No, a nuclear stress test doesn't show all blockages, especially mild ones, but it's highly effective at identifying significant blockages (usually 70% or more) that restrict blood flow to the heart muscle during stress, indicating coronary artery disease (CAD). It works by revealing poor blood flow patterns, but very small plaques or those not affecting flow aren't always detected; if results are abnormal, a more detailed test like a coronary angiogram might be needed.
What a stress test tells your doctor
Nuclear stress tests can also give doctors information about your arteries and whether they might be narrowed or blocked because of coronary artery disease.
Cardiac catheterization and angiogram.
This test can see blockages in the heart arteries. A doctor places a long, thin flexible tube called a catheter in a blood vessel, usually in the groin or wrist.
A stress test is generally highly accurate for spotting blocked arteries. Adding imaging tests, like nuclear imaging or an echocardiogram, makes them more reliable. However, without these extra images, stress tests might miss smaller blockages or issues.
While stress tests have high accuracy rates (80 to 85 percent), they often cannot detect smaller blockages, especially those due to atherosclerosis, a condition where a combination of fat, calcium and cholesterol traveling through the bloodstream forms plaque buildups on artery walls.
High accuracy: It provides detailed images of the heart's blood flow at rest and under stress, making it more accurate for the assessment of coronary artery disease than a stress ECG but, more or less at the same level as a stress echocardiogram.
A coronary calcium scan is a special computerized tomography (CT) scan of the heart. It looks for calcium deposits in the heart arteries. A buildup of calcium can narrow the arteries and reduce blood flow to the heart. A coronary calcium scan may show coronary artery disease before you have symptoms.
Other signs you may have atherosclerosis (blocked arteries)
Specialists recommend a coronary CT scan as the method of choice to rule out obstructive coronary stenosis (OCS) to avoid patients having to undergo an invasive angiogram. However, doctors only recommend this method for patients with a pretest probability of coronary heart disease of fifty percent or less.
Standard stress tests analyze heart electrical activity during exercise, which may not always reveal underlying problems. The test may miss blockages in smaller coronary arteries and those that do not cause substantial blood flow restrictions during the testing period.
Nearly half of all Americans have one of the three major risk factors for coronary artery disease: smoking, high blood pressure and high cholesterol. High blood pressure is often called “the silent killer” because you may have it without experiencing any symptoms.
What are the next steps after a nuclear stress test? If your nuclear stress test is abnormal, which suggests a significant blockage in your coronary arteries, you will need further testing. “The next step is to visualize the coronary artery directly, either with a CT scan or a cardiac catheterization,” Dr. Kelly says.
With caveats, the procedure still has a valuable role to play in diagnosing worrisome symptoms like chest pain—especially in older men with risk factors for heart disease. "An exercise stress test is not 100% accurate—no medical test is," Dr. Bhatt says. "But it helps decide what the next step should be."
A nuclear stress test can diagnose coronary artery disease and show how severe the condition is. Create a treatment plan. If you have coronary artery disease, a nuclear stress test can tell your healthcare team how well treatment is working. The test also shows how much exercise your heart can handle.
Risks of Stress Test
You may feel squeezing, pressure, heaviness, tightness or pain in the chest. It may feel like somebody is standing on your chest. The chest pain usually affects the middle or left side of the chest.
Coronary arteries with severe blockages, up to 99%, can often be treated with traditional stenting procedure. Once an artery becomes 100% blocked, it is considered a coronary chronic total occlusion, or CTO. Specialized equipment, techniques and physician training are required to open the artery with a stent.
It may seem counterintuitive, but it is entirely possible to have normal blood pressure while still having clogged arteries.
The symptoms of an artery blockage include chest pain and tightness, and shortness of breath. Imagine driving through a tunnel.
Calcium scans can be more effective at identifying plaque build-up than compared to a stress test in some instances. For example, if all of a person's arteries are blocked, a stress test's measurement would look the same across the board and not show a concern.
Many people don't know they have plaque buildup until they have a medical emergency like a heart attack or stroke. Coronary artery disease (CAD, which can lead to a heart attack) happens in the arteries that supply blood to your heart. You may experience: Shortness of breath (dyspnea) during light physical activity.
The majority of heart attacks are caused by cholesterol deposits (plaques) in the coronary arteries that are not detected by even the most advanced stress tests. These deposits are non-obstructive, meaning they do not significantly block blood flow during stress testing.
MRI is much more accurate than both nuclear and echo stress, and a cardiac stress MRI provides more information than perfusion, including viability, function and morphology, at a much higher resolution than either nuclear or echo,” he says.
Both negative and positive predictive values are better for CCTA compared to stress testing. The results are not surprising as CCTA – like the reference standard by cardiac catheterization – is a test evaluating the coronary anatomy while stress testing assesses myocardial perfusion.