Comparison of myocardial infarction with non-obstructive coronary arteries (MINOCA) versus type 2 MI with NSTEMI presentation; an Italian observation study
Authors: Aleksova A , Munaretto L , Fluca A L , Janjusevic M , Padoan L , Merro E , Barbati G , Hiche C , Di Lenarda A , Sinagra G 
Published: May 2024

Abstract

Funding Acknowledgements
None.

Background
In the last decades, NSTEMI, is the predominant phenotype of myocardial infarction (MI) and many NSTEMI patients(pts) have a non-obstructive CAD. NSTEMI, represents an umbrella for many different conditions with distinct underlying pathogenesis and exhibits significant gender discrepancies and survival differences. Further, in absence of non-obstructive CAD, pts could be wrongly comforted about their prognosis.

Purpose
In this study, we compared the characteristics and the prognosis of pts with MINOCA and type 2 MI with non-obstructive CAD. The primary outcome was a composite of all-cause mortality, non-fatal MI, hospitalization for heart failure (HF) and transitory ischemic attack or non-fatal stroke.

Methods
Were screened 18223 pts with MI, who underwent coronary angiography between 2005 and 2022. Among them, 7815 pts had NSTEMI presentation, of which 693 pts (9%) had a non-obstructive CAD. After reviewing the angiographic data and clinical presentation, 155 pts were excluded because they belonged to one of the categories known as "MINOCA mimichers" (Fig 1). Five hundred and thirty eight pts with MI, NSTEMI presentation and with non-obstructive CAD were included in the final cohort: 301 (56%) had MINOCA and 237 pts (44%) had type 2 MI (Fig 1).

Results
The mean age of the population was 68 years, and females were predominant in both groups. MINOCA pts were younger, more frequently had adverse events during pregnancy and endocrine disorders. Pts with type 2 MI were more likely to have typical CV risk factors and comorbidities such as CKD and HF. Pts with type 2 MI had a worse diastolic function, a more dilated left atrium and left ventricle(LV), and non-coronary distribution of regional LV wall-motion abnormalities.
At initial clinical presentation, the MINOCA group had typical chest pain upon awakening or at night, responsive to nitrates, while type 2 MI were more often to present with dyspnea, palpitations, and with higher blood pressure. Coronary vasospasm and embolization were the most common identified aetiologies in MINOCA pts while tachyarrhythmias were the most common trigger of type 2 MI, followed by hypertensive crisis.
The final model of the predictors of MINOCA at multivariate logistic regression analysis listed in Fig 2, yielded an AUC of 0.865, p&lt;0.01 at ROC analysis(Fig 2a). These variables were used for the generation of nomogram for MINOCA prediction(Fig 2b).
During the median follow-up of 61 months (IQR 34.2-100.35), pts with MINOCA had a significantly better survival rate; 135 of 538 pts (25.1%) reached the primary combined endpoint(Fig 3a). The primary end-point was mainly driven by the all-cause mortality, followed by HF hospitalization, non-fatal stroke, non-fatal MI recurrence. Results of Cox multivariable analysis are presented in Fig 3b.

Conclusions
MINOCA cohort was associated with unconventional risk factors and had a better prognosis compared to T2 MI, which is closer to the classical AMI-CAD.