Effectiveness Of Transcatheter Arterial Embolization Research Articles

Management of Peptic Ulcer Bleeding Refractory to Endoscopic Treatment

Background: Before the advent of transcatheter arterial embolization (TAE), emergency surgery was the only choice for patients with peptic ulcer bleeding refractory to endoscopic therapy. This study compared the effectiveness of TAE and surgery in patients with peptic ulcer bleeding refractory to endoscopic hemostasis. Materials and Methods: This was a retrospective analysis of 116 patients with peptic ulcer bleeding refractory to endoscopic treatment at our institution. Eighty-three cases were treated with surgery, and 33 cases were managed with TAE. Clinical outcomes were evaluated. Results: There were no differences between groups with respect to the mortality rate (p > 0.05), length of hospital stay, or medical diseases related to mortality. The TAE group exhibited a significantly higher rebleeding rate (p < 0.05). Rebleeding predominantly occurred in patients with type Ia peptic ulcers (Forrest classification) irrespective of the treatment approach. The rebleeding rates in such patents were 30.2% and 56.3% in the surgery and TAE groups, respectively. Patients with rebleeding after further therapy showed high mortality rates (68.6%). The rebleeding rate was not significantly different between the subgroups of patients with type Ia lesions, although there was a higher mortality rate in the TAE group (27.9% vs. 75%, p = 0.001). Conclusions: TAE may be the first-choice therapy for patients with peptic ulcer bleeding refractory to endoscopic treatment, whereas emergency surgery may be used as an alternative in patients with type Ia bleeding at institutions with no 24-hour radiology service or when no experienced radiologist is available.

The short- and long-term effectiveness of transcatheter arterial embolization in patients with intractable hematuria.

Selective transarterial embolization (TAE) of the internal iliac artery is a well-known alternative technique to control intractable bladder hemorrhage (IBH). We explored the short- and long-term effectiveness of, and clinical outcomes after, TAE in patients with IBH. In this retrospective study, we reviewed the hospital records of 18 IBHpatients non-responsive to conservative medications who underwent TAE between January 2003 and May 2014. The early- and long-term effectiveness of TAE was investigated in the context of hematuria control, complications, mortality, requirement for blood transfusions, and hematocrit level. Sixteen of the 18 patients underwent endovascular treatment; the technical success rate was 88%. TAE allowed complete remission in 16 patients (100% clinical success). On follow-up, mean hematocrit (P=0.003) and hemoglobin (P=0.005) levels significantly improved. Thirteen of the 16 patients (81%) required no further emergency admission after TAE during a mean follow-up period of 18.1months (range, 3-105months). TAE is a feasible, effective, and safe technique in both the short- and long-term for the treatment of IBH.

Transcatheter Arterial Embolization Alone for Giant Hepatic Hemangioma.

Giant hepatic hemangioma is a benign liver condition that may be treated using surgery. We studied the digital subtraction angiographic (DSA) characteristics of giant hepatic hemangioma, and the effectiveness of transcatheter arterial embolization (TAE) alone for its treatment. This was a retrospective study of 27 patients diagnosed with giant hepatic hemangioma and treated with TAE alone (using lipiodol mixed with pingyangmycin) at the Division of Hepatobiliary and Pancreatic Surgery, First Affiliated Hospital, Zhejiang University, between January 2010 and March 2013. The feeding arteries were identified using DSA. All patients were followed up for between three weeks and 12 months. Changes in tumor diameter and symptoms were observed. The 27 patients included had giant hepatic hemangiomas ranging from 5.3 to 24.5 cm (mean, 11.24±5.08 cm) in the right (n = 13), left (n = 1) or both (n = 13) lobes. Preoperative hepatic angiography showed multiple abnormal vascular lakes in the early phase, known as the “early leaving but late returning, hanging nut on a twig” sign. On the day after TAE, hepatic transaminase levels were increased (ALT: 22.69±17.95 to 94.88±210.32 U/L; ALT: 24.00±12.37 to 99.70±211.54 U/L; both P<0.05), but not total bilirubin. Six patients complained of abdominal pain, and 12 experienced transient fever. In the months after TAE, tumor size decreased (baseline: 11.24±5.08; 3 months: 8.95±4.33; 6 months: 7.60±3.90 cm; P<0.05), and the patients’ condition improved. These results indicated that TAE was effective and safe for treating giant hepatic hemangioma. TAE may be a useful alternative to surgery for the treatment of hepatic hemangioma.

Effect of transcatheter arterial embolization with a mixture of n-butyl cyanoacrylate, lipiodol, and ethanol on the vascular wall: macroscopic and microscopic studies

To compare the pathologic effect of a mixture of n-butyl cyanoacrylate (NBCA), lipiodol, and ethanol (NLE) with a mixture of NBCA and lipiodol (NL) on the embolized vascular wall. Embolization was performed using four swine with NBCA and lipiodol in a volume ratio of 1:1 (NL11 group) in the common hepatic artery (n = 1) and the internal iliac artery (n = 2); and with NBCA, lipiodol, and ethanol in a volume ratio of 1:1:2 (NLE112 group) in the common hepatic artery (n = 3) and the internal iliac artery (n = 6). NL11 casts had an intricate appearance in reticular configuration with red thrombus, while NLE112 casts presented in a single round configuration with surrounding ring-like red thrombus. Desquamation of endothelial cells and infiltration of neutrophils into the adventitial layer were found in all embolized vessels in both groups. Infiltration of neutrophils into the intermediate layer was found in the NL11 group but not in the NLE112 group. The damage to the vascular wall caused by NLE112 was milder than that by NL11, implying the adverse effects of NLE112 are within tolerable limits.

Postpartum Hemorrhage from Extravasation or Pseudoaneurysm: Efficacy of Transcatheter Arterial Embolization Using N-Butyl Cyanoacrylate and Comparison with Gelatin Sponge Particle

PurposeTo evaluate the safety and effectiveness of transcatheter arterial embolization (TAE) using N-butyl cyanoacrylate (NBCA) for the treatment of active postpartum hemorrhage (PPH) and compare the efficacy of NBCA with gelatin sponge particles. Materials and MethodsFrom January 2004 to September 2013, 26 patients with PPH underwent TAE using NBCA as the primary embolic material. All patients were actively bleeding, and 12 (46.2%) had coagulopathy. TAE was performed using 1:2–1:4 mixtures of NBCA and ethiodized oil with or without use of a coil or gelatin sponge. To compare the efficacy of NBCA with conventional embolic material, 50 patients with active bleeding who underwent TAE using gelatin sponge were also analyzed. ResultsAngiograms demonstrated pseudoaneurysm or extravasation or both. The technical and clinical success rates were 100% and 92.3% (24 of 26 patients), respectively, for NBCA and 98% and 86.0% (43 of 50 patients), respectively, for gelatin sponge. In the NBCA group, one patient recovered with conservative management, and the other patient died because of multiorgan dysfunction. There were no major or minor procedure-related complications. ConclusionsTAE using NBCA as the primary embolic agent is an effective method for treating PPH with extravasation or pseudoaneurysm; NBCA is comparable to gelatin sponge particles. TAE using NBCA seems to fill pseudoaneurysms and make devascularization more effective than using gelatin sponge.

1:38 PM, Abstract No. 109, FEATURED ABSTRACT - Feasibility and effects of transcatheter arterial embolization for frozen shoulder refractory to non-surgical management

1:38 PM, Abstract No. 109, FEATURED ABSTRACT - Feasibility and effects of transcatheter arterial embolization for frozen shoulder refractory to non-surgical management

Transarterial embolization (TAE) of sacral giant cell Tumor (GCT) using spherical parmanent embolic material superabsorbant polymer microsphere (SAP-MS)

PurposeWe retrospectively evaluated our experience of transcatheter arterial embolization (TAE) of the sacral GCT with use of a spherical permanent embolic agent, superabsorbant polymer microsphere (SAP-MS) as an alternative treatment modality.Materials and methodsFrom 1997 to 2011, four patients with sacral GCT were treated with TAE. In all cases, SAP-MS was used as an embolic material. The effects of TAE were evaluated for improvement of patients’ symptoms, radiographic change such as vascularity of tumor, size of tumor and occurrence of reossification.ResultsOf the four patients, three responded favorably to TAE with improvement in pain and neurologic symptoms with long-term follow up. Diminished vascularity, stabilization of tumor size and reossification were shown radiographically. One patient died because of tumor growth 26 months after the initial TAE.ConclusionIn sacral GCT, TAE using SAP-MS might be useful for symptom improvement, reossification of the lesion and stabilization of tumor size.

Effect of hepatic artery embolization on liver hypertrophy response in a rabbit liver VX2 tumor model

Portal vein embolization not only induces hypertrophy of the non-embolized liver, but also enhances tumor growth. The latter could be prevented by embolizing the hepatic arteries supplying the tumor-bearing liver segments. This study aimed to determine the effects of transcatheter arterial embolization (TAE) on tumor volume and liver regeneration in a rabbit VX2 tumor model. Twenty-three rabbits underwent subcapsular tumor implantation with a VX2 tumor. Two weeks after implantation, 18 rabbits were used for TAE experiments, 5 were for sham controls. Tumor response and liver regeneration response of the embolized cranial and non-embolized caudal liver lobes were assessed by CT volumetry, liver to body weight index, and the amount of proliferating hepatocytes. All super-selective arterial tumor embolization procedures were performed successfully. Despite embolization, the tumor volume increased after an initial steady state. The tumor volume after embolization was smaller than that of the sham group, but this difference was not significant. Massive necrosis of the tumor, however, was seen after embolization, without damage of the surrounding liver parenchyma. There was a significant atrophy response of the tumor bearing cranial lobe after super-selective arterial embolization of the tumor with a concomitant hypertrophy response of the non-embolized, caudal lobe. This regeneration response was confirmed histologically by a significantly higher number of proliferating hepatocytes on the Ki-67 stained slides. Super-selective, bland arterial coil embolization causes massive necrosis of the tumor, despite increase of volume on CT scan. Atrophy of the tumor bearing liver lobe is seen after arterial embolization of the tumor with a concomitant hypertrophy response of the non-embolized lobe, despite absence of histological damage of the tumor-surrounding liver parenchyma.

Retrospective 12-Year Study of the Safety and Efficacy of Transcatheter Arterial Embolization for Managing Bleeding Complications Following Hip Surgery

This study was designed to evaluate the safety and effectiveness of transcatheter arterial embolization (TAE) for stopping bleeding following hip surgery. We performed a 12-year retrospective analysis of 13 patients (M:F = 6:7, median age 72 years) who underwent angiography for bleeding following hip surgery. The types of surgery, latency time, angiographic findings, TAE details, procedure-related complications, and clinical outcomes were analyzed. Technical success was defined as no further bleeding detected on angiography following embolization. Total hip replacement arthroplasty was the most common surgery performed for these patients (n = 10). Seven of the 13 study patients underwent angiography the same day as their surgery. Angiograms showed active (n = 11) or suspicious (n = 1) bleeding in 12 of the 13 patients. Gelatin sponge particles, coils, NBCA, PVA, and their combinations were used as the embolic material. For the one patient without obvious signs of bleeding, prophylactic TAE was done to achieve bleeding control. For the 11 patients with active bleeding, 10 underwent technically successful TAE, and 1 patient underwent surgery due to a large pseudoaneurysm located near the bifurcation of the common femoral artery. There were no major procedure-related complications or patient mortality. The 30-day mortality rate was 15% (2/13), and both of these patients died of multiorgan failure. Transcatheter angiography is useful for identifying bleeding arteries. TAE is safe and effective for managing bleeding after hip surgery.

Transcatheter Arterial Embolization Using Imipenem/Cilastatin Sodium for Tendinopathy and Enthesopathy Refractory to Nonsurgical Management

PurposeTo evaluate the feasibility and effects of transcatheter arterial embolization with imipenem/cilastatin sodium (CS) to treat tendinopathy and enthesopathy that are refractory to traditional nonsurgical management. Materials and MethodsTranscatheter arterial embolization with imipenem/CS as an embolic agent was performed in seven patients (five men; mean age, 51.7 y) with tendinopathy and enthesopathy (patellar tendinopathy, n = 1; rotator cuff tendinopathy, n = 2; plantar fasciitis, n = 1; lateral epicondylitis, n = 1; iliotibial band syndrome, n = 1; and Achilles insertion tendinopathy, n = 1). All patients had unrelenting pain at the site of tendinopathy and enthesopathy before the procedure. Technical success, adverse events, and changes in visual analog scale (VAS) scores were assessed. ResultsAll procedures were technically successful, and no major adverse events developed. Compared with before the procedure, mean VAS scores were significantly decreased at 1 day, 1 week, and 1 and 4 months after the procedure (72.7 mm±9.9 vs 17.4 mm±18.5, 16.0 mm±18.1, 13.7 mm±7.3, and 9.7 mm±6.8, respectively; all P< .001). ConclusionsTranscatheter arterial embolization with imipenem/CS was feasible and effectively relieved unrelenting pain associated with tendinopathy and enthesopathy.

Giant cavernous hepatic hemangioma shrunk by use of sorafenib

Here we report a case of a 76-year-old man with a giant cavernous hepatic hemangioma of more than 20 cm in diameter. Since the hepatic hemangioma was actually growing and might possibly rupture and he complained of abdominal symptoms, we decided to perform interventional therapy. First we performed transcatheter arterial embolization (TAE) of the hepatic arteries. However, since this was not sufficiently effective, we added sorafenib (600 mg/day). As a result, the tumor shrank with symptomatic improvement. Subsequently, an adverse event occurred, and we suspended the sorafenib therapy. Then, the tumor began to grow, and we resumed administering sorafenib at 400 mg/day. The tumor shrank again, and we continued the sorafenib therapy thereafter. The tumor shrinkage, although possibly induced by the effect of TAE, is considered primarily due to the effect of treatment with sorafenib, because (1) TAE did not sufficiently reduce the blood supply to the inside of the tumor; (2) other tumors shrank in the area not targeted by TAE; and (3) the tumor grew during suspension of sorafenib therapy and shrank again after resuming the treatment.

Treatment of symptomatic polycystic liver disease: transcatheter super-selective hepatic arterial embolization using a mixture of NBCA and iodized oil

Surgical therapy for symptomatic polycystic liver disease (PLD) is effective but has substantial mortality and morbidity. Minimally invasive options such as laparoscopic fenestration, percutaneous cyst aspiration with or without injection of a sclerosing solution have had disappointing results. Because the hepatic cysts in autosomal dominant polycystic kidney disease (ADPKD) patients are mostly supplied from hepatic arteries but not from portal veins, therefore, transcatheter arterial embolization (TAE) of the hepatic artery branches that supply major hepatic cysts can lead to shrinkage of the cyst and liver size. The purpose of this study was to evaluate the safety and effectiveness of TAE using a mixture of N-butyl-2-cyanoacrylate (NBCA) and iodized oil for massive PLD in ADPKD patients. From February 2007 to March 2011, a total of 21 patients with symptomatic PLD underwent super-selective hepatic TAE with the mixture of NBCA and iodized oil. The patients consisted of 17 women and 4 men (age range 36-64years, average age 48.8years). All patients underwent contrast-enhanced computed tomography (CT) of the liver before TAE, and at every 3months for the first year after TAE and at 6-monthly intervals thereafter. Laboratory data, including routine blood tests and liver enzymes, were collected before and 1, 3, 7, and 14days, 1, 3, 6, and 12months after TAE. Technical success was achieved in all cases. No serious complications were experienced. The mean follow-up period was 34±20months (range 12-60months). At follow-up of 6-12months, symptoms notably improved in 18 (85.7%) of 21 patients, and these patients experienced further relief of the symptoms during the follow-up period. TAE failed to benefit in 3 patients (14.3%). No patient complained of worsening of the symptoms after the procedure. At follow-up CT, the total liver volume and total intra-hepatic cyst volume decreased significantly (p<0.001) compared with pre-TAE in 18 (85.7%) of 21 patients at 12months after TAE. The total liver volume decreased from 8270±3016 to 6120±2680cm(3) and the total intra-hepatic cyst volume decreased from 7120±3070 to 4530±2600cm(3). Mild elevation of the liver enzymes was shown in patients at 1-14days after TAE but returned to the normal range within 1month. The mixture of NBCA and iodized oil is an acceptable embolic agent for embolization of the hepatic artery branches that supply the hepatic cysts in ADPKD patients. This technique is an option for patient with highly symptomatic PLD who are not candidates for surgical treatment.

RNA interference of hypoxia-inducible factor-1 alpha improves the effects of transcatheter arterial embolization in rat liver tumors

Transcatheter arterial embolization (TAE) and transcatheter arterial chemoembolization are widely used palliative treatments for patients with nonsurgical hepatocellular carcinoma. TAE has been shown to increase levels of hypoxia-inducible factor-1 alpha (HIF-1α) in tumors. In this study, we investigated whether RNA interference (RNAi) of HIF-1α could improve the efficacy of TAE to treat HCC. Four treatment groups were assessed using a rat allograft model of HCC: RNAi of HIF-1α combined with TAE, RNAi of HIF-1α only, TAE only, and a control group. Rats were treated by TAE by retrograde placement of a microcatheter into the gastroduodenal artery. The results demonstrated that the RNAi of HIF-1α visibly reduced the expression of HIF-1α and vascular endothelial growth factor, suppressed tumor angiogenesis, and attenuated metastasis, which were all enhanced by TAE. The RNAi of HIF-1α synergized with TAE to significantly inhibit tumor growth. In conclusion, RNAi of HIF-1α augmented the therapeutic effects of TAE and diminished its undesirable effects.

Embolization of Polycystic Kidneys as an Alternative to Nephrectomy Before Renal Transplantation: A Pilot Study

In autosomal polycystic kidney disease, nephrectomy is required before transplantation if kidney volume is excessive. We evaluated the effectiveness of transcatheter arterial embolization (TAE) to obtain sufficient volume reduction for graft implantation. From March 2007 to December 2009, 25 patients with kidneys descending below the iliac crest had unilateral renal TAE associated with a postembolization syndrome protocol. Volume reduction was evaluated by CT before, 3, and 6 months after embolization. The strategy was considered a success if the temporary contraindication for renal transplantation could be withdrawn within 6 months after TAE. TAE was well tolerated and the objective was reached in 21 patients. The temporary contraindication for transplantation was withdrawn within 3 months after TAE in 9 patients and within 6 months in 12 additional patients. The mean reduction in volume was 42% at 3 months (p = 0.01) and 54% at 6 months (p = 0.001). One patient required a cyst sclerosis to reach the objective. The absence of sufficient volume reduction was due to an excessive basal renal volume, a missed accessory artery and/or renal artery revascularization. Embolization of enlarged polycystic kidneys appears to be an advantageous alternative to nephrectomy before renal transplantation.

Radiofrequency Ablation of the Liver: Extended Effect of Transcatheter Arterial Embolization with Iodized Oil and Gelatin Sponge on Histopathologic Changes during Follow-up in a Pig Model

To assess the extended effects of transcatheter arterial embolization with iodized oil and gelatin sponge on liver histopathologic changes in radiofrequency (RF)-ablated zones and the surrounding liver parenchyma in a pig model. Eighteen consecutive pigs subjected to 36 RF applications performed immediately after segmental embolization with iodized oil and gelatin sponge to the left lobe of the liver (embolization/RF ablation) were euthanized immediately after the procedure or 1 or 4 weeks later. The right lobes were used as controls for RF applications without embolization. The ablated zones and the surrounding liver parenchyma were measured and examined histopathologically. The average maximum ablated zone was significantly larger in the embolization/RF ablation specimens than in the RF ablation-alone specimens at all three follow-up time points. Ten of the 12 specimens obtained immediately after embolization/RF ablation showed wide hemorrhagic areas spreading to the periphery of the liver and microscopically showed marked intralobular congestion with sinusoidal dilation. This hemorrhagic change had disappeared in all the specimens obtained 1 week after embolization/RF ablation, but 10 of the 12 specimens showed wedge-shaped areas of segmental degenerative parenchyma beginning at the ablated zone and extending to the periphery of the liver; these were microscopically revealed to be areas of coagulative necrosis, indicating hepatic infarction. The sizes of these necrotic zones had decreased at 4 weeks after embolization/RF ablation. RF ablation performed immediately after embolization in normal pig liver induced large ablated zones accompanied by wedge-shaped areas of segmental infarction.

Role of arterial embolization on blunt hepatic trauma patients with type I contrast extravasation

Background Our aim was to evaluate the clinical effectiveness of transcatheter arterial embolization (TAE) in the management of hemodynamically stable blunt hepatic trauma (BHT) patients with contrast material extravasation into the peritoneal cavity, known as type I contrast material extravasation, on computed tomography (CT) scan. Methods Adult patients who sustained BHT and who were hemodynamically stable after initial resuscitation underwent abdominal CT scan. If the abdominal CT scan revealed type I contrast material extravasation, patients who remained hemodynamically stable were sent for angiography. Results During a 30-month period, 8 patients were identified with type I contrast material extravasation. Three received immediate celiotomy because of hemodynamic instability. Five patients received angiography and subsequent TAE. One patient received celiotomy after TAE. The success rate of TAE was 50% (4/8). Conclusion With TAE, nonoperative management of hemodynamically stable BHT patients with type I contrast material extravasation on CT scan was achieved in half patients.

Endovascular Therapy of Bronchial Artery Aneurysm: Five Cases With Six Aneurysms

The objective of this study was to investigate the effect of transcatheter arterial embolization (TAE) with N-butyl-2-cyanoacrylate (NBCA)-Lipiodol mixture in patients with bronchial artery aneurysm (BAA). From January 2005 to January 2010, five patients presenting hemoptysis with six BAAs were treated with NBCA-Lipiodol mixture, including intra-aneurysm embolization (IAE) in one patient. Adjuvant embolization with spherical polyvinyl alcohol (PVA) embolic microparticles or NBCA was first performed to embolize the distal engorged bronchiectatic arteries. Bronchial arterial angiography showed six BAAs (four in the right lobe and two in the left lobe) and some engorged, tortuous bronchial arteries. TAE through microcatheter was successful in all cases. Postembolization angiogram demonstrated the NBCA cast and total occlusion of BAAs and bronchiectatic engorged vessels. After these procedures, hemoptysis completely disappeared in all patients. Follow-up computed tomography (CT) scan was performed at an average of 3months (range 2 to 6), which showed no enhancement of BAAs and accumulation of NBCA. TAE is a minimally invasive, effective, and reliable approach for treatment for patients with BAA. NBCA-Lipiodol mixture provides a good choice for treatment of BAA, especially when catheterization of the efferent branches is impossible.

Preoperative transcatheter arterial embolization of hypervascular metastatic tumors of long bones

Complete resection of hypervascular metastatic tumors is often complicated by massive intraoperative blood loss. To assess the technical success and clinical effectiveness of transcatheter arterial embolization (TAE) of hypervascular metastatic tumors of long bones to reduce blood loss during orthopedic surgery. From January 2000 to September 2009, 25 patients (M:F=13:12; mean age 58.3 years) were treated with TAE of metastatic bone tumors before elective, orthopedic surgery. In all cases, the indication for TAE was preoperative devascularization. Technical success, defined as obliteration of tumor staining to 70% or more, requirement for red blood cell transfusion within 24 h following surgery, and hematologic parameters, i.e. the hemoglobin, hematocrit, and erythrocyte counts before and after surgery, were obtained. The technical success rate was 96% (24/25 patients). Gelatin sponge particles (n=21) or polyvinyl alcohol particles (n=4) were used as embolic materials. The mean amount of red blood cell transfusion within the 24 h following surgery was 1.91 units (range 0-6) in the 23 patients with technically successful TAE and who underwent surgery within 3 days after TAE. In 22 patients with technically successful TAE and available hematologic data, the mean gaps in the hemoglobin, hematocrit, and erythrocyte counts before and after operation were 1.22 g/dl, 4.07%, and 0.45 x 10(6)/mm(3), respectively. Preoperative TAE is technically successful and clinically effective to minimize intraoperative and postoperative bleeding in patients with hypervascular metastasis to long bones.

Ischemic Effects of Transcatheter Arterial Embolization with N-Butyl Cyanoacrylate-Lipiodol on the Colon in a Swine Model

This study was designed to assess the safety of transcatheter arterial embolization (TAE) with n-butyl cyanoacrylate-lipiodol (NBCA-Lp) for the large bowel and to investigate the vital response to NBCA-Lp in a swine model. In nine swine, nine arteries nourishing the colon were embolized with NBCA-Lp (1 ml of NBCA mixed with 4 ml of lipiodol): sigmoid-rectal branch artery in six swine, right colic branch artery in two, and middle colic branch artery in one. The amount of NBCA-Lp was 0.1-0.4 ml. Sacrifice was conducted 3 days after TAE to identify histological infarction. Classification was conducted retrospectively: group A, vasa recta without NBCA-Lp embolization despite TAE; group B, three or fewer vasa recta with NBCA-Lp embolization; and group C, five or more vasa recta with NBCA-Lp embolization. In one swine in group A, no necrotic focus was observed. In group B, three of four swine experienced no ischemic damage. The remaining one swine experienced necrosis of mucosal and submucosal layers in one-fourth of the circumference. In group C, all four swine with marginal artery and five vasa recta or more embolized experienced total necrosis of mucosa, submucosa, and smooth muscle layers of the whole colonic circumference. Significant difference on the extent of ischemic damage was observed between groups B and C (P < 0.05). Microscopically, NBCA-Lp induced acute vasculitis. Embolization of three or fewer vasa recta with NBCA-Lp induced no ischemic damage or limited necrosis, whereas embolization of five or more vasa recta with NBCA-Lp induced extensive necrosis.

Expression of hypoxia-inducible factor-1α in liver tumors after transcatheter arterial embolization in an animal model

To examine the effect of transcatheter arterial embolization (TAE) of liver tumors on hypoxia-inducible factor-1alpha (HIF-1alpha) expression in the residual viable tumor, a total of 30 New Zealand White rabbits implanted with VX2 liver tumor were divided into 2 groups. TAE-treated group animals (n=15) were subjected to TAE with 150-250 microm polyvinyl alcohol particles. Control group animals (n=15) underwent sham embolization with distilled water. Six hours, 3 days or 7 days after TAE, the animals were sacrificed, and samples of tumor and adjacent normal liver tissue were harvested. Expression of HIF-1alpha protein was examined immunohistochemically. Real-time PCR was performed to examine the HIF-1alpha mRNA levels. Our results showed that HIF-1alpha protein was expressed in the VX2 tumors but not in the adjacent normal liver tissue. The HIF-1alpha-positive tumor cells were located predominantly at the periphery of necrotic tumor regions. The mean levels of HIF-1alpha protein were significantly higher in TAE-treated tumors than those in control tumors (P=0.002). Among the three sacrificing time points, the difference in increase in HIF-1alpha protein was significant between the two groups at the sacrificing time point of 6 h and 3 days after TAE (P=0.020, P=0.031, respectively), whereas no significant increase was noted 7 days after TAE (P=0.502). In contrast, although HIF-1alpha mRNA was expressed in TAE-treated and control VX2 tumors, there existed no significant difference in the HIF-1alpha mRNA level between the two groups (P=0.372). It is concluded that TAE of liver tumors increases the expression of HIF-1alpha at protein level in the residual viable tumor, which could be attributed to hypoxia generated by the procedure.