NUCLEAR STRESS TEST (Lexiscan)
Definition: This is a type of nuclear scanning test also known as myocardial perfusion imagining. The test will show how well blood flows to the heart muscle. The test shows the heart at rest, and indicates changes in blood flow with exercise (also called “stress”). It does require the use of IV injections. *Pregnant patients should not have this test.
Your doctor uses the stress test to determine:
*Extent of a coronary artery blockage
*Prognosis of patients who’ve suffered a heart attack
*Effectiveness of procedures done to improve circulation in coronary arteries
*Cause(s) of chest pain
*Level of exercise that a patient can safely perform
What to expect: Upon arrival, the patient will disrobe from the waist up and will be provided a gown to wear for the duration of the study. The nuclear technician will insert an IV into the hand or arm and inject the “resting dose” of nuclear imaging material. The patient will then go to our waiting area for approximately 45-60 minutes to allow the isotope to circulate and collect in the heart.
After the 1st waiting period, the patient will be placed under the camera in a back-lying position with arms raised above the head. Pictures are obtained for 15 minutes while the patient lies still and relaxed. When these “resting” images are complete, the patient will be brought to the stress area to complete either a treadmill stress portion or a medication stress portion (The type of test ordered is determined by the ordering doctor). If a treadmill stress is done, the patient will be hooked up to a 10-lead EKG and started on a low-level exercise protocol. Every 3 minutes, the speed and elevation of the treadmill increases until the patient reaches a maximum heart rate. When the patient reaches his or her maximum level of exercise, a 2nd dose of nuclear tracer is injected into the IV site to circulate through the bloodstream just like the resting dose did. If, however, a medication stress (Lexiscan or Dobutamine) is used, a slow infusion of medication replaces the treadmill as a method of increasing blood flow in and around the heart. Whatever the method used, if a part of the heart muscle doesn’t receive a normal blood supply, this will show in the pictures that are taken approximately 45 minutes after the 2nd injection.
Preparation: Food/Drink: Because this is a “fasting” study, a patient must withhold food and drinks for AT LEAST 4 hours prior to scheduled test time.
Caffeine: There is also a caffeine restriction – No caffeine for 24 hours prior to test. This includes also caffeinated beverages, such as coffee and pop, as well as items containing caffeine, such as Aspirin and chocolate. We prefer that “Decaf” products are withheld as well, because they contain a small amount of caffeine despite the decaffeinated label.
Medications: Some blood pressure medications will interfere with the exercise portion of the test, due to the fact that they control the heart rate, which prevents the patient from reaching a maximum heart rate during exercise. These medicines, called “Beta Blockers”, “Calcium Channel Blockers” as well as others, have many names, which is one reason it is important that we know what medications our patients currently take. If a patient is on one of these meds, our staff will contact them several days ahead of time to give medication instructions. Those patients receiving the medication stress test (Lexiscan Cardiolite) DO NOT have to stop their blood pressure medications, since there is no exercise involved, and therefore is no need to obtain a high heart rate.
Clothing/Shoes: Should be a comfortable 2-piece outfit. The patient will remove clothing from the waist up and replace it with a gown. Those using the treadmill for the stress portion should wear walking/gym/tennis shoes.
Allergy: The medium used for imaging IS NOT a medication or a dye. It is a nuclear isotope. Those allergic to contrast dye, iodine, or specific medications will not be affected.
Time Required: Expect to be in our office for 3-4 hours for this study. Allow additional time if other testing or doctor appointments are scheduled the same day as the Nuclear stress test.
Getting Results: Unless the doctor makes special arrangements to give same-day results, the patient will be required to make a separate appointment approximately 2 weeks after the test is done. The doctor will explain the results of the study at that time. Special consideration is given for patients needing urgent testing, awaiting surgery, or other emergency situations.
Location: Nuclear stress testing is currently done in our Farmington Hills office and Novi office. It can also be scheduled at area hospitals, such as St. John-Providence, St. John-Providence Park, St. Mary Mercy – Livonia, and William Beaumont Hospital –Royal Oak, for those patients with insurance restrictions. We ask that cancellations are done at least 24-hours in advance due to scheduling limitations.