MEDizzy - A 57-year-old man with a history of hypertension is admitted

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Disorders of the cardiovascular system 2

A 57-year-old man with a history of hypertension is admitted to the hospital with a pulmonary embolism after having a sudden onset of chest discomfort. His blood pressure is 132/62 mmHg, heart rate is 85 bpm, and oxygen saturation is 95% on room air. Echocardiography reveals normal right heart size and function, and cardiac troponin I is undetectable. Lower extremity Doppler ultrasound reveals an extensive deep vein thrombus from the right femoral-popliteal vein. The patient is started on low-molecular-weight heparin and concomitant warfarin. On rounds the following day, he asks if insertion of an inferior vena cava (IVC) filter would be appropriate. What is the most appropriate answer?

ExplanationIn patients with PE, the two principal indications for insertion of an inferior vena cava flter are (1) active bleeding that precludes anticoagulation and (2) recurrent venous thrombosis despite intensive anticoagulation. Prevention of recurrent PE in patients with right heart failure who are not candidates for fbrinolysis and prophylaxis of extremely high-risk patients are “softer” indications for flter placement. The flter itself may fail by permitting the passage of small- to medium- size clots. Large thrombi may embolize to the pulmonary arteries via collateral veins that develop. A more common complication is caval thrombosis with marked bilateral leg swelling. Paradoxically, by providing a nidus for clot formation, flters increase the deep venous thrombosis rate, even though they usually prevent PE (over the short term). Retrievable flters can now be placed for patients with an anticipated temporary bleeding disorder or for patients at temporary high risk of PE, such as individuals undergoing bariatric surgery who have a prior history of perioperative PE. The flters can be retrieved up to several months after insertion unless thrombus forms and is trapped within the flter. The retrievable flter becomes permanent if it remains in place or if, for technical reasons such as rapid endothelialization, it cannot be removed.