There may be several situations where exercise treadmill testing may be required or recommended as part of an occupational medicine evaluation. They may be part of a pre placement or periodic surveillance exam, a return to work assessment in a physically demanding position or as part of a fitness for duty assessment for follow up assessment after a cardiac or other illness or event. Many non-essential diagnostic tests were recommended to be postponed during the COVID-19 pandemic, either to limit access to health care resources to COVID-19 for emergent needs or due to concern about exposure to either the individual being tested or those performing the assessment.
Consistent with the Centers for Disease Control and Prevention's recommendation1
to reschedule "non-urgent
outpatient visits" and "elective surgeries (guidelines continue to change for different States
as necessary, the American College of Cardiology2
identified stress testing (ECG alone or with imaging [echocardiography, radionuclide, MRI]) for suspected stable ischemic heart disease as procedures which could be deferred until the health care system had the capacity and resources in place to protect both the individual and the one doing the testing. In addition, these exercise treadmill tests create heavy and large exhalations, often are performed in small rooms and in close quarters with an examiner monitoring the individual and his or her EKG and other parameters so may present a hazard to the examiner, and potentially others entering the room prior to sufficient cleaning and airing time.
One article3 suggested that pharmacologic stress tests would be preferred during the COVID-19 pandemic over exercise stress testing due to the risk of droplet production. A shorter time required for pharmacologic testing was also noted as a benefit.
Pharmacologic stress testing may be appropriate in some situations such as in those individuals who are unable to complete the standard exercise stress test or reach the necessary heart rate for valid interpretations. This may include those with decreased functional capacity or with functional impairment due to injury, arthritis, orthopedic related, body habitus, fatigue or other reasons where a maximal heart rate might not be able to be achieved due to non-ischemic reasons. The pharmacologic stress test might also be indicated when the use of beta-blockers or other negative chronotropic agents would limit the ability to reach the desired heart rate response to exercise.
Although there may be a concern with droplet production during exercise, with appropriate distancing, the use of face covering by the examinee, and appropriate respiratory PPE by the examiner, this could mostly be addressed. However, ventilation of the room and time before reoccupying along with cleaning of equipment and surfaces may present real challenges. Facilities performing exercise stress testing should consider their current number of air changes/per hour
in determining if it is safe to provide the service under those conditions. The CDC has offered guidance on airborne contaminant removal based on air changes/hour8
. Of course, the use of a face covering during exercise may be difficult for some individuals and might possibly limit the ability to reach the exercise goal.
Pharmacologic stress tests have a much lower sensitivity than exercise stress testing, however the specificity and positive predictive value is higher.
For those occupational exercise stress tests where the concern is not only the presence or absence of ischemia but the ability to reach an appropriate level of exertion and have specific METS or max V02 criteria, a pharmacologic stress test would not be sufficient. Examples would include fire fighters4, law enforcement officers5 or airmen6 or commercial motor vehicle operators.7
Non-essential testing that entails any risk of exposure to the examiner or examinee may be postponed during the pandemic. Periodic exercise stress testing in the asymptomatic worker could be deferred for several months without significant risk. For applicants or candidates, limited certification or clearance could be considered, and once testing is permitted. Some agencies have been willing to allow examining occupational medicine physicians to temporarily clear individuals, such as firefighters, based on prior testing or clinical evaluation by the physician. Contact your client/local agency/local department of health for specific guidance