Conservative treatment vs thrombus removal for Iliofemoral vein thrombosis in patients with congenital abnormalities of the inferior vena cava: a case report and systematic review of the literature.

Congenital abnormalities of the Inferior Vena Cava (IVC) should be suspected in cases of Deep Venous Thrombosis (DVT), especially in young patients, with no other risk factors and apparent causes. Currently, there is no guidance regarding the management of such patients. We report a case of Iliofemoral vein thrombosis in a young patient with congenital absence of the IVC that was successfully treated with catheter-directed thrombolysis (CDT) and perform a systematic review of the literature to identify evidence about the epidemiology, clinical presentation, management, and prognosis of this rare cause of DVT. A total of 42 studies reporting on 56 cases were included in the review. The mean age of the patients at the presentation of their first DVT episode is 23.6 years, 83.9% of patients were males, conservative management with anticoagulation was used in 68% of the reported cases, and thrombolysis was used in 32% of the cases. Only 10.7% of patients presented with PE potentially justified by the abnormal anatomy of the deep veins which makes the propagation of thrombi into the pulmonary arteries less possible. Comparing the long-term outcomes of the two treatment groups; 42.3% of the patients treated conservatively vs 15.4% of the patients treated with thrombolysis developed chronic symptoms (residual heaviness, pain, swelling, and cramping). 11.5% of patients who received conservative treatment developed post-thrombotic syndrome. None of the patients treated with thrombolysis developed post-thrombotic syndrome. There were no procedure-related complications and thrombolysis was well tolerated by the entirety of the thrombolysis treatment group. Recurrence of DVT occurred in 13% of the patients treated conservatively and in 7.7% of patients treated with thrombolysis. Thrombus removal by means of thrombolysis is the recommended treatment and can offer excellent short and long-term results. Anticoagulation with NOACs may be prescribed for life to prevent recurrence or for at least 6 months and then reconsidered following further evaluation of patients' bleeding risk. It may be of value to organise an international registry for such patients. Guidelines issued by the relevant scientific societies will then be able to make a clear recommendation about the management of such patients.