Elsevier

Resuscitation

Volume 87, February 2015, Pages 57-62
Resuscitation

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

https://doi.org/10.1016/j.resuscitation.2014.11.010Get rights and content

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 (9 mmol/l (SD 6) vs. 6 mmol/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.

Introduction

Acute myocardial infarction (MI) complicated by cardiogenic shock (CS) is one of the most serious acute medical conditions with mortality rates of at least 40–50% in randomized clinical trials (RCT).1, 2, 3, 4, 5 The SHOCK trial assessing the effect of early aggressive revascularization showed 30-day mortality rates of 46% in patients treated with primary percutaneous coronary intervention (pPCI) or coronary artery bypass graft (CABG) and 6-month mortality of 50%.1 The recent IABP-SHOCK II study, assessing the effect of intra aortic balloon pump (IABP) counter pulsation, found 30-day and one-year mortality rates of 40% and 50%.3, 4 Mortality rates remain high today and presumably even higher in the real life clinical setting in CS patients not included in RCTs. Approximately 5% of patients with acute MI develop cardiogenic shock (CS).6, 7, 8, 9 Out-of-hospital cardiac arrest (OHCA) is estimated to occur in one in fifty MI patients, and is associated with increased early mortality in patients with ST-elevation myocardial infarction.10 Furthermore, many OHCA patients also develop CS.11 However, whether MI patients presenting with both OHCA and CS have increased mortality is not known. We therefore aimed to compare outcome in patients with acute MI and CS presenting with or without OHCA to evaluate if OHCA further increases the mortality rate in CS.

Section snippets

Inclusions

Consecutive patients presenting with CS complicating acute MI admitted to a tertiary Danish high volume PCI centre in the period from January 1st 2008 to February 1st 2013 were included. Initial registration with the diagnosis of CS was found in 517 patients. Two hundred and forty-eight patients with acute MI complicated by CS were included. The 269 excluded patients were in CS due to non-ischaemic causes (pulmonary embolism, septicaemia, hypovolemia etc.). CS was defined according to the SHOCK

Demographics

In total 248 patients were admitted with CS complicating acute MI (Fig. 1 and Table 1). In 118 patients (48%) initial presentation was OHCA with ROSC after 25 min (SD 18). Initial rhythm was ventricular fibrillation or pulseless ventricular tachycardia in 76 patients (64%), and cardiac arrest was witnessed in 84 cases (71%), with bystander cardiopulmonary resuscitation initiated in 69 (58%) of OHCA cases. Patients in the OHCA group were younger (64 years (SD 13) vs. 68 years (SD 12), p = 0.03)

Discussion

Previous studies have documented that OHCA is associated with higher mortality in STEMI patients.6, 7, 9, 10, 16 We compared patients with acute MI complicated by cardiogenic shock presenting with or without OHCA in a large contemporary unselected population, including severely haemodynamic compromised patients with severe lactate acidosis. Data suggest that although crude mortality initially was higher in the OHCA this was due to higher age and more severe metabolic acidosis and after

Conclusion

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

Conflicts of interest

None.

Acknowledgements

The study was funded by a postgraduate research scholarship in Rigshospitalet – Copenhagen University Hospital, Department of Cardiology. The work of JK is supported by the EU Interreg IV A programme Centre for Resuscitation Science in the Oresund Region.

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A Spanish translated version of the summary of this article appears as Appendix in the final online version at http://dx.doi.org/10.1016/j.resuscitation.2014.11.010.

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