A total of 33 of 62 (53%) patients on catheter treatment achieved catheter freedom. At the 24-month follow-up, they continued to enjoy ‘catheter freedom’ and had a median IPSS of 9 points. However, some patients required additional procedures or a repeat PAE, and, in one patient, an open adenoma enucleation (Millin) was necessary because of the large prostate volume (211 mL) (Table 4).

The observed reduction in prostate volume after PAE varied significantly across patients, as indicated by the wide range of percentage reductions and standard deviations. At 3 months, the median reduction in prostate volume was 11% in the LUTS group and 27% in the urinary retention group. By 24 months, these reductions increased to 20% and decreased to 9%, respectively, with considerable variability (Tables 3 and 4).

The pre-treatment medication profile revealed that most patients were on medication: 68% were taking an α-blocker, and 92% were on a 5α-reductase inhibitor, eight patients did not have pre-medication. Notably, the subgroup of patients who later required further intervention had a different pre-treatment medication profile and a slightly higher median PSA level, suggesting a possible influence of these factors on treatment outcomes (Table 2).

Figure 2. PAE procedure (a). Pre-embolization angiography of the right prostate artery. (b) Pre-embolization angiography of the left prostate artery showing contrast partially filling the left half of the prostate, which was already affected by the embolisation of the right side. (c) Post-embolization angiography demonstrating no contrast filling in the prostate and a small backflow, indicating successful embolisation of both sides.

No direct major complications (Clavien-Dindo ≥3) were reported. However, three patients experienced haematuria following the PAE procedure, with cystoscopy revealing bladder cancer in two cases. Six patients presented directly to the urology department within the first 2 days post-PAE, reporting pain and irritative urinary symptoms, which were considered part of post-embolisation syndrome. These patients were managed with a 5-day course of prednisolone at 25 mg/day.

Discussion

Our study demonstrated that PAE significantly reduces IPSS scores by a median of 7 points at 24 months post-procedure and achieves catheter freedom in 53% of patients. The procedure was performed efficiently using left radial arterial access.

In our study, two primary outcome measures were used to assess the efficacy of PAE: a reduction in the IPSS by three points and the removal of the catheter (catheter freedom). These two measures, while related, reflect different aspects of patient improvement and highlight varying levels of clinical success. The reduction in the IPSS by three points, while widely used in studies as a measure of symptomatic relief, may be considered a weaker measure of success. This MCID does not always capture the full scope of patient improvement and can result in a higher reported success rate, as seen in our study, where 79% of patients achieved this threshold, but it is worth noting that this was achieved by a significant margin, with a median IPSS decrease of 10 points. However, this outcome primarily reflects symptomatic relief rather than significant functional improvements.

In contrast, catheter removal (catheter freedom) is a stronger measure of clinical success, particularly in patients with urinary retention. Achieving catheter freedom indicates a meaningful functional improvement in the resolution of urinary retention. In our cohort, 53% of patients who required a catheter pre-PAE achieved catheter freedom at 24 months, reflecting a more substantial clinical outcome.

In this group of patients undergoing PAE, a high percentage of patients had been on α-blockers and 5α-reductase inhibitors for a minimum of 6 months before the procedure; only eight patients did not have pre-medication. One may hypothesise that the additive effect of PAE combined with pre-PAE treatment using α-blockers and, more specifically, 5α-reductase inhibitors may improve the clinical success of the procedure. Cardarelli et al. examined the 12-month post-PAE outcomes in patients using 5α-reductase inhibitors during PAE and found that these drugs did not impact the outcomes [27]. By contrast, our findings hint at an additive benefit of PAE in those previously medicated with α-blockers and 5α-reductase inhibitors. This difference in findings raises the question as to whether there is a synergistic effect between PAE and pretreatment medications. If so, this suggests a potential combined advantage that merits further exploration. While no patient has started medication again in the available follow-up data of this group, we believe it is worth considering whether continuing medical treatment after PAE can decrease symptom recurrence and/or reduce the need for additional interventions, especially in fragile patients who are not surgical candidates.

The patient group that required additional therapeutic interventions had a median prostate volume of 100 mL (SD = 44 mL). Since the European Association of Urology (EAU) guidelines recommend transurethral surgery for volumes <80 mL [28], an integrated approach involving PAE followed by TURP or other minimally invasive treatment may be considered for those with a larger prostate. However, this requires further validation before being recommended as an alternative to open adenoma enucleation. Bohlok et al. reported that transurethral enucleation of the prostate is a promising treatment option as an alternative to the open approach [29].

The PAE procedure does not require the interruption of anticoagulant treatment because the risk of peri-operative prostate bleeding is inherently not high, but this side effect is known to be a major concern with TURP, even with the latest advances in the techniques to mitigate the bleeding risk [30].

The reduction in prostate volume after PAE is thought to contribute to symptomatic relief by relieving pressure on the urethra [31, 32]. However, in our study, the extent of volume reduction did not always correlate directly with clinical success, as patients with substantial symptomatic improvement did not always show significant reductions in prostate size. This highlights the fact that PAE’s therapeutic effects may be more complex than simple volume reduction, potentially involving other mechanisms.

Additionally, the variability in prostate volume reduction (e.g. from minimal changes to reductions as high as 43%) may reflect differences in individual patient anatomy, degree of atherosclerosis, or the technical challenges encountered during the procedure. This suggests that while prostate volume reduction can indicate PAE efficacy, it should be interpreted in the context of other clinical outcomes.

Our data touch upon the potential influence of the median lobe on PAE outcomes. Contrary to the prevailing hypotheses, the presence or absence of a pronounced median lobe was not associated with poor clinical outcomes. Our findings appear to differ from those of Yu et al., who found a significant correlation between intravesical prostatic protrusion (IPP) and the outcome of PAE [33]. Although the study by Yu et al. suggests that the presence of the median lobe or IPP plays a negative role in PAE success, our data suggest a more nuanced perspective by implying that the influence of median lobe volume on PAE success may be more complex than previously thought. Differences in patient selection, treatment protocols, or follow-up durations between studies could account for these discrepancies. It is also worth mentioning that other minimally invasive treatment options are known to have a restricted effect on the median lobe [34].

In addition to reduction in prostate volume, the assessment of the IPSS yields additional insights. Notably, a considerable decrease in IPSS following PAE within the group experiencing clinical success signifies reduced symptoms. Nevertheless, there was a progressive increase in IPSS over time for some individuals, which implies the potential resurgence of symptoms or the requirement for supplementary interventions. This pattern is apparent in patients who subsequently underwent transurethral procedures, which underscores the effects of patient attributes and the potential advantages of taking an integrated approach in specific situations.

Among the nine cases of technical failure, the primary cause was severe atherosclerosis, which complicated the catheterisation of the prostatic arteries. In retrospect, these patients could have been excluded during the pre-procedural CT angiography, as significant atherosclerosis and tortuosity were apparent but underestimated regarding procedural feasibility. Additionally, one case was due to high body mass index (BMI), which complicated imaging by requiring a higher radiation dose for sufficient imaging quality. Another failure occurred due to extreme arterial tortuosity, with no catheter long enough available at the time. These patients were excluded from the analysis, as they did not undergo a successful embolisation, and thus, an intention-to-treat approach was not applied. Including these patients would not provide insight into the therapeutic efficacy of PAE itself but rather into the feasibility of the procedure in patients with challenging profiles.

These findings highlight the need for refining selection criteria during pre-procedural assessment and the steep learning curve associated with this technically demanding procedure. As operators gain more experience, better patient selection and procedural adjustments can help mitigate such challenges in the future.

Upon contacting patients for follow-up, some were unreachable, while others declined, feeling well and seeing no need for further visits. Additionally, a few patients faced unrelated health issues, such as two who were diagnosed with bladder cancer and one with a brain tumour. Sadly, two patients passed away – one due to an accident and another from pneumonia 1.5 years post-PAE. These factors contributed to the challenge of maintaining consistent follow-up, which may have influenced the overall assessment of PAE outcomes.

While our study shows significant symptom relief short to mid-term post-PAE, longer-term follow-up is necessary to determine the durability of these outcomes and to monitor for any late-onset complications.

Strengths and limitations

This study’s strengths include its single-centre design, which ensures consistency in procedural techniques and follow-up protocols, and radial artery access, which may reduce access-related complications. However, the study’s retrospective nature introduces potential biases, and the 18% loss to follow-up may limit the generalizability of our findings. Additionally, the absence of post-PAE cystometry data restricts our ability to assess changes in bladder dynamics following the procedure fully. Future prospective studies with standardized follow-up protocols are needed to validate these results and better understand the mechanisms underlying PAE’s therapeutic effects.

Despite these limitations, this study provides valuable insights into our early experience with introducing a new treatment approach at a single centre. Initially, patients were admitted overnight for observation, but we transitioned to an outpatient model. Many patients had experienced prolonged periods of discomfort and faced long waiting times for surgery, which may have influenced the outcomes and interpretations of our patients. Nevertheless, integrating PAE into our treatment options offers a less invasive alternative that can help reduce surgical wait times and alleviate systemic pressures, particularly in the wake of the COVID-19 pandemic. As more data become available, we anticipate refining patient selection criteria to offer more tailored and effective treatment plans. Although the data for patients who were lost to follow-up initially provided some insights, the absence of subsequent data poses a challenge in drawing definite conclusions from this patient subset.

Conclusions

PAE resulted in substantial reduction in IPSS in vast majority of patients with LUTS and catheter freedom in majority of patients who were catheter dependent.

This outcome provides a stronger indication of PAE’s therapeutic impact.

However, the data described here are preliminary findings and should be interpreted cautiously until more comprehensive research is conducted to confirm and build upon these observations.

Acknowledgments

We extend our gratitude to the radiology and urology departments at Central Hospital Västerås for their support and contributions to this study. We also give special recognition to our statistician, Philippe Wagner, and our urology research nurse, Taraneh Nikberg, for their invaluable assistance and dedication to this project.

Disclosure statement

The authors report no conflicts of interest.

Funding

This study was supported by the Centre for Clinical Research (CKF) in Region Västmanland.

ORCID

Emir Majbar, https://orcid.org/0000-0003-0129-3485

Jakob Swanberg, https://orcid.org/0000-0003-2610-9891

Farhood Alamdari, https://orcid.org/0000-0003-3589-7789

Abbas Chabok, https://orcid.org/0000-0001-9662-5045

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