Recent Progress on Water-based Liquid Embolic Agents in Endovascular Treatment

Vascular embolization treatment,a minimally invasive surgery for various blood vessel-related conditions,has emerged as a crucial method in treating such as hemorrhage,arteriovenous malformation,aneurysms,and hypervascular tumors.Liquid embolic agents are gaining prominence due to their distinct advantage in infiltrating distal regions,expanding the scope of embolization beyond the reach of solid agents.Recent strides in biomaterials and technologies have spurred the development of novel liquid embolic agents,addressing challenges posed by traditional options.This mini-review provides a concise overview of the recent progress in water-based liquid embolic agents,highlighting their potential to overcome limitations associated with current embolic materials.By presenting selected research outcomes,we illuminate advancements that enhance the efficacy of liquid embolic agents.Furthermore,the review outlines essential properties for effective liquid embolic agents,offering insights for future developments in this field.

Impact of Different Embolic Agents for Transarterial Chemoembolization (TACE) Procedures on Systemic Vascular Endothelial Growth Factor (VEGF) Levels

Background and Aims:Intermediate stage hepatocellular carcinoma (HCC) can be treated by transarterial chemoem-bolization (TACE).However,there appear to be side effects,such as induction of proangiogenic factors,e.g.vascular endothelial growth factor (VEGF),which have been shown to be associated with a poor prognosis.This prospective study was designed to compare serum VEGF level response after TACE with different embolic agents in patients with HCC.Methods:Patients were assigned to one of three different TACE regimens:degradable starch microspheres (DSM) TACE,drugeluting bead (DEBDOX) TACE or Lipiodol TACE (cTACE).All patients received 50 mg doxorubicin/m2 body surface area (BSA) during TACE.Serum VEGF levels were assessed before TACE treatment,24 h post-treatment and 4 weeks later.Results:Twenty-two patients with 30 TACE treatments were enrolled.Compared to baseline VEGF levels,a marked increase was observed for 24 h post-TACE (164% of baseline level) and during the 4-week follow-up (170% of baseline level) only for the cTACE arm (p < 0.05).In contrast,the increase of serum VEGF levels were only 114% and 123% for DEBDOX and 121% and 124% for DSM,respectively.Conclusions:Conventional TACE using Lipiodol shows marked increase in blood levels of the proangiogenic factor VEGF,while DEBDOX and DSM TACE induce only a moderate VEGF response.

Technical feasibility and histopathologic studies of poly (N-isopropylacrylamide) as a non-adhesive embolic agent in swine rete mirabile

Background Non-adhesive liquid embolic agents are increasingly gaining importance in the embolization of cerebral arteriovenous malformations （AVMs）. We investigated the use of poly （N-isopropylacrylamide） （PNIPAM） as a non-adhesive embolic agent in swine rete mirabile. Methods The PNIPAM hydrogel was mixed with iohexol and embolization was performed in swine rete mirabile in 30 animals. The microcatheter was examined after embolization. Follow-up angiography was performed for embolic efficacy after embolization. Embolized retia were examined histopatholgically, and the alterations of inside rete and surrounding tissue were observed. Results The copolymer hydrogel was used for rete embolization in 30 swine, 28 swine survived the procedure, 2 swine died, 1 swine died of cerebrum infarction and the other died of embolic agent reflux into the occipital artery. The inside wall of the microcatheter was smooth, without copolymer adhering to it. Follow-up angiography was performed in 22 swine, there was no rete recanalization in 20 swine and partial rete recanalization in 2 swine because of the trunk embolization of ascending pharyngeal arteries. Histopatholgically, the copolymer was found diffused into vessels of 100-- 150 μm in diameter. In acute group, neutrophils scattered surrounding the copolymer and endothelial integrity was observed, without endothelial denuding and necrosis. In subacute and chronic groups, the copolymer was found inside retia, a few mononuclear cells and eosinocytes scattered inside and surrounding it. The muscular layer was loosened with most muscular nuclei degraded. Conclusion Experimental rete embolization with PNIPAM, made radiopaque with iohexol, is technically feasible in swine. Because of its properties, PNIPAM has great potential as a therapeutic non-adhesive embolic agent.

Liquid embolic agents for interventional embolization

Minimally invasive interventional embolization has tremendous advantages over conventional surgery in the treatment of vascular diseases and malignant tumors.Particularly,liquid embolic agents have garnered much attention owing to their properties of deep vascular penetration and full occlusion of vasculature independent of thrombus formation,which relies on the patient’s coagulation system.Despite their drawbacks,traditional liquid embolic agents,such as lipiodol,N-butyl-2-cyanoacrylate,and Onyx,have benefited numerous patients.The original liquid embolic agents have been modified and optimized,and novel liquid embolic agents have also been developed using different strategies and mechanisms.This minireview provides a brief overview of liquid embolic agents,including approved and potential ones.Challenges,prospects,and rational design guidelines are also discussed.This review may spark interest in liquid embolic agents and open new avenues for the smart design of improved embolic agents in the development of personalized and precision medicine.

Impact of uterine artery embolization on ovarian function and pregnancy outcome after uterine-fibroids treatment:A prospective study

Uterine fibroids are benign tumors that originate from smooth muscle cells of the uterus.It is the most common gynecological disorder,affecting up to 80%of women of reproductive age.Uterine fibroids can cause various symptoms such as abnormal uterine bleeding,pelvic pain,infertility,and pregnancy complications.The treatment options for uterine fibroids include medical therapy,surgical intervention,and minimally invasive techniques.AIM To compare ovarian function of women with uterine fibroids who did or did not undergo uterine artery embolization(UAE).METHODS This prospective cohort study enrolled 87 women with symptomatic uterine fibroids who underwent UAE,and 87 women with the same symptoms who did not undergo UAE but received conservative management or other treatments.The two groups were matched for age,body mass index,parity,and baseline characteristics of uterine fibroids.The primary outcome was ovarian function that was evaluated by serum levels of follicle-stimulating hormone(FSH),luteinizing hormone(LH),estradiol(E2),and anti-Müllerian hormone(AMH),as well as ovarian reserve tests,such as antral follicle count(AFC)and ovarian volume(OV).The secondary outcome was fertility that was evaluated based on the menstrual cycle,ovulation,conception,pregnancy,and delivery.The participants were followed-up for 36 months and assessed at 1,3,6,12,24,and 36 months after treatment.RESULTS The study found that the most common minor complication of UAE was postembolization syndrome in 73.6% of women,resolving within a week.No significant differences were observed between the UAE group and the control group in serum levels of reproductive hormones(FSH,LH,E2,AMH)and ovarian reserve indicators(AFC,OV)at any point up to 36 months post-treatment.Additionally,there were no significant differences in conception,pregnancy,or delivery rates,with the average time to conception and gestational age at delivery being similar between the two groups.Birth weights were also comparable.Finally,there was no significant correlation between ovarian function,fertility indicators,and the type or amount of embolic agent used or the change in fibroids posttreatment.CONCLUSION UAE resulted in significantly positive pregnancy outcomes,no adverse events post-treatment,and is a safe and effective treatment for uterine fibroids that preserves ovarian function and fertility.

Exploratory study of microparticle transcatheter arterial chemoembolization combined with resection for huge hepatocellular carcinoma

Objective:To investigate the safety and clinical efficacy of microparticle transcatheter arterial chemoembolization(mTACE)combined with surgical resection for the treatment of huge hepatocellular carcinoma(hHCC;
10 cm).Methods:A retrospective descriptive study was conducted to gather the clinical data of nine patients with hHCCs treated with mTACE combined with resection in Beijing Tsinghua Changgung Hospital from December 2016 to July 2020.The outcome were as follows:(1)the excellent effect and adverse reactions of mTACE and(2)the efficacy and safety of perioperative resection.Count data were expressed as absolute numbers and percentages.The measurement data of the normal distribution is represented by XS,and the measurement data of the skewed distribution are represented by M(range).A paired t-test was used to compare the data of the same patient.p values<0.05 are considered statistically significant.Results:(1)Regarding the efficacy and safety of mTACE,all nine hHCCs were treated with mTACE one time.The tumor necrosis rate after particle TACE was(77.615.7)%(51.7%–100%);according to the modified response evaluation criteria in solid tumors,the objective response was partial response in eight patients and complete response in one patient.The alpha fetoprotein(AFP)level was abnormal in six cases(>20 ng/mL),of which three cases exceeded the maximum value(>30,000 ng/mL)pre-mTACE.In six patients with abnormal AFP levels,the AFP level decreased in five patients,with a median percentage of 74.5%(35.2%–96.0%).The PIVKA-II level in nine patients was>40 mAU/mL before mTACE and decreased to varying degrees after mTACE.The median percentage of decline was 76.0%(4.5%–99.8%).The maximum diameter of the tumor decreased from(13.91.9)cm(11.0–16.4 cm)to(12.81.9)cm(10.4–15.6 cm)(P?0.001)before surgical resection.Prior to the surgical resection,the tumor volume decreased from(897244)mL(436–1250 mL)to(750291)mL(260–1130 mL)(P?0.001),and the residual liver volume/standard liver volume increased from(42.812.8)%(25.8%–61.3%)to(50.214.9)%(28.8%–67.4%)(P?0.008).All patients had embolism syndrome such as fever and abdominal pain in varying degrees,and no serious complications such as liver abscess,liver and kidney failure,or ectopic embolism were noted.(2)For perioperative efficacy and safety,all lesions were successfully resected in(3111)days(14–48 days)after mTACE.The operation time was(39579)min(296–540 min),and the amount of intraoperative bleeding was(433158)mL(200–600 mL).Complications such as biliary fistula,abdominal bleeding,liver and kidney failure,or abdominal infection were not found.The postoperative hospital stay was(134)days(9–19 days).No tumor invasion was found at the cutting edge,and hepatic vein invasion was observed in one case.(3)The follow-up ended in November 2021,with a median follow-up of 34 months(16–46 months).Recurrence or distant metastasis occurred in four patients,of which two patients died.The survival times were 18 and 31 months,respectively.The other two patients were followed up for 34 and 41 months.The remaining five patients were followed up for 16–46 months without antitumor treatment or disease progression.Conclusions:mTACE combined with tumor resection is feasible for the treatment of patients with hHCC,which needs to be further confirmed by prospective studies.