Rutherford's 163: Congenital Occlusion or Absence of Inferior Vena Cava

#AIVC #InferiorVenaCava #DVT #DeepVeinThrombosis #VascularHealth #YoungDVT #BloodClots #RutherfordVascular #MedicalEducation #VascularSurgery This video deep dive, based on Rutherford's textbook, explores Congenital Absence of the Inferior Vena Cava (AIVC), a rare condition where the main vein returning blood from the lower body is missing or improperly formed during embryonic development. While only affecting 0.3-0.5% of the general population, AIVC is surprisingly linked to Deep Vein Thrombosis (DVT), appearing in up to 5% of young individuals (under 30-40) who experience DVT without other clear causes (idiopathic DVT). AIVC creates slow blood flow in the legs, acting like a "bottleneck", making clot formation more likely, especially when combined with other risk factors like inherited clotting disorders, strenuous exercise, immobility, or trauma. The body attempts to compensate by developing collateral veins, but these can be overwhelmed. Diagnosis typically starts with suspicion in young patients with unexplained DVT, followed by duplex ultrasound and then detailed axial imaging like CT Venography (CTV) or MR Venography (MRV) to map the anatomy and clot extent. Venography and IVUS are also used, sometimes during procedures. Management of AIVC-related DVT often involves lifelong anticoagulation to prevent future clots. While the risk of pulmonary embolism might be lower due to the missing IVC, treatment for acute DVT with severe symptoms, like catheter-directed thrombolysis or pharmacomechanical thrombectomy, is debated. Studies like KAVN2 and Cochrane suggested benefits for vein patency, but the ATTRACTI trial found increased bleeding risk without a statistically significant reduction in overall post-thrombotic syndrome rates. Treatment must be individualised, weighing risks against potential benefits. Managing chronic issues like severe swelling or ulcers is complex, with stenting in the iliofemoral veins having a high re-clotting risk, making surgery a potential last resort in selected benign cases. The condition highlights the body's resilience through collaterals and the importance of considering rare causes in medicine.