Background:
Myocardial infarction with non-obstructive coronary arteries (MINOCA) is being increasingly recognized with the frequent use of angiography following Acute Myocardial Infarction (AMI); yet there is little evaluation of these patients in the literature. The current study is a prospective, contemporary analysis of clinical features and chest pain characteristics between patients with MINOCA and Myocardial Infarction with coronary artery disease (MI-CAD).
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 3,431 angiography procedures undertaken for AMI, 359 (11%) were classified as MINOCA. MINOCA patients were younger (59 ± 15 vs. 64 ± 13, p <0.01) and more likely to be female (60% vs. 26%, p<0.01), with age adjusted analysis revealing less cardiovascular risk factors in MINOCA compared to MICAD: current smoker (21% vs. 35%, p< 0.01), hypertension (56% vs. 65%, p<0.01), dyslipidaemia (46% vs. 61%, p<0.01), and diabetes (20% vs. 32%, p<0.01). Analysis of presenting chest pain characteristics showed no significant differences between MICAD and MINOCA for the presence of retrosternal pain (81% vs. 82%, p>0.05,) or shoulder pain (27% vs. 26%, p>0.05) respectively, however MINOCA patients were less likely to experience arm pain (33% vs. 40%, p<0.01). In regards to precipitating factors, emotional stress was more common (14% vs. 5%, p<0.001) and exertion related chest pain was less common (27% vs. 40%, p<0.001) in MINOCA patients. Quality of pain for MINOCA and MICAD was similar with the most frequent descriptors being burning (11% vs. 9%, p>0.05), sharp 21% vs. 23%, p>0.05) and tightness (41% vs. 44%, p>0.05). In addition, there were no significant differences observed between groups in relieving factors and duration of chest pain
Conclusions:
In contemporary cardiology practice, MINOCA presentation is more common than previously appreciated, with younger women frequently implicated. Delineating a MINOCA patient from MICAD on the basis of chest pain characteristics is not feasible.
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