Development and Validation of a Novel Risk Stratification Model for Slow-Flow/No-Reflow During Primary Percutaneous Coronary Intervention (the RK-SF/NR Score)

In this study, we developed and validated a novel risk stratification model to predict slow-flow/no-reflow (SF/NR) during the primary percutaneous coronary intervention (PCI), namely the RK-SF/NR score. A total of 1,711 consecutive patients with ST-segment elevation myocardial infarction (STEMI) undergone primary PCI. A novel risk stratification model was developed in the development dataset and tested in the validation dataset. The overall incidence rate of SF/NR during the procedure was 28.8% (493/1,711). The final solution consisted of 9 variables: female gender (points = 2), total ischemic time ≥8 hours (points = 1), cardiac arrest at presentation (points = 2), left ventricular end-diastolic pressure ≥24 mm Hg (points = 3), left ventricular ejection fraction ≤30% (points = 2), culprit proximal left anterior descending artery (points = 3), thrombus grade ≥4 (points = 6), preprocedure thrombolysis in myocardial infarction (TIMI) 0 flow (points = 2), and lesion length ≥35 mm (points = 3). In the validation set, the area under the curve the RK-SF/NR score was 0.775 (0.722 to 0.829) and a score ≥10 has sensitivity of 77.9% (68.2% to 85.8%), negative predictive value of 87.3% (82.3% to 91.0%), specificity of 62.6% (56.0% to 68.9%), and positive predictive value of 46.3% (41.4% to 51.2%). In conclusion, RK-SF/NR score had shown good discriminating power for predicting SF/NR during primary PCI with good sensitivity and negative predictive value. Hence, the proposed model can have good clinical utility for screening patients at high risk of developing SF/NR during primary PCI.