No-Reflow Prediction in Acute Coronary Syndrome During Percutaneous Coronary Intervention: The NORPACS Risk Score

Area of Science:

• Cardiology
• Interventional Cardiology
• Clinical Risk Prediction

Background:

• Suboptimal coronary reperfusion, known as no-reflow, frequently complicates percutaneous coronary intervention (PCI) for acute coronary syndrome.
• No-reflow is linked to adverse clinical outcomes in patients undergoing PCI.

Purpose of the Study:

• To develop and externally validate a clinical risk score for predicting angiographic no-reflow.
• The score is intended for use after angiography and before PCI procedures.

Main Methods:

• A logistic regression model was developed and validated using data from two large PCI registries (Melbourne Interventional Group and British Cardiovascular Interventional Society).
• The model utilized data from over 470,000 patients undergoing PCI for acute coronary syndrome.
• Six key predictor variables were identified through adaptive least absolute shrinkage and selection operator regression.

Main Results:

• The final risk score incorporated six variables: cardiogenic shock, STEMI onset >195 min pre-PCI, stent length ≥20 mm, vessel diameter <2.5 mm, pre-PCI TIMI flow <3, and lesion location.
• The model demonstrated strong predictive performance with C statistics of 0.808 (development) and 0.741 (validation).
• Patients scoring ≥8 had a 22-27% risk of no-reflow, indicating good calibration.

Conclusions:

• The developed risk score is a simple, count-based system utilizing pre-PCI parameters to predict no-reflow risk.
• This score can assist in guiding preventative strategies and informing the design of future clinical trials for acute coronary syndrome patients.