate was 14%.ConclusionsCombined revascularization with the Solitaire stent during IVT appears to be safe and effective in the treatment of acute IAO.     

Selective Arterial Embolization with Ethylene–Vinyl Alcohol Copolymer for Control of Massive Lower Gastrointestinal Bleeding: Feasibility and Initial Experience

PurposeTo evaluate the efficacy, safety, and clinical outcomes of superselective embolization using ethylene–vinyl alcohol copolymer (Onyx Liquid Embolic System; ev3 Neurovascular, Irvine, California) as the primary treatment for acute and massive lower gastrointestinal bleeding (LGIB).Materials and MethodsBetween January 2008 and October 2013, all patients with focal massive LGIB who were treated by embolization were retrospectively analyzed. The study was approved by the hospital’s ethics committee; informed consent was obtained in all cases. Onyx was chosen as the embolic agent in all cases in an intention-to-treat fashion. Embolization was indicated in 31 consecutive patients (mean age, 80 y ± 11.1). Multidetector computed tomography and digital subtraction angiography were performed in all patients.ResultsActive bleeding was detected in all cases. A colonoscopy was performed in 11 patients. The correlation between multidetector computed tomography and angiography findings was 96.7%. The causes of bleeding were diverticula in 15 patients, iatrogenic in 7 patients, neoplasia in 3 patients, hemorrhoids in 2 patients, angiodysplasia in 2 patients, and unknown in 2 patients. Embolization was not possible in one patient, who required urgent left hemicolectomy. The technical success rate was 93.5%. The embolic material refluxed in one patient, causing an undesired embolization, without any clinical consequences. In the 30 patients who received embolization, the immediate bleeding control rate was 100%. Rebleeding at 30 days occurred in three patients (10%). There were no major complications, intestinal ischemia, or deaths attributable to the treatment. No patient needed surgery or new embolization during a mean follow-up period of 23.7 months (range, 1–71 mo).ConclusionsControl of massive LGIB using superselective embolization with Onyx is feasible and safe.     

Combined Transmesenteric and Transhepatic Recanalization of Chronic Portal and Mesenteric Vein Occlusion to Treat Bleeding Duodenal Varices

Two patients presented with bleeding duodenal varices secondary to mesenteric and portal vein chronic occlusion. After a failed transhepatic recanalization, a combined transmesenteric and transhepatic approach was used to recanalize the chronic portal and mesenteric venous obstruction. The occluded segment was treated with transmesenteric stent placement in one patient and stent placement and coil embolization of varices in the second patient. Follow-up imaging and endoscopy showed decompression of the duodenal varices in both patients and absence of further bleeding episodes.     

Long-term Outcomes of Coil Packing for Visceral Aneurysms: Correlation between Packing Density and Incidence of Coil Compaction or Recanalization

PurposeTo evaluate the correlation between packing density and the incidence of coil compaction or recanalization of visceral artery aneurysms (VAAs) after coil packing.Materials and MethodsBetween 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.ResultsThe 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 mm³ ± 5,435 (range, 72–26,235 mm³). 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.ConclusionsCoil compaction or recanalization after coil packing for VAAs more often occurs after insufficient embolization with low packing density and in patients with large aneurysms.     

Endovascular Procedures versus Intravenous Thrombolysis in Stroke with Tandem Occlusion of the Anterior Circulation

PurposeStroke with tandem occlusion within the anterior circulation presents a lower probability of recanalization and good clinical outcome after intravenous (IV) thrombolysis than stroke with single occlusion. The present study describes the impact of endovascular procedures (EPs) compared with IV thrombolysis alone on recanalization and clinical outcome.Materials and MethodsThirty patients with symptom onset less than 4.5 hours and tandem occlusion within the anterior circulation were analyzed retrospectively. Recanalization was assessed per Thrombolysis In Cerebral Infarction (TICI) classification on computed tomography, magnetic resonance imaging, or digital subtraction angiography within 24 hours. Infarct size was detected on follow-up imaging as a dichotomized variable, ie, more than one third of the territory of the middle cerebral artery. Clinical outcomes were major neurologic improvement, independent outcome (90-d modified Rankin Scale [mRS] score), symptomatic intracerebral hemorrhage (sICH; per European Cooperative Acute Stroke Study criteria), and death within 7 days.ResultsPatients treated with EPs (n = 14) were significantly younger and had a history of arterial hypertension more frequently than patients treated with IV thrombolysis alone (n = 16). Recanalization (ie, TICI score 2b/3; EP, 64%; IV, 19%; P = .01), major neurologic improvement (EP, 64%; IV, 19%; P = .01), and independent outcome (mRS score ≤ 2; EP, 54% IV, 13%; P = .02) occurred more often in the EP group, whereas infarct sizes greater than one third of the MCA territory (EP, 43%; IV, 81%; P = .03) were observed less often. Rates of sICH (P = .12) and death within 7 days (P = .74) did not differ significantly.ConclusionsHigher recanalization rate, smaller infarct volume, and better clinical outcome in the EP group should encourage researchers to include this subgroup of patients in prospective randomized trials comparing IV thrombolysis versus EP in stroke.     

Early Experience with the AMPLATZER Vascular Plug IV for the Occlusion of Pulmonary Arteriovenous Malformations

The recent generation of AMPLATZER Vascular Plug (AVP; ie, the AVP IV) was used for the occlusion of eight pulmonary arteriovenous malformations (PAVMs) in five patients. A treatment was considered successful when there was a reduction or disappearance of the aneurysmal sac. At a mean follow-up of 20.1 months, no recanalization of PAVMs was observed on multidetector computed tomographic angiography. This shows the AVP IV to be safe and effective as an embolic device to occlude PAVMs.     

Transcatheter Arterial Embolization for Secondary Postpartum Hemorrhage: Outcome in 52 Patients at a Single Tertiary Referral Center

PurposeTo assess the safety and efficacy of transcatheter arterial embolization (TAE) for the management of secondary postpartum hemorrhage (PPH) and to determine the factors associated with the clinical outcomes.Materials and MethodsA retrospective analysis of 52 patients (mean age, 31.6 y; range, 25–40 y) undergoing TAE for secondary PPH was performed. Clinical data, including maternal characteristics, delivery details, embolization details, and transfusion requirements, were obtained. Univariate analyses were performed to determine the factors related to clinical outcomes.ResultsThe major cause of bleeding was retained placental tissue (44.2%; 23 of 52). Actively bleeding foci were observed in 25 (48.1%) patients. Technical and clinical successes were achieved in 100% and 90.4% (47 of 52) of patients, respectively. Gelatin sponge particles with (n = 10) or without (n = 38) permanent embolic materials, such as microcoils or N-butyl cyanoacrylate, were most commonly used (92.3%; 48 of 52), whereas permanent embolic materials alone were used in 7.7% (4 of 52) of patients. In five patients, embolization failed, and these patients were managed by hysterectomy (n = 3), repeat TAE (n = 1), or conservative management (n = 1). Bleeding control was eventually achieved in all five patients. No maternal risk factors were related to clinical results. The median and mean follow-up periods were 3 months and 12.6 months (range, 1–62 mo). Regular menstruation resumed in all 44 patients with available follow-up, and 5 of the patients became pregnant.ConclusionsTAE for secondary PPH is safe and effective and showed technical and clinical success in 100% and 90.4% of patients, respectively. Approximately half of these patients showed a positive bleeding focus, and the use of permanent embolic materials was also common.     

Safety and Efficacy of Transcatheter Arterial Embolization for Lower Gastrointestinal Bleeding: A Single-center Experience with 112 Patients

PurposeTo assess the safety and efficacy of transcatheter arterial embolization for lower gastrointestinal bleeding (LGIB) and to determine the prognostic factors that affect clinical outcome.Materials and MethodsAll patients diagnosed with LGIB by angiography at a single institution from April 2006 to January 2013 were included in a retrospective study. The rates of technical success, early recurrent bleeding, major complications, clinical success, and in-hospital mortality for transcatheter arterial embolization were determined. The influence of possible prognostic factors on the outcome was analyzed.ResultsA total of 112 patients were included (36 with small-bowel LGIB, 36 with colon LGIB, and 40 with rectal LGIB). N-butyl cyanoacrylate (NBCA) was the embolic agent for 84 patients (75.0%), whereas gelatin sponge pledgets (n = 20), microcoils (n = 2), polyvinyl alcohol particles with adjunctive gelatin sponge pledgets (n = 1), and blood clots (n = 1) were used in the other patients. The technical success rate was 96.4%. For the entire group, the rates of early recurrent bleeding, major complications, clinical success, and in-hospital mortality were 17.4%, 4.6%, 74.5%, and 25.0%, respectively. These were 15.2%, 4.8%, 75.3%, and 26.2%, respectively, in the NBCA group. Hematologic malignancy, immobilization status, and coagulopathy were significant prognostic factors for clinical outcomes.ConclusionsTranscatheter arterial embolization is a safe and effective treatment for LGIB. NBCA could be used as a primary embolic agent for this procedure.     

Forcible Intraarterial Injection of a Nonadhesive Liquid Embolic Agent under Microballoon Occlusion: Experimental Study in Swine Liver

PurposeTo evaluate the feasibility and effectiveness of transcatheter embolization by forcible intraarterial injection of a mixture of ethylene vinyl alcohol copolymer (EVAL) and ethanol under microballoon occlusion compared with conventional transcatheter arterial embolization methods in nontumoral swine liver.Materials and MethodsNine swine were divided into three groups: embolization with EVAL/ethanol mixture (EVAL group, n = 5), with ethiodized oil (ethiodized oil group, n = 2), and with microspheres (microspheres group, n = 2). Embolization was performed at the subsegmental hepatic artery. The EVAL/ethanol mixture was injected forcibly through a microcatheter with a balloon, which was inflated to prevent backflow of the mixture during the injection. Ethiodized oil or microspheres were injected into the artery using a microcatheter without balloon occlusion. Two animals of the EVAL group were euthanized immediately after embolization, and the distribution of EVAL was assessed microscopically. The remaining seven animals were euthanized 4 weeks after embolization, and the histopathologic changes were assessed.ResultsAll procedures were technically successful. EVAL occupied > 80% of the hepatic arterial, portal venous, and sinusoidal lumens after embolization. Ischemic coagulation necrosis was observed 4 weeks after embolization in the EVAL group. Parenchymal necrosis was not observed in the ethiodized oil and microspheres groups.ConclusionsTranscatheter embolization by forcible intraarterial injection of an EVAL/ethanol mixture under microballoon occlusion was feasible and achieved the simultaneous embolization of hepatic artery, portal vein, and sinusoids in swine liver, resulting in complete necrosis of the segment that received embolization.     

Treatment of Acute Hemoptysis by Bronchial Artery Embolization with the Liquid Embolic Agent Ethylene Vinyl Alcohol Copolymer

PurposeTo determine the technical and clinical success of bronchial artery embolization (BAE) with the liquid embolic agent ethylene vinyl alcohol (EVOH) copolymer in patients with acute hemoptysis.Materials and MethodsThirty-four patients (25 male; mean age, 58 y; range, 13–78 y) who underwent BAE with EVOH were retrospectively reviewed. Reasons for acute hemoptysis included lung cancer (44%), pulmonary metastases (12%), bronchiectasis (21%), arteriovenous malformation (5%), tuberculosis (6%), aspergilloma (3%), acute respiratory distress syndrome (3%), anticoagulant overdose (3%), and scar tissue (3%). Technical and clinical success of BAE were retrospectively assessed.ResultsEmbolization was technically successful in 94% of patients. Additional embolization material was needed in 4 patients (12%). The immediate clinical success rate was 94% (32 of 34); in 2 patients (6%), hemoptysis recurred immediately after the intervention or could not be stopped. Periinterventional minor complications included headache (n = 1), fever (n = 1), and acute renal failure (n = 1). During follow-up (mean, 8.8 mo), 5 patients had a recurrence of hemoptysis (15%).ConclusionsThe use of EVOH copolymer for BAE in patients with acute hemoptysis is technically successful and safe and has a good clinical outcome with a low number of recurrences.     

Percutaneous Intraportal Application of Adipose Tissue–derived Mesenchymal Stem Cells Using a Balloon Occlusion Catheter in a Porcine Model of Liver Fibrosis

PurposeTo investigate the safety and effectiveness of a novel endovascular approach for therapeutic cell delivery using a balloon occlusion catheter in a large animal model of liver fibrosis.Materials and MethodsTranscatheter arterial embolization with ethiodized oil (Ethiodol) and ethanol was used to induce liver damage in 11 pigs. Mesenchymal stem cells (MSCs) were harvested from adipose tissue and engineered to express green fluorescent protein (GFP). A balloon occlusion catheter was positioned in the bilateral first-order portal vein branches 2 weeks after embolization to allow intraportal application of MSCs in six experimental animals. MSCs were allowed to dwell for 10 minutes using prolonged balloon inflation. Five control animals received a sham injection of normal saline in a similar fashion. Hepatic venous pressure gradient (HVPG) was measured immediately before necropsy. Specimens from all accessible lobes were obtained with ultrasound-guided percutaneous 18-gauge biopsy 2 hours after cell application. All animals were euthanized within 4 weeks. Fluorescent microscopy was used to assess the presence and distribution of cells.ResultsLiver injury and fibrosis were successfully induced in all animals. MSCs (6–10 × 10⁷) were successfully delivered into the portal vein in the six experimental animals. Cell application was not associated with vascular complications. HVPG showed no instances of portal hypertension. GFP-expressing MSCs were visualized in biopsy specimens and were distributed primarily within the sinusoidal spaces; however, 4 weeks after implantation, MSCs could not be identified in histologic specimens.ConclusionsA percutaneous endovascular approach for cell delivery using a balloon occlusion catheter proved safe for intraportal MSC application in a large animal model of liver fibrosis.     

Coils versus Gelatin Particles with or without Intraarterial Antibiotics for Partial Splenic Embolization: A Comparative Evaluation

PurposeTo compare the efficacy, complications, and inflammatory levels in partial splenic embolization (PSE) with coils or gelatin sponge (GS) particles with or without intraarterial antibiotic agents.Materials and MethodsForty-four patients with hypersplenism treated by PSE were assessed. GS particles were used in 31 patients, and coils were used in 13 patients. In 17 of the 31 patients who received GS, GS suspended in antibiotic solution was injected via the splenic artery. In the other 14 patients, antibiotic agents were not used. In all 13 coil group patients, an antibiotic solution was intraarterially injected before embolization. Platelet counts were compared between the GS and coil groups. Complications and serum C-reactive protein (CRP) levels were compared among the three groups.ResultsThere were no significant differences in platelet counts and platelet increased ratios at 6 months (10.0 × 10⁴/µL and 193% in the GS group vs 9.0 × 10⁴/µL and 221% in the coil group), and no significant differences in frequencies of complications. However, one splenic abscess occurred in a patient treated with GS without antibiotics, resulting in death. The mean serum CRP level in the GS with antibiotic group at 2 weeks was significantly lower than in the other two groups.ConclusionsThe efficacy of PSE is similar with the use of coils versus GS particles. Prophylactic intraarterial antibiotic treatment could be useful in preventing inflammatory reactions after PSE.