Nationwide trends in acute coronary syndrome by subtype in New Zealand 2006–2016

Abstract

ObjectivesRecent studies in acute coronary syndrome (ACS) have reported mixed results for trends in ACS subtypes. The All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) 31 study evaluated trends in ACS event rates, invasive management and mortality of ST-elevation myocardial infarction (STEMI), non-STEMI (NSTEMI) and unstable angina (UA) in New Zealand.MethodsAll ACS hospitalisations between 2006 and 2016 were identified from routinely collected national data and categorised into STEMI, NSTEMI, UA and MI unspecified (MIU). Annual hospitalisation, coronary procedure, 28-day and 1-year mortality rates were calculated and trends tested using Poisson regression adjusting for age and sex.ResultsOver the 11-year study period, there were 188 264 ACS admissions, of which 16.0% were STEMI, 54.5% NSTEMI, 25.7% UA and 3.8% MIU. Event rates of all ACS subtypes fell: STEMI by 3.4%/year, NSTEMI by 5.9%/year and UA by 8.5%/year, while the proportion of patients with ACS receiving angiography and revascularisation increased by 5.6% per year. Rates of percutaneous coronary intervention rose for STEMI, NSTEMI and UA, but coronary artery bypass grafting increased only for NSTEMI and UA. Mortality at 28 days and 1 year was higher for STEMI than NSTEMI and lowest for UA. There was a relative 1.6%/year decline in 1 year mortality for NSTEMI (p<0.001), but no significant change for STEMI and UA.ConclusionsWe observed declines in the event rates of all ACS subtypes and increases in revascularisation rates. The finding that mortality declined in patients with NSTEMI, but not in patients with STEMI and UA, despite increases in invasive procedures, requires further investigation.

Acute coronary syndromes: a success story but still a long way to go

“…The mortality rates in the study by Wang et al 5 are significantly higher than seen in recent large ACS studies, including the ODYSSEY Outcomes study6 and the Intracoronary Stenting and Antithrombotic Regiment (ISAR) React 5 trial 7. In the ODYSSEY study, at a median follow-up of 2.8 years, the mortality in the treatment arm was 3.5% vs 4.1% in the placebo arm,6 while in ISAR React 5 the 12-month mortality was 4.5% in the ticagrelor arm and 3.7% in the prasugrel group 7.…”

“…The majority of these advances occurred between 1990 and 2005, and while progress continues to be made in reducing the incidence of patients presenting with acute coronary syndrome (ACS) and improving their outcomes the rate of improvement has slowed. The paper by Wang et al 5 published in Heart reports on the incidence and outcomes, 28-day and 1-year mortality, in patients hospitalised with ACS in all New Zealand public hospitals between 2006 and 2016. These data were collected as part of the All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) 31 study.…”

“…The heightened awareness of the importance of primary prevention and widely available effective therapies for hypertension and hyperlipidaemia have resulted in a reduction in the number of patients presenting with ACS. Wang et al 5 report a reduction in all ACS presentations, with the most dramatic reduction seen in unstable angina presentations most likely due to the more sensitive troponin assay resulting in patients being recoded as NSTEMI. Interestingly there was a reduction seen in NSTEMI and STEMI, with the actual reduction in patients presenting with STEMI being 3.4% per year vs 5.9% per year for NSTEMI.…”

Heartbeat: When should patients consider implantable cardiac defibrillator deactivation?

“…The incidence and mortality of coronary artery disease continues to decline worldwide but there have been inconsistent findings for the relative contribution of different acute coronary syndrome (ACS) subtypes. Wang and colleagues3 report on ACS hospitalisation in the All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) 31 study which included 188 264 ACS admissions over the decade from 2006 to 2016. Event rates for all types of ACS declined over this time period while the proportion of patients treated with revascularisation increased.…”

“…The apparent paradox that higher rates of re-vascularisation were not associated with a change in mortality for ST-elevation myocardial infarction or unstable angina highlights the fact that medical therapy, not revascularisation, has had the most impact on declining coronary artery disease mortality rates over the last 40 years, as illustrated in an elegant figure by Shaw4 (figure 3). He also points out that the higher mortality rates reported using registry data, such as the study by Wang and colleagues,3 compared with randomised clinical trials, reflect the selection criteria of clinical trials versus the inclusion of all-comers in registries, including those with cardiogenic shock, comorbidities and advanced age. He also suggests: ‘The less than optimal use of guideline-directed therapy, namely invasive angiography, needs to be addressed, and there may have been lower than expected use of secondary prevention therapies, including antiplatelet and lipid-lowering therapy, which if addressed could result in improved patient outcomes.’…”