When confronted with an ambiguous angiogram, additional testing is required to make a confident decision. Myocardial perfusion imaging (MPI) could be used to determine the presence of ischemia in the vascular territory supplied by the suspect artery. Although noninvasive imaging may help discern the significance of a coronary lesion when there is single-vessel disease, the report by Melikian et al. (2) in this issue of JACC: Cardiovascular Interventions is similar to our earlier study (3), suggesting that MPI cannot be used to make these decisions in the setting of multivessel disease. Because it relies on relative flow heterogeneity, MPI usually identifies ischemia caused by the most severe stenosis; it may misclassify as normal other vascular zones supplied by less diseased but still significantly narrowed arteries. In this study by Melikian et al. (2), MPI, compared with fractional flow reserve, underestimated the number of ischemic territories in 36% of patients with multivessel disease.
Beller, G. A., & Ragosta, M. (2010, March). Decision Making in Multivessel Coronary Disease. The Need for Physiological Lesion Assessment. JACC: Cardiovascular Interventions, 3(3), 315–317. https://doi.org/10.1016/j.jcin.2010.01.007