Patient selection is particularly important in prostatic artery embolisation (PAE) because it can help to reduce the number of patients who do not respond to treatment, and analysing baseline patient characteristics allows radiologists to optimise patient selection and assessment, according to Dr. Tiago Bilhim, a consultant interventional radiologist at Centro Hepato-Bílio-Pancreático e da Transplantação, Hospital Curry Cabral, Lisbon, Portugal.

PAE is one of many treatment options for benign prostatic hyperplasia (BPH). Patient optimisation is fundamental because 10 to 20% of patients do not respond to PAE, even after a bilateral and successful PAE procedure. A drawback of PAE is that the need for further treatment is as high as 20% in up to two years, and lower bladder outlet obstruction (BOO) relief is necessary in some cases.

Fig. 1 A: T2-weighted MRI scan of a 70-year-old patient with acute urinary retention who underwent prostatic artery embolisation (PAE) for benign prostatic hyperplasia (BPH). Note the pedunculated median lobe (solid arrow) and a thickened bladder wall (dashed arrow) on coronal T2-weighted image.

Assessing BOO can easily be measured using non-invasive tests such as bladder ultrasound. Bladder ultrasound allows assessment of bladder wall thickening, diverticula, hydronephrosis, and post-void residual volume (PVR). “All of these measurements using ultrasound provide important insights into the severity of BOO and possible complications related to longstanding untreated BOO,” Bilhim told ECR Today. More invasive urodynamic tests may be required to rule out other causes, such as bladder dysfunction, where PAE is not required. When the PVR is greater than 150 mL, urodynamic studies should be performed to exclude bladder dysfunction as that is a contraindication for PAE, so appropriate patient selection is vital to avoid unnecessary treatment of patients where bladder dysfunction is the cause of BOO, he explained.

“Identifying the ‘ideal’ patient for PAE is an important area of investigation in order to minimise clinical failures after PAE. Younger patients (below 70 years) and patients with acute urinary retention or those with an International Prostate Symptom Score (I-PSS) lower than 25 points tend to respond well to PAE,” noted Bilhim. The I-PSS is a validated symptom score for use in men with lower urinary tract symptoms (LUTS). The severity of lower urinary tract symptoms measured with validated questionnaires such as I-PSS and quality of life related to LUTS (IPSS/QoL) is the starting point to quantify response to treatment.

Fig. 1 B: Axial T2-weighted MR image of same patient depicts bilateral hydronephrosis due to bladder outlet obstruction-BPH. The patient underwent a successful PAE procedure with bilateral embolisation, but removing the bladder catheter was not possible, and the patient needed bailout transurethral resection of the median lobe after PAE (provided by Dr. Tiago Bilhim).

Additional assessments should include erectile, ejaculatory and continence status, prostate volume (PV) measurements with assessment of the median lobe morphology (with transrectal ultrasound [TRUS] or MRI). Bilhim added that patients whose prostates have a central gland to total volume ratio greater than 50%, and those with central gland adenomas of 1cm or greater, also tend to do well after PAE. However, patients with pedunculated median lobes tend not to respond as well to PAE.

Treatment options should be tailored to each patient’s expectations and clinical scenario, and a fundamental element of patient care is counselling patients prior to a procedure, he continued. Patient counselling should be based on the severity of LUTS and BOO.

Bilhim advises that patients with a prostate volume under 40 mL are considered a relative contraindication to PAE, but no upper size prostate volume has been identified for PAE. Bilateral hydronephrosis due to BPH, large bladder diverticula, and bladder stones are indicators of severe BOO that may be considered relative contraindications for PAE, as surgery will allow greater BOO relief. Severe pelvic atherosclerosis/tortuosity may affect the ability to perform bilateral PAE, so can also be considered a contraindication, as unilateral PAE has been proven to be worse than bilateral PAE.

PAE is a complex procedure that should be performed by well-trained interventional radiologists in an angio suite using image guidance, according to session moderator Dr. Hanno Hoppe, a radiologist from Lindenhofspital, Bern, Switzerland. It involves catheterisation of prostatic arteries using a microcatheter and injecting microparticles to block blood flow to the prostate, causing tissue necrosis and eventually reducing the size of the prostate. Radiologists need to understand the underlying aetiology of BPH and treatment options for LUTS, said Hoppe.

Fig. 2 A & B: Elderly patient had benign prostatic hyperplasia and lower urinary tract symptoms with bladder catheter. His infrarenal aorta and iliac arteries are dilated and elongated due to atherosclerosis, as demonstrated on CT angiography reformatted images using volume rendering (A) and maximum intensity projection (B) (provided by Dr. Hanno Hoppe).

He points out the benefits of minimally invasive treatment options such as PAE, which he calls promising, especially in terms of limiting the occurrence of negative side effects. He reckons that in general a CT angiography scan should be acquired prior to PAE to generate an individual road map of each patient’s prostatic arterial supply for planning of the embolisation procedure, and fundamental knowledge of vascular anatomy is essential.

“On one hand, interventional radiologists are advised to maintain excellent interactive collaboration with their clinical partners – namely urologists – and should have the same clinical background and communicate in the same language as urologists,” Hoppe noted. “On the other hand, interventional radiologists should also establish their own consultation time for patient education and consent.”

Over the past 15 years, interventional radiology has emerged into a more clinically oriented specialty, he explained. Interventional radiologists are taking the lead and are key figures in the treatment of conditions affecting men’s health, alongside other specialties. Their ability to advance modern health care with proven, less invasive options such as PAE will contribute greatly to enhanced patient care, he added.

Hoppe is excited about the future, particularly when discussing particle size. “Particle size has yielded contradictory results, and more evidence is required concerning the potential beneficial effects of using smaller sized particles in PAE. However, radiopaque particles may be beneficial for enhanced visibility of embolic agents thus reducing the amount of contrast material,” he said.

Fig. 3 A & B: Elderly patient had benign prostatic hyperplasia and lower urinary tract symptoms with bladder catheter. A microcatheter was positioned in the left prostatic artery. A selective angiogram was performed before and after prostatic artery embolisation using microparticles. Pre-embolisation (A), there is considerable contrast blush of prostatic parenchyma (arrows). Post-embolisation (B), there is sluggish flow of contrast within the prostatic artery without parenchymal blush (arrow heads) (provided by Dr. Hanno Hoppe).

He also has high hopes for balloon-occlusion PAE, which he says is proposed to be a safe and effective procedure that can prevent reflux of embolic agents to pelvic arteries and helps to minimise embolisation to surrounding organs by creating a negative pressure inside the prostatic vasculature with reversal of blood flow through arterial anastomoses.

He insists that profound knowledge of benign BPH aetiology, symptoms, anatomy of prostatic arterial supply, and various treatment options is mandatory for radiologists when it comes to PAE.

LIVE
Special Focus Session
, Wednesday, July 15, 14:00–15:00
SF 2a Prostate embolisation

  • Chairperson’s introduction: New developments in managing benign prostatic disease
    Hanno Hoppe; Berne/CH
  • Patient selection and assessment
    Tiago Bilhim; Lisbon/PT
  • Anatomy, imaging and planning
    Charles Tapping; Oxford/UK
  • Embolisation technique
    Attila Kovács; Lübeck/DE
  • Outcome and results from trials
    Florian Wolf; Vienna/AT
  • Live Q&A: New developments in managing benign prostatic disease

FURTHER READING

Malling B, Røder MA, Brasso K, Forman J, Taudorf M, Lönn L (2019) Prostate artery embolisation for benign prostatic hyperplasia: a systematic review and meta-analysis. Eur Radiol. 29(1):287-298: european-radiology.org/5564

Lin YT, Amouyal G, Correas JM et al (2016) Can prostatic arterial embolisation (PAE) reduce the volume of the peripheral zone? MRI evaluation of zonal anatomy and infarction after PAE. Eur Radiol. 26(10):3466-73: european-radiology.org/4177

Vega J, Cobos J, Morales Garcia M, Vicente Martín JM, Meilán Hernández E, Angulo Cuesta J (2018) Prostatic artery embolization for symptomatic benign prostatic hyperplasia: results from a single-center prospective study. ECR 2018 / C-3149: myESR.org/183149

Largo Flores P, Vivancos Costaleite KH, Cuesta Perez JJ, Mingo Basail A, Friera A (2016) Prostatic Artery Embolization (PAE) for patients with high surgical risk, prostatic hyperplasia and users of permanent urinary catheter. ECR 2016 / C-1748: myESR.org/161748sds