Is a person who has been using cocaine for several years at a big risk for a heart attack if they're only a teenager?

Yes. A person can overdose on Cocaine and die at any time. Cocaine weakens the blood vessels and the connections between them. A person can die suddenly from a dissecting aneurysm. Chronic Cocaine use can cause irreversible damage to the brain. The substances used to "cut" the coke can cause severe liver damage. Cocaine addicts will either end up in jail, a hospital or the cemetery.
Yes! Yes they can die with a sudden death arrythmia even as a teenager.
Yes. When used yor blood pressure increases plus it causes the arteries of your heart to (vasoconstrict) close up and lead to a heart attack. Other effects of cocaine are stroke, and arrhythmias which can also be fatal.Although no definitive treatment is available we have promising medications that can help both with withdrawal and dependency .