What is the Optimal Rate of Invasive Coronary Angiography After Acute Coronary Syndrome? (ANZACS-QI 22)

Background Invasive coronary angiography plays a pivotal role in the management of acute coronary syndromes (ACS). Wide variability in its use has been previously documented. Our aim was to investigate whether coronary angiography is being used appropriately prior to discharge after ACS, taking into account relative contraindications of the procedure. Methods Patients presenting with ACS in 2015 to two large, demographically distinct New Zealand (NZ) District Health Boards (DHBs)-Counties Manukau (CMDHB) and Waitemata (WDHB)-were identified from the NZ Ministry of Health National Dataset using ICD-10-AM codes. Patients' clinical data were obtained from the electronic and paper clinical records. Pre-defined relative contraindications to coronary angiography were identified. Results Of the 3,809 patient admissions coded with ACS, 600 patient admissions (300 from each DHB) were reviewed. Sixty-one (61) (10%) did not meet diagnostic criteria for ACS on review of clinical data and were excluded. Of the patients reviewed, 55% received coronary angiography, with a higher rate in WDHB than CMDHB (61% and 49%, respectively) and 37.5% had relative contraindications documented. The overall rate of angiography was appropriately high in those without a relative contraindication (90.3%) and low in those with one (7.4%). There were fewer patients with relative contraindications in WDHB than CMDHB (36.7% and 48.5%) but the rate of angiography in those with (6.9% and 7.8%) and without (92.5% and 87.5%) contraindications in the two DHBs was similar. Conclusions The decision to offer coronary angiography after ACS appears to be appropriately influenced by the presence or absence of relative contraindications. Approximately 60% of patients had no documented relative contraindication suggesting that this may be an appropriate angiography rate in New Zealand practice. However, differences between the two DHBs of around 10% appear to be clinically appropriate due to variation in contraindication rates.