Transarterial Embolization Research Articles

Parasagittal dural arteriovenous fistulas

Background The majority of studies on parasagittal dural arteriovenous fistulas (DAVFs) have been limited to case reports or case series, and they are frequently reported alongside true superior sagittal sinus (SSS) DAVFs. Because of the selective bias present in the reporting of dispersed small numbers of parasagittal DAVFs, the results of each study may influence the findings. As a result, we present a large sequential cohort of parasagittal DAVFs from our institution spanning a 20-year period. Methods This study was a retrospective analysis involving 80 patients with parasagittal DAVFs who were hospitalized at a single medical center from 2002 to 2022. We explore their clinical manifestations, angioarchitecture, clinical and radiographic outcomes. Results We identified 80 patients with 85 parasagittal DAVFs. The cohort consisted of 69 men and 11 women, with a M ± SD age of 50.5 ± 11.1 years. Seventy-six patients underwent trans-arterial embolization (TAE), two underwent surgery, and two received conservative treatment. Immediate complete occlusion was achieved in 74 cases (94.9%). Fifty (96.2%) patients were cured, with no recurrence detected on final follow-up imaging. One patient died 6 months after the final subtotal occlusion, while the other patients experienced improvement or resolution of clinical symptoms following treatment. Conclusions These lesions carry a high risk of hemorrhage and nonhemorrhagic neurological deficits. In our series, TAE achieved a high cure rate for these lesions, with no major complications reported.

Management of traumatic scalp arteriovenous fistula: Case report and literature review.

Blunt traumatic arteriovenous fistula (AVF) of scalp, are uncommon and most of them can be secured by simple embolization or surgical ligation of the feeders. Our goal in writing this paper is to show patients with traumatic scalp AVFs how to prevent complications and the likelihood of recurrence. Complete treatment and reduce the recurrence rate of traumatic AVF on the scalp. Traumatic scalp AVF. Transarterial embolization and surgical resection. Complete resection of the AVF and subsequent angiography showed resolution of the contralateral lesion. Combination of endovascular embolization with subsequent surgical removal may reduce intraoperative blood loss compared with surgery alone. In addition, a well-designed scalp flap can be performed based on the angiography findings after embolization.

Efficacy of Transarterial Embolization Using Intermittent Flow Control for Tentorial Dural Arteriovenous Fistula Presenting as Myelopathy: A Technical Report

BackgroundTransarterial embolization (TAE) is generally the endovascular treatment of choice for tentorial dural arteriovenous fistula (dAVF). Although flow control of the feeder vessel has been reported to achieve complete shunt blockade, flow control in the absence of ischemia tolerance of ICA as a feeder has not been reported. we present a case in which treatment by Onyx TAE with intermittent flow control of the meningohypophyseal trunk (MHT) as the feeder was successful for a tentorial dAVF presenting with myelopathy without tolerance of ischemia. MethodsThe intermittent flow control is presented for a tentorial dAVF presenting with myelopathy without tolerance for ischemia. An inflation of the balloon in the internal carotid artery was set for 5 minutes, and the Onyx injection was repeated at intervals of at least 2 minutes. Injections and pauses were repeated to allow Onyx to reach the shunt pouch. ResultsThe patient underwent successful TAE with intermittent flow control for a tentorial dAVF presenting with myelopathy. The disappearance of the shunt was confirmed with gait disturbance resolution postoperatively. ConclusionIntermittent flow control of the MHT using a balloon may be safe and effective for cases showing no tolerance for ischemia.

Vein of galen malformations: for patients and caregivers.

Vein of Galen malformations (VOGMs), also known as Vein of Galen Aneurysmal Malformations (VGAMs), are rare and complex cerebrovascular anomalies that pose significant diagnostic and therapeutic challenges. These malformations result from abnormal arteriovenous shunts during embryonic development, leading to a range of severe clinical manifestations, including high-output cardiac failure and hydrocephalus. Advances in prenatal imaging, particularly fetal MRI, have improved early detection, allowing for timely intervention. Endovascular techniques, especially transarterial embolization, have become the primary treatment modality, often preferred over surgical approaches due to their effectiveness and lower risk. However, challenges remain, particularly in managing these malformations in neonates and infants, where the risk of complications is high. Gamma Knife radiosurgery offers a non-invasive alternative for select cases, though its effects are gradual and may carry delayed risks. Despite advancements, the management of VOGMs continues to require a multidisciplinary approach, with ongoing research focused on improving outcomes through a better understanding of the genetic and molecular underpinnings of the disease. Future directions include the integration of genetic studies into clinical practice and the refinement of treatment strategies to optimize outcomes for this complex condition.

Transarterial Coil Embolization for Type II Endoleak After Endovascular Aneurysm Repair (EVAR).

Background Endovascular aneurysm repair (EVAR) has evolved into treatment of choice for infrarenal abdominal aortic aneurysms (AAA). Type II endoleaks, although frequently benign, can lead to sac enlargement and rupture. Management of these endoleaks by endovascular means can be quite challenging and may require complex techniques and assistance of interventional radiologists, not always available in all vascular units. This is a single-center study of management of type II endoleaks with transarterial coil embolization performed by vascular surgeons and with minimum requirements regarding the necessary equipment. Methods From 2017 to 2022, 13 patients with type II endoleak were treated. Local anaesthesia and transfemoral or transbrachial approach was used. The superficial mesenteric artery (SMA) was catheterized and through the Riolan arch, coiling of the inferior mesenteric artery and/or the sac aneurysm was performed. Results The mean time period between the primary EVAR procedure and the transarterial intervention for the endoleak was 3.9 years. Primary technical success was achieved in 11 (84.6%) patients, whilesecondary technical success was 12 (92.3%). In the mean follow-up period, which was 2.6 years, the endoleak was treated successfully in 11 (84.6%) patients. Conclusions Transarterial coil embolization of type II endoleaks is a minimal low-cost procedure, with small percentage of complications, high technical and treatment success rates. It could be considered as a first-line treatment of unresolvable type II endoleaks, minimizing the need for open repair.

Comparison of the Effectiveness of Transarterial Bland Embolization and Transarterial Chemoembolization for Intermediate-Stage Hepatocellular Carcinoma: A Propensity Score–Matched Study of 1,008 Patients

PurposeTo assess the effectiveness of transarterial bland embolization (TAE) compared with transarterial chemoembolization (TACE) therapy in the treatment of patients with intermediate-stage hepatocellular carcinoma (HCC). Materials and MethodsTwo thousand two hundred ninety-seven patients with intermediate-stage HCC were screened, and 1,461 patients who underwent TAE or TACE as the first-choice treatment were retrospectively analyzed and baseline matched according to the 2 treatment methods. Subgroup analysis was performed among patients according to the Up-to-7 criteria. The primary endpoint was overall survival (OS). ResultsA total of 1,461 patients with HCC who underwent TAE or TACE were included; 730 patients underwent TACE and 731 underwent TAE. The patients in the TAE group exhibited poorer liver function and a significantly higher rate of hepatitis B infection (P < .001) compared with the TACE group. After propensity score matching, 504 well-matched pairs of patients with intermediate-stage HCC were selected for analysis. Univariate analysis showed that TACE significantly prolonged patient survival compared with TAE (P < .001). The 1-, 2-, and 3-year OS rates were 74.3%, 57.1%, and 44.4% and for the TACE group and 58.3%, 32.4%, and 21.7% for the TAE group, respectively. Multivariate analysis showed a hazard ratio of 0.517 (95% CI, 0.442–0.605; P < .001) for the TACE approach over the TAE approach for OS. The TACE group had a significantly higher overall response rate than the TAE group (35% vs 26%; P = .024). ConclusionsTACE resulted in higher response rate and longer OS compared with TAE as the initial treatment for intermediate-stage HCC.

TACE Combined with Portal Vein Tumor Thrombus 125I Seed Implantation in the Treatment of HCC with Hepatic Arterioportal Shunts.

Transarterial chemoembolization (TACE) and 125I seed implantation are methods used to treat hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT), PVTT often associated with arterioportal shunts(APS), there are few reports on the combined use of TACE and 125I seed implantation for such patients. This study aimed to evaluate the efficacy and safety of TACE combined with PVTT 125I seed implantation in the treatment of HCC patients with APS. Forty-two patients diagnosed with HCC combined with PVTT and APS between January 2020 and December 2021 were included. Appropriate materials were selected to transarterial embolization of the APS, and 125I seeds were implanted into the PVTT. The occlusion effect was observed and recorded after 3 months, the efficacy of intrahepatic lesions and PVTT was evaluated, and the patient survival, prognostic factors affecting APS recanalization were analyzed. All 42 patients completed the follow-up three months after treatment. The immediate APS improvement rate was 100%, and the APS improvement rate at the three-month follow-up was 64.29%. The disease control rates of PVTT and intrahepatic lesions were 81.00% and 78.60%, respectively. The patients' 6-month and 12-month survival rates were 78.6% and 46.8%. The median OS for all patients was 11.90 months, and the median OS was 13.30 months in the APS effective treatment group and 8.30 months in the ineffective group. The PVTT type is the only independent factor affecting APS recanalization. (P=0.02). For HCC patients with PVTT and APS, TACE combine with 125I seed implantation in PVTT is a potentially effective and safe method that contributes to prolonging patient survival.

Trans-arterial embolization versus chemoembolization for neuroendocrine liver metastases: a propensity matched analysis

IntroductionLocoregional therapies are a mainstay of treatment for patients with neuroendocrine liver metastases (NELM), yet the optimal transarterial approach remains undefined and recent studies have raised concern over the safety of transarterial chemoembolization (TACE). MethodsPatients with NELM who underwent TACE or transarterial embolization (TAE) at a single institution between 2000–2022 were retrospectively reviewed. Propensity score matching (PSM) controlling for age, sex, bilateral disease, tumor size, lobar embolization, grade, and extrahepatic disease was utilized to compare short- and long-term outcomes. ResultsAmong 412 patients with NELM, 329 underwent TACE and 83 TAE. Mean age was 60.7 ± 11.1 years. Patients primarily presented with synchronous (69.2%), bilateral (84.2%), and G1 disease (48.8%) and underwent staged procedures (55.8%). Following PSM, TACE was associated with slightly worse post-procedure laboratory values, but no difference in complications compared to TAE (23.3%vs29.3%, p = 0.247). TACE was associated with improved mean PFS (21.8vs10.7 months, p = 0.002), but no difference in radiographic size, chromogranin level, or median overall survival (50.0 months vs not met, p = 0.833). ConclusionAmong patients with NELM, TACE was associated with similar short-term outcomes and improved PFS, but no difference in OS compared to TAE. These findings highlight the need for additional research on the optimal locoregional therapy for NELM.

Comparative analysis among therapeutic modalities in ruptured hepatocellular carcinoma and identification of imaging predictors for survival

BackgroundSpontaneous rupture of hepatocellular carcinoma (rHCC) poses a life-threatening complication with a mortality rate of 25–75%. Treatment aims at achieving hemostasis and includes options such as trans-arterial embolization, perihepatic packing, and hepatic resection. The optimal treatment remains a subject of debate. Our retrospective review evaluates these treatments and investigates imaging’s role in prognosis for rHCC patients.PurposeWe aimed to compare survival outcomes among rHCC patients who received transarterial embolization (TAE), surgery (perihepatic packing, hepatectomy), or best supportive care (BSC), while also identifying predictive imaging factors in these patients.Materials and methodsAll patients diagnosed with rHCC and admitted to Maharaj Nakorn Chiangmai Hospital between January 2012 and December 2021 were included. We reviewed clinical features, imaging results, treatment modalities, and outcomes. In order to balance pretreatment confounders, inverse probability treatment weighting (IPTW) was employed. Flexible parametric survival regression was utilized to compare survival outcomes and identify imaging factors predicting the survival of rHCC patients. Hazard ratios (HR) and the difference in restricted mean survival time (RMST) were reported.ResultAmong the 186 rHCC patients included, we observed 90-day and 1-year mortality rates of 64% and 84%, respectively. Both the TAE and surgery groups exhibited significantly lower 1-year mortality rates compared to BSC. The HR were 0.56 (95% CI 0.33–0.96) for TAE and 0.52 (95% CI 0.28–0.95) for surgery compared to BSC. Both the TAE and surgery also significantly extended the 1-yeaar life expectancy post-initial treatment when compared to BSC, with an RMST difference of + 55.40 days (95% CI 30.18–80.63) for TAE vs. BSC and + 68.43 days (95% CI 38.77–98.09) for surgery vs. BSC. The presence of active contrast extravasation and bleeding in both lobes were independent prognostic factors for 1-year survival.ConclusionsTAE and surgical treatments provide comparable survival benefits for rHCC patients, extending survival time by approximately 2 months compared to best supportive care. We strongly recommend active management for all rHCC patients whenever possible.

Liver Resection for Gastroenteropancreatic Neuroendocrine Tumors with Extrahepatic Disease.

Background: Although survival outcomes for neuroendocrine liver metastases (NETLM) are improved with liver-direct therapies (LDT), including hepatic debulking and nonsurgical trans-arterial embolization, the benefit is less established in the setting of concurrent extrahepatic disease (EHD). We performed a population-based study to characterize the rates of LDT being performed for NETLM with EHD patients and whether LDT is associated with survival outcomes. Methods: Patients with NETLM and EHD were identified using the California Cancer Registry database merged with data from the California Office of Statewide Health Planning and Development between 2000 and 2012. Demographics, clinical characteristics, and survival outcomes were analyzed for these patients with and without LDT. Results: 327 NETLM patients with EHD were identified. EHD sites included lung, peritoneum, bone, and brain. A total of 71 (22%) of these patients underwent LDT. Compared to NETLM with EHD patients who did not undergo LDT, patients who received LDT had longer median overall survival (27 vs. 16 months, p = 0.006). Within the LDT group, 23 patients underwent liver resection. Liver resection was associated with longer median overall survival compared to nonsurgical LDT (138 vs. 13 months, p < 0.001). Conclusions: LDT candidacy should be determined for patients on a case-by-case basis, but the presence of EHD should not preclude LDT with appropriate patient selection.

Immunotherapy and transarterial embolization in patients with metastatic melanoma: a retrospective cohort study.

Aim: To investigate how the sequence of checkpoint immunotherapy (CPI) and transarterial embolization (TAE) affects overall survival (OS) of patients with metastatic melanoma.Materials &methods: This retrospective cohort study included 65 patients with metastatic melanoma who underwent both TAE and CPI between September 2011 and January 2022.Results: Significantly higher OS was seen in patients who received CPI before and after embolization (22months, 95% CI 14-NR, p<0.001) compared with only before embolization (4.5months 95% CI, 14-NR). ≤3 hepatic metastasis (p<0.01), more TAE procedures (p<0.001)and CPI sequence (before and after embolization) (p<0.001) were independent predictors of survival.Conclusion: Metastatic melanoma patients who underwent TAE have longer survival when CPI was sequenced both before and after embolization.

Spinal epidural arteriovenous fistula with an intraosseous shunt arising in a compression fracture vertebra: illustrative case.

Spinal epidural arteriovenous fistulas (SEAVFs) with intraosseous shunts are rare, and their underlying pathophysiological mechanisms remain unclear. A female in her 70s presented with rapidly progressive weakness in both lower extremities and urinary retention. Lumbar spine magnetic resonance imaging revealed spinal cord edema and flow voids due to venous dilation and compression fractures of the L1 and L2 vertebral bodies. Spinal angiography revealed ventral and dorsal somatic branches of the lumbar arteries at L1 and L2 flowing into the shunt. High-resolution cone-beam computed tomography revealed a shunt within the compression-fractured vertebral body bone of L2. The intravertebral shunt blood flowed into the ventral epidural venous plexus (VEVP) and returned into the perimedullary vein (PMV). Transarterial embolization was performed using N-butyl cyanoacrylate and Onyx-18 for feeder L1 and feeder L2, respectively. Onyx-18 was injected from the VEVP into the PMV, and complete occlusion of the shunt was achieved. The patient showed symptomatic improvement postoperatively. Vertebral compression fractures are common but rarely associated with SEAVFs. https://thejns.org/doi/10.3171/CASE2457.

Pancreatic Arteriovenous Malformation Presenting with Upper Gastrointestinal Bleeding: Treatment with Transarterial Embolization—A Case Report

Pancreatic Arteriovenous Malformation Presenting with Upper Gastrointestinal Bleeding: Treatment with Transarterial Embolization—A Case Report

Selective embolisation of an idiopathic bronchial artery pseudoaneurysm presenting with recurrent laryngeal nerve palsy: a case report

BackgroundBronchial artery pseudoaneurysms (BAP) or aneurysms (BAA) are rare, potentially life-threatening and remain poorly understood. They are most commonly idiopathic but may be associated with a number of other disease processes. Bronchial artery embolisation (BAE) is considered the first line treatment while surgical techniques are reserved for patients with a clear contraindication to embolisation or where anatomical factors preclude an endovascular approach.Case presentationWe present an interesting case of a 56 year-old male presenting with an idiopathic unruptured right BAP causing clinical and radiological signs of left recurrent laryngeal nerve (RLN) palsy. He was otherwise clinically well with no other reported symptoms and no significant past medical history. There were no significant findings on work-up and investigation. He was ultimately treated successfully with selective transarterial coil embolization of the right bronchial artery. This is an atypical presentation of a rare clinical entity and has not previously been published in the literature to our knowledge.ConclusionsBAPs and BAAs are highly variable in their presentation, ranging from incidental asymptomatic findings to catastrophic haemorrhage, depending on their location and if they are contained or ruptured. Timely diagnosis and referral to facilitate urgent embolisation is essential to prevent potentially serious clinical sequelae. Endovascular treatment in the form of BAE is considered first line.

Endovascular transvenous treatment of carotid–cavernous fistula

Carotid–cavernous fistulas represent abnormal communication between the carotid circulation and the cavernous sinus. They can be classified as direct or indirect. The Barrow classification is the most widely used system that categorizes the carotid–cavernous fistulas based on their arterial supply (type A–D). The mainstay of therapy for carotid–cavernous fistulas consists of transarterial or transvenous embolization, while other treatment options such as open surgery or radiosurgery are still utilized as second-line or adjuvant therapeutic options. We present the case of a 72-year-old female patient with conjunctival chemosis and exophthalmos. Computed tomography angiography detected a carotid–cavernous fistula that was confirmed with catheter angiography (Barrow type C). Through right femoral vein catheterization, detachable coils were deployed in the right cavernous sinus, adjacent to the fistula shunt point. The procedure was completed with N-butyl cyanoacrylate injection (dilution 1:2). At post-procedural digital subtraction angiography, the fistula was excluded. Endovascular transvenous treatment is a valid therapeutic option for indirect carotid–cavernous fistulas.

Preliminary Experience With Novel Straight 3-Fr Guiding Sheath for Transradial Access in Endovascular Treatment: Feasibility and Safety.

Radial artery diameter may limit whether a guiding sheath (GS) can be used via transradial artery access (TRA). A smaller GS may reduce the risk of access site-related complications. This study investigated the feasibility and safety of endovascular treatment (EVT) using a straight-shaped 3-Fr GS (Axcelguide; Medikit). Patients who underwent EVT with a straight-shaped 3-Fr GS at 3 institutions between April 2022 and March 2024 were retrospectively reviewed. Patient background, anatomic and procedural factors, and complications were recorded. Twenty-six pathologies were treated with EVT using a 3-Fr GS. Median radial artery diameter was 1.9 mm, and distal TRA (73.1%) was selected more often than TRA (26.9%) as the access site. The breakdown of target pathologies and the role of the 3-Fr GS were as follows: 12 unruptured cerebral aneurysms for intra-aneurysmal coiling, with 5 dural arteriovenous fistulas, 5 brain or head and neck tumors, 2 chronic subdural hematoma, 1 arteriovenous malformation, and 1 hereditary hemorrhagic telangiectasia for transarterial embolization. A success rate of 96.2% was achieved, with no access site- or non-access site-related complications observed within 30 days. The straight-shaped 3-Fr GS may be applicable for selected pathologies, allowing access even with RAs <2 mm in diameter and facilitating EVT without complications. Preliminary experience with the 3-Fr GS via TRA demonstrated excellent feasibility and safety.

Value of Dual Arterial Access for Improved Angiographic Control for Double-Lumen Arterial Balloon Onyx Embolization of Multifeeder Complex Cranial Dural Arteriovenous Fistulas: A Technical Nuance

Here we describe our experience managing intracranial dural arteriovenous fistulas (DAVFs) via endovascular embolization using a transarterial embolization (TAE) technique with liquid embolic agents. We illustrate the technical nuance of using dual arterial access for angiographic control runs in complex DAVFs supplied by multiple feeders from 2 distinct arterial systems. Retrospective analysis of intracranial DAVF embolization as a single treatment technique at our institution from 2013 to2023. Twenty-three patients with intracranial DAVF who underwent endovascular treatment as their initial treatment were included. All embolizations were approached transarterially with Onyx (n= 19), n-butyl cyanoacrylate (n= 2), or a combination (n= 2). Twenty-two patients (96%) had angiographic evidence of complete fistula obliteration after initial embolization. Six DAVF TAEs were performed with dual arterial access for simultaneous embolic delivery and angiographic control intraoperatively. Two patients recanalized twice postprocedure, 1 of whom was found to have incidental new DAVF at follow-up. Median patient follow-up was 12 months (interquartile range, 6-36 months), with a median modified Rankin Scale score on discharge of 1 and a Glasgow Outcome Scale score at 3 months of5. In this initial series of patients with DAVF managed by endovascular embolization, dual arterial access was feasible, safe, and effective in achieving fistula obliteration. Dual-arterial access conveniently provides simultaneous access for control angiography and embosylate delivery intraoperatively.

Intravascular Casting Radiopaque Hydrogel Systems for Transarterial Chemo/Cascade Catalytic/Embolization Therapy of Hepatocellular Carcinoma.

This paper introduces catheter-directed intravascular casting hydrogels for transarterial chemo/starvation/chemodynamic embolization (TACSCE) therapy of hepatocellular carcinoma (HCC). Comprising Mn ion-crosslinked hyaluronic acid-dopamine (HD) with glucose oxidase (for glucose decomposition to H2O2 in starvation therapy), doxorubicin (for chemotherapy), and iopamidol (for X-ray imaging), these hydrogels are fabricated for transarterial embolization therapy guided by X-ray fluoroscopy. Mn4+ (from MnO2) demonstrates strong coordination with the catechol group of HD, providing hypoxia relief through O2 generation and cellular glutathione (GSH) consumption, compared to the OH radical generation potential of Mn2+. The gelation time-controlled, catheter-injectable, and rheologically tuned multitherapeutic/embolic gel system effectively reaches distal arterioles, ensuring complete intravascular casting with fewer complications related to organic solvents. Glucose deprivation, cascade reactive oxygen species (ROS) generation, GSH depletion, and sustained release profiles of multiple drug cargos from the hydrogel system are also achieved. The combined chemo/starvation/chemodynamic efficacies of these designed hydrogel systems are confirmed in HCC cell cultures and HCC-bearing animal models. The developed radiopaque/injectable/embolic/sol-to-gel transformable systems for TACSCE therapy may offer enhanced therapeutic efficacies compared to typical transarterial embolization and transarterial chemoembolization procedures for HCC.

Bilateral Congenital Pelvic Arteriovenous Malformation: A Case Report and Review of Literature.

Through a paradigmatic case and a systematic literature review, we present various endovascular strategies for treating pelvic paravesical arteriovenous vascular malformations (AVMs), with a focus on the efficacy of accessing the shunt point through direct puncture of the venous collector. A 42-year-old male with nonspecific pelvic pain underwent a computed tomography (CT) scan, which revealed bilateral pelvic AVMs characterized by a network of arteriolar afferents originating from the internal iliac arteries and the inferior mesenteric artery, draining into 2 interconnected giant venous sacs in the bilateral paravesical space. The malformation was classified as type II according to the Cho classification. Following an unsuccessful attempt at transarterial embolization, we devised a plan for bilateral transvenous embolization in 2 separate sessions. Venous access was achieved through percutaneous transperineal ultrasound-guided puncture of the dominant outflow venous sac. A microcatheter was then placed directly into the shunt point, where sclerosant and embolic agents were specifically delivered. Follow-up imaging showed complete obliteration of both pelvic AVMs. Effective hemostasis of pelvic paravesical AVMs can be achieved by targeting the shunt point from the aneurysmal dominant outflow vein, potentially through direct percutaneous puncture. This study aims to demonstrate the effectiveness of a transvenous approach in cases of embolization of pelvic paravesical arteriovenous vascular malformations (AVMs). The key to successful treatment lies in occluding the shunt point within the aneurysmal dominant outflow vein's wall, which can be reached transvenously and potentially through direct percutaneous puncture. Although arterial occlusion can be performed additionally, it should not be performed alone due to its higher risk of AVM persistence/recurrence.

Transarterial Embolization Enhances Programmed Cell Death Ligand 1 Expression and Influences CD8+T Lymphocytes Cytotoxicity in an Orthotopic Hepatocellular Carcinoma Rat Model.

To investigate the influence of transarterial embolization (TAE) on programmed cell death-ligand 1(PD-L1) expression and CD8+T tumour infiltrative lymphocyte cytotoxicity in the Sprague-Dawley (SD) rat model of hepatocellular carcinoma (HCC). An orthotopic HCC model was established in twenty SD rats treated with TAE (lipiodol, n = 10) or sham (normal saline, n = 10) using homologous N1S1 hepatoma cells. Rats were euthanized 1week after embolization. Flow cytometry was used to assess the proportion of CD4+T, CD8+T and programmed cell death-1+(PD-1+) CD8+T lymphocytes in the spleens and tumours. Distribution of CD8+T, granzyme-B+CD8+T lymphocytes and PD-L1+ cells was assessed by immunohistochemistry (IHC) or multiplex IHC. p value < 0.05 was considered statistically significant. The CD4/CD8 ratio and PD-1+CD8+ T lymphocytes exhibited higher values in TAE-treated tumours compared to sham-treated tumours (p = 0.021 and p = 0.071, respectively). Conversely, the number of CD8+T lymphocytes was decreased in TAE-treated tumours (p = 0.043), especially in the central region (p = 0.045). However, more CD8+T lymphocytes were found infiltrating the marginal region than central region in TAE-treated tumours (p = 0.046). The proportion of granzyme-B+CD8+T lymphocytes and the PD-L1 positive areas was elevated in tumours that treated with TAE (p all < 0.05). There was a negative correlation between PD-L1 expression and the number of infiltration of CD8+ T lymphocytes (p = 0.036). Immune cells are distributed unevenly in the tumours after TAE. The intrinsic induction state of the tumour after embolization may be insufficient to elicit a maximal response to PD-1/PD-L1 inhibitors.