TEST QUESTION - Optimal timing of anticoagulation initiation in acute ischemic stroke with hemorrhagic transformation: when is it safe?

72F admitted with acute right MCA ischemic stroke, NIHSS 14. CT head at 24h shows petechial hemorrhagic transformation (HI-1). Currently on aspirin 81mg. PMH includes atrial fibrillation (CHA2DS2-VASc 6), mechanical mitral valve.

Questions:

1. When would you initiate anticoagulation given the hemorrhagic transformation?
2. Would you use heparin bridge or go straight to warfarin given the mechanical valve?
3. What imaging criteria do you use to determine safety of anticoagulation initiation?