Despite the substantial progress in modern medicine, both diagnostics and treatment of deep vein thrombosis and pulmonary embolism remain a most challenging problem of clinical practice. During the last decades, implantation of cava filters has been a major and one of the most efficacious methods for endovascular prophylaxis of pulmonary embolism in the patients with floating thrombosis. For all that, there is a potential risk of thrombotic complications related to the long-term presence of the implanted cava filters in the vascular bed which implies the necessity of adequately controlled anticoagulation therapy throughout the life span of the patients. Non-compliance with the prescribed treatment regime is fraught with the relapse of thrombosis that may acquire the uncontrollable life-threatening character. The authors describe a clinical case of bilateral thrombosis of the renal veins that almost brought the patient on the edge of death.