Advanced Stress Testing

What is Advanced Stress Testing?

Advanced stress testing is a noninvasive imaging test. It shows how well blood reaches your heart muscle, first at rest and then under stress. The test uses positron emission tomography combined with computed tomography. That combination is usually shortened to PET/CT. You receive a small amount of a radioactive tracer through a vein. The scanner then maps where that tracer travels in the heart muscle. Most patients who need this test cannot exercise hard enough. So the stress phase uses a medication rather than a treadmill. That medication widens the coronary arteries and increases blood flow. Some areas may receive less blood during stress than at rest. Those areas suggest a narrowed artery. Cardiac PET produces sharper images than older nuclear scans. It also works better in people who are overweight, and it often uses a lower radiation dose. The whole visit usually takes about one to two hours. You go home the same day.

Why Dr. Nanavati may recommend this

Advanced stress testing answers a specific question. Is any part of your heart muscle being shortchanged on blood flow? That matters for chest pain and for shortness of breath. It also guides the decision about whether a blockage needs treatment.

Dr. Nanavati may recommend it if you have:

• Chest pain, pressure, or jaw and arm discomfort that could be cardiac.
• Unexplained shortness of breath or a sharp drop in exercise tolerance.
• Known or suspected coronary artery disease that needs to be graded before deciding on treatment.
• An abnormal or inconclusive treadmill stress test or electrocardiogram.
• Difficulty walking on a treadmill because of joint disease, lung disease, or general deconditioning.
• A body habitus or breast tissue that degraded the images on a previous nuclear scan.
• A need for cardiac clearance before major noncardiac surgery.

The American Heart Association describes coronary artery disease and its warning signs. It is also worth reading the National Heart, Lung, and Blood Institute overview of heart tests.

How to prepare

Preparation for this test is stricter than for most. Skipping a step can invalidate the result.

• Avoid all caffeine for at least 12 to 24 hours before the test. That means coffee, tea, soda, energy drinks, chocolate, and decaf, which still contains a little caffeine. Caffeine blocks the stress medication and can make the scan useless.
• Do not eat for about four to six hours beforehand. Plain water is usually allowed.
• Ask specifically about theophylline, aminophylline, and dipyridamole. These often need to be stopped days in advance.
• Ask whether to hold beta blockers, nitrates, or diabetes medications on the morning of the test. Bring your medications with you so you can take them after.
• Wear a comfortable two piece outfit and leave jewelry at home. You will need to be bare from the waist up under a gown.
• Tell the office if you have asthma or emphysema, are pregnant or breastfeeding, or have had a reaction to a stress agent before.
• Allow up to two hours. Arrange a ride if you are told you may receive sedation.

What happens during the procedure

You lie flat on a padded table. The table slides into the open ring of the scanner. It is not a closed tunnel, and you can see out.

Electrodes go on your chest so the team can watch your heart rhythm continuously. A blood pressure cuff goes on your arm. A small intravenous line is started in a vein, usually in the arm.

The rest images come first. A tracer goes in through the line. The scanner then records images for a few minutes while you lie still and breathe normally. You feel nothing from the tracer itself.

Next comes the stress phase. The stress medication goes in through the same line over a short period. Many people feel warm, flushed, or briefly short of breath. Some notice a headache or a fluttering in the chest. This is expected, and it usually passes within a minute or two after the infusion ends. Tell the staff what you feel. A reversing medication can be given if the sensation is unpleasant.

A second dose of tracer is given at peak stress. The scanner then records the stress images. The intravenous line comes out, and the team watches you briefly before you leave.

Recovery and results

Most people feel back to normal within minutes of the stress phase ending. You can eat and drink right away. Unless you were sedated, you can usually drive yourself home and return to work the same day. Drinking extra water for the rest of the day helps clear the tracer. The tracer leaves your body naturally within hours.

A physician trained in cardiac imaging reads the images. The report typically reaches Dr. Nanavati within a few days. He then discusses the findings with you at a follow-up visit or by phone.

A normal scan is strong reassurance that no major artery is significantly narrowed, and often means the next step is prevention rather than procedures. A mildly abnormal scan may be managed with medication, cholesterol control, and lifestyle change, sometimes supported by advanced lipid testing. A clearly abnormal scan may involve a large area of heart muscle. That can lead to a coronary angiogram and, if needed, angioplasty or coronary stenting.

Risks and safety

Cardiac PET/CT stress testing is considered safe, and it is done thousands of times a day in the United States. Still, it is not risk free.

The stress medication commonly causes brief flushing, headache, chest tightness, shortness of breath, or nausea. These effects fade quickly. Vasodilator medications can trigger wheezing in people with asthma or significant emphysema. That is why your lung history matters. Serious reactions such as a heart attack or a dangerous rhythm are rare. The test also runs with continuous monitoring and emergency equipment on hand.

The test involves ionizing radiation. The dose from cardiac PET is generally lower than from older nuclear stress tests. We use it because the information gained outweighs the small theoretical long term risk. Tell your care team if you are or might be pregnant, since the test is usually deferred in pregnancy.

Call 911 if you develop severe chest pain or fainting after you get home. Do not wait for the report.

Related services and conditions

• Nuclear stress test, a related imaging alternative.
• Coronary CT angiography to look directly at the arteries.
• Coronary artery disease, the condition most often found.
• IHD evaluation, the broader ischemic heart disease workup.
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