Quantitative Flow Ratio to Predict Nontarget Vessel–Related Events at 5 Years in Patients With ST‐Segment–Elevation Myocardial Infarction Undergoing Angiography‐Guided Revascularization

Background In ST‐segment–elevation myocardial infarction, angiography‐based complete revascularization is superior to culprit‐lesion‐only percutaneous coronary intervention. Quantitative flow ratio (QFR) is a novel, noninvasive, vasodilator‐free method used to assess the hemodynamic significance of coronary stenoses. We aimed to investigate the incremental value of QFR over angiography in nonculprit lesions in patients with ST‐segment–elevation myocardial infarction undergoing angiography‐guided complete revascularization. Methods and Results This was a retrospective post hoc QFR analysis of untreated nontarget vessels (any degree of diameter stenosis [DS]) from the randomized multicenter COMFORTABLE AMI (Comparison of Biolimus Eluted From an Erodible Stent Coating With Bare Metal Stents in Acute ST‐Elevation Myocardial Infarction) trial by assessors blinded for clinical outcomes. The primary end point was cardiac death, spontaneous nontarget vessel myocardial infarction, and clinically indicated nontarget vessel revascularization (ie, ≥70% DS by 2‐dimensional quantitative coronary angiography or ≥50% DS and ischemia) at 5 years. Of 1161 patients with ST‐segment–elevation myocardial infarction, 946 vessels in 617 patients were analyzable by QFR. At 5 years, the rate of the primary end point was significantly higher in patients with QFR ≤0.80 (n=35 patients, n=36 vessels) versus QFR >0.80 (n=582 patients, n=910 vessels) (62.9% versus 12.5%, respectively; hazard ratio [HR], 7.33 [95% CI, 4.54–11.83], P <0.001), driven by higher rates of nontarget vessel myocardial infarction (12.8% versus 3.1%, respectively; HR, 4.38 [95% CI, 1.47–13.02], P =0.008) and nontarget vessel revascularization (58.6% versus 7.7%, respectively; HR, 10.99 [95% CI, 6.39–18.91], P <0.001) with no significant differences for cardiac death. Multivariable analysis identified QFR ≤0.80 but not ≥50% DS by 3‐dimensional quantitative coronary angiography as an independent predictor of the primary end point. Results were consistent, including only >30% DS by 3‐dimensional quantitative coronary angiography. Conclusions Our study suggests incremental value of QFR over angiography‐guided percutaneous coronary intervention for nonculprit lesions among patients with ST‐segment–elevation myocardial infarction undergoing primary percutaneous coronary intervention.