Assessment of Fractional Flow Reserve in Patients With Recent Non–ST-Segment–Elevation Myocardial Infarction

Abstract

F ractional flow reserve (FFR) has an established role in guiding percutaneous coronary intervention (PCI) in stable coronary artery disease (CAD). In this setting, the use of FFR has been associated with improved long-term outcomes and reduced healthcare costs compared with angiographic-based strategies.1 Rates of urgent revascularization are reduced whenBackground-The use of fractional flow reserve (FFR) in acute coronary syndromes is controversial. The British Heart Foundation Fractional Flow Reserve Versus Angiography in Guiding Management to Optimize Outcomes in Non-STElevation Myocardial Infarction (FAMOUS-NSTEMI) study (NCT01764334) has recently demonstrated the safety and feasibility of FFR measurement in patients with non-ST-segment-elevation myocardial infarction. We report the findings of the cardiac magnetic resonance (CMR) substudy to assess the diagnostic accuracy of FFR compared with 3.0-T stress CMR perfusion. Methods and Results-One hundred six patients with non-ST-segment-elevation myocardial infarction who had been referred for early invasive management were included from 2 centers. FFR was measured in all major patent epicardial coronary arteries with a visual stenosis estimated at ≥30%, and if percutaneous coronary intervention was performed, an FFR assessment was repeated. Myocardial perfusion was assessed with stress perfusion CMR at 3 T. The mean age was 56.7±9.8 years; 82.6% were men. Mean time from FFR evaluation to CMR was 6.1±3.1 days. The mean±SD left ventricular ejection fraction was 58.2±9.1%. Mean infarct size was 5.4±7.1%, and mean troponin concentration was 5.2±9.2 μg/L. There were 34 fixed and 160 inducible perfusion defects. There was a negative correlation between the number of segments with a perfusion abnormality and FFR (r=−0.77; P<0.0001). The overall sensitivity, specificity, positive predictive value, and negative predictive value for an FFR of ≤0.8 were 91.4%, 92.2%, 76%, and 97%, respectively. Diagnostic accuracy was 92%. The positive and negative predictive values of FFR for flow-limiting coronary artery disease (FFR≤0.8) in patients with non-ST-segment-elevation myocardial infarction (n=21) who underwent perfusion CMR before invasive angiography were 92% and 93%, respectively. Receiver operating characteristic analysis indicated that the optimal cutoff value of FFR for demonstrating reversible ischemia on CMR was ≤0.805 (area under the receiver operating characteristic curve, 0.94 [0.9-0.99]; P<0.0001). Conclusions-FFR in patients with recent non-ST-segment-elevation myocardial infarction showed high concordance with myocardial perfusion in matched territories as revealed by 3.0-T stress perfusion CMR. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT02073422.

Evaluation of intermediate coronary stenoses in acute coronary syndromes using pressure guidewire

“…Conversely, low FFR values should be considered reliable. Small studies have suggested that FFR assessment is more reliable between 4 and 6 days following the index event, [12][13][14] as soon as the microcirculation can dilate sufficiently to enable maximal hyperaemia.…”

Fractional flow reserve guided percutaneous coronary intervention results in reduced ischemic myocardium and improved outcomes

“…The diagnostic accuracy of FFR in predicting reversible ischemia compared with noninvasive stress testing has been well validated in stable CAD patients and has shown promise in acute coronary syndrome patients, as well . The presence of ischemia on stress testing has been shown to be a prognostic indicator of adverse events .…”

The new role of diagnostic angiography in coronary physiological assessment

“…43 So, when CAG-FFR is assessed against SPECT, there is a degree of discordance, but, compared with perfusion CMR, its accuracy is 92%. 44 It is important to appreciate the differences between these tests. The main one is that CMR is an excellent test of the overall and regional burden of ischaemia, whereas FFR addresses the contribution of a specific lesion in a particular artery.…”