Paradoxical pulmonary embolism with spontaneous aortocaval fistula

Paradoxical pulmonary embolisms are uncommon emergencies and can occur as a consequence of an aortocaval fistula due to unrecognized dislodgement of thrombus from aortic sac into pulmonary circulation. This study reviewed current literature and therapeutic options in this emergency condition requiring prompt management and repair. METHODS: Literature was systematically searched for paradoxical pulmonary embolism associated with aortocaval rupture. RESULTS: Eight published cases were identified. However, many other paradoxical pulmonary emboli could have remained undiagnosed due to challenging clinical presentation. Symptoms of high-output cardiac failure and respiratory distress in the presence of large aortoiliac aneurysm and venous hypertension are findings of a possible major abdominal arteriovenous fistula with paradoxical pulmonary embolism. Successful treatment depends on prevention of new embolism and proper management of perioperative hemodynamics and massive bleeding during fistula repair. Endovascular procedures have been recently used as useful tools in this field. Cava filter placement may be a first step to prevent further thrombus dislodgements during aortocaval repair. Immediate subsequent aortic stent-grafting can allow repair of aortocaval communication and exclusion of the abdominal aortic aneurysm from circulation with successful reversal of altered hemodynamic features. However, experience (especially in the long-term) is limited. CONCLUSIONS: Paradoxical pulmonary embolism from aortocaval fistula represents an extremely rare but true clinical emergency with high fatality rate. Recent advances in diagnostic technology and endovascular techniques can substantially improve outcomes of the disease. Clinical competence in early detection and diagnosis is essential for appropriate emergent management.