Short- and Long-Term Outcomes of Out-of-hospital Cardiac Arrest Following ST-elevation Myocardial Infarction Managed with Percutaneous Coronary Intervention.

Aim: Out-of-hospital cardiac arrest (OHCA) is frequently associated with ST-elevation myocardial infarction (STEMI) and has a high mortality. We aimed to identify differences in characteristics and very long-term outcomes for STEMI patients with and without OHCA managed with percutaneous coronary intervention (PCI). Methods: We analysed data from 12,637 PCI patient procedures for STEMI in the multi-centre Melbourne Interventional Group registry between January 2005 and December 2018. Multivariable models examined associations with OHCA presentation and 30-day mortality. Long-term outcomes were assessed through linkage with the Australian National Death Index. Results: Compared with patients without OHCA (N = 11,580), patients with OHCA (N = 1057) were younger, more often male, had less cardiovascular risk factors, and more often presented with cardiogenic shock. OHCA preceded an increasing proportion of STEMI PCI cases from 2005 to 2018 (2.4% vs. 9.2%). Factors independently associated with OHCA presentation were younger age, male gender, prior valve surgery, multi-vessel disease, LAD culprit, small vessel diameter, and renal impairment on presentation. Patients with OHCA had lower procedural success, higher rates of bleeding and stroke, larger infarct size (measured by peak CK), and higher 30-day mortality (37% vs. 5%; all p < 0.05). Cardiogenic shock, renal impairment and lower ejection fraction were independently associated with 30-day mortality. Long-term mortality was 44% vs. 20% (median follow-up 4.6 years), with Cox regression analysis demonstrating no difference in survival if patients survived beyond 30 days (HR 1.18, 95% CI 0.951.47). Conclusions: OHCA has a high short-term mortality and precedes an increasing proportion of STEMI PCI cases. Thirty-day survivors have an excellent long-term prognosis.