Initial experience with use of tris-acryl gelatin microspheres for uterine artery embolization for leiomyomata

Current status and prospects of gelatin and its derivatives in oncological applications: Review

Treating cancer remains challenging due to the substantial side effects and unfavourable pharmacokinetic characteristics of antineoplastic medications, despite the progress made in comprehending the properties and actions of tumour cells in recent years. The advancement of biomaterials, such as stents, implants, personalised drug delivery systems, tailored grafts, cell sheets, and other transplantable materials, has brought about a significant transformation in healthcare and medicine in recent years. Gelatin is a very adaptable natural polymer that finds extensive application in healthcare-related industries owing to its favourable characteristics, including biocompatibility, biodegradability, affordability, and the presence of accessible chemical groups. Gelatin is used as a biomaterial in the biomedical sector for the creation of drug delivery systems (DDSs) since it may be applied to various synthetic procedures. Gelatin nanoparticles (NPs) have been extensively employed as carriers for drugs and genes, specifically targeting diseased tissues such as cancer, tuberculosis, and HIV infection, as well as treating vasospasm and restenosis. This is mostly due to their biocompatibility and ability to degrade naturally. Gelatins possess a diverse array of potential applications that require more elucidation. This review focuses on the use of gelatin and its derivatives in the diagnosis and treatment of cancer. The advancement of biomaterials and bioreactors, coupled with the increasing understanding of emerging applications for biomaterials, has enabled progress in enhancing the efficacy of tumour treatment.

The impact of fibroid treatments on quality of life and mental health: a systematic review

Fibroids significantly impact the quality of life (QOL) and mental health of affected women. However, there are limited comparative data on QOL measures after medical, surgical, and radiologic interventions in women with fibroids. This study aimed to assess the current literature evaluating the impact of fibroids on QOL measures using several validated questionnaires for radiologic, medical, or surgical interventions or a combination of interventions before and after treatment. PubMed, PsycINFO, ClinicalTrials.gov, Embase, and Cochrane Library were searched from January 1990 to October 2023 to evaluate the available evidence, and the risk of bias was assessed using Cochrane RoB 2.0 or the Newcastle-Ottawa Scale. The review criteria included randomized controlled trials (RCTs) and observational cohort studies that included premenopausal women with symptomatic uterine fibroids, confirmed by imaging, who underwent an intervention to target fibroid disease. Only reports using validated questionnaires with a numerical baseline (pretreatment) and posttreatment scores were included. The exclusion criteria included perimenopausal or postmenopausal patients, conditions in addition to uterine fibroids that share similar symptoms, or studies that did not focus on QOL assessment. Abstracts were screened, and full texts were reviewed to determine whether studies met the inclusion criteria. A total of 67 studies were included after final review: 18 RCTs and 49 observational studies. All interventions were associated with a significant improvement in uterine fibroid-specific QOL measures, mental health metrics, and a reduction in symptom severity scores after treatment. These data reveal a substantial impact of uterine fibroids on the QOL and mental health of women with fibroids and indicate the metrics that can be used to compare the effectiveness of fibroid treatment options.

Incidence and changes in endometrial-leiomyoma fistula following uterine artery embolization: a single-center retrospective analysis

OBJECTIVES

To investigate whether the number and size of endometrial-leiomyoma fistulas (ELFs) change following uterine artery embolization (UAE) for leiomyoma and the correlation between ELFs and vaginal discharge (VD).

MATERIALS & METHODS

This study was a retrospective analysis of 100 patients who underwent UAE at a single institution between May 2016 and March 2021. They all underwent MRI at baseline, 4 months, and 1 year after UAE. The number and size of the ELFs were compared with the MRI images each time. The ELF tumor characteristics and the correlation between the ELFs and VD were assessed. Additional gynecologic interventions due to VD associated with ELFs were evaluated.

RESULTS

No ELF was observed at baseline. Ten ELFs were noted in nine patients at 4 months, and 35 ELFs were noted in 32 patients 1 year after UAE. The ELFs significantly increased over time (p = 0.004, baseline vs. 4 months; p < 0.001, 4 months vs. 1 year). The ELF size did not significantly change over time (p = 0.941). The tumors developing ELFs after UAE were mainly located at the submucosal or intramural area contacting the endometrium at baseline, with a mean size of 7.1 (2.6) cm. Nineteen patients (19%) had VD 1 year after UAE. There was no significant correlation between VD and the number of ELFs (p = 0.80). No patients underwent additional gynecologic interventions due to VD associated with ELFs.

CONCLUSION

ELFs increased in number and did not disappear over time after UAE in most tumors.

CLINICAL RELEVANCE STATEMENT

Despite the MR imaging findings, within the limited data of this study, ELFs were not seemingly associated with clinical symptoms, including VD.

KEY POINTS

• Endometrial-leiomyoma fistula (ELF) is a complication of uterine artery embolization (UAE). • ELFs increased in number over time after UAE and did not disappear in most tumors. • Most tumors developing ELFs after UAE were located near/contacted the endometrium and were larger.

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.

Clinical Study on the Treatment of Benign Prostatic Hyperplasia by Embolization of Prostate Artery Based on Embosphere Microspheres and Gelatin Sponge Granules

Prostatic hyperplasia can cause dysuria, such as frequent urination, urgency of urination, increased nocturia, poor urination, and other symptoms, which seriously affect the quality of life of old men. We aim to compare and analyze the safety and clinical effect of embolization of the target blood vessels of ruptured prostatic hyperplasia with gelatin sponge particles and embosphere microspheres. Methods. The transcatheter MRI was performed in 422 patients. Among them, 198 patients were treated with gelfoam particles and 224 patients were treated with embosphere microspheres. The clinical effect and adverse reactions were observed and analyzed by biochemical and imaging examination. Four hundred and twenty two cases were hemostasis. In the gelatin sponge group, 34 patients had recurrent bleeding 24–36 hours after embolization, 122 patients had different degrees of elevation of prostatic hyperplasia transaminase (31 cases increased to more than 1000 U/L), 198 patients had different degrees of elevation of bilirubin; in the microsphere group, there was no significant difference in prostatic hyperplasia function indexes between the two groups. Conclusion. Compared with the gelfoam embolic agent, the embosphere embolic microsphere has a good efficacy and safety in the treatment of prostatic hyperplasia rupture and hemorrhage, with a light adverse reaction, a low probability of recanalization, and little damage to the postoperative prostatic hyperplasia function, which is conducive to the benign recovery of perioperative patients and is worthy of clinical application.

Fat tissue as an embolic material changes the embolization time in a size-dependent manner: a basic investigation using rabbits

PURPOSE

To evaluate the usefulness of fat tissue as an embolic material and determine whether the embolization time depends on the size of the fat tissue.

MATERIALS AND METHODS

Inguinal fat tissues from 16 rabbits were processed as follows: (1) fat tissues were cut into 2-mm squares, and (2) fat tissue squares were dissociated 20 × through a syringe without a needle (1-139 μm in diameter). The distal main trunk of the right or left renal artery was completely embolized using one of the two types of fat tissue. After 1 or 7 days, renal angiography was performed.

RESULTS

On day 1 after embolization of the renal artery with 2-mm fat tissue squares (Group 1-1) and on day 7 (Group 1-2), the reperfusion rates were 4.0 ± 5.5% and 29.9 ± 6.9%, respectively. On day 1 after embolization of the renal artery with fat tissues dissociated using a 20 × pumping cycle (Group 2-1) and on day 7 (Group 2-2), the reperfusion rates were 59.9 ± 9.9% and 74.3 ± 26.0%, respectively. The reperfusion rates were significantly different between the two types of fat tissue.

CONCLUSIONS

Fat tissue serves as an embolic material that changes the embolization time in a size-dependent manner.

A systematic review of the psychosocial impact of fibroids before and after treatment

OBJECTIVE

Despite the high prevalence of uterine fibroids, the psychosocial impact of fibroids has not been evaluated across different quality of life indicators and compared with other chronic conditions. Here, we rigorously analyzed available evidence pertaining to the psychosocial burden of uterine fibroids in premenopausal women and compared validated quality of life and symptom scores before and after treatment.

DATA SOURCES

We searched PubMed, PsycINFO, ClinicalTrials.gov, Embase, and Cochrane Library for publications from January 1990 to January 2020.

STUDY ELIGIBILITY CRITERIA

We considered English-language publications that evaluated the association between uterine fibroids diagnosed by imaging studies in premenopausal women and quality of life by standardized and validated questionnaires at baseline and after treatment. We used a detailed list of terms related to quality of life, questionnaires, and uterine fibroids to conduct the search.

METHODS

Three reviewers screened titles and abstracts and then obtained full-text articles for further analysis. The reviewers assessed risk of bias using established Cochrane and Newcastle-Ottawa Scale guidelines. The quality of life scores of premenopausal women with fibroids were reviewed at baseline and compared with those of published quality of life scores in other disease populations in addition to after fibroid treatment.

RESULTS

A total of 57 studies were included in the review: 18 randomized controlled trials and 39 observational studies. Of note, the 36-Item Short Form Survey and European Quality of Life Five-Dimension Scale questionnaires both indicated a diagnosis of uterine fibroids to have a disability score that was similar to or exceeded (was a greater psychosocial stressor) a diagnosis of heart disease, diabetes mellitus, or breast cancer. Quality of life scores were lower at baseline than after treatment in all instruments measuring these variables in women with uterine fibroids, indicating significantly impaired psychosocial functioning. Uterine fibroids were associated with significant patient-reported health disabilities related to bodily pain, mental health, social functioning, and satisfaction with sex life.

CONCLUSION

A diagnosis of uterine fibroids was a significant psychosocial stressor among women at baseline and relative to other diseases. Validated quality of life instruments indicated therapeutic success and the improvement of both physical and emotional symptoms after treatment.

Endovascular treatment of uterine myomatosis: a systematic review

Uterine Artery Embolization (UAE) is a noninvasive alternative to open surgery for treatment of uterine myomatosis. This study aims to analyze the efficacy and safety of UAE in these cases. A systematic review was carried out of studies available on the Medline (via PubMed) and the LILACS and PEDro (via the Biblioteca Virtual em Saúde) databases. The searches found 817 studies, 7 of which were selected according to the eligibility criteria (analytical, longitudinal, retrospective, or prospective studies), with a total of 367 patients studied. The variables analyzed and the characteristics of the studies included were collated and input to a database. Rates of volume reduction of the uterus and the dominant myoma were 44.1% and 56.3%, respectively. Mean rate of complete infarction of the dominant myoma was 88.6% (82-100%). The mean number of complications observed was 15±8.6 cases, most of which were classified as minor, and no deaths were recorded. The mean number of re-interventions in absolute values was 12.2±15.5 cases. Therefore, in the literature analyzed, uterine artery embolization is an effective procedure with a low rate of complications for treatment of uterine leiomyomatosis.

Determination of the Frequency of Right and Left Internal Mammary Artery Embolization in Single Ventricle Patients: A Two-Center Study

Embolization of systemic to pulmonary artery collaterals to regulate pulmonary arterial flow or pressure of the cavopulmonary circulation in patients with single ventricle is a common practice. The relative incidence and impact of this practice on future interventions like coronary artery bypass grafting is poorly understood. This study aims to evaluate the frequency and implications of internal mammary artery (IMA) embolization in the single ventricle (SV) population. A retrospective chart review was performed of SV patients who underwent cardiac catheterization before and after Fontan procedure between February 2007 and 2017. Data were collected from two tertiary care centers in the Midwest. Of the 304 SV patients, 62 (20.4%) underwent embolization of one or more IMAs, whereas 242 (79.6%) did not. The rate of embolization of IMA was 40.5% in one center and 14.5% in the second center. Among patients who received IMA embolization, left internal mammary artery (LIMA) embolization was seen in 6 (9.7%) patients. Majority of patients underwent either right internal mammary artery (RIMA) embolization (n = 25; 40.3%) or RIMA and LIMA embolization (n = 27; 43.5%). IMA embolization in SV patients is common. Embolizing IMAs early in life will likely eliminate a valuable graft option for coronary artery bypass grafting should it be required in the future care of these patients. Multi-center, prospective, nation-wide studies are warranted to examine coronary artery disease in the SV population and true frequency of IMA embolization. Delineation of which IMAs were embolized is a necessary in surgical and cardiac intervention national data, such as Society of Thoracic Surgeons (STS) database. All measures should be taken to preserve IMAs patency, if deemed feasible and safe.

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.

Holmium-lipiodol-alginate microspheres for fluoroscopy-guided embolotherapy and multimodality imaging

Embolotherapy is a minimally invasive transcatheter technique aiming at reduction or complete obstruction of the blood flow by infusion of micro-sized particles in order to induce tumor regression. A major drawback of the current commercially available and clinically used microspheres is that they cannot be detected in vivo with medical imaging techniques, impeding intra- and post-procedural feedback. It can be expected that real-time monitoring of microsphere infusion and post-procedural imaging will result in better predictability and higher efficacy of the treatment. In this study, a novel microsphere formulation has been developed that can be visualized with fluoroscopy, X-ray computed tomography (CT) and magnetic resonance imaging (MRI). The microspheres were prepared with the JetCutter technique and consist of alginate (matrix-forming polymer), holmium (cross-linking and MRI contrast agent), lipiodol (radiopaque contrast agent) and Pluronic F-68 (surfactant). The mean size (±SEM) of the hydrated holmium-lipiodol-alginate microspheres (Ho-lip-ams) was 570±12 μm with a holmium content of 0.38±0.01% (w/w). Stability studies showed that the microspheres remained intact during incubation for two weeks in fetal calf serum (FCS) at 37 °C. The inclusion of lipiodol in the microspheres rendered excellent visualization capabilities for fluoroscopy and CT, whereas the holmium ions, which keep the alginate network together, also allow MR imaging. In this study it was shown that single sphere detection was possible by fluoroscopy, CT and MRI. The Ho-lip-ams were visualized in real-time, during infusion in a porcine kidney using fluoroscopy, and post-procedural, the deposition of the microspheres was examined with fluoroscopy, (cone beam rotational) CT and MRI. The different imaging modalities showed similar deposition patterns of the microspheres within the organ. The combination of intra-procedural visualization, multimodality imaging for patient follow-up and the possibility of quantification offers a new and promising method for more safe, efficient and successful embolization treatment.

Clinical long-term outcome after uterine artery embolization: sustained symptom control and improvement of quality of life

PURPOSE

To evaluate long-term clinical efficacy of uterine artery embolization (UAE) for uterine fibroids with respect to symptom control and improvement in quality of life.

MATERIALS AND METHODS

Between October 2000 and October 2007, 380 consecutive women underwent UAE. To determine long-term efficacy, the rate of reinterventions (ie, repeat UAE, hysterectomy, myomectomy) and the clinical response regarding symptoms related to bleeding and bulk were documented. Persistence, worsening, or recurrence of symptoms and reinterventions were classified as treatment failure (TF). The cumulative rate of freedom from TF was determined by Kaplan-Meier analysis. Cox regression was used to identify possible clinical or morphologic predictors of outcome. Secondary outcome measures were changes in disease-specific quality of life and onset of menopause.

RESULTS

Follow-up was available for a median of 5.7 years (range, 3.1-10.1 y) after treatment in 304 of 380 (80%) patients. There were 54 TFs with subsequent reintervention in 46 women. Kaplan-Meier analysis revealed a cumulative TF rate of 23.3% after 10 years. Cox regression demonstrated a significantly higher likelihood of TF in patients<40 years old compared with patients>45 years old (hazard ratio, 2.28; P = .049). Women without TF showed sustained normalization of disease-specific quality of life (P <.001). Cessation of menstruation at a median age of 51 years was reported by 57 (22.8%) of 250 women.

CONCLUSIONS

UAE leads to long-term control of fibroid-related symptoms and normalization of quality of life in approximately 75% of patients. Younger women seem to have a higher risk of TF than older women closer to menopause.

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.

Uterine artery embolization for the treatment of adenomyosis: a review

During the past 10 years, uterine artery embolization (UAE) has been investigated as a possible therapy for adenomyosis. All publications available from 1999 through 2010 are included in this report. Levels of evidence and trial classifications were evaluated according to the guidelines developed by the United States Preventive Services Task Force. Long-term data are available from 511 affected women from 15 studies. Improvements were reported by 387 patients (75.7%). The median follow-up was 26.9 months. UAE as treatment for adenomyosis shows significant clinical and symptomatic improvements on a short- and long-term basis.

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

OBJECTIVE

To evaluate the efficacy of acrylamido polyvinyl alcohol microspheres (a-PVAM) as an embolic agent for uterine artery embolization (UAE) compared with Tris-acryl gelatin microspheres (TAGM).

DESIGN, SETTING, PARTICIPANTS

Prospective randomized double-blind noninferiority trial. Conducted at two sites both with regional UAE practices. Forty-six women with symptomatic leiomyomas.

INTERVENTION

UAE procedure was performed with either of the two embolic agents. Either 700-900-μm a-PVAM or 500-700-μm TAGM was used.

MAIN OUTCOME MEASURES

Changes in leiomyoma perfusion, overall uterine volume, and dominant leiomyomas volume measured by contrast-enhanced magnetic resonance imaging at 1 week, 3 months, and 6 months after UAE by a reader blinded to the embolic agent used. Changes in Uterine Fibroid Symptoms and Quality of Life questionnaire scores were measured at 3, 6, and 12 months after UAE.

RESULTS

Forty-six patients were randomized and treated under the study protocol (a-PVAM n=22, TAGM n=24). There were no procedure-related complications. Two patients were excluded from analysis (one technical failure of the procedure, one withdrawal from study). Successful (>90%) leiomyoma devascularization was observed in 81% of subjects at 1 week after UAE, 97% at 3 months after UAE, and 95% at 6 months after UAE. No significant differences were observed in 14 of 15 outcome measurements, consistent with noninferiority. TAGM was slightly superior to a-PVAM on one comparison (overall quality of life at 3 months after UAE).

Arterial distribution of calibrated tris-acryl gelatin and polyvinyl alcohol embolization microspheres in sheep uterus

The purpose of this study was to compare, after embolization, the distribution in the uterine arterial vasculature of tris-acryl gelatin microspheres (TGMS) and polyvinyl alcohol microspheres (PVAMS). A limited bilateral uterine artery embolization was performed in six adult sheep under fluoroscopic control by injecting in each uterine artery 0.25 ml of 500- to 700-microm TGMS of PVAMS suspended in 50/50 saline/contrast medium. Sacrifices were performed 1 week after embolization and uteri were analyzed histologically. The number and size of microspheres and vessels were measured, as well as the histological location according to a classification in four zones of the uterus. One hundred sixty-five vessels (69 vessels occluded with TGMS and 96 vessels occluded with PVAMS) were measured. The size of the occluded vessels decreased significantly from proximal to distal zones of the uterine vasculature (P < 0.0001). The location of TGMS and PVAMS within the vasculature was significantly different (P < 0.0001) since PVAMS blocked significantly more distally than TGMS. Deformation of the microspheres within the tissue was greater for PVAMS (18.0% +/- 12.3%) than for TGMS (8.7% +/- 9.2%) (P < 0.0001). In conclusion, PVAMS have a more distal distribution in the sheep uterine vasculature, compared to TGMS. Such differences in partition, already described in the kidney embolization model, can ultimately explain the different clinical outcome reported with these two types of microspheres in uterine fibroid embolization.

Acquisition of endovascular skills for uterine artery embolization using a simulator

This study addresses endovascular training using simulators for uterine artery embolization. A review of endovascular skill training for surgeons using simulators was performed. Surgeons possess varying levels of proficiency in endovascular techniques. A simulator will improve endovascular skills in the following areas: C-arm image intensifier use, catheter selection and manipulation, understanding of the pelvic anatomy, and technique of embolization. Surgeons may gain realistic experience on the simulator prior to entry into the cath lab or procedure room. Using a simulator, surgeons can learn valuable endovascular skills necessary for successful performance of uterine artery embolization.

The role of interventional radiology in obstetric and gynaecology practice

Interventional radiology is continuing to reshape current practice in many specialties of clinical care. It is a relatively new and innovative branch of medicine in which physicians treat diseases non-operatively through small catheters guided to the target by fluoroscopic and other imaging modalities. The aim is to provide image-guided, minimally invasive alternatives to traditional surgical and medical procedures in suitable cohorts of patients. Procedures which previously required major surgery can now be performed by interventional radiologists, sometimes on an outpatient basis, with little patient discomfort. In this review, we highlight the importance of interventional radiology in treating a comprehensive range of obstetric and gynaecological pathologies.

Acrylamido polyvinyl alcohol microspheres for uterine artery embolization: 12-month clinical and MR imaging results

PURPOSE

To report the 12-month clinical and magnetic resonance (MR) imaging results of an ongoing two-center registry involving acrylamido polyvinyl alcohol (PVA) microspheres for uterine artery embolization (UAE) for leiomyomas.

MATERIALS AND METHODS

A total of 69 patients underwent UAE with 500-700-microm, 700-900-microm, and 900-1,200-mum acrylamido PVA microspheres (BeadBlock). Thirty-three patients underwent UAE with a limited embolization (protocol A) and 36 patients underwent UAE with stasis as the angiographic endpoint (protocol B). Primary objectives were clinical efficacy measured by a leiomyoma-specific quality of life (QOL) questionnaire and infarction rate of leiomyomas on early contrast agent-enhanced MR imaging. Secondary objectives were in-hospital complications, patient satisfaction, and frequency of clinical failure.

RESULTS

Bilateral embolization was technically successful in 68 of 69 patients. A significant decrease (P < .001) in symptom severity and increase in health-related QOL was observed at 3 and 12 months with no significant differences between embolization protocols. However, contrast agent-enhanced MR imaging showed a significantly lower rate of completely infarcted leiomyomas in protocol A compared with protocol B (P < .05). Early clinical failures in patients treated according to protocol A were caused by incomplete tumor infarction. Minor complications occurred in five of 69 patients. Patient satisfaction was similar between protocols.

CONCLUSIONS

Acrylamido PVA microspheres are a clinically effective and safe embolic agent for UAE. The use of 500-700-microm spheres and a limited embolization results in an unacceptably high rate of failed tumor infarction. Superior imaging results and fewer repeat interventions can be achieved with use of 700-900-microm spheres and stasis as the angiographic endpoint.

Leiomyoma infarction after uterine artery embolization: a prospective randomized study comparing tris-acryl gelatin microspheres versus polyvinyl alcohol microspheres

PURPOSE

To determine the degree of leiomyoma infarction after uterine artery embolization (UAE) performed with tris-acryl gelatin microspheres or polyvinyl alcohol (PVA) microspheres.

MATERIALS AND METHODS

Patients determined to be candidates and scheduled for UAE were randomized prospectively to receive tris-acryl gelatin microspheres or PVA microspheres. The manufacturers' recommended technique was used for both products during the UAE procedures (including the recently described refined protocol for PVA microspheres). All patients underwent magnetic resonance (MR) imaging of the pelvis with contrast agent enhancement before and after the UAE procedure. On the postprocedural MR study, the degree of tumor infarction was assessed on postcontrast images. These findings were classified as follows: 100% infarction, 90%-99% infarction, 50%-89% infarction, and less than 50% infarction. Treatment failure was defined by enhancement of more than 10% of a patient's entire tumor burden.

RESULTS

A total of 53 patients were enrolled in this study. Twenty-seven (mean age, 44.9 years) received PVA microspheres and 26 (mean age, 45.1 years) received tris-acryl gelatin microspheres. There were no significant differences in the preprocedural uterine volume, dominant tumor volume, location of dominant tumor, and presenting symptoms between populations. In the PVA microsphere group, treatment failure was seen in eight patients (29.6%). In the tris-acryl gelatin microsphere group, treatment failure was seen in one patient (3.8%), which was a significant difference between groups (P < or = .025).

CONCLUSIONS

There was a significantly greater degree of tumor infarction in patients treated with tris-acryl gelatin microspheres during UAE than in patients who received PVA microspheres administered in accordance with a newly refined protocol. Given the known risk of recurrence in patients with persistent tumor enhancement after UAE, it is concluded that tris-acryl gelatin microspheres should be the preferred agent for UAE at this time.

Analysis of prognostic factors for patients with leiomyoma treated with uterine arterial embolization

OBJECTIVE

The objective of the study was to describe a clinically useful factors index predicting long-term efficacy of uterine artery embolization (UAE).

STUDY DESIGN

Newly diagnosed patients with uterine leiomyoma wishing to retain their uterus underwent UAE at our institution. Clinical demographics and 4 prognostic factors were recovered from the medical record. A regrowth-free interval (RFI) was calculated for all patients based on leiomyoma regrowth or recurrence of any previously reported symptoms. RFI by prognostic factor was analyzed by the Kaplan-Meier method.

RESULTS

Forty-three patients were identified. Two prognostic factors were identified by multivariate analysis: vascularity (dichotomized as hypervascular vs hypovascular; RFI at 2 years, 80% vs 20%, P = .001) and number of nodules (solitary vs multiple; RFI at 2 years, 72% vs 25% at 2 years, P = .001)

CONCLUSION

UAE success may be predicted by 2 preoperative parameters. Further investigation is warranted.

Acoustic characterization of a new trisacryl contrast agent. Part I: In vitro study

The objective of the study was to acoustically characterize trisacryl polymeric microparticles (TMP), which are derived from biocompatible embolic agents. With significant acoustic properties, these polymeric particles could be potentially used as targeted ultrasound contrast agents, directed towards a specific site, with ligands conjugation on the polymeric network surface. In the in vitro study, a pulser/receiver (PRF of 1 kHz), associated to different transducers (5, 10 and 15 MHz), was used to measure the acoustic properties of the TMP inserted in a Couette flow device. Acoustic characterization according to TMP concentration (0.12-15.63 mg/ml), frequency (4.5-17 MHz, defined by each transducer bandwidth), ultrasound pressure (137-378 kPa) and exposure time (0-30 min) was conducted. Particle attenuation was also evaluated according to TMP concentration and emission frequency. Backscattering increased non linearly with concentration and maximum enhancement was of 16.4 dB+/-0.89 dB above 7.8 mg/ml. This parameter was found non-linear with increasing applied pressure and no harmonic oscillation could be noticed. Attenuation reached approximately 1.4 dB/cm at 15 MHz and for the 15.6 mg/ml suspension. The TMP have revealed in vitro ultrasound properties comparable to those observed with known contrast agents, studied in similar in vitro systems. However, such set-ups combined with a rather aqueous suspending medium, have some limitations and further investigations need now to be conducted to approach in vivo conditions in terms of flow and blood environment.

Acoustic characterization of a new trisacryl contrast agent. Part II: Flow phantom study and in vivo quantification

The biocompatible trisacryl particles (TMP) are made of a cross-linked acrylic copolymer. Their inherent acoustic properties, studied for a contrast agent application, have been previously demonstrated in a in vitro Couette device. To measure their acoustic behaviour under circulating blood conditions, the TMP backscatter enhancement was further evaluated on a home-made flow phantom at different TMP doses (0.12-15.6 mg/ml) suspended in aqueous and blood media, and in nude mice (aorta and B16 grafted melanoma). Integrated backscatter (IB) was measured by spectral analysis of the Doppler signals recorded from an ultrasound system (Aplio) combined with a 12-MHz probe. Doppler phantom experiments revealed a maximal IB of 17+/-0.88 dB and 7.5+/-0.7 dB in aqueous and blood media, respectively. IB measured on mice aorta, in pulsed Doppler mode, confirmed a constant maximal value of 7.29+/-1.72 dB over the first minutes after injection of a 7.8 mg/ml TMP suspension. Following the injection, a 60% enhancement of intratumoral vascularization detection was observed in power Doppler mode. A preliminary histological study revealed inert presence of some TMP in lungs 8 and 16 days after injection. Doppler phantom experiments on whole blood allowed to anticipate the in vivo acoustic behaviour. Both protocols demonstrated TMP effectiveness in significantly increasing Doppler signal intensity and intratumoral vascularization detection. However, it was also shown that blood conditions seemed to shadow the TMP contrast effect, as compared to in vitro observations. These results encourage further investigations on the specific TMP targeting and on their bio-distribution in the different tissues.

Degradable gelatin microspheres as an embolic agent: an experimental study in a rabbit renal model

Objective

To investigate the basic characteristics of degradable gelatin microspheres (GMSs), including their embolic behavior and degradation periods when they are used as embolic materials in the renal arteries of rabbit models.

Materials and Methods

Based on the GMS particle size, 24 kidneys were divided into 3 groups of eight kidneys, and each group was embolized with a different GMS particle size (group 1:35-100 µm, group 2: 100-200 µm, and group 3: 200-300 µm). From each group, two rabbits were sacrificed immediately after embolization (day 0), and a pair of rabbits from each group underwent an angiogram and were sacrificed on days 3, 7, and 14, respectively, after embolization. The level of arterial occlusion, the pathological changes in the renal parenchyma, and the degradation of the GMSs were evaluated angiographically and histologically.

Results

A follow-up angiogram on days 0, 3, 7, and 14 revealed the presence of wedge-shaped poorly-enhanced areas in the parenchymal phase as seen in all groups. The size of these areas tended to increase with the particle diameter, and persisted up to day 14. On days 3, 7, and 14, parenchymal infarctions were observed histologically in all cases, and this observation corresponded with the parenchyma being supplied by the embolized arteries. GMSs of group 1 mainly reached the interlobular arteries, while those of group 3 mainly reached the interlobar arteries. In all but two cases, the GMSs were identified histologically even on day 14, and sequential degradation was histologically identified in all GMS groups.

Conclusion

GMSs can be used as degradable embolic materials which can control the level of embolization.

Experimental evaluation of early and long-term effects of microparticle embolization in two different mini-pig models. Part II: liver

PURPOSE

To evaluate trisacryl-gelatin microspheres (40-120 microm) for acute and chronic tissue embolization in mini-pig livers.

METHODS

Thirteen animals were divided into four groups: group 1 (n = 3), total arterial bed occlusion with acute procedure; groups 2 to 4, chronic superselective embolization with follow-up of 1 week (group 2, n = 1), 4 weeks (group 3, n = 4) or 14 weeks (group 4, n = 5). Key endpoints were homogeneity and particle distribution in acute embolizations (group 1) and necrosis and inflammation in chronic embolizations (groups 2-4) as assessed microscopically and angiographically.

RESULTS

After liver embolization, parenchymal necrosis did not occur; only signs of vessel wall disintegration were evident. The bile ducts remained intact. A distinct foreign body reaction with sparse leukocytic infiltration and giant cells was found at 14 weeks, but no signs of major inflammation were found. Particles were seen at the presinusoidal level, but no particle transportation into the sinusoids was observed.

CONCLUSIONS

Embolization in mini-pig livers, using small trisacryl-gelatin microspheres, results in vessel fibrosis without parenchymal or bile duct necrosis. The most likely explanation for preservation of the parenchyma is portal inflow. Small trisacryl-gelatin microspheres may be ideal as an adjunct for chemoembolization.

Embolização uterina para tratamento de miomas sintomáticos: impacto na qualidade de vida

OBJETIVO: Verificar a mudança na qualidade de vida de pacientes portadoras de miomatose uterina sintomática submetidas a tratamento por embolização. MATERIAIS E MÉTODOS: Quarenta mulheres portadoras de miomatose uterina sintomática que foram tratadas com a técnica de embolização responderam a um questionário de qualidade de vida antes e 12 semanas após o procedimento. RESULTADOS: Verificou-se que o escore médio relacionado com a gravidade dos sintomas nas 40 pacientes antes da embolização foi de 62,07 ± 6,34 e se modificou, com significância estatística após o tratamento, quando se verificou escore médio de 20,42 ± 3,81. Da mesma forma, comprovou-se a melhora na qualidade de vida pela modificação dos escores antes e depois do tratamento, o que também apresentou significância estatística, passando de 40,26 ± 2,98 para 85,06 ± 2,57. CONCLUSÃO: A embolização uterina provoca alívio evidente dos sintomas relacionados com a miomatose e proporciona melhora substancial da qualidade de vida das pacientes.

Uterine artery embolization for symptomatic adenomyosis with or without uterine leiomyomas with the use of calibrated tris-acryl gelatin microspheres: midterm clinical and MR imaging follow-up

PURPOSE

To evaluate clinical and magnetic resonance (MR) imaging results after uterine artery embolization (UAE) in women with symptomatic adenomyosis with or without uterine leiomyomas.

MATERIALS AND METHODS

Thirty-eight women with symptomatic adenomyosis with or without uterine leiomyomas were treated with UAE with calibrated tris-acryl gelatin microspheres. Based on MR findings, women were categorized as having pure adenomyosis (group A; n = 15), adenomyosis dominance with fibroid tumors (group B; n = 14), or fibroid tumor dominance with adenomyosis (group C; n = 9).

RESULTS

Heavy menstrual bleeding, pain, and bulk-related symptoms at last follow-up at a median of 16.5 months (range, 3-38 months) were compared with baseline symptoms. With follow-up MR imaging at a median of 12 months (range, 3-36 months), changes in uterine volume, leiomyoma volume, junctional zone thickness, and contrast enhancement of adenomyosis were assessed. After embolization, adenomyosis infarction could be depicted on contrast medium-enhanced MR in 44.1% of cases. Median reductions of uterine volume, fibroid tumor volume, and junctional zone thickness were 44.8%, 77.1%, and 23.9%, respectively. In group A, three patients needed additional surgery after UAE, in addition to two in group B and one in group C. In the remaining 32 patients, except for one patient in group C, all preexisting symptoms (eg, bleeding, pain, bulk-related symptoms) improved or resolved after UAE. Overall, 84.2% of women were satisfied with the results of UAE.

CONCLUSION

In this study, midterm results (at a median of 16.5 months) showed that UAE in symptomatic adenomyosis with or without uterine leiomyomas is effective. Hysterectomy was avoided in the vast majority of patients. MR imaging showed reduction of uterine volume and junctional zone thickness.

Gelatin microspheres: initial clinical experience for the transcatheter arterial embolization

PURPOSE

The purpose of this study is to evaluate the embolization effects of gelatin microspheres (GMSs) when used as an embolic material for transcatheter arterial embolization (TAE) for several organs.

MATERIALS AND METHODS

We prepared GMSs that dissolves in 5 days in extravasuclar tissue. GMSs were used in five cases in total, four cases with multiple liver tumors and one case with a pelvic bone tumor.

RESULTS

In all five cases, it was possible to treat the targeted tumors by TAE with GMSs. In the contrast-enhanced CT performed 2-4 weeks later, the embolized tumors did not show an enhancement effect. Passage of GMSs in the microcatheter was excellent.

CONCLUSION

GMSs showed sufficient potential to be used as an embolic material.

Embolization Materials Made of Gelatin: Comparison Between Gelpart and Gelatin Microspheres

PURPOSE

The object of this study was to assess the level of embolization in the embolized artery and the degradation period of these two embolic agents in the renal arteries using rabbit models.

MATERIALS AND METHODS

The renal artery was embolized using 5 mg of gelatin microspheres (GMSs; diameter, 35-100 mum; group 1) or 1 mg of Gelpart (diameter, 1 mm; group 2). For each group, angiographies were performed on two kidneys immediately after the embolic procedure and on days 3, 7, and 14 after embolization. This was followed by histopathological examinations of the kidneys.

RESULTS

Follow-up angiograms on each day revealed the persistence of poorly enhanced wedge-shaped areas in the parenchymal phase in all cases. In group 1, four of six cases showed poorly enhanced small areas in the follow-up angiograms. In group 2, all cases showed poorly enhanced large areas. In the histopathological specimens, it was observed that immediately after embolization, the particles reached the interlobular arteries in group 1 and the interlobar arteries in group 2. In all cases in group 1, the particles were histologically identified even on day 14. In one case in group 2 on day 14, the particles were not identified.

CONCLUSION

In conclusion, although GMSs and Gelpart were similar in the point of gelatin particles, the level of embolization and the degradation period were different between GMSs and Gelpart.

The size of gelatin sponge particles: differences with preparation method

PURPOSE

To assess whether the size distribution of gelatin sponge particles differed according to the method used to make them and the type of original sheet.

METHODS

Gelatin sponge particles of approximately 1-1.5 x 1-1.5 x 2 mm were made from either Spongel or Gelfoam sheets by cutting with a scalpel and scissors. Particles were also made of either Spongel or Gelfoam sheets by pumping with two syringes and a three-way stopcock. The size distribution of the particles in saline was compared among the groups.

RESULTS

(1) Cutting versus pumping: When Spongel was used, cutting produced lower rates of smaller particles < or = 500 microm and larger particles > 2000 microm compared with pumping back and forth 30 times (1.1% vs 37.6%, p < 0.0001; 2.2% vs 14.4%, p = 0.008). When Gelfoam was used, cutting produced lower rates of smaller and larger particles compared with pumping (8.5% vs 20.4%, p = 0.1809; 0% vs 48.1%, p < 0.0001). (2) Spongel versus Gelfoam: There was no significant difference in the size distribution of the particles between Spongel and Gelfoam (p = 0.2002) when cutting was used.

CONCLUSION

The size distribution of gelatin sponge particles differed according to the method used to make them. More uniform particle sizes can be achieved by cutting than by pumping.

A Prospective Multicenter Comparative Study between Myomectomy and Uterine Artery Embolization with Polyvinyl Alcohol Microspheres: Long-term Clinical Outcomes in Patients with Symptomatic Uterine Fibroids

PURPOSE

To prospectively evaluate the safety and effectiveness of polyvinyl alcohol (PVA) microspheres in patients undergoing uterine artery embolization (UAE) to treat uterine fibroid tumors and to compare the long-term changes in health-related quality of life (QOL) after UAE with the changes seen after myomectomy.

MATERIALS AND METHODS

One hundred forty-six patients with uterine myomas were enrolled into this multicenter study, with 77 patients undergoing UAE with PVA and 69 patients undergoing myomectomy. Six-month follow-up was completed for the myomectomy, whereas 2-year follow-up was completed for the UAE group. Outcomes were assessed with the Uterine Fibroid QOL Questionnaire and based on adverse event incidence, time to return to normal activity, and changes in tumor symptom scores, QOL scores, and menorrhagia bleeding scores. For the UAE cohort, changes in total uterine volume and dominant tumor size on magnetic resonance (MR) imaging were assessed.

RESULTS

In the UAE cohort, 88.3% of patients experienced a reduction of tumor-related symptoms (increase >or=5 points from baseline measurement) at 6 months, with 75.4% of patients in the myomectomy group experiencing similar improvement. Median QOL questionnaire scores at 6 months were found to be significantly higher in patients treated with UAE (P = .041), with sustained improvement seen at 12 and 24 months. Both procedures resulted in significant reductions in 6-month menorrhagia bleeding scores, with sustained improvement in the UAE cohort at 12 and 24 months. MR imaging at 6 months revealed significant uterine and tumor volume reductions after UAE (P < .05). At least one adverse event occurred in 42% of patients in the myomectomy group, compared with 26% in the UAE group (P < .05).

CONCLUSIONS

UAE performed with PVA microspheres was associated with greater sustained improvements in symptom severity and health-related QOL and with fewer complications compared with myomectomy. Six-month MR imaging data demonstrated significant reductions in uterine and tumor volumes, although the degree of tissue infarction after UAE was not assessed with contrast medium-enhanced MR imaging.

Characterization of acrylic polyamide plastic embolization particles in vitro and in human tissue sections by light microscopy, infrared microspectroscopy and scanning electron microscopy with energy dispersive X-ray analysis

Vascular embolization is a well-established practice for the treatment of tumors and vascular lesions. Rounded beads (microspheres) of various materials (collagen, dextran and trisacryl-polymer-gelatin) were developed to solve problems encountered with earlier versions of embolic material. We performed histochemistry, Fourier transform infrared microspectroscopy and scanning electron microscopy with energy dispersive X-ray analysis on two uterine and one hepatic specimen with unidentified intravascular foreign material, and examined a reference embolization product for comparison. The hematoxylin and eosin stained tissue sections showed multiple foci with unidentified intravascular foreign material and fibrous obliteration of vessel lumens. Only one case had a clinical history of previous embolization but without specifying the material used. One case was submitted for identification of a 'parasite'. The material stained positively with Sirius red and mucicarmine, variably with Masson's trichrome stain and Movat pentachrome, and did not stain centrally with periodic acid Schiff with diastase. Infrared spectrophotometric analysis of the material from all three cases demonstrated the spectrum of acrylic polyamide plastic. A control sample of EmboGold exhibited infrared microspectroscopic spectra similar to the three tissue specimens. Analysis by scanning electron microscopy with energy dispersive X-ray analysis demonstrated some differences in elemental composition between the tissue sections and the selected reference material. To our knowledge, this is the first report of infrared spectrophotometric analysis with scanning electron microscopy with energy dispersive X-ray analysis of an acrylic polyamide plastic embolization product both in vitro and in human histologic tissue sections. In cases lacking appropriate clinical information, identification by these methods and/or a panel of special stains may assist pathologists unfamiliar with this material's light microscopic appearance.

Acquisition of endovascular skills for obstetrician-gynecologists

STUDY OBJECTIVE

To identify skills not part of the training of obstetrician-gynecologists that are needed to perform endovascular procedures, especially uterine artery embolization.

DESIGN

Literature review of known skills necessary to perform endovascular procedures.

RESULTS

Important areas of endovascular skills are as follows. Understanding of the modern C-arm image intensifier is basic to performing endovascular procedures safely for the patient, physician, and others in the procedure room. Many states require physicians to obtain a Fluoroscopy Supervisors Permit when doing such interventions. Arteriotomy begins every endovascular procedure. Physicians must understand catheter manipulation and selection, and the use of microcatheters. An understanding of the pelvic arterial anatomy will help the surgeon identify the uterine arteries. Once in the uterine artery, the surgeon must understand how to successfully embolize the artery. As in any surgery, prevention of complications is important as well as management of complications once they arise.

CONCLUSION

Obstetrician-gynecologists should plan on devoting a year for the acquisition of skills needed to perform endovascular procedures. Methods of acquiring such skills include simulator training, animal laboratory procedures, and observation of live procedures. Didactic courses will give physicians an overview of endovascular procedures.

Limited Uterine Artery Embolization for Leiomyomas with Tris-Acryl Gelatin Microspheres: 1-Year Follow-up

PURPOSE

To assess the safety and efficacy of uterine artery embolization (UAE) using large calibrated tris-acryl gelatin microspheres.

MATERIALS AND METHODS

One hundred fifty-eight women with symptomatic uterine fibroids underwent UAE. Embosphere was used in 105 women and Embogold microspheres in 53 women. Major and minor complications were assessed. At 12 months, relief of symptoms and patient satisfaction were assessed and volume reductions of the uterus and dominant fibroid were calculated.

RESULTS

Median age of the subjects was 43 years (mean, 42.3 y; range, 23-53 y). Preprocedural symptoms were heavy menstrual bleeding in 89%, pain in 64%, and bulk related symptoms in 57%. At 12 months follow-up, the proportion of women with heavy menstrual bleeding, pain, and bulk-related symptoms had decreased to 9%, 8%, and 8%, respectively. Patient satisfaction was grouped as follows: very satisfied 57%, satisfied 36%, and not satisfied 7%. Mean uterine and dominant fibroid volumes before UAE were 532 cm(3) and 201 cm(3), respectively. At 12-month follow-up MR imaging, mean uterine volume decreased to 260 cm(3) and mean dominant fibroid volume to 78 cm(3). These differences were statistically significant (P < .0001). There were no procedure-related deaths. No emergency hysterectomy was needed. Permanent amenorrhea occurred in 11% of women. Transient amenorrhea occurred in 13% of women, and fibroid expulsion occurred in 10% of women. Twelve women (7.6%) had additional therapy: nine underwent additional embolization and three had hysterectomy.

CONCLUSION

Targeted UAE using large calibrated microspheres is safe and effective in the relief of symptoms in the majority of patients. At 12 months, a marked fibroid and uterine volume reduction is obtained.