Incidence and Predictors of Referral for Coronary Angiography and Revascularization in Non-ST-Segment Elevation Myocardial Infarction.

Background: Routine invasive coronary angiography (ICA) is recommended for patients presenting with non-ST-segment elevation myocardial infarction (NSTEMI), but the rate of adherence to this recommendation in Australia is not known.

Aims: We sought to quantify the proportion of patients who undergo ICA and revascularization in a contemporary cohort of NSTEMI patients, and to determine predictors of clinical outcome.

Methods: This was a population-based cohort study of consecutive patients transported by emergency medical services (EMS) in Victoria, Australia with chest pain who were diagnosed with NSTEMI between January 1, 2015, and June 30, 2019. Ambulance data were linked to hospital admission, emergency department, and mortality records.

Results: There were 11,040 patients attended by EMS with NSTEMI, of which 5379 patients (48.7%) underwent ICA, with 2798 patients (25.3%) proceeding to coronary revascularization. Patients who underwent ICA were younger, more frequently male, less comorbid, and more likely to originate from a major city and a higher socioeconomic status compared to those who did not. Patients who underwent ICA had lower short- and long-term mortality, and coronary angiography was independently associated with reduced mortality on Cox-regression analysis (HR 0.45, 95% CI 0.41-0.50, p < 0.001).

Conclusion: Less than half of ambulance-transported patients with NSTEMI underwent ICA, and only a quarter of the cohort received revascularization, despite there being a survival benefit with invasive management. Although patients who do not undergo ICA are older and more comorbid, there are potentially modifiable barriers to access to care, including socioeconomic status, rurality, and sex.