What are the Disadvantage of using Surgical Processes to Treat CVD?

-Stents may Annoy the Artery causing it to Narrow again and cause Scar Tissue [Familiar?]. -Drugs has to be Taken to not allow Blood Clotting on the Stent - and Anticoagulants has its own Problems [Excessive Bleeding] -Donor Heart may not Pump Properly from Start, and also can be seen as 'foreign' from the Immune System which will then promptly Attack the New Heart. So Drugs need to be taken and Obviously they have their little Consequences as well. [Vulnerable to Infections] -Heart Surgery is Expensive, May have Permanent Damage, Infections may Occur, however, brings good Science.