This is per my expert knowledge as a licensed MD. You can easily find the sources for recommendations/guidelines on chronic coronary artery disease (CAD), acute coronary syndrome (ACS), and prevention on the ACC/AHA website.
You seem focused on angioplasty with the indication of angina (assuming refractory angina and a blockage in the heart arteries that would be causing it). After angioplasty is done, if a stent is used, you will have to be on a blood thinner for some mandatory time (up to a year...). This is to ensure that the stent does not immediately clot off causing a VERY BAD HEART ATTACK.
You have to understand that there is a big difference between a heart attack blockage and a blockage that causes a stable angina. Stable angina is what a person has due to blockages that are chronic/slowly changing. ACS (acute coronary syndrome, practically a layman "heart attack") is when a fatty blockage suddenly is opened to the inside of a blood vessel, and an acute (fast, recent) clot develops, causing sudden worsening of angina or new angina. This is a "heart attack".
What is important to understand is that the small/unseen fatty blockages that will break open and cause a heart attack are just as likely (if not more likely) than those big chronic blockages to cause a heart attack.
Simply ballooning open a fatty heart disease blockage in a vessel does NOT cure your "coronary artery disease." If you have a large blockage causing chronic angina, you are surely to have many many many more blockages, from medium to small which can all cause a heart attack.
So the answer to you question depends on whether the drugs are used to treat your angina or your heart disease itself. If you have a large blockage, then you CERTAINLY have a strong indication to continue medications that are targeted to prevent heart attacks and worsening blockages. Considering that, statins, aspirin, beta blockers (latter may also be for angina itself) and such drugs that target heart disease will almost always be continued. This includes drugs that treat underlying causes of heart disease/blockages which include high blood pressure, diabetes, smoking, etc.
For the drugs you may be on for the anginal pain itself (sometimes beta blockers, calcium channel blockers, nitrates, etc)--- these medications may no longer be necessary if your pain subsides after the angioplasty.