Anomalies of the inferior vena cava in patients with iliac venous thrombosis

Background: Cases of deep venous thrombosis in the lower extremities triggered by abnormalities of the vena cava have been reported. Objective: To describe anomalies of the inferior vena cava in patients with deep venous thrombosis. Design: Prospective, consecutive case series. Setting: University Hospital, Graz, Austria. Patients: 97 patients with deep venous thrombosis. Intervention: Sonography, venography, or both to diagnose deep venous thrombosis; magnetic resonance angiography to image the inferior vena cava. Measurements: Anomalies of the inferior vena cava imaged by magnetic resonance angiography. Results: 31 of 97 patients showed thrombotic occlusion of iliac veins (common and external iliac vein [n = 29] or external iliac vein [n = 2]). Five of 31 patients (3 men, 2 women) had an anomaly of the inferior vena cava. Anomalies were missing inferior vena cava, hypoplastic hepatic segment, and missing renal or postrenal segments. Patients with anomalies were significantly younger than the 92 patients without (mean age +/- SD, 25 +/- 6 years vs. 53 +/- 19 years; P = 0.002). In 2 patients with anomalies, the thrombotic occlusion was recurrent. Conclusions: An anomaly of the inferior vena cava should be suspected if thrombosis involving the iliac veins is seen in patients 30 years of age or younger. Patients with both an anomaly and thrombosis may be at higher risk for thrombotic recurrence.