Vasodilator stress agents are also used with positron emission tomography (PET) to diagnose CAD and determine its severity ( see Chapter 16). For patients unable to tolerate adenosine or regadenoson, dobutamine MPI can be performed. Although the diagnostic accuracy of pharmacologic vasodilator stress perfusion imaging is comparable to that achieved with exercise perfusion imaging ( see Table 61.2), treadmill testing is preferred for patients who are capable of exercising because the exercise component of the test provides additional diagnostic and prognostic information, including ST-segment changes, effort tolerance, symptomatic response, and HR and BP response ( Table 61.3).
In most nuclear cardiology laboratories, vasodilator studies account for approximately 40% to 50% of those referred for perfusion imaging. The need for pharmacologic stress should be considered for patients who are older or have claudication, pulmonary disease, orthopedic problems, or severe obesity. As a general rule, a patient should be able to walk up two flights of stairs without stopping in order to complete a standard exercise stress test.
Zipes MD, in Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine, 2019 MPI with Pharmacologic Vasodilator Stress.įor patients unable to exercise adequately, pharmacologic vasodilator stress with adenosine derivatives (and rarely dipyridamole) may be used.