The roles of the liver and pancreas in renal nutcracker syndrome

Graphical abstract: - Highlights: • The presence of the liver and pancreas may influence NCS by compressing SMA against the aorta. • The presence of the liver and pancreas at the level of the LRV is not yet recognized as an independent factor for NCS but should be. • The presence of the liver and the pancreas may allow clinicians to identify NCS patients and may influence the choice of treatment options. - Abstract: Introduction: To assess the frequency and significance of presence of the liver and pancreas at the left renal vein (LRV) level in patients with suspected renal nutcracker syndrome (NCS). Materials and methods: We included 101 patients with hematuria who underwent urography three-dimensional CT between April 2009 and November 2013. These patients were divided into NCS (n = 25) and non-NCS (n = 76) patients according to the following CT criteria: (1) the presence of beak sign and (2) hilar-aortomesenteric left renal vein diameter ratio >4. Patients were grouped according to the presence of the liver and pancreas at the LRV: group LP (both liver and pancreas), group L (only liver), group P (only pancreas), and group O (neither liver nor pancreas). The difference in the frequencies of groups was analyzed between NCS and non-NCS patients. Multivariate analysis was used to determine the independent factors between NCS and non-NCS patients. Results: The frequencies of group LP, group L, group P, and group O in NCS vs. non-NCS were 88% vs. 5.3% (p < 0.001), 4.0% vs. 2.6% (p = 0.75), 4.0% vs. 11.8% (p = 0.45), 4.0% vs. 80.3% (p < 0.001), respectively. Multivariate analysis demonstrated that group was a predictor for differential diagnosis between NCS and non-NCS (p = 0.022), and group LP was an independent factor for the presence of NCS (odds ratio, 43.8; 95% confidence interval, 3.8–500.3; p < 0.002; reference, group O). Conclusion: The presence of the liver and pancreas at the level of the LRV was frequently found in NCS and was the independent factor for NCS