Differential Prognostic Value of Angiography-Derived Microcirculatory Resistance for Coronary Artery Bypass Grafting of Intermediate Coronary Stenosis

BACKGROUNDFor patients with intermediate coronary stenoses, the prognostic value of coronary artery bypass grafting (CABG) remains controversial. The prognostic impact of CABG may be different according to Murray law-based quantitative flow ratio (QFR) and angiography-derived microcirculatory resistance (AMR) in patients with intermediate coronary stenoses. METHODS AND RESULTSClinical data of 1411 cases who were diagnosed with multivessel coronary artery disease and had coronary artery intermediate stenoses (50% to 70% by visual assessment) between January 2013 and January 2020 were collected. Patients were categorized into CABG and defer groups based on the decision to bypass intermediate stenoses. These patients were further divided into different subgroups based on QFR and AMR. The primary outcome was the major adverse cardiac and cerebrovascular events (MACCE), defined as a composite of cardiac death, target vessel myocardial infarction, target vessel revascularization and stroke. Multivariable analysis showed AMR (HR = 1.68, 95% CI 1.18-4.14, P = 0.008) was independent factor associated with MACCE in all patients. On receiver-operating characteristic (ROC) curve analysis, the estimated area under the curve was 0.75 (95% CI: 0.72-0.79) for MACCE. Using the maximum Youdens index, the optimal cutoff value for AMR to predict MACCE was 2.50 mmHg*s/cm. In defer group, MACCE was significantly lower in patients with both QFR > 0.80 and AMR < 2.50 mmHg*s/cm as compared with patients with QFR > 0.80 (13.2% vs 22.0%, P = 0.031) or AMR < 2.50 mmHg*s/cm (13.2% vs 23.6%, P = 0.012) alone. Compared with patients with both normal QFR and AMR, patients with both abnormal QFR and AMR carried the highest risk for MACCE (HR = 3.46, 95% CI 2.10-5.71, P < 0.001). CABG was associated with a lower risk of MACCE compared with the deferral strategy when both QFR and AMR were abnormal. In contrast, at normal QFR and AMR, patients in both CABG and defer groups had similar MACCE outcomes. CONCLUSIONSIn patients with intermediate coronary stenoses, the prognostic value of treatment strategy differed according to QFR and AMR, with a significant interaction. The combination of QFR and AMR can help stratify risk and guide treatment strategies for patients with intermediate coronary stenoses.