Myocardial infarction with non-obstructive coronary arteries: what is the prognosis?

Myocardial infarction in the absence of obstructive coronary stenosis (MINOCA) is a syndrome with several causes, characterized by clinical evidence of myocardial infarction and coronary angiographically normal or almost normal (stenosis <= 50%). MINOCAs represent about 10% of acute coronary syndromes. The causes of MINOCA are manifold and can be classified on the basis of the mechanism in epicardial (unstable plaque not manifested by angiography, epicardial spasm and coronary dissection) or microvascular. The latter in turn can be divided into intrinsic (microvascular spasm, Takotsubo syndrome and coronary embolization) and extrinsic (myocarditis). In the former, the dysfunctional microcirculation causes myocardial necrosis due to reduction of the lumen due to vasoconstriction and / or obstruction, while in the latter, the compression of the lumen occurs ab extrinsic due to myocardial edema. Note that the prognosis of MINOCA is extremely variable and depends on the underlying cause with high risk clinical subsets. A correct diagnostic procedure includes first level tests (clinical / anamnestic examination, ECG, myocardial necrosis enzyme dosage, trans-thoracic echocardiogram, coronary angiography, ventriculogram) and second level tests (intracoronary imaging, coronary vasomotor test, cardiac nuclear magnetic resonance and trans-esophageal or contrast ultrasound). Through this process, it is possible to identify the cause of MINOCA, fundamental for targeting therapy on the disease mechanism, thus constituting a typical example of precision medicine

Can Silent Brain Lesions Be a Target to Guide Anticoagulation Treatment in Patients With Low-Risk Atrial Fibrillation to Reduce Cognitive Impairment?

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Non-invasive anatomic and functional imaging of vascular inflammation and unstable plaque

Over the last several decades, basic cardiovascular research has significantly enhanced our understanding of pathobiological processes leading to formation, progression, and complications of atherosclerotic plaques. By harnessing these advances in cardiovascular biology, imaging has advanced beyond its traditional anatomical domains to a tool that permits probing of particular molecular structures to image cellular behaviour and metabolic pathways involved in atherosclerosis. From the nascent atherosclerotic plaque to the death of inflammatory cells, several potential molecular and micro-anatomical targets for imaging with particular selective imaging probes and with a variety of imaging modalities have emerged from preclinical and animal investigations. Yet, substantive barriers stand between experimental use and wide clinical application of these novel imaging strategies. Each of the imaging modalities described herein faces hurdles—for example, sensitivity, resolution, radiation exposure, reproducibility, availability, standardization, or costs. This review summarizes the published literature reporting on functional imaging of vascular inflammation in atherosclerotic plaques emphasizing those techniques that have the greatest and/or most immediate potential for broad application in clinical practice. The prospective evaluation of these techniques and standardization of protocols by multinational networks could serve to determine their added value in clinical practice and guide their development and deploymen

Heterogeneity of resting and hyperemic myocardial blood flow in healthy humans

Objective: Absolute myocardial blood flow (MBF) is not well-defined in large normal populations, and appears to be heterogeneous in both humans and animals. These factors contribute to the difficulties in defining resting MBF to hibernating myocardium. We therefore assessed absolute baseline and hyperemic MBF in a large population of normal humans. Methods: MBF was quantified by positron emission tomography with oxygen-15-labeled water at baseline and during hyperemia induced by either adenosine or dipyridamole in 131 men and 38 women, aged 21-86 (mean 46±12) years. MBF was corrected for workload using the rate-pressure product (RPP). Results: Uncorrected baseline MBF ranged from 0.590 to 2.050 (mean 0.985±0.230) ml/min/g (coefficient of variation=27%), and corrected MBF from 0.736 to 2.428 (mean 1.330±0.316) ml/min/g (coefficient of variation=24%). MBF in the inferior region was significantly (P<0.0001) lower than either the anterior or lateral regions. Baseline MBF in females was significantly (P<0.001) higher than in males. Conclusions: These results confirm the heterogeneity of MBF in normals and highlight the difficulty in establishing the lower limit of normal MB

Why the term MINOCA does not provide conceptual clarity for actionable decision-making in patients with myocardial infarction with no obstructive coronary artery disease

When acute myocardial injury is found in a clinical setting suggestive of myocardial ischemia, the event is labeled as acute myocardial infarction (MI), and the absence of ≥50% coronary stenosis at angiography or greater leads to the working diagnosis of myocardial infarction with non-obstructed coronary arteries (MINOCA). Determining the mechanism of MINOCA and excluding other possible causes for cardiac troponin elevation has notable implications for tailoring secondary prevention measures aimed at improving the overall prognosis of acute MI. The aim of this review is to increase the awareness that establishing the underlying cause of a MINOCA is possible in the vast majority of cases, and that the proper classification of any MI should be pursued. The initial diagnosis of MINOCA can be confirmed or ruled out based on the results of subsequent investigations. Indeed, a comprehensive clinical evaluation at the time of presentation, followed by a dedicated diagnostic work-up, might lead to the identification of the pathophysiologic abnormality leading to MI in almost all cases initially labeled as MINOCA. When a specific cause of acute MI is identified, cardiologists are urged to transition from the "all-inclusive" term "MINOCA" to the proper classification of any MI, as evidence now exists that MINOCA does not provide conceptual clarity for actionable decision-making in MI with angiographically normal coronary arteries