Hussain ST, et al. - This study investigated the link between the fractional flow reserve (FFR) value and extent of myocardial ischemia measured by cardiovascular magnetic resonance (CMR) perfusion imaging. Findings demonstrated a good correlation between the FFR value and the amount of myocardial ischemia in the subtended myocardium.

Methods

• CMR perfusion imaging was performed in 49 patients with angina.
• Researchers measured FFR in vessels with a visual diameter stenosis >40%.
• They also measured the extent of ischemia for each coronary artery by delineating the perfusion defect on the CMR images and expressing as a percentage of the LV myocardium.

Results

• Findings demonstrated that the correlation between the extent of ischemia measured by CMR and FFR was good (r = -0.85, P < 0.0005).
• It was noted that the mean FFR value was 0.67 ± 0.17 and the mean perfusion defect was 8.9 ± 9.3%.
• Researchers observed that an FFR value of ≥0.75 was not associated with ischemia on CMR.
• Data revealed that the maximum amount of ischemia (23.0±1.5%) was found at FFR values between 0.4 - 0.5.
• They also noted that in patients with one vessel disease (49%), the mean ischemic burden was 15.3±8.3%.
• Results showed that the mean ischemic burden was 26.0±12% in patients with 2 vessel disease (18%).
• Reproducibility for measurement of ischemic burden was very good with a Kappa coefficient (k=0.826, P=0.048).