Myocardial infarction or acute coronary syndrome with non-obstructive coronary arteries and sudden cardiac death: a missing connection

Abstract

Myocardial infarction with non-obstructive coronary arteries or any acute coronary syndrome (ACS) with normal or near-normal (non-obstructive) coronary arteries (ACS-NNOCA) is an heterogeneous clinical entity, which includes different pathophysiology mechanisms and is challenging to treat. Sudden cardiac death (SCD) is a catastrophic manifestation of ACS that is crucial to prevent and treat urgently. The concurrence of the two conditions has not been adequately studied. This narrative review focuses on the existing literature concerning ACS-NNOCA pathophysiology, with an emphasis on SCD, together with risk and outcome data from clinical trials. There have been no large-scale studies to investigate the incidence of SCD within ACS-NNOCA patients, both early and late in the disease. Some pathophysiology mechanisms that are known to mediate ACS-NNOCA, such as atheromatous plaque erosion, anomalous coronary arteries, and spontaneous coronary artery dissection are documented causes of SCD. Myocardial ischaemia, inflammation, and fibrosis are probably at the core of the SCD risk in these patients. Effective treatments to reduce the relevant risk are still under research. ACS-NNOCA is generally considered as an ACS with more ‘benign’ outcome compared to ACS with obstructive coronary artery disease, but its relationship with SCD remains obscure, especially until its incidence and effective treatment are evaluated.

Hyperglycemia, inflammatory response and infarct size in obstructive acute myocardial infarction and MINOCA

“…Keeping in mind that endothelial dysfunction seems to be a key pathophysiological mechanism underlying MINOCA and it is known to be impaired by hyperglycemia as well, it appears plausible that an “hyperglycemic environment” can further alter the endothelial homeostasis and negatively affect the natural history of such patients, often characterized by heart failure with preserved ejection fraction. This hypothesis clearly requires future investigations in order to evaluate whether hyperglycemia may represent a prognostic risk factor for MINOCA subjects, regardless of a concomitant diabetes diagnosis [ 46 – 51 ].…”

COVID-19 and Acute Myocardial Injury and Infarction: Related Mechanisms and Emerging Challenges

“…92 Furthermore, ACS-NNOCA may also trigger malignant arrhythmias and sudden cardiac death. 81 Thus, there is a reduced number of admissions for ACS but also a significant delay in ACS presentation consistently reported during the COVID-19 pandemic era. 7,130,131,136 There is fear supported by important preliminary evidence that this observed pattern may lead to increases in OOHCA, acute mechanical and long-term complications of MI and missed chance to implement secondary prevention therapies for patients with CAD.…”

“…Notably, the risk of sudden cardiac death (SCD) in patients with ACS-NNOCA remains a major concern; myocardial ischemia, inflammation, and fibrosis are probably at the core of the SCD risk in these patients. 81…”

Myocardial Infarction with Nonobstructive Coronary Artery Disease—Definition, Etiopathogenesis, Diagnosis, and Management

“…5 Initial presentation with refractory ventricular arrhythmias and SCD have also been reported. 22 Overall, compared with MI-CAD, patients with MINOCA have less rates of ST-segment deviation (78 vs. 46%, p < 0.001), and a lower Global Registry of Acute Coronary Events ACS risk score (54 vs. 35%, p < 0.001). 21 Nevertheless, the presence of EKG changes, biomarker elevation, and similar traditional risk factors make it all difficult to distinguish MINOCA from those with MI-CAD based on their presentation alone.…”