Chronic bleeding has been described in cases of most significant problems of oncourology. Oncologic patient can face a permanent cascade of disbalance between pathways of coagulation (Fricke et al., 2017; Salignac et al., 2002; Kennedy et al., 2016; Zhu et al., 2016). These patientsare in slightly greater risk of bleeding without any surgical procedure and greater risk of bleeding in post-operative period. The most common cause of such complication could be a diffuse bleeding from traumatized tumor tissue surface after cystoscopic punch-biopsy. Conservative methods of bleeding control (Kolev & Longstaff, 2016) (fibrinolysis inhibitors) will be ineffective in most cases. It’s a complex situation, because not each all patient from this cohort can survive cystostomy due to poor performance status. Recently, superselective embolization became the method of choice to control such bleeding. Besides, physicians choose embolization among other methods of treatment for acute bleeding: combined trauma with pelvic fractures, uncontrollable bleedings after gynecological surgical operations and complications of radiotherapy (may be chronic as well) (Agolini et al., 1997; Matityahu et al., 2013; Ali et al., 2014; Sieber, 1994; Samuel Washington & Benjamin, 2016; El-Shalakany, 2003). Usually, sequence of actions comprises bilateral diagnostic angiography of internal iliac arteries in order to determine a source of bleeding (arterial supply of bladder tumors can originate from superior and/or inferior vesical arteries, prostatic arteries, not infrequently it may be branches of internal pudendal artery, obturator arteries (Vikash Prasad, 2009)) followed by superselective embolization using various embolic agents. The most frequently-used agents are embolic spheres of different sizes, that can provide permanent tumor vessels occlusion (choosing spheres diameter depends on expected vessel penetration), but IRs also can use polymorphic PVA agents (also permanent occlusion), gelfoam particles (temporary occlusion) or combinations of those. Described method are effective alternative to surgery. Embolization can be performed even in the in patients in shock and with high procedure success. The patient does not require special preparations. Despite obvious advantages and minimally invasive character of the procedure, in some cases embolization can lead to serious complications. In retrospective study of Matityahu et al. (Matityahu et al., 2013) authors report 11% chance of complications, including one case of bladder necrosis from cohort of 98 patients. Serious complications were reported in all patients who underwent bilateral embolization. A major complication as bladder necrosis is described within the first 4–5 weeks following the embolization (Ali et al., 2014; Sieber, 1994), however, we have found data of bladder necrosis in earlier post-operative period (two weeks after intervention) (Sieber, 1994; Samuel Washington & Benjamin, 2016).
In our previous experience with over 40 embolizations of bleeding Bladder tumors we used spherical calibrated BeadBlock (BTG) and EmboGold by Merit Medical particles we did not observe such complications with similar aggressive character of performed procedures.
In our patient bladder necrosis occurred within 10 postembolization days. Factors that may contribute in developing of such life-threatening condition: tissue hypoperfusion and potential non-target embolization of non-involved in tumor supply bladder arteries, lack of good collateral flow due to patient abnormality such as atherosclerosis, hypovolemia due to developed sepsis. We associate this phenomenon with use of strictly-calibrated microspheres with high concentration of particles per unit of volume (in comparison of non-strictly calibrated PVA particles or gelfoam). Strictly calibrated embolic agent is expected to have greater ability to penetrate the arteries with an exceptional dense filling capabilities, which can despite relatively large size of each sphere (500 μm) lead to complete tumor and some bladder wall ischemia.It seems that strictly-calibrated microspheres do provide a desired haemostatic effect, but we have to carefully chooseappropriate size of embolic agent according with vessel size of the target organ.
Methods of embolization for bleeding control are firmly established in daily practice. Indisputable advantages of embolization therapy provide an opportunity to use it for patients with poor performance status, who can’t survive surgery or have contraindications for general anesthesia. Yet, even minimally-invasive treatment with overly aggressive approach can lead to life-threatening conditions. Such potential complication has to be discussed with the patient prior to the procedure and signing the informed consent. Each individual case requires a correct estimate of tumor blood supply and collateral flow followed by subtotal embolization of vessels feeding the tumor. Based on described method of bladder tumor embolization using strictly-calibrated microspheres (EmboZene) we recommend to avoid use of particles sized 500μmor less, as it can lead to total necrosis of the tumor and surrounding bladder tissue. In situations with less accessibility of catlabs for population from very remote locations, the goal is to find balance between significantly diminish the flow in tumor vessels to achieve stable hemostasis within the limits of single procedure, but not complete cease of blood flow in the tumor bed in case of compromised collateral flow.