INFERIOR VENA CAVA AGENESIS: ANATOMICAL VARIANT AS CAUSE OF RECURRENT DVT

Abstract

SESSION TITLE: Medical Student/Resident Pulmonary Vascular Disease Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: October 18-21, 2020 INTRODUCTION: Abnormalities of the inferior vena cava (IVC) are rare causes of deep venous thrombosis (DVT). The clinical presentation is often similar to that of an inherited hypercoagulabe condition. CASE PRESENTATION: A 27-year-old man with a past medical history of premature birth presented to the emergency department (ED) with left lower extremity (LLE) tightness and pain for one day. He had no history of recent travel and family history was negative for clotting disorders. Ultrasound (US) of the left leg showed an occlusive thrombus from the left common femoral to the left popliteal vein. The patient was discharged from the ED on rivaroxaban. Two weeks later, he presented to the ED again with progressive LLE swelling despite medication compliance. Physical exam was negative for testicular masses. Interventional Radiology (IR) performed a LLE venogram, which showed thrombus extention to the common iliac vein. US-assisted catheter thrombolysis (EKOS) was initiated. Heparin infusion was started and the patient was transferred to the intensive care unit. Repeat visualization the following day revealed improved clot in the left femoral and external iliac veins and a chronically thrombosed left common iliac vein. LLE pain and swelling improved and EKOS was discontinued twenty-four hours later. Hypercoagulability work-up was negative except for lupus anti-coagulant, the significance of which was difficult to determine, given prior anticoagulant exposure. On discharge, the patient was transitioned back to rivaroxaban. Five days later, the patient presented to the ED again with worsening LLE pain and swelling after initial improvement. Repeat venous US showed occlusive thrombus throughout much of the left femoral vein with only some flow at the distal aspect. An inferior vena cavogram revealed agenesis of the IVC with azygous continuation. CT angiogram of the abdomen and pelvis confirmed an occluded infra-renal IVC secondary to atresia. Patient was discharged on indefinite rivaroxaban therapy. DISCUSSION: This patient presented with an unprovoked DVT involving the common iliac vein that extended despite appropriate anticoagulation. Eventually, a venogram revealed agenesis of the IVC as the predisposing risk factor. In this condition, venous stasis presumably leads to increased risk of clotting. While bilateral DVTs are rare in the general population (approximately 10% of cases), they have been described in up to three quarters of patients with IVC abnormalities. This patient however, had extensive unilateral clot burden, usually seen in more distal anatomical abnormalities, such as May-Thurner syndrome. His premature birth likely predisposed him for an anatomical malformation. CONCLUSIONS: Unprovoked DVT in a young patient, recurrent DVTs despite medication compliance, and occlusion of the iliac veins, should raise suspicion for anatomical abnormalities, such as IVC atresia. Reference #1: 1. Chee YL, Culligan DJ, Watson HG. Inferior vena cava malformation as a risk factor for deep venous thrombosis in the young. Br J Haematol. 2001;114(4):878. Reference #2: 2. Ruggeri M, Tosetto A, Castaman G, Rodeghiero F. Congenital absence of the inferior vena cava: a rare risk factor for idiopathic deep-vein thrombosis. Lancet. 2001;357(9254):441. Reference #3: 3. Hamoud S, Nitecky S, Engel A, Goldsher D, Hayek T. Hypoplasia of the inferior vena cava with azygous continuation presenting as recurrent leg deep vein thrombosis. Am J Med Sci. 2000;319(6):414. DISCLOSURES: No relevant relationships by Amy Cohen, source=Web Response No relevant relationships by David Cohen, source=Web Response No relevant relationships by Aaron Dickinson, source=Web Response No relevant relationships by Mouhanned Eliliwi, source=Web Response No relevant relationships by Jennifer Meyfeldt, source=Web Response