Institutional review board (IRB) approval was received for this retrospective study. A review of the electronic medical records (EMR) from a single center was conducted on all patients whom underwent PAE for severe LUTS between January 2016 and January 2020. Patients were considered for PAE if they had severe LUTS that did not respond to medical therapy and were not eligible for surgery or refused surgery. Written informed consent was obtained from the patients and any accompanying images. Patients gave consent for their personal or clinical details along with any identifying images to be published in this study. Prostate volumes were calculated with magnetic resonance (MR) imaging and recorded in 529 patients whom underwent bilateral PAE before the procedure. Only 72 patients with prostate volumes larger than 200 mL were reviewed for the study. International Prostate Symptom Score (IPSS), urinary quality of life (QoL), postvoid residual volume (PVR), and prostate volume (PV) were measured and collected before PAE and 12 months and 24 months after PAE.
Clinical Metrics
Clinical assessment was performed in all patients before PAE and 12 months and 24 months after PAE with history and physical examination, IPSS and QoL questionnaires, and PVR.
Prostate MR Imaging and Volume Measurement
Prostate volumes were calculated using multiparametric MR imaging obtained before PAE and 12 months and 24 months after PAE. At our institution, multiparametric prostate MR imaging is performed using 3.0 T magnet systems (Siemens Healthcare, Erlangen, Germany). Exams are performed with phased array torso coils using the following protocol (Table 1): axial, sagittal, and coronal T2-weighted turbo spin echo images; axial b50, b500, and b800 s/mm2 diffusion-weighted images; synthetic extrapolated b1200, b1500, b2000, and b2500 diffusion-weighted images; apparent diffusion coefficient (ADC) map; axial T1 pre-contrast fat saturated volumetric interpolated breath-hold examination (VIBE) images; coronal T1-precontrast fat-saturated MR angiographic VIBE images of the pelvis; serial dynamic axial T1 pre-contrast fat saturated VIBE images obtained after intravenous gadolinium contrast injection (Gadavist 0.1 mmol/kg; Bayer Healthcare Pharmaceuticals, Wayne, New Jersey, U.S.A.); axial fat-saturated T1-weighted delayed postcontrast VIBE images.
Two diagnostic radiologists with twelve and six years of experience in interpreting multiparametric prostate MR imaging, respectively, independently reviewed the MR imaging exams before and after PAE. The radiologists used DynaCAD software (InVivo, Philips Healthcare, Amsterdam, Netherlands) on two separate workstations to perform semiautomated prostatic volumetric measurements of the prostate using the MR T2-weighted images. Prostatic volumes were manually confirmed by calculation of the ellipsoid volume formula (L x W x H x π/6). Discordant measurements were resolved by consensus agreement. The diagnostic radiologists also reviewed MR imaging before and after PAE for any prostate gland lesions suspicious for clinically significant cancer according to version 2.1 of Prostate Imaging-Reporting and Data System (PI-RADS) (29).
Prostate Artery Embolization
All PAE procedures were performed by a single operator with thirteen years of angiographic and embolization experience and four years of experience performing PAE. All patients received one dose of ciprofloxacin 400 mg administered intravenously for infection prophylaxis. All procedures were performed under moderate (conscious) sedation with local anesthesia in a therapeutic angiography unit. A unilateral left radial arterial approach was utilized in all patients. Real time ultrasound was used to visualize patency and access of the left radial artery, which entered with a micropuncture set, 21-gauge needle, and a 5-French (-F) sheath. Patients underwent digital subtraction angiography (DSA) and PAE with a digital flat-panel detector system (Innova 4100 IQ; General Electric Healthcare, Chicago, Illinois, U.S.A.) with nonionic intravenous contrast (Omnipaque 350 mg/mL; General Electric Healthcare, Chicago, Illinois, U.S.A.). Internal iliac arterial angiography in the ipsilateral oblique projection was performed to identify the right and left prostatic arteries, accessory prostatic arteries, and variant anatomy. Pelvic and prostatic arteries were catheterized using a combination of wires and catheters: 5-F Cobra 2 catheter (Cook Medical, Bloomington, Indiana, U.S.A.), 4-F Berenstein catheter (Merit Medical Systems, Incorporated, South Jordan, Utah, U.SA.), 2.4-F Progreat microcatheter (Terumo Interventional Systems, Tokyo, Japan) and 0.014-inch Transend microguide wire (Stryker Neurovascular, Fremont, California, U.S.A.). The prostatic arteries were identified with DSA. Advanced imaging was performed with localized intraoperative cone-beam computed tomography (CT) with intravenous contrast (100 mL Isovue 370, Bracco Diagnostics, Milan, Italy) prior to embolization. Cone-beam CT images were transmitted, reconstructed in three dimensions, and reviewed to confirm prostatic arterial vascular anatomy, prostate gland vascular supply, and ensure the absence of vascular supply to adjacent anatomical structures, such as the urinary bladder, penis, and rectum. Bilateral PAE was then performed to stasis with a primary embolic agent: 100 µm to 250 µm Embospheres (Merit Medical Systems, Incorporated, South Jordan, Utah, U.S.A.) and a secondary embolic agent: 2 mm and 3 mm CX coils (Boston Scientific, Marlborough, Massachusetts, U.S.A.). A band compression device was utilized to achieve radial arterial vascular access closure in all patients.
Statistical Analysis
The clinical metrics of IPSS, QoL, PVR, and PV were expressed as quantitative values with means and standard deviations (SD). These quantitative values were analyzed with a Wilcoxon signed rank test using SAS software, version 9.4 (SAS Institute Incorporated, Cary, North Carolina, U.S.A.). A probability value of P < 0.05 or lower was considered statistically significant. We had no missing information for the patients and data that were presented in this study.