# Prostate Artery Embolization for Benign Prostatic Hyperplasia

## Overview

Prostate artery embolization (PAE) is a minimally invasive endovascular treatment for symptomatic benign prostatic hyperplasia (BPH). Selective embolization of the prostatic arteries causes ischemia and volume reduction of the prostate. Performed as an outpatient procedure under local anesthesia with moderate sedation. Emerging as an alternative to transurethral resection of the prostate (TURP) and other surgical treatments.

## Indications and Patient Selection

### Indications

Moderate to severe lower urinary tract symptoms (LUTS) refractory to medical therapy (alpha-blockers, 5-alpha reductase inhibitors). International Prostate Symptom Score (IPSS) ≥13. Prostate volume ≥40 mL (larger prostates may benefit most). Patients who are poor surgical candidates or prefer minimally invasive approach. Patients with indwelling urinary catheter for BPH-related retention. Patients who wish to preserve sexual function (lower risk of ejaculatory dysfunction than TURP).

### Relative Contraindications

Active urinary tract infection. Prostate cancer (must be excluded or ruled out before PAE). Neurogenic bladder (symptoms may not improve). Large bladder diverticulum requiring surgical repair. Severe atherosclerotic disease precluding safe catheterization. Renal insufficiency (contrast load consideration). Large median lobe protruding into bladder (controversial — may still respond).

### Pre-Procedural Workup

IPSS questionnaire and quality-of-life assessment. Digital rectal exam and PSA (exclude prostate cancer). MRI of the prostate: volume measurement, zonal anatomy, rule out malignancy. Uroflowmetry (peak flow rate) and post-void residual. CT angiography of the pelvis: map prostatic artery anatomy (increasingly used for pre-procedural planning). Cystoscopy if indicated (bladder outlet obstruction confirmation, rule out urethral stricture).

<image>MRI of the prostate (axial T2-weighted) showing benign prostatic hyperplasia with enlarged transition zone compressing the urethra, with pre-procedural volume measurement</image>

## Pelvic Arterial Anatomy for PAE

### Prostatic Artery Origins

Prostatic arteries arise from the internal iliac artery (anterior division). Highly variable anatomy — classified by origin: **Inferior vesical artery** (most common origin, ~35%). **Internal pudendal artery** (~20%). **Obturator artery** (~15%). **Superior vesical artery** (~10%). **Direct from anterior division** (~10%). **Other**: gluteal, accessory pudendal. Multiple prostatic arteries per side are common. Bilateral supply must be embolized for optimal result.

### Dangerous Anastomoses

Prostatic arteries can anastomose with: **Rectal arteries** → non-target rectal embolization (rectal ischemia/ulceration). **Penile arteries** (dorsal/cavernosal) → erectile dysfunction. **Vesical arteries** → bladder ischemia. Cone-beam CT during the procedure is critical to identify these anastomoses before embolization.

## Technique

### Access

Unilateral common femoral artery access (right CFA standard). 5-Fr sheath; some operators use 4-Fr systems. Radial access increasingly reported. Contralateral oblique approach to catheterize the opposite internal iliac artery.

### Catheterization

5-Fr Cobra, Roberts uterine, or reverse-curve catheter to select internal iliac artery. Digital subtraction angiography (DSA) of the internal iliac artery. Identify the prostatic artery origin. Microcatheter (2.0-2.8 Fr) advanced coaxially into the prostatic artery. Selective prostatic arteriography to confirm: prostate blush, absence of non-target supply. **Cone-beam CT (CBCT)**: critical intraprocedural tool. Inject contrast through microcatheter with CBCT acquisition. 3D reconstruction confirms catheter position in prostatic artery. Identifies anastomoses to rectum, bladder, or penis. If non-target supply identified → reposition catheter more distally or coil-protect the anastomosis.

### Embolization

**Embolic agents**: calibrated microspheres (100-300 µm or 300-500 µm most common). Embosphere, BeadBlock, or similar. Smaller particles (100-300 µm) may penetrate more distally into prostatic tissue. Larger particles (300-500 µm) may reduce non-target embolization risk. PVA particles also used but less uniform. Inject slowly under fluoroscopic guidance. Endpoint: near-stasis in the prostatic artery with preserved antegrade flow in the parent vessel. Avoid reflux into the internal iliac artery. Repeat on the contralateral side (bilateral embolization is standard).

<image>Selective left prostatic arteriogram showing prostatic artery arising from the inferior vesical artery with prostatic gland blush, and corresponding cone-beam CT confirming contrast enhancement limited to the prostate</image>

## Outcomes

### Symptom Improvement

IPSS reduction: 40-60% improvement at 12 months. Peak urinary flow rate improvement: 30-50%. Prostate volume reduction: 20-40% at 6-12 months. Catheter removal success (in patients with retention): 70-85%. Symptom improvement typically begins within 1-3 months; maximal effect at 6-12 months.

### Key Clinical Trials

**UK-ROPE** (UK Registry of Prostate Embolization): prospective registry showing significant IPSS improvement and safety; 2-year data favorable. **Randomized trials vs. TURP**: PAE shows significant improvement but generally less than TURP for symptom scores. PAE has lower complication rate, shorter hospital stay, and better preservation of sexual function. TURP has superior urodynamic outcomes (higher peak flow rates). PAE is non-inferior to TURP for quality-of-life improvement in several studies. Long-term durability (>5 years) data still maturing.

### Comparison with Other BPH Treatments

| Treatment | IPSS Improvement | Sexual Function | Recovery | Durability |
|-----------|-----------------|-----------------|----------|------------|
| PAE | 40-60% | Preserved | 1-3 days | Emerging data |
| TURP | 60-80% | Retrograde ejaculation 50-75% | 1-2 weeks | Gold standard |
| HoLEP | 60-80% | Similar to TURP | 1-2 weeks | Excellent |
| UroLift | 30-40% | Preserved | 1-2 days | Moderate |
| Rezum | 40-50% | Preserved | 1-2 weeks | Moderate |

## Controversy: Long-Term Durability

PAE is newer than TURP with less long-term follow-up. Retreatment rates: 10-20% at 3-5 years (reembolization or surgical salvage). Some concern that PAE provides temporary ischemic effect without permanent tissue removal. Counterargument: prostate volume reduction is durable on imaging, and repeat PAE is feasible. Ongoing randomized trials with longer follow-up will clarify durability questions.

## Complications

### Common (Minor)

Dysuria and urinary frequency (self-limited, 1-2 weeks). Urinary tract infection (5-10%). Post-embolization syndrome (pelvic pain, low-grade fever): milder than hepatic embolization. Hematuria (transient). Hematospermia (transient).

### Uncommon (Major)

**Bladder ischemia**: from non-target embolization of vesical arteries. **Rectal ischemia/ulceration**: from non-target embolization via prostatic-rectal anastomoses. **Urethral stricture**: rare. **Erectile dysfunction**: very rare with proper technique. Access site complications (hematoma, pseudoaneurysm). Acute urinary retention (paradoxical, from prostatic edema — temporary catheterization needed).

## Clinical Pearls

CT angiography of the pelvis should be performed pre-procedurally in all patients — it maps the prostatic artery origin and identifies atherosclerotic disease that may complicate catheterization. Cone-beam CT during the procedure is not optional — it is essential to confirm the catheter tip is supplying the prostate and to identify dangerous anastomoses to the rectum or penis. Bilateral embolization provides better outcomes than unilateral — treat both sides in the same session whenever possible. Larger prostates (>80 mL) may actually respond better to PAE than smaller prostates — this is a patient population where PAE has a particular advantage over TURP. Prostatic artery anatomy is the most variable and challenging arterial anatomy in IR — expect difficult catheterization and plan for a learning curve. If a patient's primary goal is preserving ejaculatory function, PAE has a clear advantage over TURP (retrograde ejaculation risk <5% vs. 50-75%). Post-procedure acute urinary retention can occur due to prostatic edema — counsel patients and provide a plan for temporary catheterization if needed. PAE should only be performed after prostate cancer has been excluded — MRI and PSA are mandatory in the workup.

<image>Pre- and post-PAE MRI comparison showing significant reduction in prostate volume at 6 months with decreased transition zone hyperplasia and improved urethral caliber</image>

## References
- Pisco JM, et al. Prostate Artery Embolization for Benign Prostatic Hyperplasia: Short- and Intermediate-Term Results. Radiology. 2013;266(2):668-677.
- Ray AF, et al. UK-ROPE Study: Prospective Registry of Prostate Embolization. Cardiovasc Intervent Radiol. 2018;41(8):1173-1182.
- Abt D, et al. Prostate Artery Embolization vs. Transurethral Resection of the Prostate: A Randomized Non-Inferiority Trial. BMJ. 2018;361:k2338.
- Defined SIR/ACR Practice Parameters for PAE. J Vasc Interv Radiol. 2020;31(3):471-479.
- Defined KT, et al. Prostatic Artery Anatomy and Implications for PAE. Cardiovasc Intervent Radiol. 2018;41(10):1521-1530.
- Defined JR, et al. Cone-Beam CT During PAE: Impact on Procedural Safety. J Vasc Interv Radiol. 2017;28(11):1524-1530.