Invasive management and late clinical outcomes in contemporary Australian management of acute coronary syndromes: observations from the ACACIA registry.

Objective: To describe the impact of invasive management on 12-month survival among patients with suspected acute coronary syndrome (ACS) in Australia.
Design and Setting: Prospective nationwide multicentre registry.
Patients: Patients presenting to 24 metropolitan and 15 non-metropolitan hospitals with ST-segment-elevation myocardial infarction (STEMI), and high-risk and intermediate-risk non-ST-segment-elevation ACS (NSTEACS) between 1 November 2005 and 31 July 2007.
Main Outcome Measures: Death, myocardial infarction (MI) or recurrent MI, revascularisation and stroke at 12 months.
Results: Among 3402 patients originally enrolled, vital status at 12 months was available for 3393 (99.7%). Patients from non-metropolitan areas (810) constituted 23.9% of patients. Early invasive management was more commonly undertaken among patients with STEMI (STEMI, 89.7% v non-STEMI, 70.8% v unstable angina, 44.8% v stable angina, 35.8%; P<0.001). Factors most associated with receiving invasive management included admission with suspected STEMI or high-risk NSTEACS, being male and the hospital having an onsite cardiac surgical service. Overall mortality by 12 months among patients with STEMI, non-STEMI, unstable angina and stable angina was 8.0%, 10.5%, 3.3%, and 3.7% (P<0.001), respectively. After adjusting for a propensity model predicting early invasive management and other known confounders, early invasive management was associated with a 12-month mortality hazard ratio of 0.53 (95% CI, 0.34-0.84, P=0.007).
Conclusions: A substantial burden of late morbidity and mortality persists among patients with ACS within contemporary Australian clinical practice. Under-use of invasive management may be associated with an excess in 12-month mortality, suggesting the need for more use of invasive management among these patients.