Considerations for Stress Testing Performed in Conjunction with Myocardial Perfusion Imaging

For myocardial perfusion imaging (MPI), the best test to evaluate hemodynamic changes during stress is an exercise treadmill test. It provides independent prognostic value, including evaluation of total exercise time, performance, and capacity; heart rate response during exercise, with ischemia, and in recovery; blood pressure response; myocardial oxygen demand; and assessment of symptoms. Combining these exercise data with perfusion imaging provides the best prognostic value and risk stratification for patients. Although exercise stress testing accompanied by MPI is preferential, it is not always possible since an increasing number of patients cannot exercise to a maximal (symptom-limited) level. Further, there is much evidence in the literature demonstrating a suboptimal, non-symptom-limited (not achieving at least 4-6 min or <85% of maximum predicted heart rate) exercise test performed as part of an MPI study may result in a false-negative outcome. Therefore, pharmacologic stress agents provide an excellent alternative for those patients who cannot achieve an adequate heart rate response or adequately perform physical exercise. This article focuses on considerations for performing stress (exercise and pharmacologic) testing in conjunction with MPI. It is meant to provide a basic overview of the principles of exercise stress testing; discuss the indications, contraindications, patient preparation, and protocols for exercise stress testing; discuss the contraindications, administration protocols, and side effects for vasodilator (adenosine, dipyridamole, and regadenoson) stress testing; and discuss the contraindications, administration protocols, and side effects for dobutamine stress testing.