Comparison of the efficacy of the embolic agents acrylamido polyvinyl alcohol microspheres and tris-acryl gelatin microspheres for uterine artery embolization for leiomyomas: a prospective randomized controlled trial

The Use of Microspheres for Cancer Embolization Therapy: Recent Advancements and Prospective

Embolization therapy involving biomaterials has improved the therapeutic strategy for most liver cancer treatments. Developing biomaterials as embolic agents has significantly improved patients' survival rates. Various embolic agents are present in liquid agents, foam, particulates, and particles. Some of the most applied embolic agents are microparticles, such as microspheres (3D micrometer-sized spherical particles). Microspheres with added functionalities are currently being developed for effective therapeutic embolization. Their excellent properties of high surface area and capacity for being loaded with radionuclides and alternate active or therapeutic agents provide an additional advantage to overcome limitations from traditional cancer treatments. Microspheres (non-radioactive and radioactive) have been widely used and explored for localized cancer treatment. Non-radioactive microspheres exhibit improved clinical performance as drug delivery vehicles in chemotherapy due to their controlled and sustained drug release to the target site. They offer better flow properties and are beneficial for the ease of delivery via injection procedures. In addition, radioactive microspheres have also been exploited for use as an embolic platform in internal radiotherapy as an alternative to cancer treatment. This short review summarizes the progressive development of non-radioactive and radioactive embolic microspheres, emphasizing material characteristics. The use of embolic microspheres for various modalities of therapeutic arterial embolization and their impact on therapeutic performance are also discussed.

Our Experience with Hydrogel-Coated Trisacryl Microspheres in Uterine Artery Embolization for the Treatment of Symptomatic Uterine Fibroids and Adenomyosis: A Follow-Up of 11 Years

Uterine artery embolization (UAE) for the treatment of symptomatic uterine fibroids and non-controllable adenomyosis symptoms is a relatively new procedure for organ-preserving therapy. These benign conditions can become symptomatic in about 30% of women between the ages of 35 and 50. The purpose of the UAE either for fibroids or adenomyosis is the elimination of blood loss, the reduction in pain, and bulky or rectal pressure symptoms. The purpose of this study is to present our experience in UAE with the use of hydrogel-coated tris acryl microspheres for the treatment of symptomatic uterine fibroids and adenomyosis.

Current Trends in Gelatin-Based Drug Delivery Systems

Gelatin is a highly versatile natural polymer, which is widely used in healthcare-related sectors due to its advantageous properties, such as biocompatibility, biodegradability, low-cost, and the availability of exposed chemical groups. In the biomedical field, gelatin is used also as a biomaterial for the development of drug delivery systems (DDSs) due to its applicability to several synthesis techniques. In this review, after a brief overview of its chemical and physical properties, the focus is placed on the commonly used techniques for the development of gelatin-based micro- or nano-sized DDSs. We highlight the potential of gelatin as a carrier of many types of bioactive compounds and its ability to tune and control select drugs' release kinetics. The desolvation, nanoprecipitation, coacervation, emulsion, electrospray, and spray drying techniques are described from a methodological and mechanistic point of view, with a careful analysis of the effects of the main variable parameters on the DDSs' properties. Lastly, the outcomes of preclinical and clinical studies involving gelatin-based DDSs are thoroughly discussed.

Current Strategies for Prevention of Infection After Uterine Artery Embolisation

Uterine artery embolisation (UAE) is a safe and effective procedure for symptomatic uterine fibroids with an estimated rate of post-operative intra-uterine infection of 0.9-2.5%. While rates of infection have remained low over the past two decades, there is variation in infection prevention practices. Intra-uterine infection after UAE may occur via access site haematogenous spread or ascension of vaginal flora through the cervical canal. Although the evidence base is immature, risk factors for infection including previous pelvic infection, hydrosalpinx, endocervical incompetence, diabetes, smoking, obesity, respiratory disease, and immunosuppression should be assessed during the pre-operative consultation with the interventional radiologist to tailor a plan for minimising infection, which may include optimisation of any modifiable risk facts and prophylactic antibiotics.

Choice of primary and secondary outcomes in randomised controlled trials evaluating treatment for uterine fibroids: a systematic review

BACKGROUND

Core outcome sets aim to reduce research heterogeneity and standardise reporting, allowing meaningful comparisons between studies.

OBJECTIVES

To report on outcomes used in randomised controlled trials (RCTs) investigating uterine fibroid treatments, towards the development of a core outcome set for fibroid research.

SELECTION STRATEGY

Database search of MEDLINE, PubMed, EMBASE and CINAHL (inception to July 2021) for all English-language RCTs involving surgical or radiological fibroid treatments.

DATA COLLECTION AND ANALYSIS

A total of 1885 texts were screened for eligibility by two reviewers independently according to PRISMA methodology. JADAD and Management of Otitis Media with Effusion in Cleft Palate (MOMENT) scores were used to assess methodological and outcome reporting quality of studies, respectively. Outcomes were mapped to nine domains. Non-parametric tests for correlation and to compare group medians were undertaken.

MAIN RESULTS

There were 23 primary outcomes (23 outcome measures) and 173 secondary outcomes (95 outcome measures) reported in 60 RCTs (5699 participants). The domains with highest frequency of primary outcomes reported were bleeding and quality of life (QoL). The most frequent primary outcomes were postoperative pain, QoL and menstrual bleeding. No primary outcomes were mapped to fertility domains. Median MOMENT outcome score was 5 (interquartile range 3). There was correlation between MOMENT outcome score and JADAD scores (r = 0.491, P = 0.0001), publishing journal impact factor (r = 0.419, P = 0.008) and publication year (r = 0.332, P = 0.01).

CONCLUSION

There is substantial variation in the outcomes reported in fibroid RCTs. There is a need for a core outcome set for fibroid research, to allow improved understanding regarding the effects of different treatments.

One-step preparation of photoclick method for embolic microsphere synthesis and assessment for transcatheter arterial embolization

Vascular embolization is a well-known therapeutic treatment against hepatocellular carcinoma. However, existing embolic agents require complex synthesis, toxic organic solvents and sometimes produce only low yields. In this study, a novel photopolymerization technique, which addresses these issues, was used to prepare embolic microspheres successfully from the sucrose multi-allyl ether monomer in one step. Compared to the preparation of such microspheres always involved in multiple steps or complicated conditions, we obtained the microspheres used photoclick method in a soft template with simple, economic and feasible procedure. This work focuses on the synthesis of new materials by conducting a photopolymerzation in the presence of the sucrose monomer and the photoinitiator. Then, the embolic microspheres obtained were characterized by morphology assay, degradation, and swelling test. Cell experiments showed that the microspheres had good biocompatibility. Rabbit embolizations showed that the microspheres had long-term embolic effects. It is manifested that one-step preparation of photoclick method hold great potential and competitiveness of being used in preparation embolic microspheres in clinic.

Randomised trial of two embolic agents for uterine artery embolisation for fibroids: Gelfoam versus Embospheres (RAGE trial)

Background

Uterine artery embolisation (UAE) is an established treatment option for women with symptomatic uterine fibroids who wish to avoid surgery. However the most efficacious embolic agent remains uncertain.

Methods

We conducted a pilot double blind randomized controlled trial comparing Gelfoam with Embospheres in women undergoing UAE. Outcomes recorded at baseline, 24-h, 1 and 6 months included complications, inflammatory, haematological markers and ovarian function. Contrast enhanced MRI (CEMRI) was acquired at baseline, 24-h and 6 months. Pain score (visual analogue) was measured at 24-h, quality of life (UFS-Qol) at baseline, 1 and 6 months. All patients were followed to 6 months.

Results

Twenty patients were randomized 1:1 to receive either Gelfoam (G) or Embospheres (E). The UFS-Qol symptom score improved in both groups at 6 months mean of 64 ± 18 to 23 ± 16 and 54 ± 15 to 32 ± 26 in the E and G groups respectively. UFS-Qol HRQL also improved in both groups at 6 months, mean 41 ± 28 to 79 ± 20 and 53 ± 19 to 78 ± 21 in the E and G groups respectively.

Uterine volume at 6 months reduced from 1018 ± 666mls to 622 ± 436 (p = 0.001) and from 1026 ± 756 to 908 ± 720 (p = 0.15) in the E and G groups respectively. There was a significant difference between groups for this parameter p = 0.01. All uterine arteries were patent at 24-h and 6 months. Complete (100%) fibroid infarction rates were 5(50%) and 2(20%) in the E and G groups respectively. None of the other outcome measures showed any between group differences. There were no re-interventions in either group.

Conclusion

The only significant between group differences was for a greater reduction in uterine volume at 6 months in the E group. A larger trial (estimate 172 subjects) is required to determine whether other apparent differences are clinically and statistically significant.

Trial registration

ISRCTN67347987

An Academic Tertiary Referral Center's Experience with a Vascular Surgery-Based Uterine Artery Embolization Program

BACKGROUND

Despite growing endovascular experience within the vascular surgery community, some catheter-based interventions-such as uterine artery embolization (UAE)-remain outside the clinical scope of most vascular surgeons, owing in part to established referral patterns and limited awareness among referring colleagues. We present our experience with a vascular surgery-based, multidisciplinary UAE program at an academic tertiary referral center.

METHODS

In a collaborative effort between vascular surgeons and gynecologists, a pelvic vascular disease program has been established to provide palliative, prophylactic, and therapeutic embolizations including, but not limited to, UAE. For UAE, inclusion criteria are women over the age of 18 years with symptomatic uterine fibroids demonstrated on magnetic resonance imaging and a negative endometrial biopsy. Exclusion criteria are desire for future pregnancy and previous embolization(s). Technique and perioperative protocol is presented. Data including symptom resolution, reintervention rates, and complications were prospectively gathered and retrospectively reviewed.

RESULTS

Over an 18-month period, 30 patients with symptomatic fibroids were referred for potential UAE. Five patients were excluded because of uncertainty about future pregnancy wishes (4) and prior embolization (1). Twenty-four bilateral and 2 unilateral UAEs were performed (mean age, 46.3 years [range 28-53 years]). Presenting symptoms were pelvic and abdominal pain (25), cramps (25), menorrhagia (25), dysmenorrhea (25), urinary frequency (12), and dyspareunia (5). Technical success, defined as successful microcatheterization of uterine arteries and delivery of a particulate liquid embolic agent (embospheres, 500-700 microns), was 100%. There were no perioperative or delayed complications. Twenty-one patients (87.5%) reported complete symptomatic relief without further intervention at the time of last follow-up. Three patients (12.5%) reported pain relief but had persistent vaginal bleeding requiring hysterectomy 12 months after UAE. All patients underwent a 23-hr observation postoperatively for pain control. Mean follow-up was 7.4 months (1-23 months) and included pelvic ultrasound assessment of fibroid size at 1, 3, and 6 months after UAE and annually thereafter. One patient was lost to follow-up. Fibroid shrinkage was noted in all patients. Given the willingness and capability to work-up, admit, treat, and follow-up patients, vascular surgery was deemed the preferred service for UAE by the referring gynecologists.

CONCLUSION

Within the framework of a collaborative, multidisciplinary program, vascular surgery can play a prominent role in providing safe and effective UAE.

Updates on Uterine Artery Embolization

Uterine fibroids (leiomyomas) are the most common benign neoplasm of the female pelvis and have a lifetime prevalence exceeding 80% among African American women and approaching 70% among Caucasian women. Approximately 50% of women with fibroids experience symptoms which may include menorrhagia that may result in anemia, bulk symptoms with bladder and bowel dysfunction and abdominal protrusion, dysmenorrhea, and infertility. Hysterectomy remains the most common treatment option for fibroids and concerns have been raised about the overuse of this procedure. Uterine artery embolization (UAE) is now a well-established uterine preserving and minimally invasive therapy for symptomatic fibroids. Since its introduction, strong evidence for safety and efficacy of UAE has been generated with low rates of complications. This review will discuss UAE for the management of symptomatic uterine fibroids with special focus on emerging technical approaches and novel periprocedural patient care.

Uterine fibroid embolization with acrylamido polyvinyl microspheres: prospective 12-month clinical and MRI follow-up study

Background Uterine fibroid embolization (UFE) is an effective minimally invasive treatment aimed to obtain complete fibroid infarction. Purpose To evaluate the degree of fibroid infarction after embolization with acrylamido polyvinyl alcohol microspheres (Bead Block). Material and Methods This prospective study included 26 pre-menopausal women in the period October 2013 to January 2015. UFE with the use of Bead Block microspheres 700-900 µm was obtained until flow stasis was achieved. Contrast-enhanced magnetic resonance imaging (MRI) was used to define residual contrast enhancement in the total fibroid burden and enhancement >10% was defined as insufficient embolization. The dominant fibroid volume and total uterine volume changes were assessed. Clinical outcome was analyzed using the quality of life questionnaire (UFS-QOL). Results Twenty-four of the 26 patients (92%) had a technically successful UFE with complete flow-stop in both uterine arteries. Twenty-two of the 26 patients (85%) completed 3 months of MRI control and 20 patients (77%) completed 12 months of MRI control. There were 16 of 22 patients (73%) with complete fibroid burden infarction and/or without residual contrast enhancement of the fibroids of more than 10% at 3 months of control. Six of 22 patients (27%) had insufficient fibroid burden infarction with residual contrast enhancement of more than 10%. Twenty-two and 18 of 26 patients completed the 3-month and 12-month questionnaire, respectively. UFS-QOL analyses showed that 91% of the patients had significant clinical improvement. Conclusion Sixteen of the 22 patients had complete fibroid burden infarction using Bead Block microspheres (700-900 µm); however, unacceptably high insufficient fibroid burden infarction in almost one-fourth of the patients were recorded.

Effects of TGF-β on uterine fibroids of women of childbearing age and uterine artery embolization

PURPOSE

To evaluate the effects of transforming growth factor-β (TGF-β) on uterine fibroids of women of childbearing age and uterine artery embolization (UAE) using Embosphere microspheres.

MATERIAL AND METHODS

A total of 128 eligible women were randomly divided into an experimental group and a control group (n = 64) who received UAE using Embosphere microspheres and panhysterectomy, respectively. Another 128 healthy women receiving physical examination in the same period were also enrolled. Serum TGF-β levels were detected by enzyme-linked immunosorbent assay (ELISA). Serum TGF-β level, size of uterine fibroid and prognosis were followed up.

RESULTS

The serum TGF-β level of patients was significantly higher than that of healthy subjects. After treatment, the red blood cell counts and hemoglobin levels of the two patient groups significantly increased compared with those before (p < .05). After UAE, the diameter of uterine fibroids was significantly smaller than that before treatment, and the TGF-β level significantly decreased (p < .05). The expression of TGF-β in uterine fibroids was significantly higher than that in surrounding normal tissue (p < .05).

CONCLUSION

With the uterus retained, the therapeutic effect of UAE was similar to that of panhysterectomy. TGF-β expression level was associated with growth of uterine fibroid in women of childbearing age, which can be used as a target for treatment.

Tris-acryl gelatin microspheres versus gelatin sponge particles in uterine artery embolization for leiomyoma

Background

Tris-acryl gelatin microspheres (TAGM) and gelatin sponge particles (GS) have been used in uterine artery embolization (UAE) for leiomyoma. No direct comparisons of both embolic agents have been reported.

Purpose

To compare the outcomes of UAE with TAGM with those of UAE with GS for uterine leiomyoma.

Material and Methods

This was a non-randomized, single-institute, non-inferiority study. Between July 2008 and August 2015, 67 consecutive patients with symptomatic leiomyoma underwent UAE. GS was used for the first 49 patients and TAGM was used for the following 18 patients. The primary endpoint was tumor infarction on contrast-enhanced magnetic resonance imaging (MRI) 1 week after UAE. The secondary endpoints were changes in symptoms and quality-of-life scores with UFS-QOL questionnaires at 4 months, and adverse events (AEs) in the 4 months after UAE.

Results

The baseline characteristics of both groups were similar. Complete or nearly complete tumor infarction (≥90%) was achieved in 94.4% (17/18) of the TAGM group and 93.6% (44/47) of the GS group. This difference (0.8%; 95% CI, –11.9% to 13.5%) indicated the non-inferiority of the TAGM group to the GS group, with a pre-specified non-inferiority margin of 20%. No significant differences were observed in improvements in symptoms or quality-of-life scores at 4 months ( P = 0.56 and P = 0.19) or in 4-month AEs ( P = 0.29).

Conclusion

The outcomes of UAE with TAGM were comparable to those of UAE with GS, suggesting that both embolic agents are acceptable for the treatment of leiomyoma.

Polymeric materials for embolic and chemoembolic applications

Percutaneous transcatheter embolization procedures involve the selective occlusion of blood vessels. Occlusive agents, referred to as embolics, vary in material characteristics including chemical composition, mechanical properties, and the ability to concurrently deliver drugs. Commercially available polymeric embolics range from gelatin foam to synthetic polymers such as poly(vinyl alcohol). Current systems under investigation include tunable, bioresorbable microspheres composed of chitosan or poly(ethylene glycol) derivatives, in situ gelling liquid embolics with improved safety profiles, and radiopaque embolics that are trackable in vivo. This article reviews commercially available materials used for embolization as well as polymeric materials that are under investigation.

Unexpected complications with head and neck hydrogel microsphere particle embolization: A case series and a technical note

Endovascular particle embolization is a common procedure with a relatively safe profile. We report here four cases in which cranial nerves, skin and mucosal ischemic complications occurred with the use of hydrogel microspheres (250-500 µm in size). Given the compressibility and higher penetration potential of microsphere particles compared with polyvinyl alcohol particles of similar size, we suggest oversizing hydrogel microsphere particles for head and neck embolizations.

Efficacies of uterine artery embolization for symptomatic uterine fibroids using gelatin sponge: a single-center experience and literature review

AIM

The aim of this study was to retrospectively analyze the efficacies of uterine artery embolization (UAE) using gelatin sponge for symptomatic uterine fibroids.

METHODS

A series of 60 consecutive premenopausal women underwent UAE using gelatin sponge particles or porous gelatin particles. Patients were routinely followed up at 1, 3, 6, and 12 months after the procedure and asked to report any procedure-related complications. At each follow-up, an original clinical questionnaire was completed by the patients to evaluate changes in fibroid-related symptoms. Pelvic magnetic resonance imaging was performed before and at 3 and 12 months after the procedure, and the changes in volume of the dominant fibroid were calculated.

RESULTS

Bilateral UAE was successfully performed in all the patients. Median age was 45 years (range 34-53 years), and median follow-up period was 25.2 months (range 1-116 months). At the 3- and 12-month follow-up, the dominant fibroid volumes were found to be significantly decreased by 33.4% (95% confidence interval [CI]: 24.9-41.1) and 48.4% (95% CI: 40.7-56.1) compared to baseline volumes, respectively. Excluding patients not having menorrhagia or bulk-related symptoms, at 12 months 49 of 50 (98%) women showed improvement in menorrhagia, and 45 of 47 (95.7%) women showed improvement in bulk-related symptoms. During the follow-up period, ten patients (16.7%) required further interventions including two patients who had undergone hysterectomy. No sequelae were experienced by any of the patients.

CONCLUSION

UAE using gelatin sponge was associated with a high clinical success rate and good fibroid volume reduction compared to UAE using other embolic agents.

Uterine artery embolization: a vascular surgery procedure? One vascular surgery group's experience

Uterine artery embolization (UAE) has been performed by interventional radiology since the 1990s for symptomatic uterine fibroids with considerable success. Endovascular-trained vascular surgeons possess the necessary skills to successfully perform this procedure after an adequate but brief training period. Fourteen successful UAE procedures were performed by two vascular surgeons over a one-year period. Indications for the procedures were bleeding (12/14 patients, 86%), pain/bloating/pressure (13/14 patients, 93%) and dyspareunia (2/14 patients, 14%). All patients were initially evaluated by a gynecologist and referred for this procedure. Complications were minor and limited. Clinical follow-up demonstrated near-complete to complete symptom resolution in all but one patient for a 93% short-term success rate. Follow-up ultrasound studies demonstrated a reduction in the uterine fibroid size in all patients three months or more postprocedure. The mean fibroid size reduction was 4.07-3.26 cm (20%), P < 0.005. UAE is a procedure of proven benefit, well-matched to many vascular surgeons' skills and practice. Up to this point, few vascular surgeons have incorporated this endovascular procedure into their practices. This initial and somewhat limited study demonstrates one vascular surgery group's early success with this procedure.

Improved infarction rates in fibroids after the introduction of contrast-enhanced ultrasound during uterine artery embolization

BACKGROUND

In order to achieve sustained symptom control and minimize the risk of recurrence, uterine artery embolization (UAE) should aim at complete infarction of all fibroids.

PURPOSE

To retrospectively evaluate the infarction rate of uterine fibroids in patients that had undergone uterine artery embolization (UAE) after the introduction of contrast-enhanced ultrasound (CEUS) during UAE procedures at our institution.

MATERIAL AND METHODS

Thirty patients treated with UAE between February 2006 and August 2009 were included. MR images obtained before, at 3 months, and 12 months after the procedure were reviewed. We evaluated volume changes in dominant fibroids as well as the infarction rate of all fibroids in each patient. Clinical results were evaluated by reviewing the medical records. The study was approved by the institutional review board.

RESULTS

CEUS was technically successfully performed during the UAE procedure in all patients. In five cases the endpoint of embolization was adjusted based on findings at CEUS. The mean volume shrinkage of dominant fibroids was 39.8% after 3 months and 59.8% after 12 months. There was complete infarction of all fibroid tissue in 97% of patients at 3 months and 96% at 12 months. No major complications were observed.

CONCLUSION

After the introduction of CEUS during UAE procedures in our institution, high infarction rates were achieved.