Outcomes of cardiogenic shock complicating acute coronary syndromes

OBJECTIVES: We aimed to assess the outcomes of cardiogenic shock (CS) complicating acute coronary syndromes (ACS). BACKGROUND: CS remains the leading cause of mortality in patients presenting with ACS despite advances in care. METHODS: We studied 13,184 patients undergoing percutaneous coronary intervention (PCI) for all subtypes of ACS enrolled prospectively in a large multicentre Australian registry (Melbourne Interventional Group registry) from 2005 to 2013. All-cause mortality was obtained via linkage to the National Death Index. Patients were divided into those with and those without CS. RESULTS: Compared to the non-CS group (n = 12,548, 95.2%), the CS group (n = 636, 4.8%) had a higher proportion of out-of-hospital cardiac arrest (OHCA) (31.1 vs. 2.2%) and ST-elevation myocardial infarction (STEMI) presentation (89 vs. 34%), both p < .01. Patients in the CS group had higher rates of in-hospital (40.4 vs. 1.2%) and 30-day (41 vs. 1.7%) mortality compared to the non-CS group. Long-term mortality over a median follow-up of 4.2 years was higher in the CS group (50.6 vs. 13.8%), p < .001. Trends of in-hospital and 30-day mortality rates of CS complicating ACS were relatively stable from 2005 to 2013. Predictors of long-term NDI-linked mortality within the CS group include severe left ventricular systolic dysfunction (HR 3.0), glomerular filtration rate (GFR) <30 (HR 2.56), GFR 30-59 (HR 1.94), OHCA (HR 1.46), diabetes (HR 1.44), and age (HR 1.02), all p < .05. CONCLUSIONS: Rates of CS-related mortality complicating ACS have remained very high and steady over nearly a decade despite progress in STEMI systems of care, PCI techniques, and medical therapy.