Prostate Artery Embolization (PAE)

Prostate Artery Embolization (PAE) is a minimally invasive endovascular procedure employed for the treatment of benign prostatic hyperplasia (BPH). It involves the selective catheterization and occlusion of the prostatic arteries, thereby inducing an ischemic state within the prostate gland.

BPH is characterized by the non-malignant proliferation of prostatic glandular and stromal tissue, resulting in the progressive enlargement of the prostate gland. These individuals frequently experience lower urinary tract symptoms (LUTS) stemming from the mechanical obstruction imposed by the enlarged prostate on the urethra. LUTS can manifest as obstructive symptoms, irritative symptoms, or a combination of both. Obstructive symptoms primarily encompass hesitancy, weak urinary stream, intermittency, straining to void, and a sensation of incomplete bladder emptying. Irritative symptoms, on the other hand, encompass urgency, frequency, nocturia (excessive urination at night), and urgency incontinence (involuntary urine leakage accompanied by a strong desire to urinate).

In addition to LUTS, patients may also present with complications resulting from BPH. These complications may include urinary retention, recurrent urinary tract infections (UTIs), bladder stones, and renal dysfunction secondary to obstructive uropathy.

The embolization process provokes a series of physiological responses, including local tissue inflammation, subsequent necrosis, and fibrosis. These changes promote a reduction in the size of the prostate gland and alleviate the symptoms associated with BPH. Moreover, the procedure preserves the integrity of the neurovascular bundles adjacent to the prostate, reducing the risk of potential complications such as erectile dysfunction and urinary incontinence.

PAE presents an interventional approach that would otherwise treat BPH through surgical interventions including Transurethral Resection of the Prostate (TURP), open prostatectomy, laser enucleation techniques, Transurethral Incision of the Prostate (TUIP), or prostatectomy.

A&I Protocol

Pre-procedure:

A software program on the angiography system (e.g. VesselNavigator, Philips Healthcare) can be used to work-up a pre-existing Prostate CTA (computed tomography angiogram) for fusion with the live fluoroscopy.
The vessels of interest (including the aortic bifurcation, left and right common iliac arteries, internal iliac arteries and prostatic arteries) are segmented and selected.

Patient Preparation:

Upon arrival of the patient in the angiography suite, the IR or nurse will perform a Modified Allen’s Test to check the arterial blood flow to the left hand for potential percutaneous Radial artery access. The radiographer will scan under ultrasound to check for radial artery patency. If both tests are passed then the patient will be positioned on the foot end of the table for a radial puncture.
When the patient is on the angiography table and has been attached to monitoring, the radiographer can perform an on-table, non-contrast (injector coupling disabled) CBCT (cone-beam CT) prior to sterile draping.
This non-con CBCTcan be used to register with the work-up CTA volume by matching 3 anatomical landmarks.
When the c-arm is in position over the abdomen and pelvis the Live Guidance will show the 3D vessels as an overlay to the live fluoroscopy.
ALTERNATIVE ACCESS - If the patient fails the Modified Allen’s Test, right femoral artery access is preferred. The patient is positioned on the head end of the angiography table. On table, non-contrast XperCT is performed prior to sterile draping for use with VesselNavigator. At the end of the procedure, a closure device is used to seal the right femoral artery access.

Radial approach:

Seldinger technique is used to gain access into the left radial artery.
A 5F C2 catheter is checked with fluoroscopy from the axilla to aortic arch and down the abdominal aorta.
Once the detector is over the abdominal area, the Live Guidance will show the 3D vessel overlay.
The 3D vessel overlay is used to gain access into the left internal iliac artery and anterior branch.
A long 150cm+ 1.3F or 0.016" microcatheter and 190cm 0.014" wire are used. A long support catheter (0.0018") can also be used.
DSA is acquired to demonstrate the left prostatic artery and its origin, either in PA or oblique. Example injections are 16mL @ 4mL/s and 12mL @ 4mL/s.
This is used as a roadmap and live fluoroscopy is digitally zoomed.
Following microcatheter selective catheterization of the left prostatic artery, a contrast CBCT is performed to confirm catheter position and prostatic artery supply into the left hemisphere of the prostate. This is also to exclude any non-target vessels. Example CBCT injection is 8s X-ray Delay, 0.4mL/s and 14s Injector Delay.
If the contrast CBCT scan shows optimal position and supply, then embolization using Embozene 250µm x 2mL (followed by Embozene 400µm x 2mL if indicated) is to commence on the left prostatic artery.
NOTE: Anatomical variants may present more than one left prostatic artery supply. Therefore, more than one DSA run and CBCT scan may be used.
During embolization, the interventional radiologist may request for digitally zoomed live fluoroscopy, sometimes high fluoroscopy dose and may request between DSA and Single Shot imaging.
After the left prostatic artery is embolized, the 3D vessel overlay is again used to guide the access into the right internal iliac artery and anterior branch.
DSA is acquired to demonstrate the right prostatic artery and its origin, either in PA or oblique. Example injections are 16mL @ 4mL/s and 12mL @ 4mL/s.
This is used as a roadmap and live fluoroscopy is digitally zoomed.
Following microcatheter selective catheterization of the right prostatic artery, an contrast CBCT is performed to confirm catheter position and prostatic artery supply into the right hemisphere of the prostate. This is also to exclude any non-target vessels.
If the contrast CBCT scan shows optimal position and supply, then embolisation using Embozene is to commence on the right prostatic artery.
NOTE: Anatomical variants may present more than one right prostatic artery supply. Therefore, more than one DSA run and CBCT scan may be used.
During embolization, the interventional radiologist may request for digitally zoomed live fluoroscopy, sometimes high fluoroscopy dose and may request between DSA and Single Shot imaging.
After the right prostatic artery has been embolized, X-rays are turned off and accessed is removed from the left radial artery (TR band used).

DSA run showing an overview of the left internal iliac artery branches, including the Superior Vesical Artery (SVA), Prostatic Artery, Obturator artery, Internal Pudendal artery, Superior Gluteal artery (SGA), and Inferior Gluteal Artery (IGA).

DSA run showing contrast flowing into the left Prostatic Artery, as the microcatheter position for embolization.

Right internal iliac (RII) angiogram showing an overview of the RII branches, including the Superior Vesical Artery (SVA), Prostatic Artery, Obturator artery, Internal Pudendal artery, Superior Gluteal artery (SGA), and Inferior Gluteal Artery (IGA).

Right Prostatic Artery angiogram, showing contrast flowing into the right hemisphere of the prostate and final microcatheter position for embolization.

References

Teichgräber U, Aschenbach R, Diamantis I, von Rundstedt FC, Grimm MO, Franiel T. Prostate Artery Embolization: Indication, Technique and Clinical Results. Rofo. 2018 Sep;190(9):847–55.
Young S, Golzarian J. Prostate Artery Embolization: State of the Evidence and Societal Guidelines. Tech Vasc Interv Radiol. 2020 Sep;23(3):100695.
Noor A, Fischman AM. Prostate Artery Embolization as a New Treatment for Benign Prostate Hyperplasia: Contemporary Status in 2016. Curr Urol Rep. 2016 Jul;17(7):51.
Powell T, Kellner D, Ayyagari R. Benign Prostatic Hyperplasia: Clinical Manifestations, Imaging, and Patient Selection for Prostate Artery Embolization. Tech Vasc Interv Radiol. 2020 Sep;23(3):100688.
Davis C, Golzarian J, White S, Fischman A, Rastinehad A, Isaacson A, et al. Development of Research Agenda in Prostate Artery Embolization: Summary of Society of Interventional Radiology Consensus Panel. J Vasc Interv Radiol. 2020 Jan;31(1):108–13.