Abstract 3332: Fractional Flow Reserve (FFR) And MIBI SPECT: A comparison In Patients With Multi-vessel Coronary Disease
INTRODUCTION In patients with angiographic 3 vessel disease only 29% have been reported to have perfusion defects. However the association between physiological evidence for ischemia per vessel derived from fractional flow reserve (FFR) and MIBI SPECT (SPECT) in multivessel disease (MVD) is unknown. We comapred this association in patients with MVD.
METHOD In 84 vascular territories in 28 patients (mean age 63.9±9.8 years, LV ejection fraction 69±12%) with angiographic MVD (>50% stenosis in at least 2 vessels) results of SPECT (rest / stress adenosine) were compared to FFR measurements in each coronary vessel. AHA semi-quantitative 5 point scorning system using a 17-segment model was used to report SPECT scans. A FFR <0.80 was taken as evidence for ischemia.
RESULTS MIBI was positive in at least 1 territory in 19 (67%) and FFR <0.80 in at least 1 territory in 23 (82%) of patients. 7 (25%) patients with no perfusion defect on SPECT had FFR <0.80 in at least 2 territories. The association between MIBI and FFR in each patient and per vascular territory are summarised below. Per patient there was no concordance between SPECT and FFR (Kappa −0.11) and per vascular territory there was poor concordance between SPECT and FFR (Kappa 0.23). In 8 (29%) patients both SPECT and FFR detected identical ischemic territories [mean number of ischemic territories: 1.5±0.9 for both; P=1.00]. In the remaining 20 patients in comparison to FFR, SPECT either underestimated [9 (32%) patients − mean number of ischemic territories, SPECT: 0.3±0.7, FFR: 1.9±0.6; P=0.001] or overestimated [11 (39%) patients -mean number of ischemic territories, MIBI: 2.0±1.0, FFR: 1.0±0.9; P=0.02] the number of ischemic territories. There was a weak correlation between severity of ischemia as assessed by SPECT in each vascular territory and the actual FFR value (r=0.34; P=0.001).
CONCLUSION In patients with multivessel disease, the concordance between SPECT and FFR to localise hemodynamically significant stenosis is poor.