Coronary angiography, a diagnostic procedure that x-rays the heart anatomy and blood vessels after infusion of a contrast dye, is critical to patient care following a heart attack. It helps physicians visualize the extent of heart damage and narrowing of blood vessels following the attack to determine the need for coronary artery bypass graft (CABG) surgery or coronary angioplasty. Nevertheless, a recent study found that 42 percent of people who suffered a heart attack (acute myocardial infarction, AMI) from various U.S. regions did not undergo needed coronary angiography following the attack.
The study, which was supported by the Agency for Healthcare Research and Quality (HS08071), showed that underuse of the procedure ranged from 24 to 58 percent across regions. Disparities in care were related both to sociodemographic factors and the technological capabilities of hospitals. However, regional variation in underuse was not related to regional differences in patient or hospital characteristics.
Researchers from Harvard University, Brigham & Women's Hospital, Boston University, and St. Louis University used data from the Cooperative Cardiovascular Project on 9,458 Medicare patients in 95 hospital referral regions in seven States. The patients were hospitalized for AMI in 1994 and 1995, and angiography was rated necessary based on clinical criteria. The researchers calculated underuse of the procedure based on patient and hospital characteristics.
The odds of not undergoing necessary angiography were 49 percent higher among black patients compared with white patients and 28 percent higher among females compared with males. Among patients treated by a generalist physician, the odds of not undergoing necessary angiography were more than twice that of patients treated by a cardiologist.
Patients treated at a hospital with angiography or angiography and CABG services were much more likely to receive needed angiography than those treated at hospitals that lacked these capabilities. Finally, patients with certain clinical characteristics—such as prior CABG surgery, congestive heart failure, and renal insufficiency—were less likely to undergo angiography. However, some of these conditions may make the procedure more risky than beneficial and may represent appropriate clinical judgment.
More details are in "Understanding individual and small area variation in the underuse of coronary angiography following acute myocardial infarction," by Pushkal P. Garg, M.D., Mary Beth Landrum, Ph.D., Sharon-Lise T. Normand, Ph.D., and others, in Medical Care 40(7), pp. 614-626, 2002.