Prostate Artery Embolization
Prostatic Artery Embolization (PAE) is presently considered for individuals with moderate to severe lower urinary tract symptoms due to benign prostatic obstruction. This consideration arises when medications have not yielded satisfactory results or when patients find these medications intolerable due to side effects. Generally, treatment is recommended for prostate glands with volumes of 40 mL or larger. Specific inclusion criteria may vary among published studies, but as a general guideline, patients should exhibit moderate to severe lower urinary tract symptoms (IPSS ≥13–18 and quality-of-life score ≥3) and demonstrate reduced urinary flow (Qmax rate <12–15 mL/sec) or recent urinary retention.
Mechanism of PAE in BPH Treatment
| Mechanism of PAE in BPH Treatment | Description | Clinical Implications |
|---|---|---|
| Ischemic Necrosis | Induces ischemic necrosis and apoptosis in the prostate | Leads to shrinkage of the prostate gland due to ischemic cell death |
| Ischemic Apoptosis | Ischemia-induced apoptosis as a mechanism of prostate ablation | Prostate shrinkage due to extensive apoptosis |
| Androgen-Related Apoptosis | Blocking the androgen-signaling axis by terminating blood supply to the prostate | Reduction in intraprostatic testosterone and DHT levels, leading to apoptosis and subsequent prostate shrinkage |
| Intraprostatic Denervation | Interruption of the functional androgen-signaling axis, affecting smooth muscle tone | May contribute to relief of LUTS/BPH symptoms even before significant prostate volume reduction occurs |
| Decreased a1-Adrenergic Receptors | Possible decrease in the number of a1-adrenergic receptors, leading to decreased muscle tone and reduced urinary outflow obstruction | May contribute to immediate improvement in urinary flow after PAE |
| Smooth Muscle Relaxation | PAE may mimic the effect of medications (a1-blockers) used for BPH in relaxing smooth muscle | Patients may experience a softer and smoother prostate on digital rectal examination after PAE |
| Nitric Oxide (NO) Pathway Activation | Immediate increase in intraprostatic levels of nitric oxide (NO) following PAE | NO plays a pivotal role in the relaxation of prostate smooth muscle, potentially contributing to transient symptom relief |
| Parameter | Keypoint |
|---|---|
| Anatomical variation | 1. Type I - inferior vesicle artery (IVA) and superior vesical artery (SVA) trunk originates from the anterior division of the IIA (internal iliac artery). 2. Type II - IVA inferior to the SVA, both descending from the anterior division of the IIA. 3. Type III - the IVA arises from the obturator artery. 4. Type IV - the IVA originates from the internal pudendal artery (collateral supply to rectum can be present - can lead to non target embolization). 5. Type V - rare variants (like origin from posterior division of IIA, inferior epigastric artery, accessory pudendal artery) |
| Blood supply | Dual supply in a single lobe can be seen in nearly half of patients |
| Indications | 1. For patients with prostate volume > 40 ml 2. Moderate to severe LUTS, IPSS ≥ 13-18 and quality of life ≥ 3 3. Decreased urine flow rates Qmax < 12-15 ml/sec 4. Acute urinary retention 5. Intravesical prostate protrusion (IPP) >1.5 cm 6. Prostatic urethral angle (PUA) >35° 7. At least 6 months of medical management taken by patient for BPH |
| Contraindications | 1. Malignancy 2. Renal insufficiency 3. Large bladder diverticula 4. Bladder stone 5. Neurogenic bladder 6. Neurological disease effecting bladder function 7. Detrusor Failure 8. Urethral stricture 9. Active urinary infection 10. Prostatitis |
| Route | 1. Trans-radial - safer with less complications, decreased procedure time, use of contrast material and better patient compliance 2. Transfemoral |
| Foley's catheter | Optional, Used as landmark for prostatic artery identification. Can be removed the next day to procedure if no urinary retention is observed. |
| Angulation (Fluoroscopy) | 1. Separate anterior and posterior division of internal iliac artery - 35-55 degree ipsilateral and 10 degree craniocaudal |
| Cone-Beam CT | 1. Performed after nitroglycerine administration - confirms perfusion of prostate |
| Embolizing material | 1. Polyvinyl alcohol particles (PVA) 2. Tris-Acryl gelatin microspheres 3. Hydrogel microspheres with proprietary coating Most common size used is 300-500 μm, larger particles cause proximal occlusion and smaller particles cause distal occlusion with better necrosis but also more complications |
| Techniques | 1. Slow infusion of dilute particles to achieve a complete embolization 2. Proximal embolization first then embolize distal (PErFecTED) - proximal embolization performed from mid prostatic artery till near stasis is achieved and later microcatheter is advanced. 3. Coil embolization of potential non-target vessel to reduce risk of non-target embolization 4. Balloon occlusion - prevent reflux in proximal branch and reduces pressure thereby causing flow reversal through prostatic anastomosis |
| Follow up | 1. Symptom scores 2. Prostate gland volume 3. PSA level 4. Urine flow studies at 1 and 3 months |
| Previous Medications | 1. 5-α-reductase inhibitors - Stop prior to procedure 2. α-adrenergic blockers - wean off medication after 1 month follow up |
| Non-target embolization | Penis, rectum and bladder |
| Minor Complications | 1. Post - embolization syndrome - anti-inflammatory drugs or non-steroidal anti-inflammatory drugs (NSAIDs) such as Ibuprofen 2. Dysuria - Analgesia such as Tramadol 3. Urinary tract infection - Broad-spectrum antibiotic against gram-negative bacteria, such as third-generation Cephalosporins 4. Hematuria (accidental embolization of posterior wall of the urinary bladder) - self-limiting 5. Hematospermia (accidental embolization of the seminal vesicles) - self-limiting |
| Publications | Link |