Background:
Myocardial infarction with non-obstructive coronary arteries (MINOCA) is an enigma that is being increasingly recognized with the frequent use of angiography following Acute Myocardial Infarction (AMI). The current study is a prospective, contemporary analysis of MINOCA vs. Myocardial Infarction with obstructive coronary artery disease (MI-CAD) in regards to prevalence, clinical features, and in-hospital outcomes.
Methods:
All consecutive patients undergoing coronary angiography for AMI (as per the Third Universal AMI Definition) in South Australian public hospitals from January 2012 - December 2013 were included. Data was captured by Coronary Angiogram Database of South Australia (CADOSA), a comprehensive registry compatible with the NCDR® CathPCI® Registry. The AMI patients were classified as MI-CAD or MINOCA on the basis of the presence or absence of a significant stenosis (≥50%) on angiography.
Results:
From 4,189 angiography procedures undertaken for AMI, 468 (11%) were classified as MINOCA. Patients with MINOCA were younger (59±15 vs. 64±13 years, p <0.01) and more likely to be female (53% vs. 26%, p <0.01), compared to those with MI-CAD. Age-adjusted analysis comparing patients with MINOCA to MI-CAD revealed differences in: (1) cardiovascular risk factors including hypertension (52% vs. 66%, p<0.01), diabetes (19% vs. 32%, p<0.01), dyslipidemia (46% vs. 62%, p<0.01), and current smoker status (27% vs. 37% p<0.01); (2) AMI type and size with fewer ST elevation myocardial infarcts (27% vs. 41%, p<0.01) and lower peak troponin values (180 ng/L, IQR 353 vs. 264 ng/L, IQR 680, p<0.01) amongst MINOCA patients. Furthermore, the GRACE Score for acute coronary syndrome risk stratification was lower for the MINOCA patients compared to MICAD (150±34 versus 160±35, p <0.01). Despite fewer cardiovascular risk factors, the absence of obstructive coronary artery disease, smaller infarcts, and a lower GRACE score, the in-hospital mortality was similar for MINOCA and MI-CAD patients (2.2% vs. 3.0%, p=0.22). Moreover, MINOCA patients were less likely to receive secondary prevention therapies at discharge including antiplatelet therapy (60% vs. 92%, p<0.01) beta-blockers (41% vs. 65%, p<0.01), statin (55% vs. 88%, p<0.01), ACE-inhibitor/angiotensin receptor blocker (59% versus 81%, p<0.01), or referral to cardiac rehabilitation (15% versus 52%, p<0.01).
Conclusions:
In contemporary cardiology practice, MINOCA may be more frequent than previously appreciated and has a guarded prognosis despite its apparent lower risk profile. Improving the use of secondary prevention therapies in these patients may improve their prognosis.
Rates Of Acute Coronary Events And All Cause Mortality In Patients With Stable Coronary Artery Disease (Cad) After Myocardial Infarction And Additional Cardiovascular Risk Factors
