Coronary artery disease (CAD) is a condition where the arteries supplying blood to your heart gradually narrow due to a buildup of fatty deposits called plaque. It affects an estimated 254 million people worldwide and caused roughly 9 million deaths globally in 2021, making it the single leading cause of death on the planet. The disease develops slowly over years or even decades, often producing no symptoms until an artery is severely blocked.
How Plaque Builds Up in Your Arteries
CAD begins with damage to the inner lining of a coronary artery. High blood pressure, high cholesterol, smoking, and chronic inflammation can all injure this delicate lining, which is only one cell thick. Once damaged, LDL cholesterol (the “bad” kind) seeps into the artery wall and gets trapped there. White blood cells rush in to clean up the cholesterol, but they become engorged and die, forming a soft, fatty layer called a fatty streak. This is the earliest visible sign of the disease, and it can appear as early as adolescence.
Over time, the fatty streak grows. Smooth muscle cells migrate into the area and produce a tough fibrous cap over the fatty core, creating what doctors call a fibrous plaque. Beneath that cap sits a mix of dead cells, cholesterol, and debris known as the necrotic core. As calcium deposits accumulate, the plaque hardens. At this advanced stage, reversal becomes unlikely. The artery progressively narrows, reducing blood flow to the heart muscle.
The most dangerous moment comes if the fibrous cap cracks or ruptures. When that happens, the body treats it like a wound and forms a blood clot on the spot. That clot can partially or completely block the artery within minutes, triggering a heart attack.
Symptoms You Might Notice
CAD is sometimes called a “silent” disease because many people have no symptoms at all until they experience a heart attack or another serious event. When symptoms do appear, they typically show up during physical activity or emotional stress, when your heart needs more blood than the narrowed arteries can deliver.
The hallmark symptom is angina: chest pain or discomfort that feels like pressure, squeezing, tightness, or burning. It often spreads to the shoulders, arms, neck, jaw, or back. Shortness of breath during activity is another common sign. These symptoms usually ease with rest and return when you’re active again.
Women are somewhat less likely than men to experience classic chest pain during a heart attack. Instead, women more often report extreme tiredness, nausea, stomach pain, dizziness, or a vague pressure in the chest. Because these symptoms can mimic indigestion or fatigue, heart disease in women is more frequently missed or dismissed.
What Raises Your Risk
Several well-established factors increase your chances of developing CAD. High blood pressure (generally defined as 140/90 mmHg or above) forces the heart to work harder and damages artery walls over time. High total cholesterol, particularly above about 4.65 mmol/L (roughly 180 mg/dL), shows a strong, graded relationship with coronary disease: the higher the number, the greater the risk. Smoking, diabetes, obesity, and a sedentary lifestyle all contribute as well.
Age and family history also matter. Men face higher risk starting around age 45, while women’s risk rises sharply after menopause. Having a parent or sibling who developed heart disease at a young age increases your own likelihood. Risk calculators like the Framingham score combine several of these factors (age, sex, blood pressure, cholesterol, smoking status, and diabetes) to estimate your overall 10-year probability of a heart event.
How CAD Is Diagnosed
An electrocardiogram (ECG) is typically the first test. It records the electrical signals of your heartbeat and can reveal irregular rhythms or signs of a current or past heart attack. The test is quick, painless, and involves small sticky patches placed on your chest.
If your resting ECG looks normal but your doctor suspects CAD, the next step is usually a stress test. You walk on a treadmill or ride a stationary bike while your heart is monitored. Because exercise forces the heart to pump harder, problems that don’t show up at rest become visible. A nuclear stress test adds a small amount of radioactive tracer injected into a vein, which lets an imaging machine map blood flow through your heart and pinpoint areas that aren’t getting enough.
When these tests suggest significant blockages, coronary angiography provides the most detailed picture. A thin, flexible tube is threaded through a blood vessel in the wrist or groin and guided to the heart. Dye injected through the tube makes the coronary arteries visible on X-ray, showing exactly where and how severely they’re narrowed. Treatments can sometimes be performed during the same procedure.
Treatment Options
Treatment depends on how severe the disease is and how many arteries are affected. For mild to moderate CAD, medications and lifestyle changes are the primary approach. Cholesterol-lowering drugs reduce plaque growth and can stabilize existing plaque so it’s less likely to rupture. Blood-thinning medications help prevent clots from forming at plaque sites. Blood pressure drugs reduce the workload on the heart and protect artery walls.
When blockages are more severe, two procedures can restore blood flow. Percutaneous coronary intervention (commonly called angioplasty with stenting) threads a balloon-tipped catheter to the blockage, inflates it to widen the artery, and leaves behind a small mesh tube called a stent to keep the artery open. This tends to work best for patients with one or two discrete blockages and otherwise healthy heart function.
Coronary artery bypass grafting (CABG) is a surgical option typically reserved for more extensive disease. A surgeon takes a healthy blood vessel from another part of the body, usually the chest wall or leg, and grafts it around the blocked section. Bypass surgery tends to produce better long-term outcomes in patients with blockages in three or more arteries, disease of the left main artery, weakened heart muscle, or diabetes. In one major trial of patients with diabetes, seven-year survival was significantly higher after bypass surgery compared to angioplasty alone.
What Happens Without Treatment
Left unmanaged, CAD follows a predictable and dangerous path. As arteries narrow further, the heart muscle is chronically starved of oxygen. This can lead to heart failure, where the heart becomes too weak to pump blood effectively. You might notice increasing fatigue, swelling in the legs and ankles, and worsening shortness of breath, even at rest.
A heart attack occurs when a plaque ruptures and a clot suddenly blocks an artery. The heart muscle downstream begins to die within minutes. Even if you survive, the damaged area is replaced by scar tissue that can’t contract, permanently weakening the heart’s pumping ability. This decline in pump function is a clear marker of progression toward chronic heart failure. Irregular heart rhythms (arrhythmias) are another common complication after a heart attack and can, in the worst case, cause sudden cardiac death.
Lifestyle Changes That Slow the Disease
Physical activity is one of the most effective tools for both prevention and management. The American College of Cardiology recommends at least 30 minutes of moderate-intensity exercise on five or more days per week, or 20 minutes of vigorous exercise three days per week. Moderate intensity means activities like brisk walking, cycling on flat ground, or swimming at a comfortable pace. For people already diagnosed with CAD, cardiac rehabilitation programs typically prescribe 30 to 60 minutes daily at 40 to 80 percent of peak heart rate, combined with resistance and flexibility training two to three days per week.
Diet matters just as much. Reducing saturated fat, trans fat, and sodium while increasing fruits, vegetables, whole grains, and healthy fats (like olive oil and fatty fish) can lower LDL cholesterol and blood pressure. Quitting smoking delivers rapid benefits: within a year, your excess risk of heart disease drops by about half. Managing stress, maintaining a healthy weight, and keeping blood sugar under control if you have diabetes all contribute to slowing plaque progression and reducing the chance of a life-threatening event.