How is this test different than a standard treadmill stress test?
Cardiopulmonary Metabolic Exercise Stress Testing (CMET) is a non-invasive measurement of cardiac, respiratory and functional capacities that replaces the traditional model of treadmill stress testing. It is a sensitive diagnostic tool that provides extensive data on each of these areas for the physician.
With prevalence adjusted risk stratification, CMET provides the best Sensitivity and Specificity of all non-invasive tests-thus a higher predictive value.
What are some common problems with traditional stress testing?
1. Low sensitivity and specificity
2. Higher incidence of false positives
3. Poor estimate of O2 consumption
4. Limited estimate of functional capacity & METS
5. Often inappropriate protocols & poor patient tolerability
6. High rate of indeterminate & inconsistent results and poor reproducibility
My practice has its own stress test equipment. Why do I need this test?
Having Frontera perform testing in your office will free up your time and allow you to see more patients. You will receive far more comprehensive data on your patients and receive higher reimbursements than just performing cardiac stress tests.
Depending on your patient population and number of referrals per week, Frontera would schedule one day a week for the CMET patient testing. On the other days of the week, the physician can continue to perform their standard stress tests as usual.
How accurate is CMET?
According to Dr. Donald Zavala, specificity is 95%, that is to say, if the test is negative then it is accurate 95% of the time. If the test is positive (sensitivity), then accuracy is about the same as treadmill stress testing, for example 68-70 percent.
How is this test different than a stress echo?
CMET complements many other tests for cardiovascular and pulmonary disorders limiting exercise. First, not all patients with myocardial ischemia have chest pain, and not all cardiologists actually do the echo immediately after the exercise test or during exercise. Under these conditions the myocardial oxygen supply oxygen requirements balance are not the same as it was during exercise at a level that the patient likes to function. Therefore, the readings could be spuriously normal.
But the major point that physicians should be aware of is that the CMET is the most comprehensive test to diagnose shortness of breath and fatigue with exercise. For instance, many patients with shortness of breath or exercise fatigue cannot be diagnosed with the stress echo and thallium scan. These are the type of patients who become unhappy with their physician because the physician does not know how to get at these diagnoses, unless they are familiar with CMET. There is no test in medicine that gives as much information for such little money as CMET. It is regarded as the most economical test in the cardiopulmonary medicine because if you do this test first in the work-up, it will not be necessary to do many other tests that would be read as normal.
What is most unique about this test?
Although most complete physical examinations include a check of the heart at rest with an electrocardiogram (ECG or EKG), the results are limited to what is seen at the time of the examination and are limited in their ability to detect disease or dysfunction. The CMET challenges the cardiopulmonary (heart and lungs) system and the entire physical body to determine the capacity of each system. This type of test provide tremendous amount of information that relates not only present health but also to future health outcomes such as your risk for cardiovascular or pulmonary disease and your capacity to do any type of physical activity.
The advantage of this type of test can be illustrated by the analogy of a mechanic taking an automobile for a test drive as opposed to trying to evaluate the vehicle while idling or even turned off.
What type of patients are proper candidates for the test?
Although many patients would benefit from this test, most all patients who experience breathlessness, chest or abdominal discomfort, and lack of stamina are appropriate candidates. Other ideal candidates include patients with diabetes, elevated risk factors such as lipid disorders, smoking, hypertension, sedentary living and “dismetabolic syndrome X.” Known heart or pulmonary disease patients can be evaluated for the severity, risk level and functional outcomes. Contraindication guidelines provided describe inappropriate candidates such as high-risk patients who are unstable, with acute infections or life-threatening symptoms.
What are some clinical applications for the CMET test?
1. To detect an abnormality causing unexplained shortness of breath or inability to exercise. In particular, to determine whether the shortness of breath and inability to exercise is due to a heart or lung problem.
2. To identify the cause of shortness of breath not revealed by pulmonary function tests, electrocardiogram or other procedures.
3. To detect lung disease that is apparent only during exercise.
4. In people seeking disability evaluation, to determine the level of physical exertion they are able to achieve.
Why use cardiopulmonary exercise stress testing with a pulmonary evaluation?
This test combines measurements of the patient’s ventilation, respiratory gas exchange in the lungs, electrocardiogram (EKG), blood pressure and physical responses before, during and following a progressive exercise protocol. Consequently, it provides the physician with an integrated view of the pathological and physiological limitations unavailable by any other means. Many health professionals and patients are discovering the benefits and how the data may be used in a wide variety of applications.
What is the difference between a Bike Ergometer and a Treadmill CMET?
The argument for the treadmill focuses on the fact that the oxygen uptake (VO2max) is generally 10 percent higher than what we see on the bike. This is well-documented as a functional difference that has an important impact in sports medicine and athletic performance. However, the primary issue in this type of testing in the clinical environment is whether any difference exists in the diagnostic outcomes with using one versus the other. The purpose of using progressive exercise is to challenge the cardiovascular and respiratory systems under monitored conditions. Consequently, it is not the absolute VO2 or workloads that the patient can achieve but rather the relative workloads or percent of maximum (%VO2max) that the patient achieves that impact the diagnostic sensitivity. Both the bike and treadmill produce maximal efforts that produce peak heart rates and peak VO2 values that indicate the limitations of heart, lungs, circulation or conditioning.
Some other advantages in using a Bike Ergometer include:
1. Patients with knee or hip problems tend to perform better and report being more comfortable on the bike.
2. It is independent of the patient’s weight (treadmill results are influenced by weight).
3. Holding handle bars does not affect the test (holding treadmill handrails can significantly affect results).
How many patients can be tested in a single day?
The test takes roughly an hour to perform, which allows for up to six patients to be tested in a normal business day.
How do I interpret the results?
Frontera compiles and scores the test results into a concise, easy-to-read format. The results are reviewed by a team that is under the supervision of the Medical Director and significantly helps with diagnoses.
Do most insurance plans cover the test?
Yes. Most major insurance plans, including Medicare, cover the test.
Do I need additional insurance to have this test performed in my office?
No. This is considered a low-risk procedure. However, insurance plans vary, so check with your provider to make sure.
Do I need to be present during the whole test?
The standard of care for this type of test requires a physician to be in the building while the test is conducted.
Where do I learn more about the test?
Check out our website for insightful articles and case studies, or submit a request form on our website and we will forward you more information.