Influence of admission shock index on short-term and long-term prognosis in terms of heart failure and mortality among patients hospitalized with acute myocardial infarction undergoing primary percutaneous coronary intervention

Abstract

Objective To investigate the influence of admission shock index (SI) on the short-term and long-term prognosis in terms of heart failure and mortality among patients hospitalized with acute ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Methods Patients hospitalized in Department of Cardiology, People′s Hospital of Linyi between May 2012 and September 2015 with acute STEMI undergoing primary PCI were enrolled and divided into two groups according to admission SI, the ratio of heart rate (bpm) to systolic blood pressure (mmHg) on admission, namely, high SI group (SI>0.7) and low SI group (SI≤0.7). Patients discharged alive were followed up by clinic or telephone until September 2018 to investigate the occurrence of major adverse cardio-cerebrovascular events (MACCE, including death, heart failure, malignant arrhythmia, non-fatal myocardial infarction, revascularization of target vessels and stroke). Multivariate logistic and Cox regression analysis was used to evaluate the predictors of MACCE during hospitalization and long-term follow-up, respectively. Results A total of 1 256 patients were enrolled in this analysis. The in-hospital heart failure (19.0% vs 11.6%) and mortality (6.5% vs 3.3%) were significantly higher in high SI group (n=279) than those in low SI group (n=977) (both P<0.05). Of 1 206 patients discharged alive, 1 081 completed follow-up (lost rate of follow-up of 10.4%) with a median duration of 4.2 years. Compared to patients in low SI group (n=845), the incidence of heart failure (15.7% vs 23.7%), cardiovascular mortality (4.5% vs 8.5%) and all-cause mortality (10.8% vs 16.1%) during the long-term follow-up were significantly higher among those in high SI group (n=236) (all P<0.05). Logistic regression analysis showed that admission SI was an independent predictor of heart failure [odds ratio (OR) 3.16, 95% confidence interval (CI) 1.04-10.28, P<0.01] and death (OR 2.76, 95%CI 1.23-6.18, P<0.05) in hospital. Cox regression analysis showed that admission SI was also an independent predictor of heart failure [hazard ratio (HR) 1.97, 95%CI 1.23-5.32, P<0.05] and cardiovascular death (HR 2.09, 95%CI 1.21-4.48, P<0.05) during long-term follow-up. Conclusions For patients with STEMI undergoing primary PCI, the occurrence of heart failure and mortality during hospitalization and follow-up increased significantly in those with admission SI>0.7. Increased admission SI was an independent predictor not only for in-hospital heart failure and death but also for long-term heart failure and cardiovascular death. Key words: Myocardial infarction; Percutaneous coronary intervention; Shock index; Prognosis