Prevalence of left kidney vein entrapment signs on computed tomography angiography images of kidney donors.

Background: The Nutcracker phenomenon (NC-P) is the entrapment of the left kidney vein (LKV) between the superior mesenteric artery and the abdominal portion of the aorta. We aimed to evaluate the frequency of significant left renal vein compression in a healthy population.

Materials and methods: The computed tomography angiography images of the 131 healty patients who underwent living kidney donor nephrectomy at our institution were enrolled in this retrospective, descriptive anatomic study.

Results: Three (2.3%) cases had severe, 26 (19.8) had moderate stenosis. The mean aorto-mesenteric angle was more narrow in females (p< 0.05). The mean LKV diameter ratio and beak angle were shorter and more narrow in females (p< 0.05,p < 0.01; respectively). Thirteen cases (9.9%) showed three or four positive criteria for NC-P. As patients got younger and had BMI < 30 kg/m², the rate of positive criteria determination was increased (p< 0.05,p < 0.01; respectively).

Conclusions: The NC-P criteria were seen with a high frequency in healthy individuals. Female and younger individuals with less BMI showed a greater prevalence of positive criteria. Revision of the current standards for NC-P with a distinct classification between sex, age, andBMI is required to assess LKV compression better.