FFR Derived From Coronary CT Angiography in Nonculprit Lesions of Patients With Recent STEMI

Objectives This study sought to determine the diagnostic performance of noninvasive fractional flow reserve (FFR) derived from coronary computed tomography angiography (CTA) (FFR_CT) for the diagnosis of lesion-specific ischemia in nonculprit vessels of patients with recent in ST-segment elevation myocardial infarction (STEMI). Background In patients with stable angina, FFR_CT has high diagnostic performance in identification of ischemia-causing lesions. The potential value of FFR_CT for assessment of multivessel disease in patients with recent STEMI has not been evaluated. Methods Coronary CTA with calculation of FFR_CT and invasive coronary angiography with FFR were performed 1 month after STEMI in patients with multivessel disease. Coronary CTA and invasive coronary angiography stenosis >50% were considered obstructive. Lesion-specific ischemia was assumed if FFR_CT was ≤0.80. FFR ≤0.80 was the reference standard. To evaluate the influence of vessel size, the total coronary vessel lumen volume relative to left ventricular mass (volume-to-mass ratio) was calculated and compared with that of patients with stable angina. Results The study evaluated 124 nonculprit vessels from 60 patients. Accuracy, sensitivity, and specificity of FFR_CT were 72%, 83%, and 66% versus 64% (p = 0.033), 93% (p = 0.15), and 49% (p < 0.001) for CTA and 72% (p = 1.00), 76% (p = 0.46), and 70% (p = 0.54) for invasive coronary angiography. Following STEMI, median volume-to-mass ratio was lower than in patients with stable angina, 53 versus 65 mm³/g (p = 0.009). In patients with volume-to-mass ratio ≥65 mm³/g (upper tertile) accuracy, sensitivity, and specificity of FFR_CT were all 83% versus 56% (p = 0.009), 75% (p = 0.61), and 44% (p = 0.003) in patients with <49 mm³/g (lower tertile). Conclusions The diagnostic performance of FFR_CT for staged detection of ischemia in STEMI patients with multivessel disease is moderate. STEMI patients have a smaller vessel volume than do patients with stable angina. The diagnostic performance of FFR_CT is influenced by the volume-to-mass ratio. This study does not support routine use of FFR_CT in the post-STEMI setting. (Assessment of Coronary Stenoses Using Coronary CT-Angiography and Noninvasive Fractional Flow Reserve; NCT01739075)