What Causes Angina?

You should always take chest pain seriously. However, it isn’t always a sign of a heart attack. 

“Sudden or acute chest pain that persists requires immediate medical attention,” says Raymond Kwong, MD, MPH, a Mass General Brigham cardiologist who cares for patients at Brigham and Women’s Hospital. “But chest pain that comes and goes, such as angina, is more common.”

Just because chest pain doesn’t signal a heart attack doesn’t mean it’s not serious. Angina is a sign of coronary artery disease. Most of the time, angina is not serious, especially when doctors treat a patient with highly effective medications. Still, you need medical care for the underlying cause — without interventions, coronary artery disease can be dangerous and lead to potentially life-threatening heart problems.

What causes angina?

Coronary artery disease causes most cases of angina. According to the National Institutes of Health (NIH), approximately 20 million Americans have coronary artery disease. Many of them experience angina as a symptom. 

“Plaque deposits build up inside the coronary arteries, restricting the flow of oxygen-rich blood to the heart,” says Dr. Kwong. “We call this lack of blood flow ischemia. Angina or chest pain is a warning sign that your heart is ischemic, which means it’s not getting enough blood.” 

Angina warning signs

Everyone experiences angina or chest pain differently. Some people feel pressure or a squeezing sensation in their chest. This pain or pressure may affect other parts of the upper body, such as the shoulders, arms, neck, back, and jaw. 

 In addition to chest pain, you may also have:

• Extreme fatigue
  
• Nausea or vomiting
  
• Profuse sweating
  
• Shortness of breath

While chest pain doesn’t necessarily mean you’re having a heart attack, it’s still a major warning sign and could be a medical emergency. If your chest pain is sudden and doesn’t go away, seek medical attention immediately.  

Types of angina  

If you’re having chest pain but doctors determine it’s not a heart attack, you may have one of these types of angina: 

Stable angina 

Stable angina (also called angina pectoris) is the most common type. “The chest pain follows a certain predictable pattern,” says Dr. Kwong. “It comes on during or after physical activity, or a stressful period. Plus, the pain doesn’t last long and gets better with rest or medication.”  

Unstable angina 

With unstable angina, you feel chest pain suddenly and unexpectedly, regardless of whether you’re resting or exerting yourself. The pain is stronger and lasts longer (at least 20 minutes) than with stable angina. Unstable angina can be a sign of an artery blockage that can lead to a heart attack. It’s a medical emergency.  

Microvascular angina 

Microvascular disease (MVD) causes microvascular angina, a type of chest pain that’s more common in women or people assigned female at birth. Damage to the small blood vessels that branch off the coronary arteries causes MVD. Microvascular angina causes intense chest pain that may last for up to 30 minutes. The pain can come on with daily activities, physical exertion, or rest.  

Variant angina 

Younger, healthy people are more likely to experience variant angina (also called Prinzmetal’s variant angina and angina inversa). Spasms in the coronary arteries cause this type of angina, which may occur during rest or sleep. 

Diagnosing angina

Sudden chest pain is a top heart attack warning sign. An electrocardiogram (EKG/ECG) and blood tests can detect or rule out a heart attack. To diagnose chronic chest pain that isn’t an emergency (such as stable angina), your health care provider evaluates your symptoms and risk factors. 

“Someone diagnosed with coronary artery disease or risk factors like high blood pressure, high cholesterol, diabetes, or a history of smoking is more likely to have angina,” says Dr. Kwong. 

Providers typically start with stress echocardiograms to determine the cause of angina. This ultrasound test captures images of your heart while you walk on a treadmill or pedal a stationary bike. If you’re unable to exercise, you may receive an IV medication to increase your heart rate and stress your heart. 

Testing if coronary artery disease is causing your angina

If your angina symptoms continue but are mild and manageable with medications, you may not need additional testing. But providers also may order these tests to see if coronary artery disease is causing angina:

• CT coronary angiogram (CTCA): An injectable dye moves through the coronary arteries while a specialized CT scanner captures images. 
• Single-photon emission CT (SPECT) scan: A safe, injectable or oral radioactive substance called a radiotracer travels through the coronary arteries while a specialized nuclear imaging camera captures images.

“A CTCA test only looks at blood vessels, not the heart muscle,” says Dr. Kwong. “A normal result can’t always show whether narrowed arteries or another issue are causing the chest pain.” SPECT scans also provide images of the heart muscle. However, they aren’t as accurate as other tests. As Dr. Kwong explains, this is why there’s been a shift in the last decade for providers to use cardiac positron emission tomography (PET) scans and stress cardiac MRIs to diagnose angina.

• Stress cardiac MRIs use an IV medication, and strong magnetic fields and radio waves (an MRI), to capture heart images and blood flow to the heart.
  
• PET scans use an injectable radiotracer (similar to a SPECT scan) to create 3D images of the heart from different angles.

Using cardiac MRIs with artificial intelligence (AI) to diagnose angina

“Cardiac MRIs are a powerful diagnostic tool that shows the health of the heart muscle with high accuracy,” says Dr. Kwong. “It looks at how well the heart is contracting (like a stress echo), as well as blood flow to the heart muscle (like a PET scan). And it provides this information without using radiation.” 

But not all medical centers have this advanced technology. At Mass General Brigham, cardiologists like Dr. Kwong use stress cardiac MRIs that incorporate artificial intelligence (AI). “AI manages the scanning step with a high 90% degree of accuracy,” explains Dr. Kwong. “It shortens the imaging process for both the patient and staff, reducing scan time on average by about 30%.”

Thanks to AI advancements, Mass General Brigham cardiologists perform more cardiac MRIs. “The wait time to get one of these tests went from 6 weeks to two or 3 days, which means patients have a diagnosis and start treatment faster,” says Dr. Kwong. 

Angina treatments 

Treatments for angina depend on the type you have, your chest pain severity, and the underlying cause. Cardiologists always start with the least invasive treatment first.

Nonsurgical angina treatments

Most people with angina don’t need surgery. They benefit from:

• Lifestyle changes, such as a heart-healthy diet, exercise, and managing conditions like high cholesterol, diabetes, or obesity
• Beta blockers or other medications to control high blood pressure (hypertension)
• Heart medications, such as ranolazine, to minimize chronic chest pain (stable angina)
• Nitrates to open (dilate) the coronary arteries so more blood reaches the heart

Surgical angina treatments

Severe coronary artery disease often requires one of these surgeries:

• Angioplasty and stenting to open a blocked coronary artery and place a stent (small metal coil) that keeps the artery open
• Coronary bypass surgery to create a new pathway around a blocked artery, improving blood flow to the heart

While angina is worrisome, Dr. Kwong notes that lifestyle changes and medications are highly effective in easing chest pain. “The chances of someone with stable angina having a heart attack or dying from it is extremely low,” he says. “Still, it’s important to regularly see your cardiologist to protect your heart health.”