No DVT. AC started due to extensive size of initial LLE SVT, with continued SVT of contralateral RLE despite therapeutic anticoagulation with apixaban. Prior work up for malignancy negative by imaging, and APLS negative for cardiolipin and beta 2 glycoprotein antibodies with no lupus anticoagulant due to continued anticoagulation.
Would a venogram to assess for anatomic anomalies of the proximal vessels be helpful? Would you consider expanded thrombophilia testing for protein C or S deficiency?