SHAPE (Submaximal Heart and Pulmonary Evaluation)
Shortness of breath (SOB) is one of the most common symptoms used by patients as their chief complaint. Evaluation of these patients can be very challenging as the physician considers cardiac, pulmonary, obesity, deconditioned status, sleep apnea and psychologic basis for the symptom. Taking a history to discern whether SOB is a problem with patients can be difficult in itself.
Cardiopulmonary stress testing has been used to assess patients with SOB of unknown etiology for years. These complex tests take an hour to perform and necessitate significant effort by patients, who need to ride a bicycle until they reach their anaerobic threshold and measure the patient’s peak oxygen consumption (peak VO2). In addition, this is a very costly procedure requiring expensive equipment and technical support.
We now have a screening option called SHAPE, short for Submaximal Heart and Lung Evaluation. This 6 minute test can be done on almost any patient as a maximal stress test is not needed. Peak CO2 is measured at rest and during exercise and has been found to be just as reliable if not superior to VO2 measurements. The patient breaths through a mouth piece for one minute, then goes up and down a step (while holding on to the frame) for 3 minutes. Results are interpreted by a cardiologist or pulmonologist and returned to the PCP within 48 hours.
This screening test can help assess a patient in many ways but first one must remember that there are 3 physiologic parameters that drive our ability to bring in O2 and eliminate CO2. The muscular system, including such factors as ATP and hematocrit, the heart and anything that can effect cardiac output and the lungs as well as any disease worsening its ability to exchange O2 and CO2.
As a primer, these are some of the major parameters measured by a SHAPE exam.
- Functional limitation if there is one. FC 1 is normal and FC 2-4 denotes worsening limitations. This is assessed as the VE/VCO2 which is the ability and efficiency of a patient to bring in O2 and eliminate CO2.
- FC and VE/VCO2 are excellent ways to follow patients as interventions are initiated to treat any disorders.
- CO2 at rest before the patient starts the test is called PETCO2 and if abnormal (low) indicates increased pulmonary vascular resistance which usually indicates the right ventricle and pulmonary arteries have been over worked.
- The change in CO2 from rest to peak stress is called the Delta PETCO2 and indicates a decrease in cardiac output and an elevation in pulmonary vascular resistance with exercise. This could also indicate primary pulmonary hypertension.
- Cardiopulmonary reserve can assess how well the 3 wheels are working together.
- CRI or chronotropic response index assesses the neurohumoral response to stress and gives us a handle on the autonomic nervous system.
- Aerobic capacity is assessed as long as the patient works to a critical level (85 %).
- PeCO2 or mixed end tidal CO2 is a formula calculating ETCO2 throughout the stress test and when divided by PETCO2 allows for the differentiation between lung disease, cardiac abnormality and both. This is in patients that are FC 2-4 and have a functional limitation. (PeCO2/PetCO2)
- Decrease in O2 saturation of more than 5 from rest to stress is indicative of lung disease. Cardiopulmonary shunting can also cause desaturation.
Two groups of patients should be considered for SHAPE testing.
A. Patients with unexplained SOB: I never ask patients if they are SOB, but ask what they can do before they get SOB, tired or have to stop exerting themselves. I ask if this has changed in the last few months or within the last year. Many patients that are obese, sedentary, deconditioned or limited in any way from being active should be thought of as having SOB until proven otherwise. This includes most all metabolic syndrome patients and most patients with a BMI over 30.
B. Patients with conditions where SOB and thus a SHAPE test will be used to follow their condition, help guide therapy as well as any appropriate intervention. These conditions include:
- Patients with cardiomyopathies or any patient with an EF < 45.
- Patients with systolic (myocardial infarction) or diastolic (HTN) heart disease who will need optimization of their cardiac output, fluid status, autonomic nervous system, pulmonary status etc, will have quantitative guidance of therapy with the SHAPE results.
- Patients who have, or probably have sleep apnea. Symptomatic, large RV or elevated pulmonary pressures on echo, and patients with a large neck or who snore are a few of the stigmata. The SHAPE can help follow patients on treatment or be used to motivate a patient to undergo a recommended sleep study, or work harder on using appropriate therapy for their sleep apnea.
- Patients with valvular disease like aortic stenosis, aortic insufficiency or mitral stenosis where SOB is a key determinant in the optimal timing of potential valve surgery. For example, a patient with FC 1-2 at baseline who presents with symptoms consistent with SOB can have a quantitative assessment of any change. Historical assessment can be very difficult in many patients and often not possible if they are sedentary.
- Metabolic syndrome patients are usually obese, hypertensive or both. These are patients at risk for cardiopulmonary problems and often sedentary. SHAPE testing can be used to assess their cardiopulmonary system and provide a baseline assessment.
- Patients with DVT and or PE can be followed by cardiopulmonary stress testing and help make difficult decisions, such as needing an umbrella, more quantitative.
In summary, we now have a very easy, inexpensive ($200 reimbursement) and reproducible test to assess patients that are “SOB” or have conditions where assessment of potential SOB is important. Please consider SHAPE testing on these patients. Results will help guide further evaluation as well as allow for serial testing to assess therapy, change in symptoms or as needed to reevaluate the patient.
The report will be returned to the PCP within 48 hours and the summary by the cardiologist or pulmonologist will include these findings and recommendations:
- FC designation 1-4
- Whether there are abnormal cardiac and or pulmonary findings
- Recommendations for cardiac and or pulmonary consultations
- Recommendations for repeat testing and appropriate intervals
Patients with FC 2-3 are recommended to be seen by the appropriate specialist(s).
The following examples of SHAPE results will hopefully increase your comfort and understanding of this test.
Please contact me with any questions or recommendations.
James S Rellas, MD
Dr. Rellas Answers Important Questions About SHAPE Testing
What kind of patients are being tested with SHAPE HF?
Patients being examined by HeartFirst doctors not only include the traditional patients requiring medication and possibly a heart transplant, but now, because of the SHAPE screening test, any person suffering from shortness of breath, whether from obesity, a sedentary lifestyle, or some unknown cause can be effectively tested, diagnosed, and treated.
What are the advantages of SHAPE HF?
The advantages of a Submaximal Heart and Pulmonary Evaluation (SHAPE) HF over traditional cardiopulmonary stress tests include more patients being qualified to take it, the assessment of CO2 transfer as opposed to maximum O2 consumption, and patients don't have to exert as much physical energy. Also, the SHAPE costs less and takes less time to complete.
What clinical advantage does SHAPE HF give a doctor?
SHAPE (Submaximal Heart and Pulmonary Evaluation) gives doctors the ability to quickly and easily discern a patient's Shortness of Breath problem.
Areas of Specialty for Dr. James Rellas - HeartFirst MD
Dr. James Rellas has practiced Cardiology for nearly 20 years in most of the North Dallas, Carrollton and Plano hospitals, Dr. Rellas has become a leader in preventive cardiology as well as cardiac imaging. One of the first cardiologists in the country to become Board Certified in CTA, Dr. Rellas works with Prestonwood Imaging which has the latest in CTA equipment called Dual Source, or 128 Slice-CTA.
Better Diagnosis of Patient through SHAPE HF
SHAPE (Submaximal Heart and Pulmonary Evaluation) gives doctors another dimension of testing for patients to determine whether a Shortness of Breath problem is heart-related, lung-related, or both.
How easy is SHAPE HF to use?
SHAPE (Submaximal Heart and Pulmonary Evaluation) is quick and easy for both the health care professional and the patient, and is able to provide instant results upon completion. SHAPE is even easy to take for patients who use a cane or walker.
How easy is it to understand SHAPE HF reports?
SHAPE (Submaximal Heart and Pulmonary Evaluation) reports and software are easy to understand. For primary care physicians, the reports are neat and organized. It is the job of the cardiologist or pulmonologist to put the results together in an overall clinical picture.
HeartFirst doctors excited about potential of SHAPE HF test
Dr. James Rellas and the doctors at HeartFirst are excited about the potential of SHAPE HF to benefit their patients. Continued research with sleep apnea patients is encouraged.
What type of patients would benefit from SHAPE?
A Submaximal Heart and Pulmonary Evaluation (SHAPE) can assist a variety of patients. Now, any patient suffering from Shortness of Breath can be effectively diagnosed. Shortness of Breath is even more common in patients than chest pain.
How does SHAPE HF help in the therapy decision?
A Submaximal Heart and Pulmonary Evaluation (SHAPE) is a screening test administered by HeartFirst doctors that assesses a heart patient's heart and lung function. It helps cardiologists, diagnose, guide therapy, and optimize treatment for patients suffering from such problems as sleep apnea and shortness of breath.