Abstract
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.
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