Risk assessment in the era of high-speed myocardial perfusion imaging

Excerpt

Over the last three decades, myocardial perfusion imaging (MPI) has had a proven track record for providing valid and useful prognostic information.1,2 Although its name implies that the test evaluates myocardial perfusion, several other prognostic variables have been derived from MPI over the years as shown in Figure 1. Just as with any other diagnostic and/or prognostic test, the relative strength of each of these variables for the prediction of risk depends on patient selection, definition of normal/abnormal, definition of endpoint, and duration of follow-up. Even simple characterization of the MPI images as “normal” or “abnormal” separates patients into low- and high-risk groups with several folds difference in risk for hard cardiac endpoints.3 The patients with normal MPI have exceedingly low risk of cardiac events (although patients with normal vasodilator stress MPI have a higher event rate than those with normal exercise MPI),4 while patients with abnormal MPI have a higher event rate that increases commensurate with the degree of abnormality.

…