Background: In patients with acute myocardial infarction (AMI) and multivessel coronary disease, revascularization of non-culprit lesions guided by proof of ischemia requires a staged ischemia testing. Quantitative flow ratio (QFR) has been shown to be effective in assessing the hemodynamic relevance of lesions in stable coronary disease. However, its suitability in AMI is unknown. In this study we tested the diagnostic value of QFR based on acute angiograms (aQFR) during AMI to assess the hemodynamic relevance of non-culprit lesions.

Methods: We retrospectively assessed the diagnostic efficiency of aQFR in 280 non-culprit vessels from 220 patients with AMI, comparing it with staged ischemia testing using elective coronary angiography with FFR (n=47), stress cardiac MRI (n=200) or SPECT (n=33).

Results: aQFR showed a very good diagnostic efficiency (AUC=0.89, 95%-CI 0.83-0.94, p<0.001) in predicting ischemia of non-culprit lesions, significantly superior to coronary lesion´s geometry as assessed by quantitative coronary angiography (see Fig. 1A). Optimal cut-off of aQFR for predicting ischemia was 0.80 (sensitivity=83.7%, specificity=86.1%). Maintaining a predefined level of 95% sensitivity and specificity, we could create a decisional model based on aQFR: lesions with aQFR≤0.75 should be treated, lesions with aQFR≥0.92 do not yield any hemodynamic significance, and lesions in the “grey zone” (aQFR 0.75-0.92) benefit from further ischemia testings, as reported in Fig. 1B. This model would allow to reduce staged ischemia tests by 43.6 % without a relevant loss in diagnostic efficiency.

Conclusion: Our data demonstrate that aQFR allows an effective assessment of hemodynamic relevance of non-culprit lesions in AMI and may guide interventions of non-culprit coronary lesions.