Patients
Between February 2009 and January 2015 in our institution, a total of 139 patients (mean age, 72.0 years±10.5 [standard deviation]) diagnosed with moderate or severe LUTS (International Prostate Symptoms Score [IPSS] > 18 points, quality of life [QoL] score > 3, and/or urinary retention with urinary catheter removal failure) due to BPH who were refractory to medical treatment for at least 6 months underwent PAE.
PAE protocols
The selection criteria included patients with a diagnosis of severe LUTS, negative screening for prostate cancer, prostate volume (PV) > 40 mL measured by MRI, and bladder outlet obstruction (BOO) confirmed by urodynamic examination, peak urinary flow rate (Qmax) < 12 mL/sec, and PVR post-void residual urine (PVR) > 150 mL evaluated by ultrasound, biopsy was performed to rule out prostate malignant if PSA level > 4.0 ng/mL. The patient selection was evaluated by a multidisciplinary team that included urologists, anaesthesiologists, and interventional radiologists. Exclusion criteria included pelvic malignancy, chronic renal failure, large bladder diverticula (> 5 cm), active urinary tract infection, large bladder stones (> 2 cm), unregulated coagulation parameters, neurogenic bladder, allergy to intravenous contrast media, detrusor failure and urethral stricture diagnosed through pressure flow studies or urethrography [1, 9].
The preparative clinical observation included IPSS, QoL, peak urinary flow rate (Qmax), post-void residual volume (PVR), international index of erectile function short form (IIEF-5) score, and PV before PAE and at 1, 3, 6 and every 6 months after the procedure. All patients underwent 1.5-T multiparametric enhanced MRI (GE Healthcare, Milwaukee, Wisconsin, USA) of the prostate to measure PV and to rule out cancer before PAE using a phased-array 12-channel body coil. For each patient, the MRI protocol was the same, including axial, coronal, and sagittal T2-weighted imaging (T2WI) and contrast- and non-contrast enhanced T1-weighted imaging (T1WI).
Embolization technique
The details of the procedure of PAE have been described previously [10]. The PAEs were performed by two senior interventional radiologists (M.Q.W. and K. Y., with 26 and 12 years of vascular and interventional radiology experience, respectively), using a therapeutic angiography unit equipped with a digital flat-panel detector system (INNOVA 4100 IQ; GE Healthcare, Milwaukee, Wisconsin, USA). PAE was performed under local anaesthesia through a single right femoral approach using a 4-Fr vascular sheath (Radifocus, Terumo, Japan). Digital subtraction angiography (DSA) and cone-beam computed tomography (CB-CT) were performed to identify prostatic arteries (PAs). Embolization was performed with 100-μm non-spherical PVA particles (90~ 180-μm, PVA, Cook Incorporated, Bloomington, IN, USA). The endpoint of embolization was occlusion of the identifiable vessels supplying the prostate.
Follow-up
Follow-up was performed at 1, 3, 6, and every 6 months after PAE by the interventionalists and the urologists. IPSS, QoL, IIEF-5, PSA, Qmax, PVR, and PV on MRI were evaluated at those dates to measure clinical and radiological changes after PAE.
Imaging evaluation
All MR images were assessed independently by two radiologists (reader 1 and reader 2, with 11 years and 15 years of experience in interpreting body MR images, respectively) without knowing the outcomes of the PAE. If there was disagreement, the relevant MR images were reassessed by a third independent reader (reader 3, with 20 years of experience in interpreting body MR) to reach a consensus.
The procedural angiographic images, including DSA, rotational angiography, and CB-CT, were reviewed retrospectively by two interventional radiologists (G. D. Z. and M.Q.W., with 16 and 25 years of vascular and interventional radiology experience, respectively), highlighting the possibility of the blood supplying the SV (“vesiculo-deferential artery”). After independent interpretations were achieved, the differences in evaluations between the two radiologists were resolved by consensus.