Case Reference No. CC-0798-02 A 32-year-old woman with moderate exertional dyspnea underwent a perfusion lung scan which revealed almost no perfusion to the right lung (not shown). The patient had no leg symptoms and a Doppler study failed to reveal any source of embolus in the legs or pelvis. Pulmonary arteriography revealed a saddle embolus blocking the right pulmonary artery (Fig. 1). A pulse spray catheter was placed within the embolus and 1.75 million units of urokinase was infused in the form of pulse and drip. On the following day the perfusion lung scan became normal. Because the source of the embolus was suspected to be the internal iliac veins, the patient underwent repeat arteriography on the third day. This also provided us with the opportunity to look in the pulmonary arteries. Both pulmonary arteries were free of embolus (Figs. 2, 3). A large, partially obstructing thrombus was discovered at the junction of the contralateral common and external iliac veins, which on re-examination was also visible on Doppler. This clot was not subjected to urokinase infusion but the patient was fully heparinized. Questions: 1) Do you think minimally symptomatic patients with pulmonary embolism should be treated with urokinase? 2) Do you routinely perform IVC or pelvic venography before pulmonary angiography? If so, what is your yield? 3) Do you think Doppler venography is reliable? 4) Do you think we should have proceeded with lysis for the pelvic thrombus with or without filter protection? Related cases: Case 0498_06 -- Thrombectomy and thrombolysis of iliac veins and inferior vena cava Case 1097_05 -- Pulmonary embolism with selective thrombolysis Case 697_05 -- Lower extremity venous thrombolysis MM#96-32 Caval thrombosis and thrombolysis after filter placement

Fig. 1. Main pulmonary arteriogram reveals a right saddle embolus. Fig. 2. Right pulmonary arteriogram after urokinase infusion. Fig. 3. Left pulmonary arteriogram after urokinase infusion.