Hirohiko Tanihata

Evaluation of Transcatheter Arterial Embolization with Gelatin Sponge Particles, Microcoils, and N-butyl Cyanoacrylate for Acute Arterial Bleeding in a Coagulopathic Condition

PURPOSE To evaluate the outcome of transcatheter arterial embolization with gelatin sponge particles, microcoils, and N-butyl cyanoacrylate (NBCA) for acute arterial hemorrhage in the setting of coagulopathy. MATERIALS AND METHODS Coagulopathy is defined by a platelet count less than 5 x 10(4)/microL and/or International Normalized Ratio (INR) greater than 1.5. Forty-six patients (31 male patients; mean age, 62 years) with acute arterial hemorrhage in a coagulopathic condition were treated by transcatheter arterial embolization with gelatin sponge particle, microcoils, and NBCA. RESULTS Because of failure of hemostasis or recurrent hemorrhage, 10 patients who underwent gelatin sponge particle embolization also received transcatheter arterial embolization with microcoils or NBCA embolization and two patients who underwent microcoil embolization also received transcatheter arterial embolization with NBCA. The gelatin sponge particle group consisted of 27 hemorrhagic arteries in 25 patients, the microcoil group had 20 in 20 patients, and the NBCA group had 16 in 13 patients. The mean platelet count and mean INR value were 5.8 x 10(4)/microL +/- 3.5 and 1.81 +/- 0.50, respectively. The primary hemostatic rate, recurrent hemorrhage rate, and mean treatment time for the gelatin sponge particle, microcoil, and NBCA groups were 67%, 23%, and 25 minutes +/- 10; 80%, 0%, and 37 min +/- 19; and 100%, 0%, and 9 min +/- 4, respectively. Primary and secondary hemostasis were achieved in 50 (80%) and 60 (95%) of the 63 hemorrhagic arteries, respectively. Three hemorrhagic arteries in which transcatheter arterial embolization failed were treated with surgical repair. CONCLUSIONS Although transcatheter arterial embolization with microcoils took a greater amount of time, transcatheter arterial embolization with NBCA or microcoils was more effective and feasible than that with gelatin sponge particle in terms of hemostasis and prevention of recurrent hemorrhage in a coagulopathic condition.

Feasibility and efficacy of single photon emission computed tomography-based three-dimensional conformal radiotherapy for hepatocellular carcinoma 8 cm or more with portal vein tumor thrombus in combination with transcatheter arterial chemoembolization.

PURPOSE To assess the feasibility and efficacy of single photon emission computed tomography-based three-dimensional conformal radiotherapy (SPECT-B 3D-CRT) for large hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT). METHODS AND MATERIALS HCC patients with PVTT in the first branch or main trunk, 8 cm or greater in size, were admitted to the study. SPECT, using Tc-99m-galactosyl human serum albumin, was used in radiation treatment planning to explore the optimal irradiation beam angle. SPECT enabled the minimum possible irradiation of functional liver (FL). Clinical target volume (CTV) included the main tumor and PVTT. SPECT-B 3D-CRT targeted the CTV to a total dose of 45 Gy/18 fractions. HCC outside the CTV was treated by transcatheter arterial chemoembolization (TACE). RESULTS Nineteen cases were enrolled in this study. The mean maximum dimension, mean CTV, and mean dose to FL were 11.0 cm (range, 8.0-20.0), 435 cm(3) (range, 60-2,535), and 1,102 cGy (range, 691-1,695), respectively. Follow-up SPECT demonstrated radiation-induced dysfunctional liver. Despite the inclusion of 6 cases of Child-Pugh B or C, no patients experienced Grade 3 or worse radiation-induced liver disease. The cumulative non-progression rates of PVTT and PVTT plus main tumor were 78.0 and 43.2%, respectively. Survival rates at 1 and 2 years were 47.4 and 23.7%, respectively. CONCLUSIONS SPECT-B 3D-CRT with TACE appears to be tolerable to cirrhotic liver and to provide promising prognosis for patients with HCC sized 8 cm or more, in comparison with previous treatment methods. A longer follow-up period is required to evaluate these findings.

Attempted Induction of Chronic Portal Venous Hypertension with Polyvinyl Alcohol Particles in Swine

PURPOSE Creation of presinusoidal chronic portal venous hypertension by means of repeated portal vein (PV) embolization was explored in an attempt to improve a porcine model of transjugular intrahepatic portosystemic shunt (TIPS) patency. MATERIALS AND METHODS Six microswine underwent weekly PV embolization for 5 weeks with a total of 10.4-12.6 g of polyvinyl alcohol (PVA) particles (0.149-0.250 mm in size). Portography, liver function tests, pressure measurement in the PV and inferior vena cava (IVC) before and after PV embolization, and histopathologic evaluation of the livers were performed. RESULTS Transhepatic portal venography performed after each embolization demonstrated diffuse PV branch occlusion in all cases. At weekly follow-up, reconstitution of flow was demonstrated in these branches; permanent occlusion of PV branches was not achieved. The mean PV pressure elevated acutely from 17.3 mm Hg +/- 0.9 to 24.5 mm Hg +/- 4.2 (P < .01) after each embolization. However, the pressure always returned to baseline on the follow-up studies 1 week later. Liver function tests were normal. Histopathologic evaluation of the liver showed, in multiple PV branches, central plugs of PVA with peripheral recanalization. The liver parenchyma was otherwise normal. CONCLUSION Massive embolizations of PV with PVA at weekly intervals failed to create permanent portal hypertension or induce hepatic fibrosis.

SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY-BASED THREE-DIMENSIONAL CONFORMAL RADIOTHERAPY FOR HEPATOCELLULAR CARCINOMA WITH PORTAL VEIN TUMOR THROMBUS

PURPOSE To evaluate the safety and efficacy of three-dimensional conformal radiotherapy (3D-CRT) using single photon emission computed tomography (SPECT) in unresectable hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT). METHODS AND MATERIALS Patients with HCC with PVTT in the first branch and/or main trunk were selected for this study. The optimal beam directions for 3D-CRT were explored using a Tc-99m-galactosyl human serum albumin SPECT image for guidance. The SPECT image was classified as either wedge type or localized type. The clinical target volume to a total dose of 45 or 50 Gy per 18-20 fractions included the main tumor and PVTT in the wedge type and PVTT alone in the localized type. RESULTS Twenty-six patients were enrolled: 18 with wedge type and 8 with localized type. Mean tumor size was 7.1 cm (range, 4.4-12.3 cm). Clinical target volumes of wedge type vs. localized type were 111.2 cm(3) vs. 48.4 cm(3) (p = 0.010), respectively. Mean dose to normal liver and mean dose to functional liver were 1185 cGy and 988 cGy (p = 0.001) in wedge type and 1046 cGy and 1043 cGy (p = 0.658) in localized type, respectively. Despite an incidence of Child-Pugh B and C of 57.7%, no patients experienced radiation-induced liver disease. The progression of PVTT was inhibited, with an incidence of 92.2%; survival rates at 1 and 2 years were 44% and 30%, respectively. CONCLUSION Single photon emission computed tomography-based 3D-CRT enables irradiation of both the main tumor and PVTT with low toxicity and promising survival.

Effectiveness of Hepatic Arterial Embolization on Radiofrequency Ablation Volume in a Swine Model: Relationship to Portal Venous Flow and Liver Parenchymal Pressure

PURPOSE To evaluate the effectiveness of transcatheter arterial embolization (TAE) on radiofrequency (RF) ablation volume and compare portal vein (PV) flow and liver parenchymal pressure before and after treatment. MATERIALS AND METHODS Eight healthy female swine were divided into four groups to be treated with RF ablation alone (RF-only group), RF ablation after TAE with gelatin sponge particles (GSPs; RF/TAE group), RF ablation after TAE with Lipiodol plus GSPs (RF/TAE/Lipiodol group), and PV embolization (PVE) with GSPs after TAE with Lipiodol plus GSPs (RF/TAE/Lipiodol/PVE group). Five ablations were created in each swine, with 10 ablations per group. A 2-cm expandable LeVeen needle electrode was used for RF ablation. RESULTS The greatest ablation volume (18,410.1 mm(3) +/- 3,986.4) was observed in the RF/TAE/Lipiodol/PVE group. Of the RF-only, RF/TAE, and RF/TAE/Lipiodol groups, the RF/TAE/Lipiodol group (14,835.5 mm(3) +/- 2,743.2) had a significantly larger ablation volume than the RF-only (8,002.6 mm(3) +/- 2,788.3) and RF/TAE groups (10,398.5 mm(3) +/- 2965.8; P < .05/3). PV pressures increased significantly after TAE (P < .01) compared with the pressure before TAE in the RF/TAE/Lipiodol and RF/TAE/Lipiodol/PVE groups, but not in the RF/TAE group. A marked increase in liver parenchymal pressure was seen during RF ablation; however, there were no significant differences among groups. Accumulation of Lipiodol was noted in the sinusoids in the RF/TAE/Lipiodol and RF/TAE/Lipiodol/PVE groups. CONCLUSIONS TAE with blockade of PV flow before RF ablation was associated with greater ablation volumes. Liver parenchymal pressure showed no correlation with increased ablation volume.

Preoperative microcoil embolization of the common hepatic artery for pancreatic body cancer

AIM To evaluate safety and feasibility of microcoil embolization of the common hepatic artery under proper or distal balloon inflation in preoperative preparation for en bloc celiac axis resection for pancreatic body cancer. METHODS Fifteen patients (11 males, 4 females; median age, 67 years) with pancreatic body cancer involving the nerve plexus surrounding the celiac artery underwent microcoil embolization. To alter the total hepatic blood flow from superior mesenteric artery (SMA), microcoil embolization of the common hepatic artery (CHA) was conducted in 2 cases under balloon inflation at the proximal end of the CHA and in 13 cases under distal microballoon inflation at the distal end of the CHA. RESULTS Of the first two cases of microcoil embolization with proximal balloon inflation, the first was successful, but there was microcoil migration to the proper hepatic artery in the second. The migrated microcoil was withdrawn to the CHA by an inflated microballoon catheter. Microcoil embolization was successful in the other 13 cases with distal microballoon inflation, with no microcoil migration. Compact microcoil embolization under distal microballoon inflation created sufficient resistance against the vascular wall to prevent migration. Distal balloon inflation achieved the requisite 1 cm patency at the CHA end for vascular clamping. All patients underwent en bloc celiac axis resection without arterial reconstruction or liver ischemia. CONCLUSION To impede microcoil migration to the proper hepatic artery during CHA microcoil embolization, distal microballoon inflation is preferable to proximal balloon inflation.

Optimal Covering Material for Stent-Grafts Placed in the Portal Vein in a Canine Model

Purpose We evaluated the suitability of Dacron, polytetrafluoroethylene (PTFE), and small intestinal submucosa (SIS) as a covering material for stent-grafts placed in the portal vein as compared with a bare stent.MethodsUsing 24 beagle dogs, either bare stents or stent-grafts covered with Dacron, PTFE, or SIS were placed in the main trunk of the portal vein in 6 animals each. Portography was performed immediately after stent placement, and at 2, 4, and 12 weeks thereafter. Next, the extracted stents or stent-grafts were examined histopathologically. Neointimal thickness adjacent to the stent wire and at the midportion between the stent wires was compared among the groups. Then, the neointimal thickness at the sub- and supragraft sites was compared between each stent-graft group. Serial changes in the histologic features of the thickened neointima were also investigated.ResultsNo significant difference was noted in the mean stenotic ratio of the portal vein diameter between the bare stent and PTFE groups, whereas it was significantly higher in the Dacron and SIS groups compared with the bare stent group. In neither of the studies on neointimal thickness adjacent to the stent wire and at the midportion between the stent wires were any significant differences noted between the neointimal thickness of the bare stent group and the sum of the neointimal thickness of the PTFE group, whereas the sum of the neointimal thickness of the Dacron and SIS groups was significantly greater than that of the bare stent group at both sites. In the comparison of the supragraft neointimal thickness, the SIS group showed significantly greater thickness than the PTFE group, while the difference between the Dacron and PTFE groups was not significant. In the comparison of the subgraft neointimal thickness, the Dacron and SIS groups showed significantly greater thickness than the PTFE group.ConclusionThe present results indicate that of the three covering materials examined here, PTFE is the most suitable material for grafts placed in the portal vein.

Effects of hepatic artery chemoembolization using cisplatin-lipiodol suspension with gelatin sponge particles on swine liver.

PURPOSE To define the effects of hepatic artery chemoembolization with cisplatin-lipiodol suspension and gelatin sponge particles on swine liver tissue and estimate the concentration of cisplatin that would have a minimal negative effect on normal liver parenchyma. MATERIALS AND METHODS Twelve pigs were divided into four groups: group A was the control group in which hepatic arteries were embolized with lipiodol and gelatin sponge particle (n = 3); group B animals were embolized with 10 mg/mL cisplatin-lipiodol suspension plus gelatin sponge particle (n = 3), group C with 20 mg/mL cisplatin-lipiodol suspension plus gelatin sponge particle (n = 3), and group D with 30 mg/mL cisplatin-lipiodol suspension plus gelatin sponge particle (n = 3). Pigs were euthanized 1 week after embolization, and the resected livers were cut into 10-mm-thick sections. The livers and necrotic foci were contoured in each section, and the necrosis volume ratio was calculated. RESULTS The necrosis volume ratios of the livers in groups A, B, C, and D were 0.832% +/- 0.334, 2.324% +/- 1.126, 8.056% +/- 3.276, and 11.82% +/- 4.921, respectively. Significant differences (P < .05) in necrosis volume ratio were found between groups A and C, groups A and D, groups B and C, and groups B and D; no significant difference was found between groups A and B. CONCLUSIONS Hepatic artery chemoembolization with higher doses of cisplatin causes greater damage to liver tissue; 10 mg/mL cisplatin-lipiodol suspension causes minimal damage, similar to that without cisplatin, and is related to minimal negative changes in a swine model.

Percutaneous Osteoplasty with a Bone Marrow Nail for Fractures of Long Bones: Experimental Study

PURPOSE To develop percutaneous osteoplasty with the use of a bone marrow nail for fixation of long-bone fractures, and to evaluate its feasibility and safety in vivo and in vitro. MATERIALS AND METHODS Six long bones in three healthy swine were used in the in vivo study. Acrylic cement was injected through an 11-gauge bone biopsy needle and a catheter into a covered metallic stent placed within the long bone, creating a bone marrow nail. In the in vitro study, we determined the bending, tug, and compression strengths of the acrylic cement nails 9 cm long and 8 mm in diameter (N = 10). The bending strength of the artificially fractured bones (N = 6) restored with the bone marrow nail and cement augmentation was then compared with that of normal long bones (N = 6). RESULTS Percutaneous osteoplasty with a bone marrow nail was successfully achieved within 1 hour for all swine. After osteoplasty, all swine regained the ability to run until they were euthanized. Blood tests and pathologic findings showed no adverse effects. The mean bending, tug, and compression strengths of the nail were 91.4 N/mm(2) (range, 75.0-114.1 N/mm(2)), 20.9 N/mm(2) (range, 6.6-30.4 N/mm(2)), and 103.0 N/mm(2) (range, 96.3-110.0 N/mm(2)), respectively. The bending strength ratio of artificially fractured bones restored with bone marrow nail and cement augmentation to normal long bone was 0.32. CONCLUSIONS Percutaneous osteoplasty with use of a bone marrow nail and cement augmentation appears to have potential in treating fractures of non-weight-bearing long bones.

Repair of Traumatic Abdominal Aortic Pseudoaneurysm Using N-Butyl-2-Cyano-Acrylate Embolization

Embolization using N-butyl-2-cyano-acrylate (NBCA) has been highly regarded for treating pseudoaneurysm, arteriovenous malformation, and hemorrhage of the visceral arteries. We report the case of a patient who fell from a cliff and sustained hemorrhagic shock with blunt abdominal aortic rupture and who underwent embolization using NBCA. This treatment achieved immediate hemostasis and stabilization of vital signs. Although the long-term durability of NBCA is unknown, it appears that certain types of acute aortic hemorrhage with narrow-necked pseudoaneurysm can be controlled by embolization using NBCA.