Predictors of Hospital Mortality in Patients with Acute Coronary Syndrome Complicated by Cardiogenic Shock

Abstract

As demonstrated by earlier studies, pre-hospital triage with trans-telephonic electrocardiogram (TTECG) and direct referral for catheter therapy shows great value in the management of out-of-hospital chest pain emergencies. It does not only improve in-hospital mortality in ST-segment elevation myocardial infarction, but it has also been identified as an independent predictor of higher in-hospital survival rate. Since TTECG-facilitated triage shortens both transport time and percutaneous coronary intervention (PCI)-related procedural time intervals, it was hypothesized that even high-risk patients with acute coronary syndrome (ACS) and cardiogenic shock (CS) might also benefit from TTECG-based triage. Here, we decided to examine our database for new triage- and left ventricular (LV) function-related parameters that can influence in-hospital mortality in ACS complicated by CS. ACS patients were divided into two groups, namely, (1) hospital death patients (n = 77), and (2) hospital survivors (control, n = 210). Interestingly, TTECG-based consultation and triage of CS and ACS patients were confirmed as significant independent predictors of lower hospital mortality risk (odds ratio (OR) 0.40, confidence interval (CI) 0.21-0.76, p = 0.0049). Regarding LV function and blood chemistry, a good myocardial reperfusion after PCI (high area at risk (AAR) blush score/AAR LV segment number; OR 0.85, CI 0.78-0.98, p = 0.0178) and high glomerular filtration rate (GFR) value at the time of hospital admission (OR 0.97, CI 0.96-0.99, p = 0.0042) were the most crucial independent predictors of a decreased risk of in-hospital mortality in this model. At the same time, a prolonged time interval between symptom onset and hospital admission, successful resuscitation, and higher peak creatine kinase activity were the most important independent predictors for an increased risk of in-hospital mortality. In ACS patients with CS, (1) an early TTECG-based teleconsultation and triage, as well as (2) good myocardial perfusion after PCI and a high GFR value at the time of hospital admission, appear as major independent predictors of a lower in-hospital mortality rate.

Keywords: acute heart failure; myocardial perfusion; prehospital triage; telemedicine.

Figure 1

CONSORT diagram showing patient flow at each stage of the data collection. ACS = acute coronary syndrome; CS = cardiogenic shock.

Figure 2

The Kaplan–Meier curve depicts the in-hospital survival rate (value ± 95% confidence intervals) of all the acute coronary syndrome patients with cardiogenic shock in the first 48 days.

Figure 3

Odds ratios and 95% confidence intervals for hospital mortality in the individual subgroups, defined on the basis of baseline characteristics, blood chemistry, and percutaneous coronary intervention-related procedural data. Only selected parameters, and variables displaying a p value of p < 0.2 with the comparative analysis are shown. The sizes of the symbols reflect the number of patients in each group. For some parameters (time to symptom onset to hospital, door to balloon time, age, AAR, AAR QuBE, LV QuBE, LVEF, CK_max, hemoglobin, and GFR), confidence intervals are within the symbols. AAR = area at risk; CK_max = peak creatine kinase level; GFR = glomerular filtration rate; LV = left ventricle; LVEF = left ventricular ejection fraction; PAD = peripheral artery disease; QuBE = blush score; TTECG = transtelephonic electrocardiogram.