Study finds substantial decrease in use of cardiac imaging procedure

There has been a sharp decline since 2006 in the use of nuclear myocardial perfusion imaging (MPI; an imaging procedure used to determine areas of the heart with decreased blood flow), a decrease that cannot be explained by an increase in other imaging methods, according to a study in the March 26 issue of JAMA.

Nuclear myocardial perfusion imaging accounted for much of the rapid growth in cardiac imaging that occurred from the 1990s through the middle 2000s. Edward J. McNulty, M.D., of Kaiser Permanente Medical Center, San Francisco, and colleagues conducted a study to examine trends in MPI use within a large, community-based population. They obtained patient data for MPI performed from 2000-2011 for members ages 30 years or older from the clinical databases of Kaiser Permanente Northern California, an integrated health care delivery system that provides inpatient and outpatient care for more than 2.3 million adults.

Overall, MPI was used for 302,506 patients at 19 facilities. From 2000 until 2006, MPI use increased by a relative 41 percent. Then between 2006 and 2011, MPI use declined a relative 51 percent. Declines from 2006 to 2011 were greater for outpatients than inpatients (58 percent vs 31 percent) and for persons younger than 65 years. Use of cardiac computed tomography (a newer imaging procedure) increased during this time period, and could have accounted for 5 percent of the observed decline in overall MPI use if performed as a substitute.

"Although the abrupt nature of the decline suggests changing physician behavior played a major role, incident coronary disease, as assessed by [heart attack], also declined [by 27 percent]. We could not determine the relative effects of these factors on MPI use," the authors write.

"… the substantial reduction in MPI use demonstrates the ability to reduce testing on a large scale with anticipated reductions in health care costs."