Applicability of the Zwolle score for selection of very high-risk ST-elevation myocardial infarction patients treated with primary angioplasty

Abstract

The Zwolle risk score was designed to stratify in-hospital mortality risk of ST-elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (pPCI) and for decision-making in the unit where patients are admitted. We assessed the accuracy of Zwolle risk score for in-hospital mortality estimation compared with the GRACE score in all patients (n = 4446) admitted for STEMI in 3 university hospitals. Only one fourth of the patients were classified as high-risk by the Zwolle risk score vs 60% by the GRACE score. In-hospital mortality was 10.6%. A statistically significant increase in in-hospital mortality, adjusted by age, gender, and revascularization, was observed with both scores. The assessment of the optimal cut-off points verified the accuracy of Zwolle score ≥4 as optimal threshold for high-risk categorization. In contrast, GRACE score ≥140 had very low specificity as well as percentage of patients correctly classified; GRACE score ≥175 was fairly better. The reclassification index of the Zwolle score after applying the GRACE score was 35.5%. Selection of high-risk STEMI patients treated with pPCI based on the Zwolle risk score has higher specificity than the GRACE score and might be useful in clinical practice.