Ongoing Continuous Quality Improvement Strategy Using Pharmacological Stress with Intravenous Dipyridamole and Pharmacist Intervention to Reduce Suboptimal Exercise Myocardial Perfusion Scans

Abstract

Exercise electrocardiogram (ECG) testing in conjunction with radionuclide imaging provides prognostic, diagnostic, and important physiological information regarding the presence of ischemia. However, many patients cannot or will not exercise to 85% of maximal heart rate. When this occurs, potential disparities in regional myocardial perfusion may not be apparent. Pharmacological stress testing with intravenous (IV) dipyridamole provides an alternative method of increasing intracoronary blood flow in these patients and decreasing the incidence of suboptimal exercise myocardial perfusion scans. An ongoing program was begun in 1992 to determine the effect of using pharmacological stress testing with IV dipyridamole (in selected patients) on the incidence of suboptimal exercise myocardial perfusion scans. Myocardial perfusion scans from the months of February 1991 and February 1992 were reviewed. Data collected included demographic variables, heart rate, percent of maximum predicted heart rate, anti-anginal drug therapy, and any underlying conditions that could influence the patient's ability to exercise adequately. There was only a slight reduction in inadequate exercise tests between the two study periods, 30% in February 1991 and 23% in February 1992, without pharmacist intervention. There was an increase in the number of dipyridamole perfusion scans, one (<1%) in February 1991 and 10 (6%) in February 1992. These data were presented to physicians as part of an educational program on the availability and appropriate use of pharmacological stress testing with IV dipyridamole. Several suggestions were made to assist in decreasing the incidence of suboptimal exercise myocardial perfusion scans. The review was repeated in February 1993. There was a further increase in the number of dipyridamole perfusion scans (18, or 11% over previous levels); however, the rate of suboptimal exercise tests remained at 24%. This review offered an easy and unique opportunity for the pharmacy to be involved in multidisciplinary continuous quality improvement with nuclear medicine and cardiology. It is anticipated that with continued education and a change in patient screening procedures, along with the development and use of drug use guidelines, a decrease in the number of suboptimal exercise myocardial perfusion scans may be realized.