Predictors of Mortality in Patients with ST-Segment Elevation Acute Myocardial Infarction and Resuscitated Out-of-Hospital Cardiac Arrest.

Introduction: In patients with out-of-hospital cardiac arrest (OHCA) complicating an ST-segment elevation myocardial infarction (STEMI), the survival depends largely on the restoration of coronary flow in the infarct related artery. The aim of this study was to determine clinical and angiographic predictors of in-hospital mortality in patients with OHCA and STEMI, successfully resuscitated and undergoing primary percutaneous intervention (PCI).

Methods: From January 2013 to July 2015, 78 patients with STEMI presenting OHCA, successfully resuscitated, transferred immediately to the catheterization unit and treated with primary PCI, were analyzed. Clinical, laboratory and angiographic data were compared in 28 non-survivors and 50 survivors.

Results: The clinical baseline characteristics of the study population showed no significant differences between the survivors and non-survivors in respect to age (p=0.06), gender (p=0.8), the presence of hypertension (p=0.4), dyslipidemia (p=0.09) obesity (p=1), smoking status (p=0.2), presence of diabetes (p=0.2), a clinical history of acute myocardial infarction (p=0.7) or stroke (p=0.17). Compared to survivors, the non-survivor group exhibited a significantly higher incidence of cardiogenic shock (50% vs 24%, p=0.02), renal failure (64.3% vs 30.0%, p=0.004) and anaemia (35.7% vs 12.0%, p=0.02). Three-vessel disease was significantly higher in the non-survivor group (42.8% vs. 20.0%, p=0.03), while there was a significantly higher percentage of TIMI 3 flow postPCI in the infarct-related artery in the survivor group (80.% vs. 57.1%, p=0.03). The time from the onset of symptoms to revascularization was significantly higher in patients who died compared to those who survived (387.5 +/- 211.3 minutes vs 300.8 +/- 166.1 minutes, p=0.04), as was the time from the onset of cardiac arrest to revascularization (103.0 +/- 56.34 minutes vs 67.0 +/- 44.4 minutes, p=0.002). Multivariate analysis identified the presence of cardiogenic shock (odds ratio [OR]: 3.17, p=0.02), multivessel disease (OR: 3.0, p=0.03), renal failure (OR: 4.2, p=0.004), anaemia (OR: 4.07, p=0.02), need for mechanical ventilation >48 hours (OR: 8.07, p=0.0002) and a duration of stay in the ICU longer than 5 days (OR: 9.96, p=0.0002) as the most significant independent predictors for mortality in patients with OHCA and STEMI.

Conclusion: In patients surviving an OHCA in the early phase of a myocardial infarction, the presence of cardiogenic shock, renal failure, anaemia or multivessel disease, as well as a longer time from the onset of symptoms or of cardiac arrest to revascularization, are independent predictors of mortality. However, the most powerful predictor of death is the duration of stay in the ICU and the requirement of mechanical ventilation for more than forty-eight hours.