Population-level incidence and outcomes of myocardial infarction with non-obstructive coronary arteries (MINOCA): Insights from the Alberta contemporary acute coronary syndrome patients invasive treatment strategies (COAPT) study.

BACKGROUND: Myocardial infarction with non-obstructive coronary arteries (MINOCA) is a known clinical conundrum with limited investigation. Using a large population-based cohort, we examined the incidence, demographic profile, use of evidence-based medicines (EBM) and clinical outcomes of MINOCA patients. METHODS: Patients hospitalized with a primary diagnosis of MI who underwent coronary angiography between 01/04/2002 and 31/03/2014 in Alberta, Canada, were included in the study. Comparisons were made between patients with MINOCA versus obstructive coronary disease (OCD). The primary composite endpoint was 1-year all-cause death or re-MI. RESULTS: Of 35,928 patients hospitalized with MI, 2092 (5.8%) had MINOCA. In-hospital mortality rate was 0.8% among MINOCA, and 2.7% among patients with OCD (p < 0.0001). At 6 months, cardiovascular EBM rates were significantly lower among MINOCA patients compared to OCD patients. One-year death/re-MI rate was 5.3% in MINOCA and 8.9% in patients with OCD (adjusted hazard ratio (AHR) 0.75, 95% confidence interval (CI) 0.62-0.92, p < 0.0001). Five-year mortality rates were 10.9% in MINOCA and 16.0% in patients with OCD. Upon further stratification, 770 (36.8%) of MINOCA patients had no angiographic evidence of CAD (i.e. normal angiograms). EBM rates were even lower among these patients. One-year death/re-MI rate among these patients was 3.9% as compared to 6.1% among MINOCA patients with stenosis <50% (AHR 0.68, 95% CI 0.44-1.07, p = 0.028). CONCLUSIONS: The population-level incidence of MINOCA is approximately 5%. Despite their apparently benign anatomic findings, efforts must be made to improve secondary prevention strategies to reduce the burden of long-term adverse outcomes in this population.

Hospital variation in treatment and outcomes in acute coronary syndromes: Insights from the Alberta Contemporary Acute Coronary Syndrome Patients Invasive Treatment Strategies (COAPT) study.

BACKGROUND: We examined variation in hospital treatment and its relationship to clinical outcome in a large population-based cohort of ACS patients within a single payer-government funded health care system. METHODS: Patients hospitalized in 106 hospitals in Alberta, Canada with a primary diagnosis of ACS were included (July 1, 2010-March 31, 2013) with comparisons made across the three cardiac catheterization-capable hospitals (Sites A-C). Cox proportional-hazard regression models were used to examine the multivariable-adjusted association between site and 1-year death or repeat cardiovascular (CV) hospitalization (primary endpoint). RESULTS: Of 14,155 patients, 1938 (13.7%) were admitted to a community hospital without transfer to an invasive hospital (10.7% in-hospital death). The remaining were admitted (n=4514, 36.9%) or transferred (n=7703, 63.1%) to an invasive hospital (A:5480; B:3621; C:3116) where 11,247 (92.1%) underwent catheterization. Comorbidities and angiographic disease burden differed across sites. Variation in 30-day revascularization (PCI: 71.3%, 72.0%, 68.7%, p<0.001; CABG: 6.2%, 6.4%, 9.3%, p<0.001) and drug-eluting stent use for PCI (24.3%, 54.6%, 50.5%, p<0.001) were observed. After adjustment for patient demographics and comorbidities, variation in rates of 1-year death or CV hospitalization was observed among those with 30-day revascularization (p(interaction)<0.001; B versus A: HR 0.78, 95%CI 0.66-0.91; C versus A: HR 0.77, 95%CI 0.65-0.91; B versus C: HR 1.01, 95%CI 0.84-1.21). CONCLUSIONS: Despite a government funded health system, we have shown variation in hospital treatment exists. Following adjustment hospital site was associated with differences in clinical outcome within 1year. Hence, further efforts may be warranted to help address potential disparities in ACS care.