Exercise vs pharmacological myocardial perfusion imaging (MPI) studies: A trend observed in two Chicago hospitals

Objectives In patients (pts) who cannot exercise and are unable to achieve 85% of predicted heart rate for an exercise MPI, "stress" may be induced pharmacologically with various agents. Two Hospitals 30 miles apart in the Chicago area have noted an increased in the use of pharmacologic agents (Ph-MPI) compared to exercise stress (Ex-MPI) since 2007.We initiated a retrospective study to better understand some of the factors that may have contributed to this shift.

Methods MPI data from 378 pts [258 from a suburban university hospital (location A) and 120 from an inner city university hospital (location B) performed during the last 3 months of 2009 were collected and analyzed.

Results Relevant data collected in this study is presented in the table below. The mean age, weight and height are not dramatically different in the two populations. Increased used of Ph-MPI was noted in both institutions. Location A showed a 7 % increase in Ph-MIP (58% to 65%) and Location B showed a dramatic 48% increased use of Ph-MPI compare to Ex MPI The % of outpatient in Location A is 33% and 64% for Location B. The % of preoperative pts in Location A is 9.34% which is basically unchanged from 2007. At location B, 35% of the pts were pre-operative up from 19%. The % of cases for chest pain in Location A is 40.3% and for Location B is 45%. Both institutions noticed that the ability of pts to undergo Ex-MPI has decreased. An increase in the % of obese, diabetic & elderly pts in both locations may explain in part this shift. Also any increased in the number of in-pt programs can cause a shift. There was a dramatic increase in the number of preoperative pts in Location B due to the introduction of an active transplant program.

Conclusions The introduction of a new transplant program (location B) plus increasing pt weight, age and diabetes in both locations may explain the shift in increased use of Ph-MIP studies