Characteristics of Patients with Cardiogenic Shock Complicating Acute Coronary Syndrome and its Influence on Clinical Outcomes

Background: Cardiogenic shock (CS) complicates ∼5% of patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI), with the highest mortality in certain subgroups despite contemporary ACS treatment. Methods: Patients with ACS enrolled in the Melbourne Interventional Group registry (2005–2013) with CS (n = 636) were analysed according to pre-specified subgroups. Those with STEMI were compared to non-STEMI, and multivessel PCI compared to single-vessel PCI. Short-term MACE (death, MI, target-vessel revascularisation) and long-term National Death Index (NDI)-linked mortality were assessed between the subgroups. Results: Patients with CS presented with high rates of STEMI (89%) and a preponderance of multivessel disease (70%), however, only 12% underwent multivessel PCI. In-hospital and 30-day MACE were high in the CS cohort (46% and 47% respectively). Long-term NDI-linked mortality was 51% in the entire CS cohort. Subgroup analyses revealed greater in-hospital, 30-day and NDI-linked mortality among those who presented with non-STEMI compared to those with STEMI (63% vs. 38%, 64% vs. 38%, and 79% vs. 47%, respectively, all p < 0.01). There was a trend towards higher in-hospital and 30-day mortality among those who underwent multivessel PCI (50% vs. 39%, p = 0.07 and 50% vs. 40%, p = 0.09). Higher long-term NDI-linked mortality was observed in the multivessel PCI subgroup (63% vs. 49%, p < 0.05). Conclusion: Cardiogenic shock complicating ACS portends very poor short and long-term survival with particularly high mortality in the non-STEMI and multivessel PCI subgroups.