Can I Have a Reverse Tummy Tuck After a Whipple Surgery & C-section? I Have Been Warned About Blood Flow Due to Scar Tissue.

Based on your picture and information provided, a reverse tummy tuck may be possible but an in-person exam would be needed. You would also need to address the cardiomyopathy and any other medical problems first. 

The reverse tummy tuck is not done very often.  Besides placing the scar in a more visible location, it seems the blood supply to the remaining skin may not be as good. The scar is not an issue with you since you already have one. If your C-section scar goes horizontally, I would probably not do it, since that would block the circulation from below. If it goes vertically, then it might be doable, but conservatism is the key. Your main problem seems to be with the diastasis, so the undermining of the skin could be more restricted, just enough to repair the diastasis without having puckering.  All of this obviously would need to be discussed with your plastic surgeon.  good luck