Abstract 19472: Clinical and Angiographic Factor for the Mismatch Between Myocardial Perfusion Imaging and Pressure-Derived Fractional Flow Reserve
Background: Myocardial perfusion imaging (MPI) with single-photon emission computed tomography (SPECT) is well-established modality to detect myocardial ischemia noninvasively. But it has been reported that MPI can underestimate ischemic region of myocardium, particularly in patients with multivessel coronary artery disease or previous myocardial infarction.
Method: We analyzed the records of MPI and pressure-derived fractional flow reserve (FFR) retrospectively, and investigated what is the clinical and angiographic factor of discordance between MPI and FFR result. Myocardial ischemia is defined by an FFR≤0.75. Adenosinse or exercise Thallium201 scintigraphy was underwent within 3 months before the FFR study. The clinical and angiographic features were compared with the patients who have myocardial ischemia identified by both MPI and FFR (concordance group).
Result: Two hundred and sixty-three vessels in 220 patients were enrolled. Thirty-nine vessels in 37 patients were FFR-positive (i.e.FFR≤0.75), but MPI-negative (discordance group). Thirty patients (81.1%) in discordance group have multivessel coronary artery disease, and 18 patients (37.8%) have previous myocardial infarction. To compare with concordance group (40 vessels in 37 patients), there were no significant differences in basic characteristics, angiographic lesion complexity, and minimum lumen diameter. Two groups have same frequency of history of infarction (discordance group 46.2% vs. concordance group 42.5%; p=ns), but non-infarct-related-arteries were more often included (and misdiagnosed) in discordance group than concordance group (83.3% vs. 50%; p<0.05).
Conclusion: In patients with previous myocardial infarction, MPI may underestimate myocardial ischemia. MPI should be carefully interrupted in these patients, and the measurement of FFR should be considered to evaluate myocardial ischemia accurately.
- © 2012 by American Heart Association, Inc.