Background: The incidence of inferior vena cava anomalies in patients with horseshoe kidney is higher than that reported in the general population. As far as we know, no studies have reported the incidence and variations of superior vena cava (SVC) anomalies using multidetector-row computed tomography (MDCT) in patients with horseshoe kidney.
Methods and results: Using MDCT, 71 patients with a horseshoe kidney (group A: 45 males, 26 females; mean age, 60.1 ± 10.2 years) and 2,292 patients without a horseshoe kidney (group B: 1,385 males, 907 females; mean age, 61.1 ± 13.5 years) were retrospectively evaluated for the incidence and variations of SVC anomalies, and the incidence of an anomalous SVC was compared between groups. An anomalous SVC was identified in 3 group A patients (4.2%) (double SVC, n=2; persistent left SVC without a right SVC, n=1) and 5 group B patients (0.22%) (double SVC, n=3; persistent left SVC without a right SVC, n=2). MDCT revealed a significantly higher incidence of anomalous SVC in patients with a horseshoe kidney than in those without a horseshoe kidney (P<0.001).
Conclusions: Patients with horseshoe kidney frequently have an anomalous SVC. Although the incidence of horseshoe kidney is related in some way to that of an anomalous SVC, the reasons for their coexistence remain unclear.