Comparison of Nonspherical Polyvinyl Alcohol Particles and Microspheres for Prostatic Arterial Embolization in Patients with Benign Prostatic Hyperplasia

Four Ounces Can Move a Thousand Pounds: The Enormous Value of Nanomaterials in Tumor Immunotherapy

The application of nanomaterials in healthcare has emerged as a promising strategy due to their unique structural diversity, surface properties, and compositional diversity. In particular, nanomaterials have found a significant role in improving drug delivery and inhibiting the growth and metastasis of tumor cells. Moreover, recent studies have highlighted their potential in modulating the tumor microenvironment (TME) and enhancing the activity of immune cells to improve tumor therapy efficacy. Various types of nanomaterials are currently utilized as drug carriers, immunosuppressants, immune activators, immunoassay reagents, and more for tumor immunotherapy. Necessarily, nanomaterials used for tumor immunotherapy can be grouped into two categories: organic and inorganic nanomaterials. Though both have shown the ability to achieve the purpose of tumor immunotherapy, their composition and structural properties result in differences in their mechanisms and modes of action. Organic nanomaterials can be further divided into organic polymers, cell membranes, nanoemulsion-modified, and hydrogel forms. At the same time, inorganic nanomaterials can be broadly classified as nonmetallic and metallic nanomaterials. The current work aims to explore the mechanisms of action of these different types of nanomaterials and their prospects for promoting tumor immunotherapy.

Prostatic Artery Embolization: Technical Pearls

Benign prostatic hyperplasia (BPH) is a condition that primarily affects men between the fourth and seventh decades of life, occurring due to enlargement of the prostate which subsequently causes compression of the prostatic urethra causing chronic obstruction of the urinary outflow tract. BPH can cause significant quality-of-life issues such as urinary hesitancy, intermittency, decreased urinary stream, a sensation of incomplete emptying, dysuria, urinary retention, hematuria, and nocturia. Several medical and surgical treatment modalities are available for the treatment of lower urinary tract symptoms and other BPH-related sequela; however, increasingly prostate artery embolization is being utilized in this patient population. Technical demands for this procedure in this population can be significant. This article describes the optimal techniques, tricks, and advanced imaging techniques that can be used to achieve desired technical outcomes.

Prostate artery embolization on lower urinary tract symptoms related to benign prostatic hyperplasia: A systematic review and meta-analysis

BACKGROUND

Prostate artery embolization (PAE) is a promising minimally invasive therapy that improves lower urinary tract symptoms (LUTS) related to benign prostatic hyperplasia (BPH). Transurethral resection of the prostate (TURP) is the gold standard therapy for LUTS/BPH.

AIM

To evaluate the efficacy and safety of PAE vs TURP on LUTS related to BPH.

METHODS

A literature review was performed to identify all published articles on PAE vs TURP for LUTS/BPH. Sources included PubMed, Embase, Cochrane library databases, and Chinese databases before June 2022. A systematic review and meta-analysis were conducted. Outcome measurements were combined by calculating the mean difference with a 95% confidence interval. Statistical analysis was carried out using Review Manager 5.3.

RESULTS

Eleven studies involving 1070 participants were included. Compared with the TURP group, the PAE group had a similar effect on the International Index of Erectile Function (IPSS) score, Peak urinary flow rate (Qmax), postvoid residual volume (PVR), Prostate volume (PV), prostatic specific antigen (PSA), The International Index of Erectile Function short form (IIEF-5) scores, and erectile dysfunction during 24 mo follow-up. Lower quality of life (QoL) score, lower rate of retrograde ejaculation and shorter hospital stay in the PAE group. There was no participant death in either group. A higher proportion of haematuria, urinary incontinence and urinary stricture was identified in the TURP group.

CONCLUSION

PAE may be an appropriate option for elderly patients, patients who are not candidates for surgery, and patients who do not want to risk the potential adverse effects of TURP. Studies with large cases and long follow-up time are needed to validate results.

Nononcologic Embolization

The scope of conditions managed by embolization, which was initially used for the treatment of hemorrhage and vascular malformations, is constantly expanding. Apart from oncologic indications, embolization is used to treat a wide range of benign pathology, including uterine fibroids and benign prostatic hyperplasia. While various particulate embolic agents are successfully used for benign embolization, there is growing evidence that unique properties of these may result in different outcomes. This article reviews available evidence comparing various particles used for uterine fibroid embolization and prostate artery embolization. In addition, we provide an overview of periprocedural pharmacology and protocols facilitating same-day discharge for these interventions.

Particle Distribution in Embolotherapy, How Do They Get There? A Critical Review of the Factors Affecting Arterial Distribution of Embolic Particles

Embolization has tremendously evolved in recent years and has expanded to treatment of a variety of pathologic processes. There has been emerging evidence that the level of arterial occlusion and the distribution of embolic particles may play an important role in the clinical outcome. This is a comprehensive literature review to identify variables that play important role in determination of level of occlusion of blood vessels and distribution of embolic particles. The literature searches between 1996 to 2020 through PubMed and Ovid-MEDLINE yielded over 1030 articles of which 30 studies providing details on the level of occlusion are reviewed here. We divided the playing factors into characteristics of the particles, solution/injection and vascular bed. Accordingly, particle size, type and aggregation, compressibility/deformability, and biodegradability are categorized as the factors involving particles' behavioral nature. Infusion rate and concentration/dilution of the medium are related to the carrying solution. Hemodynamics and the arterial resistance are characteristics of the vascular bed that also play an important role in the distribution of embolic particles. Understanding and predicting the level of embolization is a complex multi-factor problem that requires more evidence, warranting further randomized controlled trials, and powered human and animal studies.

Outcomes of Prostate Artery Embolisation in Patients with Severe Symptoms of Benign Prostate Hyperplasia

Background

Benign prostatic hyperplasia (BPH) is associated with severe lower urinary tract symptoms (LUTS). The severity of LUTS is assessed by the International Prostate Symptoms Score (IPSS). Prostate artery embolisation (PAE) is a newly available method for combating LUTS. This study aims to assess the outcomes of PAE in reducing LUTS and prostate volume in patients with BPH.

Methods

Patients diagnosed with BPH with severe LUTS who had undergone PAE were included. Their IPSS score was ≥ 20 despite medical therapy. PAE was performed via the unilateral femoral artery using various types of embolic material. Bilateral or unilateral embolisation of the prostate artery was considered a technical success. The severity of LUTS pre- and post-PAE were assessed using IPSS while prostate volume pre- and post-PAE were assessed by ultrasound and magnetic resonance imaging (MRI).

Results

Ninety percent of patients had technical success and one required transurethral resection of the prostate (TURP). The mean IPSS reduction at the final follow-up was 12.9 (P < 0.028). The mean reduction of prostate volume at the last follow-up by ultrasound was 114.99 mL (P < 0.028) and by MRI was 29.17 mL (P < 0.028).

Conclusion

PAE is safe and effective in reducing severe LUTS and prostate gland volume in BPH patients.

Superselective vesical artery embolization versus intravesical formalin for intractable hematuria in patients with bladder cancer

OBJECTIVE

Intractable hematuria is a leading critical problem occurring in patients with advanced stage bladder cancer (BCa) that are not suitable for radical cystectomy. The present study, for the first time in the literature, aimed to compare the effectiveness of intravesical formalin (IF) and superselective vesical artery embolization (SVAE) in the management of intractable and life-threatening hematuria in BCa patients.

METHODS

The retrospective study included 40 BCa patients who underwent SVAE or IF treatment due to intractable hematuria after failure of other methods. Patients were divided into two groups based on the procedures administered: SVEA Group (n = 24) and IF Group (n = 16).

RESULTS

The success rate at first-line therapy was 50% (12/24) in SVAE Group and 82% (13/16) in IF Group (p = 0.046). Based on the success rates at first- and second-line therapies, the overall success rate in SVAE Group was 75% and this rate was similar to that of IF Group (p = 0.439). Complication rate was significantly higher in IF patients than in SVAE patients (37.5% vs. 8.3; p = 0.024), whereas duration of postoperative hospital stay was significantly longer in SVAE Group (15.8 vs. 6 days; p = 0.041).

CONCLUSION

The advantages of IF appear to include shorter postoperative hospital stays and higher success rates at a single session, while the advantages of SVAE seem to include non-requirement of spinal/general anesthesia, easy repeatability, and low complication rates. In the management of patients with intractable hematuria, patients' general condition, comorbidities, and anesthesia-related risks should be taken into consideration.

Microspheres present comparable efficacy and safety profiles compared with polyvinyl alcohol for bronchial artery embolization treatment in hemoptysis patients

Background

The present study aimed to compare the efficacy and safety profiles of microspheres versus (vs.) polyvinyl alcohol (PVA) for bronchial artery embolization (BAE) treatment in patients with hemoptysis.

Methods

Totally, 152 patients with hemoptysis who were about to receive BAE treatment were consecutively enrolled and divided into microspheres group (N = 62) and PVA group (N = 90). Technical success and clinical success were assessed after BAE procedure, and the hemoptysis-recurrence status, survival status and adverse events were recorded during follow-up.

Results

Technical success rates were both 100% in microspheres group and PVA group; clinical success rate (96.8% vs. 100.0%, P = 0.165), 6-month (9.7% vs. 7.8%, P = 0.681) and 1-year (9.7% vs. 8.9%, P = 0.869) hemoptysis recurrence rate, 6-month (4.8% vs. 2.2%, P = 0.374) and 1-year (4.8% vs. 3.3%, P = 0.639) mortality were similar between microspheres group and PVA group. Furthermore, hemoptysis-free survival (P = 0.488) and overall survival (P = 0.321) were of no difference between two groups. In addition, all adverse events were mild, and there was no difference of adverse events between two groups (all P > 0.05). These data were validated by further multivariate regression analysis.

Conclusions

Microspheres present comparable efficacy and safety profiles compared with PVA for the BAE treatment in patients with hemoptysis, providing evidence for embolic agent selection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02947-7.

Prostatic artery embolization for giant prostatic hyperplasia: a single-center experience

Objective

To describe the safety and efficacy of prostatic artery embolization (PAE) in patients with a markedly enlarged prostate.

Materials and Methods

This was a retrospective study including 18 consecutive patients (mean age, 74 years) with benign prostatic hyperplasia, all with a prostate volume ≥ 200 cm³, who were enrolled to receive PAE for the treatment of moderate-to-severe lower urinary tract symptoms.

Results

The PAE procedure was technically successful in 17 patients (94.4%). During follow-up, clinical failure (defined as an International Prostate Symptom Score [IPSS] ≥ 8) was observed in two (11.1%) of those 18 patients. At 3 months of follow-up, there was significant improvement over baseline in all relevant outcome measures: total IPSS (from 15.7 to 2.9); IPSS quality of life score (from 5.2 to 1.0); prostate specific antigen (from 11.4 to 1.82 ng/mL); peak urinary flow rate (from 7.45 to 18.6 mL/s); prostate volume (from 252.4 to 151.6 cm³); and post-void residual volume (from 143.7 to 28.3 mL)-p < 0.05 for all. Of the 18 patients, one (5.6%) presented detachment of prostate tissue and self-limited hematuria, which did not require specific treatment.

Conclusion

In patients with a markedly enlarged prostate, PAE proved to be safe and effective, resulting in significant improvements in clinical, imaging, and urodynamic parameters.

Superselective vesical artery embolization versus intravesical formalin for intractable hematuria in patients with bladder cancer

OBJECTIVE

Intractable hematuria is a leading critical problem occurring in patients with advanced stage bladder cancer (BCa) that are not suitable for radical cystectomy. The present study, for the first time in the literature, aimed to compare the effectiveness of intravesical formalin (IF) and superselective vesical artery embolization (SVAE) in the management of intractable and life-threatening hematuria in BCa patients.

METHODS

The retrospective study included 40 BCa patients who underwent SVAE or IF treatment due to intractable hematuria after failure of other methods. Patients were divided into two groups based on the procedures administered: SVEA Group (n=24) and IF Group (n=16).

RESULTS

The success rate at first-line therapy was 50% (12/24) in SVAE Group and 82% (13/16) in IF Group (p=0.046). Based on the success rates at first- and second-line therapies, the overall success rate in SVAE Group was 75% and this rate was similar to that of IF Group (p=0.439). Complication rate was significantly higher in IF patients than in SVAE patients (37.5% vs. 8.3; p=0.024), whereas duration of postoperative hospital stay was significantly longer in SVAE Group (15.8 vs. 6 days; p=0.041).

CONCLUSION

The advantages of IF appear to include shorter postoperative hospital stays and higher success rates at a single session, while the advantages of SVAE seem to include non-requirement of spinal/general anesthesia, easy repeatability, and low complication rates. In the management of patients with intractable hematuria, patients' general condition, comorbidities, and anesthesia-related risks should be taken into consideration.

Prostatic Artery Embolization for Benign Prostatic Hyperplasia: Bleomycin-Eluting versus Bland Microspheres in a Canine Model

PURPOSE

To prospectively assess safety and efficacy of prostatic artery embolization (PAE) with bleomycin-eluting microspheres for benign prostatic hyperplasia (BPH) in a canine model.

MATERIALS AND METHODS

Twelve adult male beagles (mean age, 1.6 y ± 0.2; range, 1.2-2.0 y) were randomly assigned to group A (n = 6; PAE with bleomycin-eluting 30-60-μm HepaSphere microspheres) and group B (n = 6; PAE with bland 30-60-μm HepaSphere microspheres) between April 2017 and November 2018. Plasma bleomycin concentration in group A was measured within 7 days. Prostate volume (PV) and ischemic volume after PAE were measured by magnetic resonance imaging. Prostates and adjacent organs were harvested after the last magnetic resonance study and histopathologically examined.

RESULTS

Plasma bleomycin concentration peaked at 10 minutes at 2,055.0 ng/mL ± 606.1 and lasted for 1,440 min at low levels after PAE. PV reduction percentage was greater in group A than in group B at 1 month (74.1% ± 4.3 vs 63.7% ± 3.5; P = .006) and 3 months (61.5% ± 6.7 vs 46.1% ± 3.8; P = .001) after PAE. Proportion of prostate ischemic volume was greater in group A than in group B (75.3% ± 3.0 vs 62.0% ± 7.1; P = .006) at 1 month after PAE. Proportion of prostate ischemic volume at 1 month positively correlated with PV percentage reduction at 3 months in group A (r = 0.840, P = .036) and group B (r = 0.844, P = .035). There were no complications or nontarget embolization to surrounding organs after the procedures.

CONCLUSIONS

In a canine model, PAE with bleomycin-eluting microspheres was feasible and well tolerated and caused ischemic necrosis and reduction in PV.

Prostatic artery embolization: Progress and prospect

Prostate artery embolization is a well-known and promising treatment for benign prostatic hyperplasia, with the quantum leaps of research in medicine. We aim to provide an up-to-date review of the novel technique, including large retrospective studies and randomized control trials, ends with discussions of advantages and disadvantages of this minimally invasive technique.

Sexual and functional outcomes of prostate artery embolisation: A prospective long-term follow-up, large cohort study

AIM OF THE STUDY

Among minimally invasive procedures for treating benign prostate hyperplasia (BPH) prostate artery embolisation (PAE) is described as safe and effective. Aim of this study is to report our results, focusing on sexual outcomes (erectile and ejaculatory functions sparing) of PAE in patients suffering from bladder outlet obstruction (BOO) secondary to BPH.

METHODS

We prospectively enrolled and submitted to PAE subjects suffering from BOO secondary to BPH. All patients were not suitable for surgery or declined invasive approaches. All subjects were preoperatively and postoperatively (3, 6, 12 and 18 months after) evaluated by urinary flowmetry, post voiding residual volume, prostate volume, serum PSA levels, International Index of Erectile Function, International Prostate Symptom Score and QoL scores.

RESULTS

PAE was performed in 147 patients (mean age 72.5 y.o.). PAE was technically successful in all patients. The procedure lasted a mean time of 94.3 minutes, with a mean fluoroscopic time of 42.5 minutes. Twelve months follow-up data were available for all patients, while 126 patients (85%) completed the 18 months follow up. At 12 months follow up, the mean IPSS and QoL scores significantly decreased, and all the objective parameters (mean Qmax, PVR and prostate volume) reported a significant improvement. A total of 130 patients (88.5%) at 12 months reported the antegrade ejaculation preserved, and a slight not significant improvement of IIEF scores. The 18 months after PAE outcomes confirmed the significant improvement of all the variables evaluated (even for PSA values and IIEF scores). No major complications occurred.

CONCLUSIONS

Our results evidence prostate artery embolisation as highly feasible and safe procedure with interesting outcomes. In particular, in our study PAE reported promising results in preserving antegrade ejaculation and erectile function. Our data are in line with the literature, confirming how PAE reduces obstructive symptoms in BPH patients not suitable or refusing standard surgical approaches.

Effectiveness of Contrast-enhanced MR Angiography for Visualization of the Prostatic Artery prior to Prostatic Arterial Embolization

Background A major technical challenge of prostatic arterial embolization (PAE) is the identification and catheterization of the prostatic arteries (PAs). Recently, MR angiography has been shown to help visualize PAs, but the clinical utility of MR angiography for this purpose is not known. Purpose To determine the efficacy of contrast material-enhanced MR angiography in identifying the PA and to evaluate its role in PAE for benign prostatic hyperplasia (BPH). Materials and Methods In this prospective study, 100 consecutive men who were scheduled to undergo PAE for BPH from January 2015 to May 2017 were assigned by using a randomized block design to either group A (n = 50; mean age, 71.7 years ± 11.9 [standard deviation]) without MR angiography or group B (n = 50; mean age, 72.3 years ± 12.2) with MR angiography prior to PAE. MR angiography findings of the PA anatomy were compared with those of digital subtraction angiography (DSA). The Student t test and Wilcoxon rank-sum test were used to compare the differences between the parameters indicating the performance of PAE. Results The mean age of the 100 men in the study was 72.0 years ± 11.8 (range, 51-88 years). Compared with DSA as the reference standard, MR angiography identified PAs with a sensitivity of 91.5% (97 of 106) and a positive predictive value of 100% (97 of 97). With the knowledge of tube obliquity and anatomy, group B had lower procedure times than group A (82.3 minutes ± 5.4 vs 123.9 minutes ± 12.4, P < .001) and shorter fluoroscopy times (13.8 minutes ± 2.7 vs 28.5 minutes ± 8.0, P < .001). Additionally, radiation dose was reduced for group A versus group B, from a median of 920 to 339 mGy (P = .004). Conclusion Contrast-enhanced MR angiography can accurately show anatomy for the prostate arteries, leading to shorter prostatic artery embolization times and lower radiation dose than when preprocedural prostate MR angiography is not performed. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Prince in this issue.