Shock Index More Sensitive Than Cardiogenic Shock in ST-Elevation Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention.

BACKGROUND

Cardiogenic shock (CS) is a strong predictor of mortality in patients with ST-elevation myocardial infarction (STEMI), but there is evidence that shock index (SI), taking into account both blood pressure and heart rate, is a more sensitive and powerful predictor. We investigated the independent impact of SI and CS on 30-day and 1-year mortality in patients with STEMI, treated by primary percutaneous coronary intervention (PCI).

METHODS AND RESULTS

In 7,412 consecutive patients with STEMI treated with primary PCI, the predictive value of either SI or CS on 1-year mortality was assessed. Best cut-off value of SI, determined using receiver operating characteristic (ROC) curve, was 0.7, with an ROC AUC of 0.66 (95% CI: 0.65-0.67), compared with an ROC AUC of 0.60 (95% CI: 0.59-0.61) for CS (P<0.001). At admission, 387 patients (5.2%) had CS and 1,567 patients (21.1%) had SI ≥0.7. The adjusted hazard ratio of mortality in patients with SI ≥0.7 and in CS patients was, respectively, 3.3 (95% CI: 2.4-4.6) and 3.1 (95% CI: 2.1-4.6) after 30 days, and 2.3 (95% CI: 1.8-2.9) and 3.1 (95% CI: 2.2-4.2) after 1 year.

CONCLUSIONS

SI identifies more patients with increased risk of mortality, and seems to be a more sensitive prognostic predictor than CS in patients with STEMI treated by primary PCI.