Andrew McRae: Development of a patient decision aid for ED patients with possible coronary artery disease

Coronary artery disease is the second most common cause of death in Canada. Patients with chest pain and symptoms of acute myocardial infarction (MI, heart attacks) account for over 600,000 emergency department (ED) visits annually in Canada. 85% of these patients do not have an MI, and most are discharged from the ED after a thorough evaluation. Among patients with chest pain who have had an MI ruled out in the ED, the risk of a short-term adverse cardiac event such as death or a subsequent MI is less than 0.5%. However, a large proportion of these patients are referred for further outpatient cardiac testing after ED discharge, leading to an estimated annual healthcare expenditure of over CAD $45,000,000, as well as potential harms from false-positive testing and unnecessary procedures. Reasons for these low-risk referrals include suggestions from specialty practice guidelines, fear of medicolegal complaints related to missed cardiac events, and perceived patient expectations for additional testing. 

An important missing component to the literature on ED evaluation of patients with possible coronary artery disease is the voice of the patient. There is no literature describing patients’ views on the risks and potential benefits of additional testing, and on expectations for communication of diagnosis and prognosis during an ED encounter for chest pain or symptoms of possible MI. 

Improve communication between physicians and patients can reduce unnecessary testing while improving patient experience. 

Prior randomized, controlled trials in the United States have shown that decision aids–tools that help clarify diagnosis, treatment options and patients’ personal values—can reduce additional cardiac testing for low-risk patients from 57% to 37%, while improving patient’s knowledge of their cardiovascular health. However, testing 37% of patients still represents over-testing in the Canadian context. Moreover, the Mayo Clinic tool was developed with minimal patient input and only described patients’ risk of a short-term cardiac event. It did not describe risks and potential benefits of additional testing, alternative diagnoses, or other information that our patient partners have identified as being important.

We believe that a novel decision aid, that addresses patient-important concerns, can both improve patients’ experience in the ED and lead to further reductions in unnecessary testing of low-risk patients. We propose to develop this decision aid for ED patients with possible coronary artery disease in three patient-engaged phases.

Phase 1 involves qualitative interviews with and physician informants. These interviews will elicit data on physicians’ and patients’ views on the risks of cardiac events after ED discharge, weighed against the risks of subsequent testing, and what information patients value after an ED evaluation for symptoms of coronary disease. This patient-important information will feed the development of the decision aid.

Phase 2 will employ a panel of physicians and patients to narrow essential content and format for a decision aid using a modified Delphi process.

Phase 3 involves development and testing of a decision aid for ED patients with symptoms of possible coronary disease. Accepted user-centered design principles will be used to refine the tool in an iterative process. 

The impact of the decision aid on patient experience, patient outcomes and resource utilization will be evaluated in a subsequent prospective trial.