Clinical analysis of acute myocardial infarction caused by coronary embolism

Factor Xa Inhibition with Apixaban Does Not Influence Cardiac Remodelling in Rats with Heart Failure After Myocardial Infarction

BACKGROUND

Heart failure (HF) is considered to be a prothrombotic condition and it has been suggested that coagulation factors contribute to maladaptive cardiac remodelling via activation of the protease-activated receptor 1 (PAR1). We tested the hypothesis that anticoagulation with the factor Xa (FXa) inhibitor apixaban would ameliorate cardiac remodelling in rats with HF after myocardial infarction (MI).

METHODS AND RESULTS

Male Sprague-Dawley rats were either subjected to permanent ligation of the left ascending coronary artery (MI) or sham surgery. The MI and sham animals were randomly allocated to treatment with placebo or apixaban in the chow (150 mg/kg/day), starting 2 weeks after surgery. Cardiac function was assessed using echocardiography and histological and molecular markers of cardiac hypertrophy were assessed in the left ventricle (LV). Apixaban resulted in a fivefold increase in anti-FXa activity compared with vehicle, but no overt bleeding was observed and haematocrit levels remained similar in apixaban- and vehicle-treated groups. After 10 weeks of treatment, LV ejection fraction was 42 ± 3% in the MI group treated with apixaban and 37 ± 2 in the vehicle-treated MI group (p > 0.05). Both vehicle- and apixaban-treated MI groups also displayed similar degrees of LV dilatation, LV hypertrophy and interstitial fibrosis. Histological and molecular markers for pathological remodelling were also comparable between groups, as was the activity of signalling pathways downstream of the PAR1 receptor.

CONCLUSION

FXa inhibition with apixaban does not influence pathological cardiac remodelling after MI. These data do not support the use of FXa inhibitor in HF patients with the aim to amend the severity of HF. Graphical Abstract.

Coronary artery thromboembolism from left appendage mural thrombus- a rare complication from atrial fibrillation

A 54-year-old man with recurrent, persistent atrial fibrillation was found dead unexpectedly. He was reportedly non-compliant with his medications and was not on anti-coagulant therapy. He was found dead in his residence after complaining of abdominal discomfort a day prior to death. Postmortem examination revealed a thromboembolus occluding the left anterior descending coronary artery that originated from a mural thrombus in the left appendage, in addition to kidney infarcts. Although atrial fibrillation-related thromboembolism is often speculated to be a cause of myocardial infarction with non-obstructive coronary arteries, supporting pathological evidence is rare. This case documents radiological, macroscopic and microscopic images of this important complication from atrial fibrillation.

Acute Myocardial Infarction Attributed to Coronary Artery Embolism in a Patient with Atrial Fibrillation Secondary to Thyrotoxicosis - An Underrecognized Entity: A Case Report and Literature Review

Nonatherosclerotic causes of acute myocardial infarction (MI) are infrequent, with atrial fibrillation as the most common etiology in cases of embolic MI. This entity, however, along with other causes of coronary embolus remains underappreciated as a probable cause of acute coronary syndromes.^[1] Our case delineates a rare presentation of STEMI due to cardioembolic origin secondary to atrial fibrillation in a patient with thyrotoxicosis, previously undiagnosed to have an abnormal cardiac rhythm.

Remifentanil protects against myocardial ischemia/reperfusion injury via miR-205-mediated regulation of PINK1

Myocardial ischemia/reperfusion (I/R) injury could lead to severe cardiovascular ischemic disease, including myocardial infarction and contractile dysfunction. Remifentanil demonstrated protective effect on myocardial I/R injury. The underlying pathophysiological mechanism was then investigated in this study. In the current study, primary cardiomyocytes were isolated from rats, and then preconditioned with remifentanil. Rats, tail vein injected with miR-205 antagomir, were subjected to infusion of remifentanil, and then subjected to regional ischemia followed by reperfusion. The results demonstrated that cell viability of hypoxia/reoxygenation-induced cardiomyocytes was increased post remifentanil, while the apoptosis was decreased accompanied with reduced cleaved caspase-3 expression. Hypoxia/reoxygenation treatment increased miR-205 and decreased PINK1 (PTEN induced putative kinase 1) expression. However, preconditioning with remifentanil reduced miR-205 and enhanced PINK1. Moreover, over-expression of miR-205 decreased PINK1 expression and counteracted the effects of remifentanil-induced increase of cell viability and decrease of cell apoptosis in hypoxia/reoxygenation-induced cardiomyocytes. Injection with miR-205 antagomir improved remifentanil-induced decrease of infarct size and LDH (lactic acid dehydrogenase) activity in rat model with I/R injury. In conclusion, miR-205 might participate in the protective effect of remifentanil in rat myocardial I/R injury via regulation of PINK1, providing a potential target for amelioration of cardiovascular ischemic disease.

Acute Myocardial Ischemia Secondary to Embolization of Left Atrial Myxoma to Coronary Artery

Cardiac myxoma is the most common primary cardiac tumor. Rarely it can present with systemic or coronary embolization due to fragmentation of the tumor mass. We present a case of a young male who presented with an acute myocardial ischemia secondary to embolization of a left atrial myxoma originating from the left atrium. The patient underwent successful emergency surgical management of both the myxoma and the occlusion of the coronary artery. In this scenario, the surgery is the only effective treatment. The case also highlights the significance of performing emergency echocardiography in the setting of acute myocardial ischemia to look for possible associated pathology which can inform management plan.

Embolic myocardial infarction. Literature review and own research results

Patients with embolic myocardial infarction (MI) represent a high-risk group and, accordingly, require special attention of clinicians. This article discusses the most common causes of MI, related diagnostic criteria, antithrombotic therapy, and myocardial revascularization in this category of patients. The data of own clinical experience are also given.

[Myocardial Infarction in the Group of Patients With Atrial Fibrillation]

Prevalence of patients with myocardial infarction (MI) and atrial fibrillation (AF) has been growing every year. These patients represent a highest risk group and, thus, require special attention of clinicians. The article foсused on mechanisms of the AF and MI interaction, special aspects of prediction depending on the type of AF and MI, and the issue of antithrombotic therapy in this patient category. A group of AF-associated, embologenic MIs was isolated, and diagnostic criteria and therapeutic regimens were provided.

Saddle coronary embolism precipitates flash pulmonary edema

Coronary artery embolism is as an infrequent but important cause of acute myocardial infarction. We present a rare case of a large saddle embolism in the coronary vasculature which led to an acute myocardial infarction and consequently flash pulmonary edema. Despite intensive medical management, our patient did not survive.

Coronary Embolism and Myocardial Infarction: A Scoping Study

Coronary embolism is a cause of acute myocardial infarction (AMI)in which obstructive foci enter the coronary circulation, block normal blood flow and precipitate ischemia. Precise studies focusing on patient population affected, pathophysiological mechanisms, and treatment strategies are scanty, in spite of a reported prevalence estimated at 2.9%. As the understanding of myocardial infarction without evidence of coronary artery disease continues to grow, an in-depth review of this previously seldomly reported subtype of coronary ischemia was in order. Patients suffering coronary embolism are 15 to 20 years younger than traditional AMI patients with a slight predominance towards male sex, which resembles the gender data of the populations affected by non-traditional myocardial infarction in published reports. While the expected prevalence rate of cardiovascular disease risk factors such as hypertension and hyperlipidemia are present, this population also has a relatively high prevalence of atrial fibrillation and valve pathology, especially endocarditis. Initial presentation is indistinguishable from other causes of myocardial infarction however fever is commonly present, when endocarditis with valvular involvement is the primary cause of the coronary embolism. Mechanical thrombectomy is the mainstay of treatment, followed by percutaneous coronary intervention. Mortality is the highest in patients who do not receive targeted treatment for the coronary embolism, particularly if only antimicrobial agents or anticoagulation without thrombolytic agents are employed. The unique features of coronary embolism highlighted in this historical study justify further examination in contemporary patient populations.