Clinical profile and prognosis of Myocardial Infarction with Non-Obstructive Coronary Arteries (MINOCA) in patients with previous Acute Coronary Syndrome (ACS)
Authors: Alvarez Bello M , Fraile Sanz A , Martin Munoz M , Perela Alvarez C , Nieto Ibanez D , Olsen Rodriguez R , Abad Romero R , Gil Mancebo N , Rodriguez Montes P , Humanes Ybanez S , De La Serna Real De Ansua M , Izquierdo Coronel B , Espinosa Pascual M J , Mata Caballero R , Alonso Martin J J 
Published: October 2024

Abstract

Introduction
Myocardial infarction with non-obstructed coronary arteries (MINOCA) may occur in patients with a personal history of ischaemic heart disease, making diagnosis even more difficult. In addition, the role of cardiovascular risk factors, which are well known in patients with acute myocardial infarction with obstructed arteries (MICAD), is less well defined in MINOCA. The aim of this study is to define the clinical characteristics, risk factors and long-term prognosis in patients with MINOCA and previous acute coronary syndrome (ACS).

Methods
A prospective, analytical, observational study was designed. Included all patients admitted to our centre with ACS between 2016 and 2023 in which a coronary angiography was performed. Patients were classified as MINOCA according to the definition of the 2020 European ACS guidelines. MINOCA patients with and without a history of previous ischaemic heart disease were compared. At follow-up, MACE was defined as all-cause death, hospitalisation, reinfarction and stroke. The median follow-up was 43 [IQR 20-71].

Results
A total of 136 patients were included, of whom 17 had a history of ACS. The proportion of men was significantly higher in the group with previous ACS (82% vs 48%; p=0.008).
Patients with a history of ACS had higher rates of smoking (71% vs 51%, p=0.139), more night work (80% vs 39%, p=0.017) and less stress (33% vs 61%, p=0.152). They also had more peripheral vascular disease (24% vs 3%, p=0.005), diabetes (41% vs 19%, p=0.042), dyslipidaemia (71% vs 43%, p=0.04) and a higher rate of atrial fibrillation (29% vs 9%, p=0.032). However, despite a higher rate of previous ventricular dysfunction (24% vs 3%, p=0.005), they had lower troponin levels on admission (62 [IQR 37-368] vs 152 [IQR 49-424]). We found no differences in the other comorbidities analysed (Table 1).
On admission, patients with previous ACS had significantly more non-ST-segment elevation (29% vs 10%, P=0.05) and received more beta-blocker treatment (82% vs 57%, p=0.046). When analysing the mechanism of infarction, patients without previous ACS were more likely to have vasospasm and coronary embolism. However, there was a significantly higher rate of type II AMI (41% vs 18%, p=0.044) in the group with previous ACS.
During follow-up, patients with a history of ACS are more likely to have a new infarction (7% vs 3%, p=0.3) or stroke (14% vs 6%, p=0.2). There was also a trend towards a higher incidence of MACE in patients with prior ACS, although this did not reach statistical significance (HR 2.379, 95% IC 0,883-6,405) (Table 2).

Conclusion
MINOCA patients with a history of ACS have distinct and worse epidemiological features in which classic cardiovascular risk factors play a significant role, with more ventricular dysfunction and atrial fibrillation. In addition, they appear to have a worse prognosis with increased cardiovascular complications. That might suggest a more MICAD-like profile.