If an expert panel can agree on the appropriate indications for coronary angiography (imaging of the heart after injecting a dye to track blood flow and detect blockages) following a heart attack, it will permit development of a guideline for clinicians to follow when using this procedure. However, expert agreement is not unilateral, finds a study supported by the Agency for Health Care Policy and Research (HS08071).
A multispecialty panel of nine medical experts rated the appropriateness of using coronary angiography to diagnose heart disease in a group of patients who had just suffered a heart attack (acute myocardial infarction, AMI). In round one, the panel rated the appropriateness of the procedure on a 9-point scale for patients presenting with each of the indications for the procedure, and then rated it again in round two after a panel discussion.
The experts agreed that angiography was inappropriate for older patients with no post-AMI angina, good ventricular function, maximal medical therapy, negative or no noninvasive test results, and no evidence of silent ischemia. They also tended to agree that angiography was highly appropriate for younger patients with positive results in noninvasive tests, such as the treadmill stress test. However, variability in expert opinion significantly contributed to overall variability in appropriateness ratings. Experts who had strong beliefs about the benefits of angiography tended to rate all indications as more appropriate than those with less strong beliefs in the procedure's benefits, notes Barbara J. McNeil, of Harvard Medical School.
Experts disagreed the most about the usefulness of coronary angiography within 12 hours of symptom onset for five indications describing older patients with shock complicating their AMI. Although there was more agreement on ratings in round two than in round one, the panel discussion following round one was clearly unable to resolve the differences in opinion regarding the impact of age, shock, pulmonary edema, post-AMI angina with mild exertion, and silent ischemia on angiography appropriateness after an AMI. However, overall, the presence of clinical complications far outweighed the impact of patient age or time since symptom onset in viewing angiography as useful during hospitalization for AMI.
See "Understanding variability in physician ratings of the appropriateness of coronary angiography after acute myocardial infarction," by Mary Beth Landrum, Ph.D., Barbara J. McNeil, M.D., Laurie Silva, Ph.D., and Sharon-Lise T. Normand, Ph.D., in the April 1999 Journal of Clinical Epidemiology 52(4), pp. 309-319.