Prognostic implication of out-of-hospital cardiac arrest in patients with cardiogenic shock and acute myocardial infarction

Abstract

Objectives: To compare outcome in patients with acute myocardial infarction (MI) and cardiogenic shock (CS) presenting with and without out-of-hospital cardiac arrest (OHCA).

Background: Despite general improvement in outcome after acute MI, CS remains a leading cause of death in acute MI patients with a high 30-day mortality rate. OHCA on top of cardiogenic shock may further increase mortality in these patients resulting in premature withdrawal of supportive therapy, but this is not known.

Methods and results: In a retrospective study from 2008 to 2013, 248 consecutive patients admitted alive to a tertiary centre with the diagnosis of CS and acute MI were enrolled, 118 (48%) presented with OHCA and 130 (52%) without (non-OHCA patients). Mean lactate level at admission was significantly higher in OHCA patients compared with non-OCHA patients (9mmol/l (SD 6) vs. 6mmol/l (SD 4) p<0.0001). Co-morbidities were more prevalent in the non-OHCA group. By univariate analysis age (Hazard ratio (HR)=1.02 [CI 1.00-1.03], p=0.01) and lactate at admission (HR=1.06 [CI 1.03-1.09], p<0.001), but not OHCA (HR=1.1 [CI 0.8-1.4], p=NS) was associated with mortality. In multivariate analysis, only age (HR=1.02 [CI 1.01-1.04], p=0.003) and lactate level at admission (HR=1.06 [1.03-1.09], p<0.001) were independent predictors of mortality. One-week mortality was 63% in the OHCA group and 56% in the non-OHCA group, p=NS.

Conclusion: OHCA is not an independent predictor of mortality in patients with acute MI complicated by cardiogenic shock. This should encourage active intensive treatment of CS patients regardless of OHCA.

Keywords: Cardiac arrest; Cardiogenic shock; Ischaemia; Lactate; Mortality.