This study looks at how well a new medicine, AZD0780, works compared to a placebo (a pill with no medicine) for people with heart problems or at high risk for heart problems. The medicine is an oral PCSK9 inhibitor, which helps lower bad cholesterol. Participants will be in the study from when they start taking the medicine until the study ends. People can join if they have had heart problems like heart attacks or strokes, or if they have risk factors like high cholesterol, diabetes, or are older.

Key Points:

• **Length of Study**: Participants stay in the study until the study closure visit after the primary analysis date.
• **Eligibility**: Must have a history of heart problems or risk factors like high cholesterol, diabetes, or being older.
• **Exclusions**: Cannot have certain medical conditions or treatments that could interfere with study results.