Prognostic impacts of prehospital age shock index in patients with acute myocardial infarction

Abstract

Abstract Introduction Early identification of high-risk patients is the cornerstone of managing patients with acute myocardial infarction (AMI). Age Shock index (ASI; age multiplied by the ratio of heart rate/systolic blood pressure) has been reported to be similar to Global Registry of Acute Coronary Events (GRACE) risk score for predicting mortality in patients with AMI. However, prognostic impacts of prehospital ASI (pre-ASI) in patients with AMI remain unknown. Methods We analyzed of 2578 AMI patients who underwent emergency primary percutaneous coronary intervention (PCI) from January 2013 to March 2018, using data from Mie ACS Registry, a prospective and multicenter registry in Japan. Pre-ASI was recorded by emergency medical services at the first contact with the patient before admission, and in-hospital ASI (in-ASI) was recorded prior to PCI at admission. The primary end point was defined as all-cause death. Results Median follow-up duration was 753 days (497–838 days). All-cause death was observed in 230 (8.9%) patients. The ROC-AUC (Receiver operating characteristic-area under the curve) of pre-ASI for all- cause death was 0.76 (p<0.001), which was similar to that of in-ASI (0.78, p<0.001) (p=0.25 for pre-ASI versus in-ASI). The cut-off value for pre-ASI and in-ASI was for the prediction of all-cause death was both 45 with a sensitivity of 0.66 and a specificity of 0.78, with a sensitivity of 0.68 and a specificity of 0.76 respectively. According to the Kaplan-Meier survival analysis by combination of pre-ASI≥45 and in-ASI≥45, the patients with pre-ASI≥45 and in-ASI≥45 showed significantly higher all-cause mortality compared to the patients with pre-ASI≥45 and in-ASI<45, the patients with pre-ASI<45 and in-ASI≥45, and the patients with pre-ASI<45 and in-ASI<45 (p<0.001) (Figure). The addition of pre-ASI≥45 to in-ASI≥45 (global chi-squared score: 205) resulted in a significantly increased global chi-squared score, suggesting the incremental prognostic value of pre-ASI (267; p<0.001). Multivariate cox proportional hazard regression analysis for all-cause mortality demonstrated pre-ASI≥45 was a significant independent predictor (HR: 4.86; 95% CI: 3.36 to 7.02, p<0.001). It was strongest predictor compared to left ventricular ejection fraction<40% (HR: 2.45; 95% CI 1.67 to 3.58, p<0.001), hemodialysis (HR: 3.45; 95% CI 1.66 to 7.17, p=0.001), door to balloon time>90 minutes (HR: 1.66; 95% CI 1.18 to 2.34, p=0.004). Conclusions High pre-ASI predict increase mortality and assessment of both high pre-ASI and high in-ASI enhance risk stratification in patients with AMI. Early recognizing high pre-ASI may help us make better strategies and improve prognosis for high-risk AMI patients. Figure 1 Funding Acknowledgement Type of funding source: None