Association of left anterior descending artery involvement on clinical outcomes among patients with STEMI presenting with and without out-of-hospital cardiac arrest

Abstract

Background: ST-segment elevation myocardial infarction (STEMI) outcomes are influenced by the location of the culprit vessel with worse outcomes portended with a left anterior descending (LAD) culprit lesion. However, relatively little is known about the independent association of LAD involvement with clinical outcomes of patients with STEMI with and without out-of-hospital cardiac arrest (OHCA).

Methods: We identified 91 patients with and 929 without a preceding OHCA within the Vancouver Coastal Health Authority who presented with an acute STEMI and underwent primary percutaneous coronary intervention between 26 June 2007 and 31 March 2016.

Results: Patients with STEMI with OHCA had higher rates of in-hospital cardiac arrest (43.3% vs 8.3%, p<0.001), heart failure (50.5% vs 11.3%, p<0.001), cardiogenic shock (49.5% vs 5.7%, p<0.001), mortality (35.2% vs 3.3%, p<0.001) and reduced left ventricular ejection fraction (LVEF; 42.9% vs 47.3%, p<0.001) compared with those without OHCA. Among patients without OHCA, LAD involvement was associated with increased heart failure (18.1% vs 5.2%, p<0.001), in-hospital cardiac arrest (10.7% vs 6.2%, p<0.014), cardiogenic shock (8.4% vs 3.3%, p<0.001), reduced LVEF (43.0% vs 51.2%, p<0.001) and mortality (5.2% vs 1.3%, p=0.003) compared with patients without LAD involvement. With the exception of LVEF, these associations were not seen among patients with STEMI with OHCA and an LAD culprit. The presence of an LAD culprit was not independently associated with increased hospital mortality among patients with OHCA after adjusting for potential confounding factors.

Conclusion: Our study has demonstrated a differential impact of LAD involvement on clinical outcomes among patients with STEMI who present with and without OHCA. Our data highlight the complexity surrounding the prognostication following OHCA complicating STEMI and demonstrate that other mechanisms other than LAD involvement contribute to the high mortality associated with OHCA as a result of STEMI.

Keywords: coronary artery disease; coronary intervention (PCI); resuscitation; sudden cardiac death.

Figure 1

The cohort derivation from the initial study population, through exclusions, to the final study population. OHCA, out-of-hospital cardiac arrest; PCI, percutaneous coronary intervention; pPCI, primary percutaneous coronary intervention; STEMI, ST-segment elevation myocardial infarction; VHCA, Vancouver Coastal Health Authority; CABG, Coronary artery bypass grafting.

Figure 2

Unadjusted in-hospital outcomes in patients with ST-segment elevation myocardial infarction with out-of-hospital cardiac arrest (OHCA), by left anterior descending (LAD) involvement. CHF, congestive heart failure; LVEF, left ventricular ejection fraction.

Figure 3

Unadjusted in-hospital outcomes in patients with ST-segment elevation myocardial infarction without out-of-hospital cardiac arrest (OHCA), by left anterior descending (LAD) involvement. CHF, congestive heart failure; LVEF, left ventricular ejection fraction.

Figure 4

Logistic regression examining the impact of ischaemic territory (left anterior descending (LAD) vs non-LAD) and out-of-hospital cardiac arrest (OHCA) on mortality. FMC, first medical contact.