Morphological features of polycystic kidney in acute renal artery occlusion

Background. Autosomal dominant polycystic kidney disease (ADPKD) is an inherited disease characterized by cystic transformation of the kidneys and other organs. Nephromegaly is an absolute contraindication to kidney transplantation. Currently, the most effective strategy for surgical treatment of patients has not been determined. The use of transarterial embolization (TAE) of the renal arteries leads to a decrease in the total volume of the kidneys. Studies of the pathophysiology of polycystic kidneys in conditions of acute occlusion of the renal arteries have not been carried out, and the mechanism of reduction of total renal volume after embolization was unclear. When writing the article, information about the morphology of the kidneys in ADPKD, the use of renal TAE for the treatment of patients with polycystic kidney disease published in the PubMed databases ( https://www.ncbi.nlm.nih.gov/pubmed/), the Scientific Electronic Library of the Russian Federation - Elibrary.ru (https://elibrary.ru/) and on the websites of professional urological and nephrological associations was used. The databases were searched using the following keywords: ADPKD, TAE, renal cysts, angiogenesis. At the first stage, 35 sources no older than 5 years were found, including systematic reviews and meta-analyses that were relevant to this topic. Conference abstracts, short communications, and duplicate publications were excluded. After this, based on the relevance of the data, the reliability of the sources, the impact factors of the journals and the sequence of presentation of the material in the manuscript, 15 articles from scientific international peer-reviewed journals, practical guidelines and clinical recommendations were selected directly for citation in the article.

Clinical case. The practical part of the work is presented in the form of a description of a clinical case of a patient with ADPKD, end-stage kidney disease (ESKD), treated with hemodialysis, who underwent combined treatment: laparoscopic bilateral nephrectomy with preliminary TAE of the right kidney. A pathomorphological study of the removed native kidneys was performed. Contrasting of vessels and walls of cysts, histological examination, tonometry of cysts were performed, and a description of the mechanism of renal volume reduction in the right polycystic kidney after TAE was performed.

Results. The volume of the right kidney when calculated using manual multislice computed tomographic planimetry 1.5 months after TAE was 2190 ml; the volume of the right kidney decreased by 30% (≈916 ml). When measuring intracystic pressure in a polycystic kidney after embolization, a decrease in pressure to 10 mm Hg was noted. on average by 47.5% compared with a kidney without embolization. After the injection of a dye solution into the cyst of a removed native kidney after TAE, when the lumen of the cyst was opened, intense staining of the vascular bed with the dye was macroscopically observed. During a microscopic examination of a polycystic kidney after TAE, attention was drawn to healed areas due to renal infarction and an extensive neomicrovascular network. Small cysts completely regressed and were replaced by fibrous tissue. Drainage of intracystic fluid was carried out into neocapillaries: venules and lymphatic vessels.

Conclusion. Thus, we have practically proven the communication of cysts with a wide vascular network, which means that embolization leads to a decrease in the volume of cysts. The reduction in renal volume occurs primarily due to a series of microcirculatory events. TAE is an effective and minimally invasive technical procedure that can be used in the combined treatment of patients with ADPKD and ESKD. The combined use of renal artery TAE followed by delayed bilateral nephrectomy will improve the results of surgical treatment of patients with ESKD and ADPKD by reducing renal volume.