Natural History of Renal Vein Thrombosis: Incidence of Recurrent Venous Thromboembolism and Survival.

Renal vein thrombosis (RVT), although uncommon, is associated with considerable morbidity and mortality. Neither the etiology nor the natural history of RVT has been adequately described in a large case series.

Objective: To determine whether incident RVT is associated with an increased likelihood of recurrent local and systemic venous thromboembolic disease.

Methods: Cases were identified by reviewing the Diagnostic Index for all patients with RVT at our institution between 1981 and 2000.

Results: The study group consisted of 240 patients (34% women) with a mean age 55± 19 years. The diagnosis of RVT was made by CT (35%), Duplex Ultrasound (35%), MRI±gadolinium (10%) and either at surgery or autopsy in the remainder. The underlying etiology was deemed to be malignancy in 65% of cases. Of these, renal cell carcinoma (74%) and Wilms tumor (3%) made up the majority. Nephrotic syndrome primarily membranous glomerulonephritis was the second most common underlying etiology (23%). Of those tested, a definable thrombophilia was found in only 13 cases including lupus anticoagulant/antiphospholipid antibody (n=4); deficiencies of protein C or S, (n=2 each); heparin induced thrombocytopenia (n=2); antithrombin deficiency, dysfibrinogenemia and hyperhomocysteinemia (n=1 each). Eighty-one patients (34%) were treated with warfarin. Over a mean follow up of 3 years, the rate of recurrence of venous thrombosis at any site was 5%. The mortality rate over this time period was 49%.

Conclusion: RVT represents a distinct clinical entity relative to venous thromboembolism of the lower extremity. The observed low rate of recurrence may be explained by the high mortality rate owing to a high percentage of renal malignancy. RVT should prompt an evaluation for an underlying renal malignancy.