LAUSR

To the Editor, We read with great interest the article by Salet et al. recently published in CVIR and reporting outcomes of prostate artery embolization (PAE) using n-butyl cyanoacrylate (NBCA) glue for symptomatic benign prostate hyperplasia (BPH) [1]. We have several comments. First of all, we would like to congratulate the authors for their study which represents the first study to date reporting safety and efficacy of PAE with the use of NBCA as compared to microspheres in such a setting. Indeed, microparticles were historically used for PAE because most interventional radiologists (IRs) are familiar with the use of flow-directed particulate embolization [2, 3]. Using NBCA for peripheral applications such as PAE requires more experience. The authors first showed that PAE using glue provided similar safety and clinical success rates for symptomatic BPH compared to microspheres. They also demonstrated that PAE using NBCA was significantly faster, leading to lower radiation exposure as compared to microspheres [1]. Although conclusions from this retrospective study must be drawn with caution, these results should be considered of utmost importance. We are completely in line with the authors. Indeed, we recently published the first clinical study reporting the role of PAE with NBCA for the treatment of patients with BPH [4]. We found statistically significant improvements in the IPSS, QoL score, PSA level, and prostate volume after a median follow-up of 3 months compared to baseline, with a safe profile. Here, the authors have taken a new step thanks to the comparative character with microparticles which are considered as the gold standard embolic agent for this purpose. Although a large proportion of IRs are unfortunately afraid of using NBCA, glue has many benefits, especially for PAE [4, 5]. The main advantage is the shorter procedural time compared to particulate embolization, which decreases the fluoroscopy time and the radiation dose to the patient. In our experience, the NBCA/Lipiodol mixture injection time is less than 15 s on each side, which is very welcome notably in patients with complex time-consuming catheterism [4]. Another advantage of NBCA is that the fast polymerization and the viscosity of the mixture avoid the opening of pre-existing vascular anastomoses, an event recorded with microparticles, thereby potentially decreasing the risk of nontarget embolization and ischemic complications [1, 4]. On the other hand, Lipiodol makes the embolic agent radiopaque, allowing for easier fluoroscopy guidance compared with microparticles that are not directly visualized, with a clearer endpoint. Furthermore, NBCA is a liquid and may therefore be used to embolize arteries in which the microcatheter cannot be advanced, according to the blocked-flow technique. This situation is particularly frequent in PAE, given the small size of prostatic arteries and the flow rate which is low. In a blocked manner, it is frequent to obtain an even better and more controlled injection in the distal bed of the prostate gland. In addition, the Lipiodol is taken up by the gland, and the distribution & Romaric Loffroy [email protected]