Tris-acryl Gelatin Microspheres Research Articles

Resorbable Microspheres versus Trisacryl Gelatin Microspheres for Uterine Artery Embolization: A Randomized Controlled Trial.

Background There are insufficient data comparing resorbable microspheres (RMs) with permanent trisacryl gelatin microspheres (TAGMs) for uterine artery embolization (UAE). Purpose To compare therapeutic efficacy and clinical outcomes in participants with symptomatic fibroids after UAE with RMs or TAGMs. Materials and Methods This randomized controlled trial included participants undergoing UAE for symptomatic fibroids at a single institution (from May 2021 to May 2023). Participants were randomized one-to-one to undergo UAE with either RMs or TAGMs. Numeric rating scale pain scores and cumulative fentanyl consumption were assessed for 24 hours after undergoing UAE. Anti-Mullerian hormone was measured to assess effects of UAE on ovarian function. MRI was performed before and 3 months after UAE to evaluate fibroid necrosis and uterine artery recanalization. Repeated variables such as pain were analyzed using Mann-Whitney U test with post hoc Bonferroni correction. Results Sixty female participants (mean age, 45.7 years ± 3.6 [SD]) completed the study, with 30 in each group. No evidence of a difference in pain scores was observed between groups (P > .99). Moreover, there was no evidence of a difference in the total fentanyl consumption at 24 hours after UAE between groups (median: RMs, 423 [IQR, 330-530] vs TAGMs, 562 [IQR, 437-780]; P = .15). Serum anti-Mullerian hormone 3 months after UAE showed no evidence of a difference between groups (RMs vs TAGMs, 0.71 ng/mL ± 0.73 vs 0.49 ng/mL ± 0.45, respectively; P = .09). No evidence of a difference in the rate of complete necrosis of the dominant fibroid was observed between groups (97% [29 of 30] for both groups; P > .99). The rate of uterine artery recanalization was higher in RM versus TAGM groups (70% [21 of 30] vs 17% [five of 30], respectively; P < .001). Conclusion UAE with RMs, compared with UAE with TAGMs, showed no evidence of a difference in terms of therapeutic effectiveness or postprocedural pain scores in participants with symptomatic fibroids. Clinical trial registration no. NCT05086770 © RSNA, 2024 See also the editorial by Spies in this issue.

Comparing embolic particles for prostatic artery embolization to treat lower urinary tract symptoms in patients with benign prostatic hyperplasia.

Compare the safety and efficacy of polyvinyl alcohol particles (PVA) versus trisacryl gelatin microspheres (Embospheres) versus hydrogel microspheres coated with polyzene-F (Embozenes) for prostatic artery embolization (PAE) to treat patients with benign prostatic hyperplasia (BPH). A single-center prospective cohort study from 2019 to 2023, including patients with international prostate symptom score (IPSS) ≥ 15 and/or quality of life score (QoL) ≥ 4. Allocation to embolic agents was performed chronologically: 100-300 µm PVA (n = 53), followed by 300-500 µm Embospheres (n = 50), and finally, 400 µm Embozenes (n = 50). All patients were evaluated at baseline and at 1 and 6 months after PAE with IPSS/QoL; peak urinary flow rate, post-void residual volume, and prostate volume with ultrasound and prostate-specific antigen. Adverse events and the need for prostatic re-interventions were assessed. There were no significant baseline differences between the three groups except for patient age (62.5 years PVA; 66.1 years Embospheres and 66.6 years Embozenes; p = 0.019). There were no major adverse events and no differences between groups regarding minor adverse events. All outcome measures improved significantly from baseline, with no significant differences between groups. Mean ± standard deviation IPSS/QoL improvement at 6 months: -10.7 ± 7.9/-2.2 ± 1.7 PVA; -10.4 ± 7.3/-2.0 ± 1.5 Embospheres; -10.4 ± 7.0/-2.2 ± 1.6 Embozenes (p = 0.987). Re-intervention rates after 6 months: 9% (n = 5/53) PVA; 14% (n = 7/50) Embospheres; 8% (n = 4/50) Embozenes (p = 0.591). PAE with PVA particles, Embospheres, and Embozenes is equally safe and effective in treating BPH-related lower urinary tract symptoms. This is the first prospective study showing equivalence between the most frequently used embolic agents for prostatic artery embolization. Different particles can be used interchangeably for prostatic artery embolization. The improvements in measured metrics were the same between groups, with no differences in adverse events. The need for prostatic medication and re-intervention rates were the same at 1 and 6 months after embolization.

Comparing Deposition Characteristics of Various Embolic Particles Using an In Vitro Prostate Microvasculature Model

PurposeTo compare spatial distributions of radiopaque glass (RG) microspheres, tris-acryl gelatin (TAG) microspheres, and polyvinyl alcohol (PVA) nonspherical foam particles within a planar in vitro microvascular model of the hyperplastic hemiprostate. Materials and MethodsA microvascular model simulating hyperplastic hemiprostate was perfused with a water-glycerin mixture. A microcatheter was positioned distal to the model’s prostatic artery origin, and embolic particles (RG, 50 μm, 100 μm, and 150 μm; TAG, 100–300 μm and 300-500 μm; and PVA, 90–180 μm and 180–300 μm) were administered using a syringe pump. Microscopic imaging and subsequent semantic segmentation were performed to quantify particle distributions within the models. Distal penetrations were quantified statistically via modal analysis of the particle distributions. ResultsMaximum distal penetration was observed for RG microspheres of 50 μm, followed by RG microspheres of 100 μm and then TAG microspheres of 100–300 μm and RG microspheres of 150 μm. TAG microspheres of 300–500 μm, PVA particles of 90–180 μm, and PVA particles of 180–300 μm exhibited the lowest distal penetrations. The distal penetration metrics between groups were significantly different (P < .05) except between TAG microspheres of 100–300 μm and RG microspheres of 150 μm and between PVA particles of 90–180 and 180–300 μm. ConclusionsComparing the spatial distributions of embolic particles in an in vitro microvascular model simulating the hyperplastic hemiprostate revealed that noncompressible particles and those with narrower size calibrations and smaller relative diameters exhibited higher degrees of distal packing. The embolization front was less distinct for particles with wider size calibrations, which resulted in smaller, more distal emboli along with larger, more proximal emboli. Both PVA particles and TAG microspheres of 300–500 μm exhibited relatively low overall distal penetration.

Radiofrequency Ablation Combined with Hepatic Artery Embolization Using a Tris-acryl Gelatin Microsphere for Colorectal Liver Metastases-Initial Experience.

We aim to evaluate retrospectively the feasibility, safety, and initial therapeutic outcomes of radiofrequency ablation combined with hepatic artery embolization using a tris-acryl gelatin microsphere for colorectal liver metastases. Six consecutive patients (4 men and 2 women) with median age of 68 years (range 57-78 years) underwent computed tomography fluoroscopy-guided radiofrequency ablation immediately after hepatic artery embolization using microspheres. This study evaluated tumor visibility on noncontrast-enhanced computed tomography immediately after hepatic artery embolization; analyzed local tumor progression; defined technical success as the coverage of the tumor by the ablative zone; and assessed adverse events based on Common Terminology Criteria for Adverse Events v5.0. Ten tumors with median maximum diameter of 9 mm (range 5-52 mm) were treated in nine sessions. Eight tumors (80%, 8/10 tumors) were detected as high-attenuation nodules. One tumor was treated in two sessions because follow-up computed tomography revealed an insufficient ablative margin. Therefore, the primary and secondary technical success was 90% (9/10 tumors) and 100% (10/10 tumors), respectively. Grade 2 pneumothorax was observed in one session (11%, 1/9 sessions). No grade 3 or higher adverse event was observed. The local tumor progression rate was 20% (2/10 tumors) during the median follow-up of 14 months. Radiofrequency ablation following microsphere embolization may be a feasible, safe, and useful therapeutic option for controlling small colorectal liver metastases.

Prostatic Artery Embolization (PAE)

Benign prostatic hyperplasia (BPH) is a common condition affecting the majority of men over 60 years of age. BPH incidence increases with age and often leads to lower urinary tract symptoms including frequency, urgency, and straining. In patients that do not respond to pharmacological therapy, options include transurethral procedures such as transurethral resection (TURP) or photovaporization, surgical prostatectomy and prostate artery embolization (PAE). The goal of PAE is to occlude arterial supply to the prostate by selective catheterization and subsequent embolization, most commonly with spherical tris-acryl gelatin microspheres. Over weeks to months, reduced blood flow leads to necrosis of prostatic adenomatous tissue, resulting in reduction of prostate size and decreased urethral impingement, eventually allowing for long-term resolution of symptoms in a majority of patients. Advantages of this technique compared with the standard surgical option, TURP, include faster recovery times, fewer side effects, and lower complication rates with near equal efficacy.

Comparison of polyvinyl alcohol particles and tris-acryl gelatin microspheres embolic agents used in uterine artery embolization: A systematic review and meta-analysis.

To identify the preferred agent by comparing the therapeutic efficacy, degree of infarction, and side effects of polyvinyl alcohol particles (PVA) and tris-acryl gelatin embolization (TAGM) agents in uterine artery embolization. We included available articles comparing PVA with TAGM embolization agents in the management of fibroids. The primary outcomes included the decrease in uterine volume (%), decrease in dominant tumor volume (%), fibroid infarction rate, complete infarction fibroid, complications, pain score after 24 h, procedure time (minutes), duration of hospital stay, fluoroscopy time (minutes), and the change in symptom severity score. Eight articles that met our inclusion criteria were included in this study. Our analysis yielded an overall superiority of PVA compared to TAGM regarding complete fibroid infarction rate at the first 24 h. However, TAGM was better than PVA concerning <90% infarction rate outcome. While both embolization techniques showed similar effects regarding the change in symptom severity score, the percentage of decrease in uterine volume, percentage of decrease of dominant tumor volume, 90-99% infarction rate, complete infarction rate when assessed after the first 24 h, pain score after the first 24 h, procedure time, fluoroscopy time, minor, and major complications. Both PVA and TAGM embolization agents are effective and safe modalities in treating patients with fibroids, with no significant variation of both agents in most outcomes.

Two-year outcomes comparing Embosphere® microspheres versus Imipenem Cilastatin for genicular artery embolization in patients with moderate to severe knee osteoarthritis

BackgroundGenicular artery embolization (GAE) is a novel technique and has the potential to provide midterm relief of pain for patients with mild-to-moderate knee osteoarthritis resistant to conservative management. This study compares the efficacy and safety of trisacryl gelatin microspheres to Imipenem/Cilastatin particles for GAE with 2 years of clinical follow-up. MethodsIn this retrospective study, eight patients with knee osteoarthritis (11 knees) who underwent GAE with 100–300 μm trisacryl gelatin microspheres particles were compared with six patients (nine knees) who underwent GAE with Imipenem/Cilastatin particles. Clinical outcomes were evaluated at 3-month and 24-month follow-ups and compared to baseline using the WOMAC questionnaire. ResultsThe median follow-up was 796 days (range: 736–808). There were no significant differences in clinical outcome measures at the 3-month or 24-month follow-up. Both embolic materials resulted in a decrease in Pain WOMAC and Total WOMAC scores at 3 months (p < 0.05), and the effect of treatment on Pain WOMAC and Total WOMAC score reduction was sustained until the 24-month follow-up (p < 0.05). Minor events (Clavien-Dindo classification grade I) included transient cutaneous color change (n = 3) and transient leg numbness (n = 1) after embolization with trisacryl gelatin microspheres particles (p = 0.08). All minor adverse events resolved spontaneously. There were no major adverse events. ConclusionOne hundred to three hundred μm trisacryl gelatin microspheres particles can be considered for genicular artery embolization and is comparable to Imipenem/Cilastatin particles in pain reduction of moderate to severe knee osteoarthritis. A sustained effect is observed for up to 2 years of follow-up.

Comparison of Soluble Gelatin Sponge Particles and Tris-acryl Gelatin Microspheres for Bariatric Arterial Embolization in Swine

The purpose of this study was to compare complications and the number of ghrelin-expressing cells (GECs) after bariatric arterial embolization (BAE) using soluble gelatin sponge particles (SGSs) or tris-acryl gelatin microspheres (MSs) in swine. Twelve swine underwent embolization of gastric fundal arteries with SGSs (n = 4) or MSs (n = 4) or underwent saline infusion (n = 4, control group). One week later, the number of gastric ulcers and the percentage of GECs were compared among the 3 groups. There were no ulcers in the SGS and control groups. Two swine in the MS group had 4 large ulcers (12–50 mm in size). The mean percentages of GECs were significantly lower in the SGS (2.7% ± 0.9%) and MS (2.5% ± 1.0%) groups compared with the control group (3.7% ± 1.3%; P = .038 and P = .016, respectively). SGSs may be safer than MSs for BAE while inducing a similar reduction of GECs in swine.

Transarterial Embolization Modulates the Immune Response within Target and Nontarget Hepatocellular Carcinomas in a Rat Model.

Background Transarterial embolization (TAE) is the most common treatment for hepatocellular carcinoma (HCC); however, there remain limited data describing the influence of TAE on the tumor immune microenvironment. Purpose To characterize TAE-induced modulation of the tumor immune microenvironment in a rat model of HCC and identify factors that modulate this response. Materials and Methods TAE was performed on autochthonous HCCs induced in rats with use of diethylnitrosamine. CD3, CD4, CD8, and FOXP3 lymphocytes, as well as programmed cell death protein ligand-1 (PD-L1) expression, were examined in three cohorts: tumors from rats that did not undergo embolization (control), embolized tumors (target), and nonembolized tumors from rats that had a different target tumor embolized (nontarget). Differences in immune cell recruitment associated with embolic agent type (tris-acryl gelatin microspheres [TAGM] vs hydrogel embolics) and vascular location were examined in rat and human tissues. A generalized estimating equation model and t, Mann-Whitney U, and χ2 tests were used to compare groups. Results Cirrhosis-induced alterations in CD8, CD4, and CD25/CD4 lymphocytes were partially normalized following TAE (CD8: 38.4%, CD4: 57.6%, and CD25/CD4: 21.1% in embolized liver vs 47.7% [P = .02], 47.0% [P = .01], and 34.9% [P = .03], respectively, in cirrhotic liver [36.1%, 59.6%, and 4.6% in normal liver]). Embolized tumors had a greater number of CD3, CD4, and CD8 tumor-infiltrating lymphocytes relative to controls (191.4 cells/mm2 vs 106.7 cells/mm2 [P = .03]; 127.8 cells/mm2 vs 53.8 cells/mm2 [P < .001]; and 131.4 cells/mm2 vs 78.3 cells/mm2 [P = .01]) as well as a higher PD-L1 expression score (4.1 au vs 1.9 au [P < .001]). A greater number of CD3, CD4, and CD8 lymphocytes were found near TAGM versus hydrogel embolics (4.1 vs 2.0 [P = .003]; 3.7 vs 2.0 [P = .01]; and 2.2 vs 1.1 [P = .03], respectively). The number of lymphocytes adjacent to embolics differed based on vascular location (17.9 extravascular CD68+ peri-TAGM cells vs 7.0 intravascular [P < .001]; 6.4 extravascular CD68+ peri-hydrogel embolic cells vs 3.4 intravascular [P < .001]). Conclusion Transarterial embolization-induced dynamic alterations of the tumor immune microenvironment are influenced by underlying liver disease, embolic agent type, and vascular location. © RSNA, 2022 Online supplemental material is available for this article. See also the editorials by Kennedy et al and by White in this issue.

Abstract No. 15 Two-year outcomes of comparing Embosphere microspheres versus imipenem–cilastatin for genicular artery embolization in patients with knee osteoarthritis

Genicular artery embolization (GAE) has potential to provide midterm relief of pain for patients with mild-to-moderate knee osteoarthritis resistant to conservative management. The study compares use of trisacryl gelatin microspheres (ES) to imipenem-cilastatin (IMP/CS) particles for GAE on a cohort of patients with two-year of clinical follow-up. In a prospective study, a total of ten patients (15 knees) who had GAE with 100-to 300-μm ES particles were compared with a subsequent cohort of eleven patients (18 knees) who underwent GAE with IMP/CS. Clinical outcomes were evaluated at 6-month and 24-month follow-up and compared to baseline using WOMAC questionnaire. There was no significant difference in sex, age, BMI, duration of pain before the procedure, prior treatment, or Kellgren-Lawrence grade between the 2 cohorts. Baseline median pain WOMAC and total WOMAC scores were 13 (IQR 4) and 46 (IQR 4) in the ES group and 13 (IQR 3) and 47 (IQR 28) in the IMP/CS groups (P = 0.875 and P = 0.738), respectively. The median follow-up was 796 days (range, 736-808). Clinical success (50% reduction in WOMAC pain score vs baseline) was achieved in 69.23% of the embolized knee joints in both groups (P = 1.0) at 6 months, and 61.5% versus 53.8% of in ES and IMP/CS groups, at 2-years of follow-up, respectively (P = 1.0). Both embolic materials resulted in significant decrease in Pain WOMAC and Total WOMAC scores at 6 months (compared to baseline) (P< 0.05) and the effect of GAE on Pain WOMAC and Total WOMAC scores was sustained until the 24-month follow-up visit in both groups (P< 0.05). Minor events included transient cutaneous color change (five patients) or transient leg numbness (one patient) and was only identified after GAE with ES particles (P = 0.00387), which resolved spontaneously at 1-month follow-up (Clavien-Dindo classification grade I). There was no major adverse event. 100- to 300-μm ES particles can be considered for GAE and is comparable to IMP/CS in pain reduction of moderate to severe knee osteoarthritis and with sustained effect up to two-years of follow-up.

Superior Rectal Artery Embolization with Tris-Acryl Gelatin Microspheres: A Randomized Comparison of Particle Size

PurposeTo evaluate the safety and efficacy of superior rectal artery embolization (SRAE) with different-sized tris-acryl gelatin microspheres in symptomatic hemorrhoidal disease (HD). Materials and MethodsForty-two patients (male, 30; female, 12; median age, 45 years) with symptomatic HD (2 grade I, 8 grade II, 17 grade III, and 15 grade IV) were divided into 3 experimental arms (500–700 μm, 700–900 μm, and 900–1,200 μm groups; each had 14 patients) in a prospective randomized style to perform SRAE. Follow-up was performed by rectoscopy, clinical examination, and questionnaires. The primary outcome measure was the clinical success rate at 12 months. Secondary outcome measures were technical success rate, recurrence rate, procedure-related mortality, procedure-related complications, and any outcome changes between particle sizes. ResultsNo procedure-related deaths or major morbidities were observed. There was a 54% minor complication rate (n = 23/42) in the treated zone: 45% sustained small superficial ulcerations (n = 19/42), 7% small rectosigmoid junction ulcerations (n = 3/42), and 2% small fibrotic scar tissue (n = 1/42). The clinical success rate was 93%. Of the groups, the best French bleeding score decrease was obtained in the 900–1,200 μm group. There were improvements in the quality of life score and visual analogue scale score after the SRAE procedure, although not in the Goligher score. No recurrent disease was observed. ConclusionsSRAE with tris-acryl gelatin microspheres for symptomatic HD is a safe and efficient treatment, with results favoring the use of larger microspheres.

Whole-liver transcatheter arterial chemoinfusion and bland embolization with fine-powder cisplatin and trisacryl gelatin microspheres for treating unresectable multiple hepatocellular carcinoma

PurposeTo evaluate the safety and effectiveness of whole-liver transcatheter arterial chemoinfusion and bland embolization (TACBE) with fine-powder cisplatin and trisacryl gelatin microspheres for the treating unresectable multinodular hepatocellular carcinoma (HCC).Materials and methodsThe medical records of all patients who underwent TACBE sessions were retrospectively reviewed. 15 patients (11 men, 4 women; mean age, 72.5 years) and 22 procedures (BCLC B;17 C;5) were included in the analysis. The cisplatin resulting solution and microspheres were infused through a microcatheter placed nonselectively. Overall survival (OS) was defined as the time from commencement of initial TACBE until any cause of death. Toxicity was assessed by the CTCAE version 5.0, and the tumor response was evaluated by the mRECIST. Liver function was assessed by the albumin–bilirubin (ALBI) score.ResultsThe 1-year OS rate was 64.6% (95% CI 0.438–0.955). Severe adverse effects were not observed except for grade 3 increase in the ALT, ALT, vasovagal episode. The objective response and disease control rare were 54.5% and 68.2%, respectively. The ALBI scores from pre-treatment to the follow-up ranged from − 2.39 to − 2.26 (p = 0.38).ConclusionWhole-liver TABCE with fine-powder cisplatin and trisacryl gelatin microspheres was well tolerated and effective in patients with multinodular HCC.

Clinicopathologic Factors Associated with Tumor Necrosis after Preoperative Embolization of Meningiomas.

Preoperative embolization of meningiomas induces necrosis prior to surgery and facilitates resection. Lack of contrast enhancement on postembolization MRI correlates with pathological findings of necrosis and can be used to assess embolization efficacy. This study aimed to examine clinicopathologic factors associated with tumor necrosis after embolization. A total of 119 patients with intracranial meningioma who underwent 145 surgical resections between 2010 and 2019 at our institute were reviewed. Inclusion criteria for the study were preoperative embolization with trisacryl gelatin microspheres (Embosphere) or absorbable gelatine sponge (Gelfoam). Postembolization Gd-enhanced T1-weighted and angiographic imaging, and histopathologic examination results were reviewed to evaluate the effectiveness of embolization. In all, 66 patients satisfied the inclusion criteria. In total, 36 patients were embolized with Embosphere and 30 patients were embolized with Gelfoam. Patients embolized with Embosphere had a significantly higher necrosis rate (NR) than patients with Gelfoam (21% vs. 7.1%, P <0.01). The 36 Embosphere patients were analyzed regarding clinicopathologic factors associated with NR. Tumors in 12 patients were located in the parasagittal/falx region; these patients had a significantly lower NR compared with tumors in other locations (10.6% vs. 26.2%, P = 0.016). In all, 13 patients had feeders arising from only the middle meningeal artery (MMA), which was associated with a significantly higher NR (29.3% vs. 14.4%, P = 0.015). In total, 11 patients had meningeal feeders arising from internal carotid artery (ICA), which was associated with a significantly lower NR (9.0% vs. 26.3%, P <0.01). This study showed embolization agent, tumor location, and blood supply were important factors predicting necrosis after preoperative embolization.

Targeted septal branch microcirculatory embolization with tris-acryl gelatin microspheres in hypertrophic obstructive cardiomyopathy

Abstract Background Alcohol septal ablation (ASA) has been shown to be an effective treatment in patients with hypertrophic obstructive cardiomyopathy (HOCM) who are refractory to medical treatment. ASA may cause some life-threatening complications including conduction disturbances, hemodynamic compromise, ventricular arrhythmias, distant and massive myocardial necrosis. Tris-acryl gelatin microspheres provide consistent and predictable results for effective targeted microcirculatory embolization. Purpose We aimed to report our initial experience in tris-acryl gelatin microspheres for septal ablation in HOCM. Methods Microspheres are biocompatible, hydrophilic, non-resorbable microspheres which are available in a range of calibrated sphere sizes. In our method, after the cannulation of the left anterior descending by a 6F-7F guiding catheter, a 0.014-inch guidewire is introduced through the catheter and advanced into the septal branch. This septal artery is selectively cannulated with a 4F catheter over the guidewire. Selective angiography of the septal artery is performed to show the anatomy and collateral branches to other coronary arteries. Contrast echocardiography is performed to make sure that the pertinent septal artery is the target vessel supplying the hypertrophied septum. A microcatheter is then advanced deep enough into the septal artery through the 4F catheter. Microspheres/contrast solution infused slowly under fluoroscopic guidance into the targeted septal branches initially using coronary arteriolar sized small particles (diameter 100–300 μm); then the particle size was stepped up to larger particles (diameter 300–500 μm) until a complete block of the arteriolar flow is achieved. Results Septal ablation with tris-acryl gelatin microspheres was performed in 6 patients (mean age = 47.8±11.5; 5 males). Immediately after the procedure peak left ventricular outflow (LVOT) gradient reduced significantly both for direct catheter (69.0±13.8 vs. 8.2±3.7 mmHg, P&amp;lt;0.001) and Doppler echocardiographic measurements (78.8±19.9 vs. 12.0±5.1 mmHg, P&amp;lt;0.001). Post-procedure peak serum CK- MB fraction concentration was 82±22 ng/ml (reference range is 0 - 4.9 ng/mL) and peak serum troponin T concentration was 1.2 ng/ml [(interquartile range, 0.4–1.4), (reference range is 0 - 0.017 ng/mL)]. LVOT tract gradient reduction persisted after 6 months follow-up. There was no significant complication during the procedure and within a 6 months follow-up period. Conclusions The novel strategy by targeted septal branch microcirculatory embolization with tris-acryl gelatin microspheres seems to be an efficient and safe approach to HOCM. Further experience is needed in order to assess the long-term efficacy and safety of this technique. Funding Acknowledgement Type of funding source: None

A comparative study on preoperative portal vein embolization using tris-acryl gelatin microspheres versus coils

Objective To compare preoperative portal vein embolization (PVE) using tris-acryl gelatin microspheres (TAGM) versus coils. Methods From March 2016 to June 2018, 21 consecutive patients with a future liver remnant (FLR) ratio of less than 45% before planned major hepatectomy for malignant or benign liver diseases were enrolled from the First Department of Biliary Surgery, Eastern Hepatobiliary Surgery Hospital into this study. The patients were divided to receive portal vein embolization (PVE) using TAGM distally and coils proximally (the TC group) and PVE using multiple coils (the CC group). Post-PVE complications, liver function, routine blood tests; FLR hyperplasia, types of liver resection, operation time, intraoperative blood loss, and postoperative complications were compared between the two groups. Results Eight patients were included in the TC group. There were 4 males and 4 females, with a mean age of (55.3±7.7) years. Of 13 patients included into the CC group, there were 11 males and 2 females, with a mean age of (52.6±11.3) years. There were no significant differences in sex, age, types of hepatic diseases, volume of FLR, ratio of FLR, ratio of standard FLR, types of surgery, operation duration, blood loss, major complications, and liver failure rates between the two groups. All patients in the two groups had successful PVE. The TC group developed effective growth of volume of FLR with one patient who failed to undergo surgery because of tumor progression. In the CC group, four patients failed to undergo liver resection: one patient developed thrombosis of the left branch and main trunk of portal vein; tumor progression occurred in one patient and two patients had insufficient FLR growth. Compared with the CC group, the TC group had a significantly higher volume of FLR hyperplasia [(9.0±2.8) % vs. (5.2±3.8) %, P 0.05], a greater but insignificant increase in percentage of proliferation [(33.6±20.1) % vs. (20.9±15.1) %, P>0.05]. Conclusions This study showed that PVE with TAGM plus coils is safe and effective. It induced a better degree of hypertrophy of FLR compared to PVE using multiple coils. Key words: Liver diseases; Portal vein embolization; Tris-acryl gelatin microsphere; Coils; Major hepatectomy

3:27 PM Abstract No. 230 Comparison of embolic-associated immune response in a translational model of hepatocellular carcinoma and transarterial embolization

Transarterial chemoembolization and transarterial embolization (TAE) induce tumor necrosis and expose the immune system to tumor debris with a demonstrated potential for immune activation; however, there remains limited data regarding differences in the immune response to different embolic agents. The goal of this study was to characterize the local immune response adjacent to two different embolics commonly used in the clinic. TAE was performed in a translational rat model (n = 20) of DEN-induced autochthonous HCC using either 40-120 um tris-acryl gelatin microspheres (TAGM) - Embosphere Microspheres (Merit Medical Systems) or 70-150 um polyvinyl alcohol 2-acrylamido-2-methylpropanesulfonate sodium salt (PVA-AMPS) - DC Bead LUMI (Biocompatibles Ltd). After embolization, paraffin embedded tumors were processed for Hematoxylin and Eosin (H&E) and immunohistochemical (IHC) staining with anti-CD3, anti-CD8a and anti-FoxP3. H&E samples were analyzed by an attending pathologist. Quantitation of immune cell populations on IHC was performed using BZ-X Analyzer (Keyence corp. Osaka, Japan). Data are reported as means and standard deviations with statistical comparisons made using a student’s t-test. H&E analysis demonstrated a foreign body reaction adjacent to TAGM that was nearly or fully absent when using PVA-AMPS beads. IHC staining revealed a quantitative difference in the number of Tumor Infiltrating Lymphocytes (TILs) around the beads. This difference was present in CD3+ T-cells (7.06 ± 5.1 vs. 3.16 ± 3.9, N = 36 and 19 respectively, P <0.005), CD8+ T-cells (5.71 ± 4.0 vs. 2.05 ± 1.9, N = 35 and 21 respectively, P <0.0005), and FoxP3+ve cells (3.15 ± 2.7 vs. 1.14 ± 1.7, N = 34 and 21 respectively, P <0.005). Additionally, TAGM beads demonstrated a bead dependent increase in the number of CD3 (P <0.005) and CD8 (P <0.005) infiltrating cells while PVA-AMPS did not. Embolization using TAGM demonstrated a prominent foreign body reaction adjacent to embolics in embolized tumors, associated with an increase in CD3+, CD8+ and FoxP3+ T-cells as compared to embolization performed with PVA-AMPS. Further studies are required to understand the underlying mechanism and therapeutic implications.

3:45 PM Abstract No. 170 Randomized controlled trial comparing therapeutic effect, pain, and inflammatory response after uterine artery embolization for symptomatic fibroids using nonspherical polyvinyl alcohol or tris-acryl gelatin microsphere

To prospectively compare the therapeutic effect, pain and inflammatory response after uterine artery embolization (UAE) using nonspherical polyvinyl alcohol (PVA) or tris-acryl gelatin microsphere (TGM). 54 patients were randomized into two groups, PVA group (355-550 μm, n = 27) and TGM group (500-700 μm, n = 27). Both groups received fentanyl-based intravenous patient-controlled analgesia during the 24 hours after UAE and additional analgesics were allowed as needed. Inflammatory responses were assessed by white blood cell count (WBC), neutrophil to lymphocyte count (NLR) and platelet to lymphocyte count (PLR) at 24 hours post UAE. Contrast-enhanced MRI was performed 1 day after UAE to evaluate the necrosis of the predominant fibroids (F1) and degree of ischemia of normal myometrium. Health-related quality of life (HRQOL) and symptom severity score (SSS) were compared before and 3 months after the procedure. There was no significant difference in the clinical outcomes (HRQOL and SSS) 3 months after UAE between two groups. Although pain scores were similar (P >0.999), the amount of additional analgesics was significantly higher in the PVA group (P = 0.0495) The cumulative dose of fentanyl was higher in the PVA group than TMG group without a statistical significance (981 μg versus 858 μg P = 0.492). Inflammatory markers including WBC count, NLR and PLR were significantly higher in the PVA group (P = 0.0462, P = 0.0477 and P = 0.0417, respectively). The rates of complete necrosis of the F1 were not significantly different in both groups (P = 0.671), but the rates of incomplete necrosis of the F1 was higher in the TGM group, which did not reach a statistical significance (14.8% versus 0%, P = 0.111). Severe degree of transient ischemia in the normal myometrium was more common in the PVA group (P = 0.038). There were no significant differences in terms of therapeutic effects and pain after UAE between the two groups. However, in the PVA group, more analgesics were required and higher degree of inflammatory response and severe ischemia in the normal myometrium were provoked. This may suggest that nonspherical PVA (355-550 μm) is associated with more potent embolization effect than TGM.

Abstract No. 415 Uterine artery embolization for anticoagulant-associated uterine bleeding

Abnormal uterine bleeding (AUB) affects up to two thirds of women on anticoagulation (AC) therapy. In women on AC for venous thromboembolism (VTE), AUB is linked to recurrent VTE, likely due to interrupted therapy. Treatment options for anticoagulant-associated AUB (AA-AUB) are limited, as estrogen-containing treatments increase thrombotic risk and endometrial ablation or hysterectomy lead to infertility. While uterine artery embolization (UAE) is a well-established treatment for symptomatic fibroids, its role in acute AA-AUB is limited to case reports. This study describes a series of patients who underwent UAE for the treatment of acute AA-AUB, focusing on technique, safety and outcomes. The institutional review board approved this retrospective review on 16 patients who underwent UAE for acute AA-AUB at a single academic medical center between Feb 2014 and Feb 2019. Three board-certified interventional radiologists performed UAE cases using 500-700 micron tris-acryl gelatin microspheres (Merit Medical Systems). In one case, tris-acryl gelatin microspheres were used in combination with Gelfoam. Medical, surgical, and radiologic records were reviewed. Statistical analysis were performed using MATLAB version R2018b (Mathworks). 16 patients were included with mean age 42 ± 7, on warfarin (38%), heparin drip (38%), or NOACs (25%). All patients demonstrated concurrent fibroids and/or adenomyosis and no patient had known endometrial malignancy. VTE, due to various etiologies, was the most common indication (88%) for AC. Cessation of acute AA-AUB was noted in the short term, defined as 3 days post-UAE, in 15 (94%) patients. 2 patients (12.5%) ultimately underwent hysterectomy due to failure of UAE to control AA-AUB in either the short or long term. Among patients who did not undergo hysterectomy for whom follow-up data was available, 9 (90%) maintained menses post-UAE. All patients were able to re-initiate or continue anticoagulation following UAE. UAE is an effective treatment strategy for acute AA-AUB. As an initial alternative to hysterectomy, endometrial ablation, or medical management, UAE allows patients to preserve menses and continue anticoagulation.Tabled 1Demographics Total cases16 Age (years)42 ± 7Indication for anticoagulation Cardiac valve prothesis1 Coronary arterial stent1 Venous thromboembolism14Timing of medical management of AA-AUB Concurrent with UAE7 Failure leading to UAE5 Not attempted4Anticoagulation post-UAE Re-initiated (previously held)6 Continued (not previously held)10 Stopped0Cessation of AUB post-UAE Resolved in short and long term10 Resolved in short term only; long term control with conservative or medical management3 Resolved in short term only; long term control with hysterectomy1 Resolved in short term; unable to assess long term efficacy due to hysterectomy for other indication1 Did not resolve, leading to hysterectomy1Loss of menses post-UAE No9 Yes1 N/A (hysterectomy shortly after UAE)2 N/A (inadequate follow up)4 Open table in a new tab

Intra-Arterial Lidocaine Is Not Found to Be Effective for Reducing Pain after Uterine Fibroid Embolization in a Retrospective Study: Now What?

I would like to thank the authors for undertaking and publishing the study titled “Intra-arterial lidocaine administration for anesthesia after uterine artery embolization with trisacryl gelatin microspheres for leiomyoma.” With uterine artery embolization (UAE) for fibroids being a frequently performed interventional radiology procedure in many practice settings, the subject matter is undoubtedly relevant to Journal of Vascular and Interventional Radiology readers. Also, there is limited understanding of the mechanism in question—that is, the way in which intra-arterial lidocaine can reduce pain in an embolized uterine artery.

Intra-Arterial Lidocaine Administration for Anesthesia after Uterine Artery Embolization with Trisacryl Gelatin Microspheres for Leiomyoma.

To evaluate whether administration of lidocaine into the uterine artery for anesthesia immediately after uterine artery embolization (UAE) with trisacryl gelatin microspheres (TAGM) for leiomyoma is safe and effective. In a single-institution retrospective study, 100 patients underwent UAE using TAGM with a pruned tree endpoint between June 2014 and April 2019. The first 50 patients (control group) underwent UAE without lidocaine; in the second 50 patients (study group), lidocaine was administered into the uterine artery immediately after UAE. Baseline characteristics and technical and periprocedural outcomes were compared. Visual analog scale (VAS) scores 0, 3, 6, 9, 12, and 18 hours after UAE were compared between the groups with repeated measures analysis of variance. Each multivariate-adjusted VAS score < 24 hours was compared with analysis of covariance. No significant differences were observed in baseline characteristics or technical and periprocedural outcomes, including the volume of morphine used (P= .415), between the groups. No significant differences were found in crude or multivariate-adjusted VAS scores at each time point < 24 hours. Only the multivariate-adjusted VAS score 3 hours after UAE was 0.7 lower in the study group (mean ± SE, 2.2 ± 0.3 vs 2.9 ± 0.3); however, no significant difference was noted (P= .070). No adverse events associated with lidocaine were detected. Intra-arterial lidocaine administration immediately after UAE with TAGM for leiomyoma was safe, but did not contribute to significant reductions in pain or volume of narcotic agent administered.