Brilinta is there to help prevent another heart attack.
When people have heart attacks we typically implant stents, which are metal scaffolds to open the artery.
Your heart, like most of your body isn't particuarly fond of having foreign objects inside of it. It will respond to this like an injury, by trying to form a clot or a "scab" if you will; over the top. This would cause another heart attack in the stent.
Brilinta is a blood thinner, aka anti-platelet that prevents this from happening. Without this medicine you would die.
Typically after about 1 year of having the stent scar tissue, or endothelium forms over the surface, when this occurs you can consider transitioning off brilinta. However being on it longer is a good precaution to avoid another heart attack.
Aspirin is there to help make the brilinta more potent. Going off either will increase your risk for another heart attack.
Both Lisinopril and Metoprolol help to reduce blood pressure. This helps reduce the workload of the heart and also reduces your risk of stroke. The doses of both these medicines for you is very small, if you get good control off these medicines as it is then removing them is a bad idea.
Blood pressure has a rebound effect. So removong the lower dose of meds could put you in a situation where a higher dose is required in the future.
In short all of your meds are lifesaving. I would not advise pulling them.
None of them have any sort of serious adverse effects in the long term. Aspirin and brilints can cause problems with ulcers and bleeding.
Lisinopril and metoprolol both modify your bodies natural hormonal and nervous system mechanics to achieve an effect. Their mechanisms of action are discreet.
The literature you are looking for is this:
That is the AHA/ACC/ESC consensus update on DAPT (Aspirin/Brilinta)
This document is created as the result of a meeting between all the cardiologists, cardiothoracic surgeons, hematologists etc. In the world. Its basically the law.