Association of congenital left renal vein anomalies and unexplained hematuria: multidetector computed tomography findings

Anatomical Variants of the Renal Veins and Their Relationship with Morphofunctional Alterations of the Kidney: A Systematic Review and Meta-Analysis of Prevalence

Background: Variations in renal veins are quite common, and most people do not experience issues due to them. However, these variations are important for healthcare professionals, especially in surgical procedures and imaging studies, as precise knowledge of vascular anatomy is essential to avoid complications during medical interventions. The purpose of this study was to expose the frequency of anatomical variations in the renal vein (RV) and detail their relationship with the retroperitoneal and renal regions. Methods: A systematic search was conducted in the Medline, Scopus, Web of Science, Google Scholar, CINAHL, and LILACS databases from their inception until January 2024. Two authors independently carried out the search, study selection, and data extraction and assessed methodological quality using a quality assurance tool for anatomical studies (AQUA). Ultimately, consolidated prevalence was estimated using a random effects model. Results: In total, 91 studies meeting the eligibility criteria were identified. This study included 91 investigations with a total of 46,664 subjects; the meta-analysis encompassed 64 studies. The overall prevalence of multiple renal veins was 5%, with a confidence interval (CI) of 4% to 5%. The prevalence of the renal vein trajectory was 5%, with a CI of 4% to 5%. The prevalence of renal vein branching was 3%, with a CI of 0% to 6%. Lastly, the prevalence of unusual renal vein origin was 2%, with a CI of 1% to 4%. Conclusions: The analysis of these variants is crucial for both surgical clinical management and the treatment of patients with renal transplant and hemodialysis.

Endovascular treatment of anterior nutcracker syndrome and pelvic varices in a patient with an anterior and a posterior renal vein

There are few data on endovascular treatment of anterior nutcracker syndrome and pelvic varices in patients with anterior and posterior renal veins. Our objective is to report a case, identify occurrences and compare diagnosis and treatments. A 42-year-old woman presented with flank and pelvic pain and hematuria. She had anterior nutcracker syndrome and pelvic varices with an anterior and a posterior renal vein. A successful complete endovascular approach was done with stent implantation in the anterior renal vein and left gonadal vein embolisation. After 12-month follow-up, the patient remained asymptomatic with good results on CT. Only two case reports of patients with nutcracker syndrome with anterior and posterior renal veins were identified. In both, a self-expanding stent was implanted in the anterior renal vein. In conclusion, endovascular treatment represents a safe and successful option in patients with nutcracker syndrome and pelvic varices with an anterior and a posterior renal vein.

Anatomical variants of renal veins: A meta-analysis of prevalence

The main aim of this article is to establish the actual prevalence of renal vein variations (circumaortic renal vein, retroaortic renal vein, double renal vein), and to increase awareness about them. To this purpose, we have performed a meta-analysis of prevalence, using the MetaXL package, We included 105 articles in the final analysis of prevalence, of which 88 contained data about retroaortic renal vein, 84 - about circumaortic renal vein, and 51 - about multiple renal veins. The overall prevalence for retroaortic renal vein was 3% (CI:2.4-3.6%), for circumaortic renal vein - 3.5% (CI:2.8-4.4%), and for multiple renal veins - 16.7% (14.3-19.2%), much higher on the right 16.6 (14.2-19.1%) than on the left side 2.1 (1.3-3.2%). The results were relatively homogenous between studies, with only a minor publication bias overall.

Anterior Nutcracker Syndrome with Left Gonadal Vein Varicosities on Multiphasic Computed Tomography: An Unexpected Cause of Pyeloureteral Junction Obstruction

The anterior nutcracker syndrome is defined by the compression of the left renal vein between the aorta and superior mesenteric artery, usually related to the occurrence of hematuria. We report the case of an uncommon complication of the nutcracker syndrome. A 75-year-old woman was referred to our institution for left flank pain without hematuria. Multiphasic computer tomography urography showed a condition of left renal vein entrapment between the aorta and superior mesenteric artery with the development of left gonadal vein varicosities at the level of the renal hilum; a pyeloureteral junction compression with dilation of the pyelocalyceal system coexisted. To our knowledge, this is the first report of the association between nutcracker syndrome and pyeloureteral junction obstruction.