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

Abstract

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 131 healthy 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 stenosis, and 26 (19.8) cases had moderate stenosis. The mean aorto-mesenteric angle was narrower in females (p < 0.05). The mean LKV diameter ratio and beak angle were shorter and narrower in females (p < 0.05, p < 0.01, respectively). Thirteen cases (9.9%) showed 3 or 4 positive criteria for NC-P. Younger pateitns and those with body mass index (BMI) < 30 kg/m2 had increased rates of positive criteria determination (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 lower BMI showed a greater prevalence of positive criteria. Revision of the current standards for NC-P with a distinct classification between sex, age, and BMI is required to better assess LKV compression.