Cardiovascular outcomes are predicted by exercise-stress myocardial perfusion imaging: impact on death, myocardial infarction, and coronary revascularization procedures

Background — The aim of this study was to determine the impact of myocardial perfusion imaging (MPI) on the outcomes of death, myocardial infarction (MI), and late coronary revascularization procedures.

Methods — In patients undergoing exercise-stress MPI (January 1, 2003-March 31, 2007), the authors determined the impact of summed stress score (SSS) and percent left ventricular (LV) ischemia on (a) death or MI and (b) composite of death, MI, or late coronary revascularization occurring more than 90 days post-MPI.

Results — During 35,007 person-years of follow-up among 9,605 patients (mean ± SD age 54.4 ± 13.2 years, 60.3% men), there were 290 deaths, 175 MIs, and 525 coronary revascularization procedures. Of those who attained ≥10 metabolic equivalents (METS) workload, major stress perfusion defects (SSS ≥7) were present in 4.2% overall and in 3.7% without ST-segment shifts, whereas large ischemic defects (≥10% LV ischemia) were present in 1% overall and 0.7% without ST-segment shifts. For those with 1% to 4%, 5% to 9%, and ≥10% LV ischemia, adjusted hazard ratios were 1.40 (95% CI 1.13–1.73, P = 0.002), 2.07 (95% CI 1.56–2.74, P < 0.001), and 3.03 (95% CI 2.21-4.16, P < 0.001) for the outcome of late revascularization, MI, or death versus no ischemia. Summed stress scores ≥7 were associated with increased risk of death or MI, with an adjusted hazard ratio of 1.57 (95% CI 1.16–2.13, P = 0.004) compared with those with no stress perfusion defects.

Conclusion — Although workload ≥10 METS conferred lower frequency of major ischemia (≥10%), %LV ischemia predicted the occurrence of cardiovascular events and death (eg, MI, late coronary revascularization, or death). Presence of a large stress perfusion defect (SSS ≥7) predicted increased risk of MI or death.