Abstract 12972: Reduction of Unnecessary Radiation Exposure for Cardiovascular Patients by Adoption of a Stress-First Protocol for Nuclear-Based Cardiac Stress Testing

Abstract

Background: In 2010, the FDA issued the Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging. The purpose of this study was to determine the total radiation exposure for cardiovascular patients and the relative contribution of nuclear-based cardiac stress testing. Method: The electronic medical record was reviewed to identify all patients who underwent cardiac stress testing in 1 institution over a 10-year period. The type and number of all radiation-based diagnostic tests were identified, and a hospital-determined or published radiation dose was used to calculate each patient’s gender-specific total annualized radiation exposure expressed in mSv. Therapeutic radiation-based procedures were excluded. Results: Between 2003 and 2012, a total of 50,737 patients underwent 88,108 stress tests, 501,239 diagnostic radiology exams, and 17,194 diagnostic coronary angiograms, with 177,957 patient years of follow-up. Mean age at first stress test was 60±14 years, 56% of the patients were men, and the total number of stress tests per patient was 1.8±1.4 (range 1-18). When patients undergoing a nuclear-based stress test (PET-Rb/SPECT) at any time were compared to those who never had a nuclear-based stress test, 0.8±0.6 vs 0.7±0.4 total stress tests/year were performed, respectively (p<.001), with a total radiation exposure (including stress tests, all radiology exams, and diagnostic coronary angiography) of 16.2±18.5 vs. 6.0±15.5 mSv/patient-year (p<.001), and an aggregate total radiation exposure from diagnostic angiography of 16 vs. 11%. For patients undergoing a nuclear-based stress test at any time, the total aggregate radiation exposure from nuclear stress testing was 37% (for both men and women). If a stress-first/stress-only protocol was adopted, which would decrease isotope exposure by 75% as a result of administering only a single dose of isotope, using an institutional normal test rate of 57% over the study period, the aggregate radiation exposure from radiation-based testing dropped to 25% for the group. Conclusion: Adoption of a stress-first/stress-only protocol for nuclear-based cardiac stress tests results in a significant reduction in unnecessary radiation exposure for patients undergoing cardiac stress testing.