Angio‐based coronary functional assessment predicts 30‐day new‐onset heart failure after acute myocardial infarction

AIMS: Suboptimal perfusion leading to heart failure (HF) often occurs after ST‐segment elevation myocardial infarction (STEMI), despite restoration of epicardial coronary flow in primary percutaneous coronary intervention (PPCI) era. We determined the clinical implications of angio‐based coronary functional assessment in evaluation of suboptimal perfusion and further outcomes among STEMI patients after successful PPCI. METHODS AND RESULTS: In this study, STEMI patients in the Chinese STEMI PPCI registry trial (NCT04996901) who achieved post‐PPCI thrombolysis in myocardial infarction grade 3 flow were retrospectively screened. Post‐procedural quantitative flow ratio (QFR), angio‐based microvascular resistance (AMR), and coronary flow velocity (CFV) of the infarct‐related artery were calculated. QFR and AMR measure epicardial stenosis severity and microvascular resistance, respectively. QFR+ was defined as QFR < 0.90 while QFR− was QFR ≥ 0.90. AMR+ was defined as AMR ≥ 250 mmHg*s/m while AMR− was AMR < 250 mmHg*s/m. The primary outcome was 30‐day new‐onset HF. The Kaplan–Meier curves were used to establish the associations between QFR, AMR, CFV, and HF incidences. The relationship between CFV and combined QFR and AMR indices was further assessed. Independent predictors were determined using Cox regression analysis. The receiver‐operating characteristic curve was used to assess discriminant ability to predict HF. A total of 942 patients (mean age was 57.8 ± 11.7 years and 84.6% were men) were enrolled. Among them, 129 patients had new‐onset HF episodes. Patients in the QFR−/AMR− group had a low risk of HF compared with those in the QFR+/AMR+ group (10.5% vs. 27.3%, P = 0.027). A higher CFV ≥ 17.4 cm/s was associated with low HF incidences as compared with CFV < 17.4 cm/s (10.3% vs. 16.8%, P = 0.005), whereas isolated QFR or AMR did not reveal any marked differences in HF incidences (P = 0.150 and 0.079, respectively). The highest and lowest medians of CFV were observed in the QFR−/AMR− and QFR+/AMR+ groups, respectively. CFV correlated well with the QFR/AMR ratio (adjusted R (2) = 1, P < 0.001) and post‐PPCI CFV was found to be an independent predictor of post‐STEMI HF (adjusted hazard ratio: 0.61, 95% confidence interval: 0.41–0.90, P = 0.012). The area under curve estimate of the multivariable regression model was 0.749. CONCLUSIONS: CFV is an integrated coronary physiological assessment approach that incorporates epicardial and microcirculatory contributions. Patients with post‐PPCI CFV < 17.4 cm/s were strongly associated with a high risk for post‐STEMI HF, even achieving thrombolysis in myocardial infarction grade 3 flow. The immediate angio‐based coronary functional assessment is a feasible tool for evaluating suboptimal perfusion and risk stratification.