Use of doxorubicin-eluting bead transarterial chemoembolization for unresectable hepatocellular carcinoma with portal vein invasion: a prospective study

Background@#/Aim: To evaluate the applicability of transarterial chemoembolization (TACE) treatment with doxorubicin drug-eluting beads (DEBs) in advanced hepatocellular carcinoma (HCC) patients with portal vein invasion (PVI). @*Methods@#This prospective study was approved by the institutional review board and informed consent was obtained from all participants. A total of 30 HCC patients with PVI received DEB-TACE between 2015 and 2018. The following parameters were evaluated: complications during DEB-TACE, abdominal pain, fever, and laboratory outcomes, including liver function change. Overall survival (OS), time to progression (TTP), and adverse events were also analyzed and assessed. @*Results@#DEBs measuring 100–300 μm in diameter were loaded with doxorubicin (150 mg per procedure). There were no complications during DEB-TACE and no significant differences in the levels of prothrombin time, serum albumin, or total bilirubin at follow-up compared to baseline. The median TTP was 102 days (95% confidence interval [CI], 42–207 days) and the median OS was 216 days (95% CI, 160–336 days). Three patients (10%) had severe adverse reactions, including transient acute cholangitis (n=1), cerebellar infarction (n=1), and pulmonary embolism (n=1), but no treatment-related death occurred. @*Conclusions@#DEB-TACE may be a therapeutic option for advanced HCC patients with PVI.

Transarterial radioembolization versus tyrosine kinase inhibitor in hepatocellular carcinoma with portal vein thrombosis

Background/Aims@#Transarterial radioembolization (TARE) has shown promising results in treating advanced hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT). However, whether TARE can provide superior or comparable outcomes to tyrosine kinase inhibitor (TKI) in patients with HCC and PVTT remains unclear. We compared the outcomes of TARE and TKI therapy in treatment-naïve patients with locally advanced HCC and segmental or lobar PVTT. @*Methods@#This multicenter study included 216 patients initially treated with TARE (n=124) or TKI (sorafenib or lenvatinib; n=92) between 2011 and 2021. Baseline characteristics were balanced using propensity score matching (PSM) or inverse probability of treatment weighting (IPTW). The primary outcome was overall survival (OS). The secondary outcomes included progression-free survival (PFS) and objective response rate (ORR). @*Results@#In the unmatched cohort, the median OS of the TARE and TKI groups were 28.2 and 7.2 months, respectively (p<0.001), and the TARE group experienced significantly and independently longer OS compared to the TKI group (adjusted hazard ratio=0.41, 95% confidence interval=0.28–0.60, p<0.001). Similar results were observed in the study cohorts balanced with IPTW (p=0.003) or PSM (p=0.004). Although PFS was comparable between the two groups, the TARE group showed a trend of prolonged PFS in a subpopulation of patients with Vp1 or Vp2 PVTT (p=0.052). In the matched cohorts, the ORR of the TARE group was 53.0–56.7%, whereas that of the TKI group was 12.3–15.0%. @*Conclusions@#For patients with advanced HCC with segmental or lobar PVTT and well-preserved liver function, TARE may provide superior OS compared to sorafenib or lenvatinib.

Radioembolization for hepatocellular carcinoma: what clinicians need to know

Transarterial radioembolization (TARE) with yttrium 90 (90Y) has been used in the management of hepatocellular carcinoma (HCC) for more than 10 years in Korea. There are two types of 90Y radioactive microspheres available, namely, glass and resin microspheres, with comparable clinical outcomes. In general, TARE outperforms transarterial chemoembolization regarding post-embolization syndrome, time to progression, tumor downsizing for liver transplantation, and hospitalization stay. Although TARE is commonly recommended for patients with unresectable large HCCs, it can be an alternative to or performed in combination with ablation, surgical resection, and systemic treatment. This review aimed to address 90Y radioactive microspheres, patient selection, clinical outcomes, simulation tests, radioembolization procedures, follow-up imaging, and complications.

Liver Directed Interventional Treatments for Pancreatic Neuroendocrine Tumor with Liver Metastasis / 대한췌담도학회지

Pancreatic neuroendocrine tumors (PNETs) are rare, but the frequency of detection is constantly increasing due to recent advances in diagnostic technology. Since liver metastasis (LM) of PNETs is highly correlated with long-term survival, active treatment is important. Liver-directed treatment is recommended for patients with unresectable LM from PNET if symptomatic or progressing despite medical management. Liverdirected intervention treatment, including locally ablative techniques and hepatic arterial embolotherapy has a vital role in controlling symptoms and improving overall survival rates. The purpose of this article is to address the recent advances in liverdirected intervention treatments for the treatment of LM of PNETs.

Prospective Multi-Center Korean Registry of Transcatheter Arterial Chemoembolization with Drug-Eluting Embolics for Nodular Hepatocellular Carcinoma: A Two-Year Outcome Analysis

Objective@#To assess the two-year treatment outcomes of chemoembolization with drug-eluting embolics (DEE) for nodular hepatocellular carcinoma (HCC). @*Materials and Methods@#This study was a prospective, multicenter, registry-based, single-arm trial conducted at five university hospitals in Korea. Patients were recruited between May 2011 and April 2013, with a target population of 200. A DC Bead loaded with doxorubicin was used as the DEE agent. Patients were followed up for two years. Per-patient and perlesion tumor response analysis, per-patient overall survival (OS) and progression-free survival (PFS) analysis, and per-lesion tumor control analysis were performed. @*Results@#The final study population included 152 patients, with 207 target lesions for the per-lesion analysis. At one-month, six-month, one-year, and two-year per-patient assessments, complete response (CR) rates were 40.1%, 43.0%, 33.3%, and 19.6%, respectively. The objective response (OR) rates were 91.4%, 55.4%, 35.1%, and 19.6%, respectively. The cumulative two-year OS rate was 79.7%. The cumulative two-year PFS rate was 22.4% and the median survival was 9.3 months. In multivariable analysis, the Child-Pugh score (p = 0.019) was an independent predictor of OS, and tumor multiplicity (p < 0.001), tumor size (p = 0.020), and Child-Pugh score (p = 0.006) were independent predictors of PFS. In per-lesion analysis, one-month, six-month, one-year and two-year CR rates were 57.5%, 58.5%, 45.2%, and 33.3%, respectively, and the OR rates were 84.1%, 65.2%, 46.6%, and 33.3%, respectively. The cumulative two-year per-lesion tumor control rate was 36.2%, and the median time was 14.1 months. The Child-Pugh score (p < 0.001) was the only independent predictor of tumor control. Serious adverse events were reported in 11 patients (7.2%). @*Conclusion@#DEE chemoembolization for nodular HCCs in the Korean population showed acceptable survival, tumor response, and safety profiles after a two-year follow-up. Good liver function (Child-Pugh score A5) was a key predictor of per-patient OS, PFS, and per-lesion tumor control.

Prospective Multi-Center Korean Registry of Transcatheter Arterial Chemoembolization with Drug-Eluting Embolics for Nodular Hepatocellular Carcinoma: A Two-Year Outcome Analysis

Objective@#To assess the two-year treatment outcomes of chemoembolization with drug-eluting embolics (DEE) for nodular hepatocellular carcinoma (HCC). @*Materials and Methods@#This study was a prospective, multicenter, registry-based, single-arm trial conducted at five university hospitals in Korea. Patients were recruited between May 2011 and April 2013, with a target population of 200. A DC Bead loaded with doxorubicin was used as the DEE agent. Patients were followed up for two years. Per-patient and perlesion tumor response analysis, per-patient overall survival (OS) and progression-free survival (PFS) analysis, and per-lesion tumor control analysis were performed. @*Results@#The final study population included 152 patients, with 207 target lesions for the per-lesion analysis. At one-month, six-month, one-year, and two-year per-patient assessments, complete response (CR) rates were 40.1%, 43.0%, 33.3%, and 19.6%, respectively. The objective response (OR) rates were 91.4%, 55.4%, 35.1%, and 19.6%, respectively. The cumulative two-year OS rate was 79.7%. The cumulative two-year PFS rate was 22.4% and the median survival was 9.3 months. In multivariable analysis, the Child-Pugh score (p = 0.019) was an independent predictor of OS, and tumor multiplicity (p < 0.001), tumor size (p = 0.020), and Child-Pugh score (p = 0.006) were independent predictors of PFS. In per-lesion analysis, one-month, six-month, one-year and two-year CR rates were 57.5%, 58.5%, 45.2%, and 33.3%, respectively, and the OR rates were 84.1%, 65.2%, 46.6%, and 33.3%, respectively. The cumulative two-year per-lesion tumor control rate was 36.2%, and the median time was 14.1 months. The Child-Pugh score (p < 0.001) was the only independent predictor of tumor control. Serious adverse events were reported in 11 patients (7.2%). @*Conclusion@#DEE chemoembolization for nodular HCCs in the Korean population showed acceptable survival, tumor response, and safety profiles after a two-year follow-up. Good liver function (Child-Pugh score A5) was a key predictor of per-patient OS, PFS, and per-lesion tumor control.

Cone-Beam Computed Tomography-Hepatic Arteriography as a Diagnostic Tool for Small Hypervascular Hepatocellular Carcinomas: Method and Clinical Implications

OBJECTIVE: This study proposes a novel reference standard for hypervascular hepatocellular carcinomas (HCCs), established by cone-beam computed tomography-hepatic arteriography (CBCT-HA) and two-year imaging follow-up, and discusses its clinical implication on tumor staging and understanding the intrahepatic distant recurrence (IDR) in relation to dynamic computed tomography (CT).MATERIALS AND METHODS: In this retrospective study, 99 patients were enrolled, who underwent CBCT-HA during initial chemoembolization for HCC suspected on CT. All patients underwent chemoembolization and regular clinical and imaging follow-up for two years. If IDR appeared on follow-up imaging, initial CBCT-HA images were reviewed to determine if a hypervascular focus pre-existed at the site of recurrence. Pre-existing hypervascular foci on CBCT-HA were regarded as HCCs in initial presentation. Initial HCCs were classified into three groups according to their mode of detection (Group I, detected on CT and CBCT-HA; Group II, additionally detected on CBCT-HA; Group III, confirmed by interval growth). We assessed the influence of CBCT-HA and two-year follow-up on initial tumor stage and calculated the proportion of IDR that pre-existed in initial CBCT-HA.RESULTS: A total of 405 nodules were confirmed as HCCs, and 297 nodules initially pre-existed. Of the initial 297 HCCs, 149 (50.2%) lesions were in Group I, 74 (24.9%) lesions were in Group II, and the remaining 74 (24.9%) lesions were in Group III. After applying CBCT-HA findings, 11 patients upstaged in T stage, and 4 patients had a change in Milan criteria. Our reference standard for HCC indicated that 120 of 148 (81.1%) one-year IDR and 148 of 256 (57.8%) two-year IDR existed on initial CBCT-HA.CONCLUSION: The proposed method enabled the confirmation of many sub-centimeter-sized, faintly vascularized HCC nodules that pre-existed initially but clinically manifested as IDR. Our reference standard for HCC helped in understanding the nature of IDR and the early development of HCC as well as the clinical impact of tumor staging and treatment decision.

Imaging Evaluation Following ⁹⁰Y Radioembolization of Liver Tumors: What Radiologists Should Know

Radioembolization using beta-emitting yttrium-90 microspheres is being increasingly used for the treatment of primary and metastatic liver cancers. It is a form of intra-arterial brachytherapy which delivers intense radiation to liver tumors with little embolic effect; this mode of action results in unique post-treatment imaging findings. It is important to understand these imaging findings to avoid misinterpretation of tumor response and to determine further management of the disease. Herein, we discuss the current concepts for assessing tumor response, common post-treatment imaging features, and associated complications following radioembolization.

Balloon-Occluded Retrograde Transvenous Obliteration versus Transjugular Intrahepatic Portosystemic Shunt for the Management of Gastric Variceal Bleeding

BACKGROUND/AIMS: Gastric varices (GVs) are a major cause of upper gastrointestinal bleeding in patients with liver cirrhosis. The current treatments of choice are balloon-occluded retrograde transvenous obliteration (BRTO) and the placement of a transjugular intrahepatic portosystemic shunt (TIPS). We aimed to compare the efficacy and outcomes of these two methods for the management of GV bleeding. METHODS: This retrospective study included consecutive patients who received BRTO (n=157) or TIPS (n=19) to control GV bleeding from January 2005 to December 2014 at a single tertiary hospital in Korea. The overall survival (OS), immediate bleeding control rate, rebleeding rate and complication rate were compared between patients in the BRTO and TIPS groups. RESULTS: Patients in the BRTO group showed higher immediate bleeding control rates (p=0.059, odds ratio [OR]=4.72) and lower cumulative rebleeding rates (log-rank p=0.060) than those in the TIPS group, although the difference failed to reach statistical significance. There were no significant differences in the rates of complications, including pleural effusion, aggravation of esophageal varices, portal hypertensive gastropathy, and portosystemic encephalopathy, although the rate of the progression of ascites was significantly higher in the BRTO group (p=0.02, OR=7.93). After adjusting for several confounding factors using a multivariate Cox analysis, the BRTO group had a significantly longer OS (adjusted hazard ratio [aHR]=0.44, p=0.01) and a longer rebleeding-free survival (aHR=0.34, p=0.001) than the TIPS group. CONCLUSIONS: BRTO provides better bleeding control, rebleeding-free survival, and OS than TIPS for patients with GV bleeding.

Clinical Usefulness of Unenhanced Computed Tomography in Patients with Acute Pyelonephritis

BACKGROUND: Unenhanced computed tomography (UCT) may be useful for evaluating acute pyelonephritis; however, no study has compared UCT with enhanced computed tomography (ECT) as a diagnostic tool. We evaluated a clinical usefulness of UCT versus ECT in acute pyelonephritis (APN). METHODS: We reviewed the clinical and radiological data from 183 APN-suspected patients who underwent UCT and ECT simultaneously at emergency room (ER) over a two-year period. Demographic, clinical parameters and computed tomography (CT) parameters of 149 patients were compared. RESULTS: The average patient age was 61.2 (± 10) years: 31 patients were men. Ninety-nine (66.4%) patients showed stones (18.7%), perinephric infiltration (56%), swelling (21%), and hydronephrosis (6.7%) on UCT. Seventeen patients (11.4%) had an atypical clinical course, requiring additional tests for accurate diagnosis. In 7 patients UCT and ECT results did not differ; in 10 patients, the diagnosis changed on ECT. On ECT, 112/149 (75.2%) patients had stones (16.7%), perinephric infiltrations (57%), swelling (21%), and hydronephrosis (6.7%); 62.5% showed parenchymal involvement: 34 (22.8%) patients had no abnormal ECT findings. APN CT findings are similar on stone, perinephric infiltration, swelling and hydronephrosis on both CTs. Twelve patients (8.0%) had an abnormal ECT finding, i.e., low-grade (1 and 2) parenchymal involvement. Six (4%) patients developed contrast-induced acute kidney injury within 2 days after ECT. CONCLUSION: We demonstrate that UCT is not inferior to ECT as an initial tool for evaluating APN for screening nephrolithiasis and hydronephrosis without the risk of contrast-induced acute kidney injury (CIAKI). However, patients with an atypical clinical course may still need ECT.

Radioembolization for the treatment of hepatocellular carcinoma

Transarterial radioembolization (TARE) with yttrium 90 (⁹⁰Y), an intra-arterial procedure performed by interventional radiologists, has begun being utilized in managing hepatocellular carcinoma (HCC) in Korea. There are two available TARE products: glass and resin microspheres with different physical characteristics. All patients undergoing TARE must be assessed with clinical examination and laboratory tests as well as a thorough angiographic evaluation. TARE is safe and effective in the treatment of unresectable HCC, as it has longer time-to-progression, greater ability to downsize tumors for liver transplantation, less post-embolization syndrome, and shorter hospitalization compared with chemoembolization. TARE can also serve as an alternative to ablation, surgical resection, portal vein embolization, and sorafenib. The utility of TARE continues to expand with new insights in interventional oncology.

Efficacy of Retrievable Metallic Stent with Fixation String for Benign Stricture after Upper Gastrointestinal Surgery

OBJECTIVE: To determine the efficacy of retrievable metallic stent with fixation string for benign anastomotic stricture after upper gastrointestinal (UGI) surgery. MATERIALS AND METHODS: From June 2009 to May 2015, a total of 56 retrievable metallic stents with fixation string were placed under fluoroscopy guidance in 42 patients who were diagnosed with benign anastomotic stricture after UGI surgery. Clinical success was defined as achieving normal regular diet (NRD). RESULTS: The clinical success rate after the first stent placement was 57.1% (24/42). After repeated stent placement and/or balloon dilation, the clinical success rate was increased to 83.3% (35/42). Six (14.3%) patients required surgical revision to achieve NRD. One (2.4%) patient failed to achieve NRD. Stent migration occurred in 60.7% (34/56) of patients. Successful rate of removing the stent using fixation string and angiocatheter was 94.6% (53/56). Distal migration occurred in 12 stents. Of the 12 stents, 10 (83.3%) were successfully removed whereas 2 could not be removed. No complication occurred regarding distal migration. CONCLUSION: Using retrievable metallic stent with a fixation string is a feasible option for managing early benign anastomotic stricture after UGI surgery. It can reduce complications caused by distal migration of the stent.

A Case of SAPHO Presented with Venous Engorgement: Successful Treatment with Adalimumab

No abstract available.

Transarterial Chemoembolization versus Radiofrequency Ablation for Small Hepatocellular Carcinomas with Discrepant Features on Computed Tomography and Magnetic Resonance Imaging

BACKGROUND/AIMS: This study compared the outcomes of patients with small hepatocellular carcinomas (HCCs) who were treated using transarterial chemoembolization (TACE) or radiofrequency ablation (RFA). METHODS: This was a post-hoc analysis of a prospective study that evaluated the diagnostic efficacy of magnetic resonance imaging (MRI) and computed tomography (CT). We analyzed 41 small hepatic nodules in 32 patients that showed typical radiologic hallmarks on both CT and gadoxate-enhanced MRI (typical nodules) and 25 small hepatic nodules from 22 patients that showed atypical radiologic hallmarks on CT and typical radiologic hallmarks on MRI (discrepant nodules). RESULTS: There were no significant differences in the baseline characteristics of the patients with typical and discrepant nodules. Complete response rates 1 month after TACE or RFA were 75.0% (18/24) and 94.1% (16/17; P=0.20), respectively, for the patients with typical nodules and 58.8% (10/17) and 100% (8/8; P=0.05), respectively, for the patients with discrepant nodules. Treatment failure rates after TACE or RFA were 33.3% (8/24) and 5.8% (1/17; P=0.15), respectively, for the patients with typical nodules and 47.0% (8/17) and 0.0% (0/8; P=0.02), respectively, for the patients with discrepant nodules. Among patients achieving complete response, there were no significant differences in the risk of marginal recurrence. CONCLUSIONS: RFA provided higher complete response rates and significantly lower treatment failure rates than TACE for patients with discrepant nodules of HCC. Therefore, a treatment modality such as RFA may be preferable for small HCCs which show discrepancy on two imaging modalities.

An insulinoma with an aberrant feeder from the splenic artery detected by super-selective arterial calcium stimulation with venous sampling

No abstract available.

The Safety and Clinical Outcomes of Chemoembolization in Child-Pugh Class C Patients with Hepatocellular Carcinomas

OBJECTIVE: To evaluate the safety and clinical outcomes of chemoembolization in Child-Pugh class C patients with hepatocellular carcinomas (HCC). MATERIALS AND METHODS: The study comprised 55 patients with HCC who were classified as Child-Pugh class C and who underwent initial chemoembolization between January 2003 and December 2012. Selective chemoembolization was performed in all technically feasible cases to minimize procedure-related complications. All adverse events within 30 days were recorded using the Common Terminology Criteria for Adverse Events (CTCAE). The tumor response to chemoembolization was evaluated using the modified Response Evaluation Criteria In Solid Tumors. RESULTS: Thirty (54.5%) patients were within the Milan criteria, and 25 (45.5%) were beyond. The mortality of study subjects at 30 days was 5.5%. Major complications were observed in five (9.1%) patients who were all beyond the Milan criteria: two hepatic failures, one hepatic encephalopathy, and two CTCAE grade 3 increases in aspartate aminotransferase/alanine aminotransferase abnormality. The mean length of hospitalization was 6.3 ± 8.3 days (standard deviation), and 18 (32.7%) patients were discharged on the next day after chemoembolization. The tumor responses of the patients who met the Milan criteria were significantly higher (p = 0.014) than those of the patients who did not. The overall median survival was 7.1 months (95% confidence interval: 4.4-9.8 months). CONCLUSION: Even in patients with Child-Pugh class C, chemoembolization can be performed safely with a selective technique in selected cases with a small tumor burden.

Role of C-Arm Cone-Beam CT in Chemoembolization for Hepatocellular Carcinoma

With the advent of C-arm cone-beam computed tomography (CBCT), minimally-invasive procedures in the angiography suite made a new leap beyond the limitations of 2-dimensional (D) angiography alone. C-arm CBCT can help interventional radiologists in several ways with the treatment of hepatocellular carcinoma (HCC); visualization of small tumors and tumor-feeding arteries, identification of occult lesion and 3D configuration of tortuous hepatic arteries, assurance of completeness of chemoembolization, suggestion of presence of extrahepatic collateral arteries supplying HCCs, and prevention of nontarget embolization. With more improvements in the technology, C-arm CBCT may be essential in all kinds of interventional procedures in the near future.

Does Establishing a Safety Margin Reduce Local Recurrence in Subsegmental Transarterial Chemoembolization for Small Nodular Hepatocellular Carcinomas?

OBJECTIVE: To test the hypothesis that a safety margin may affect local tumor recurrence (LTR) in subsegmental chemoembolization. MATERIALS AND METHODS: In 101 patients with 128 hepatocellular carcinoma (HCC) nodules (1-3 cm in size and < or = 3 in number), cone-beam CT-assisted subsegmental lipiodol chemoembolization was performed. Immediately thereafter, a non-contrast thin-section CT image was obtained to evaluate the presence or absence of intra-tumoral lipiodol uptake defect and safety margin. The effect of lipiodol uptake defect and safety margin on LTR was evaluated. Univariate and multivariate analyses were performed to indentify determinant factors of LTR. RESULTS: Of the 128 HCC nodules in 101 patients, 49 (38.3%) nodules in 40 patients showed LTR during follow-up period (median, 34.1 months). Cumulative 1- and 2-year LTR rates of nodules with lipiodol uptake defect (n = 27) and those without defect (n = 101) were 58.1% vs. 10.1% and 72.1% vs. 19.5%, respectively (p < 0.001). Among the 101 nodules without a defect, the 1- and 2-year cumulative LTR rates for nodules with complete safety margin (n = 52) and those with incomplete safety margin (n = 49) were 9.8% vs. 12.8% and 18.9% vs. 19.0% (p = 0.912). In multivariate analyses, ascites (p = 0.035), indistinct tumor margin on cone-beam CT (p = 0.039), heterogeneous lipiodol uptake (p = 0.023), and intra-tumoral lipiodol uptake defect (p < 0.001) were determinant factors of higher LTR. CONCLUSION: In lipiodol chemoembolization, the safety margin in completely lipiodolized nodule without defect will not affect LTR in small nodular HCCs.

Percutaneous Aspiration Embolectomy Using Guiding Catheter for the Superior Mesenteric Artery Embolism

OBJECTIVE: To evaluate the technical feasibility and clinical outcome of percutaneous aspiration embolectomy for embolic occlusion of the superior mesenteric artery (SMA). MATERIALS AND METHODS: Between January 2010 and December 2013, 9 patients with embolic occlusion of the SMA were treated by percutaneous aspiration embolectomy in 2 academic teaching hospitals. The aspiration embolectomy procedure was performed with the 6-Fr and 7-Fr guiding catheter. Thrombolysis was performed with urokinase using a multiple-sidehole infusion catheter. The clinical outcome was investigated retrospectively. RESULTS: Superior mesenteric artery occlusion was initially diagnosed by computed tomography (CT) in all patients, and all patients had no obvious evidence of bowel infarction on CT scan. Percutaneous aspiration embolectomy was primarily performed in 6 patients, and thrombolysis was initially performed in 3 patients. In 3 patients who received primary thrombolysis, percutaneous aspiration was undertaken because the emboli were resistant to urokinase. Complete angiographic success was achieved in 6 patients and partial angiographic success was accomplished in 3 patients. One patient underwent bowel resection. One patient died of whole bowel necrosis and sepsis, and 8 patients survived without complications. CONCLUSION: Percutaneous aspiration embolectomy is a useful tool in recanalization of embolic occlusion of the SMA in select patients.

Tissue Responses to Stent Grafts with Endo-Exo-Skeleton for Saccular Abdominal Aortic Aneurysms in a Canine Model

OBJECTIVE: We evaluated the effect of close contact between the stent and the graft on the induction of endothelial covering on the stent graft placed over an aneurysm. MATERIALS AND METHODS: Saccular abdominal aortic aneurysms were made with Dacron patch in eight dogs. The stent graft consisted of an inner stent, a expanded polytetrafluoroethylene graft, and an outer stent. After sacrificing the animals, the aortas with an embedded stent graft were excised. The aortas were inspected grossly and evaluated microscopically. RESULTS: The animals were sacrificed at two (n = 3), six (n = 3), and eight months (n = 2) after endovascular repair. In two dogs, the aortic lumen was occluded at two months after the placement. On gross inspection of specimens from the other six dogs with a patent aortic lumen, stent grafts placed over the normal aortic wall were covered by glossy white neointima, whereas, stent grafts placed over the aneurysmal aortic wall were covered by brownish neointima. On microscopic inspection, stent grafts placed over the normal aortic wall were covered by thin neointima (0.27 +/- 0.05 mm, mean +/- standard deviation) with an endothelial layer, and stent grafts placed over the aneurysmal aortic wall were covered by thick neointima (0.62 +/- 0.17 mm) without any endothelial lining. Transgraft cell migration at the normal aortic wall was more active than that at the aneurysmal aortic wall. CONCLUSION: Close contact between the stent and the graft, which was achieved with stent grafts with endo-exo-skeleton, could not enhance endothelial covering on the stent graft placed over the aneurysms.