CAD stands for Coronary Heart Disease , which is a treatable disease that comes from a waxy substance called ''Plaque'' and not the plaque at shows up on your teeth but it's a substance that builds up along the walls of the coronary arteries . These arteries are very important because it helps supply oxygen to the muscles in the heart. Smoking ,High levels of certain fats and cholesterol in the blood, High blood pressure,High levels of sugar in the blood due to insulin resistance or diabetes, and
Blood vessel inflammation . But, many have this disease due to Smoking and the intake in fat and cholesterol. There are very rare signs and symptoms of this disease that's why it is called the silent killer but to treat it you can start with an health diet lifestyle and consider cutting down on fatty foods and low concentrated oils and sweeteners. High blood pressure is often called "the silent killer" because it typically has no symptoms until after it has done significant damage to the heart and arteries.
References
https://www.nhlbi.nih.gov/health/health-topics/topics/cad/treatment.