Diagnosis of Coronary Embolism: A Review1

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.

A Ghost in Coronary Artery - Coronary Artery Embolism After Discontinuation of Rivaroxaban in a Patient With Atrial Fibrillation: Case Report and Review of Literature

Coronary artery embolism (CAE) is a rare clinical entity that can cause acute myocardial infarction (AMI). The exact prevalence of coronary artery embolism is unknown. CAE was found to be associated with conditions that can lead to thrombo-embolism, including infective endocarditis, atrial fibrillation, mitral valve disease, valve surgery. Herein, we report a 78-year-old male with a past medical history of atrial fibrillation on rivaroxaban who presented to the hospital emergency department complaining of chest pain. The patient's anticoagulation therapy was recently held due to a concern for gastrointestinal bleeding. After further evaluation of the patient's symptoms and reviewing his electrocardiogram (ECG) which showed ST-depression in lateral leads and ST-elevation in aVR, urgent cardiac catheterization was done which showed left main coronary artery thrombosis extending into the left anterior descending artery (LAD) and left circumflex artery (LCX). The patient was started on a heparin drip and underwent a successful aspiration thrombectomy with subsequent improvement in his symptoms.

Acute Coronary Syndrome with Non-ruptured Plaques (NONRUPLA): Novel Ideas and Perspectives

PURPOSE OF REVIEW

In this review article, we focus on the mechanisms and features of acute coronary syndromes (ACS) with no ruptured plaque (NONRUPLA) highlighting the uncertainties over diagnostic evaluation and treatment.

RECENT FINDINGS

The most common cause of ACS is obstruction due to atherosclerotic plaque ruptured or erosion. In 14% of patients who present in the Emergency Department as myocardial infarction, the final diagnosis is ACS with NONRUPLA. Although the clinical presentation of NONRUPLA may mimic myocardial infarction, the underlying pathogenesis is different, and it may guide therapeutic approaches and overall prognosis that vary according to etiology. The possible mechanisms of ACS with NONRUPLA are coronary embolism, acute dissection of the aorta or coronary artery, vasospasm, microvascular dysfunction, the imbalance between oxygen demand and supply, coronary trauma and stent complications, direct cellular toxicity and damage, Takotsubo syndrome, and myocardial infarction with non-obstructive coronary arteries (MINOCA).

Clinical features and prognosis of acute myocardial infarction caused by non-tumor origin coronary artery embolism

BACKGROUND

Several studies have indicated that acute myocardial infarction (AMI) secondary to coronary artery embolism (CE) has a poor prognosis. However, in the latter studies, CE of tumor origin accounts for a considerable proportion of cases and the clinical features and contribution to overall prognosis of non-tumor CE are unknown and therefore the subject of this study.

METHODS

We retrospectively studied 2006 consecutive patients with AMI at our medical center from January 2014 to October 2018. Non-tumor CE was diagnosed based on angiographic, biochemical, and imaging criteria. Patients were divided into two groups: patients without CE (control) and patients with non-tumor CE.

RESULTS

Atrial fibrillation was the most frequent etiology (n = 32, 69.6%) in the non-tumor CE group (n = 46). Compared with the control group, the non-tumor CE group had (all p < 0.05): higher incidence of atrial fibrillation; larger left atrial diameter, left ventricular end-diastolic diameter and left ventricular end-systolic diameter; lower left ventricular ejection fraction, ST-segment-elevation myocardial infarction incidence and low density lipoprotein cholesterol level; lower incidence of multivessel coronary stenosis, level of culprit lesion stenosis and proportion of angioplasty; higher ratio of manual thrombectomy and antithrombotic drugs alone therapy; lower thrombolysis in myocardial infarction (TIMI) grade and higher corrected TIMI frame counts (CTFC) after reperfusion; and statistically similar overall survival at median 864 (interquartile range, 413-1272) days.

CONCLUSIONS

The overall incidence of non-tumor CE was 2.3%, with atrial fibrillation as its most common etiology. Midterm overall survival was similar between AMI patients secondary to non-tumor CE and those without CE.

Coronary Embolism: A Systematic Review

BACKGROUND

Coronary embolism is a rare and potentially fatal phenomenon that occurs primarily in patients with valvular heart disease and atrial fibrillation. There is a lack of consensus regarding the diagnosis, treatment, and management of coronary embolism, leaving management at the discretion of the treating physician. Through this review, we aim to establish a better understanding of coronary embolism, and to identify treatment options - invasive and non-invasive - that may be used to manage coronary embolism.

METHODS AND RESULTS

Our systematic review included 147 documented cases of coronary embolism from case reports and case series. The average age of our population was 54.2 ± 17.6 years. The most common causes of coronary embolism included infective endocarditis (22.4%), atrial fibrillation (17.0%), and prosthetic heart valve thrombosis (16.3%). Initial presentation was indistinguishable from an acute coronary syndrome (ACS) due to coronary atherosclerosis, and the diagnosis required a high level of suspicion and evaluation with angiography. Treatment strategies included, but were not limited to, thrombectomy, thrombolysis, balloon angioplasty and stent placement. Myocardial dysfunction on echocardiography was observed in over 80% of patients following coronary embolism. "Good outcomes" were reported in 68.7% of case reports and case series, with a mortality rate of 12.9%.

CONCLUSION

Coronary embolism is an under-recognized etiology of myocardial infarction with the potential for significant morbidity and mortality. To improve outcomes, physicians should strive for early diagnosis and intervention based on the underlying etiology. Thrombectomy may be considered with the goal of rapid restoration of coronary flow.

Renal arterial atherothrombosis due to catheter-induced dissection: Necessity of urgent intervention in a patient with a solitary functioning kidney

BACKGROUND

Renal artery stenosis (RAS) is a leading cause of hypertension, renal failure, pulmonary edema, and loss of renal mass. Atherothrombotic renal disease is a well-described entity, known primarily for its high mortality rate.

CASE

Here, we present a case of acute unrecognized atherothrombosis of RAS due to catheter-induced dissection in a patient with a limited functioning renal artery and solitary kidney. A fifty-two-year-old patient recently diagnosed with hypertension was admitted to our cardiology clinic showing symptoms of uncontrolled hypertension. A renal angiography revealed 90% stenosis in the proximal segment of the right renal artery and totally occluded left renal artery. We decided to perform a percutaneous revascularization. However, the patient did not accept it. During follow-up, the patient's clinical condition deteriorated abruptly due to acute iatrogenic atherothrombosis. A percutaneous transluminal angioplasty was performed, and the patency of the renal artery was secured.

CONCLUSION

Renal angiography may cause acute iatrogenic atherothrombosis due to catheter-induced dissection in patients with solitary functioning kidneys. Percutaneous transluminal angioplasty may secure the patency of the renal artery.

Prevalence, Clinical Features, and Prognosis of Acute Myocardial Infarction Attributable to Coronary Artery Embolism

BACKGROUND

Coronary artery embolism (CE) is recognized as an important nonatherosclerotic cause of acute myocardial infarction. Its prevalence, clinical features, and prognosis remain insufficiently characterized.

METHODS AND RESULTS

We screened 1776 consecutive patients who presented with de novo acute myocardial infarction between 2001 and 2013. CE was diagnosed based on criteria encompassing histological, angiographic, and other diagnostic imaging findings. The prevalence, clinical characteristics, treatment strategies, in-hospital outcomes, and long-term risk of CE recurrence or major adverse cardiac and cerebrovascular events (cardiac death, fatal arrhythmia, or recurrent thromboembolism) were evaluated. The prevalence of CE was 2.9% (n=52), including 8 (15%) patients with multivessel CE. Atrial fibrillation was the most common cause (n=38, 73%). Only 39% of patients with CE were treated with vitamin K antagonists, and the median international normalized ratio was 1.42 (range, 0.95-1.80). Eighteen of the 30 CE patients with nonvalvular atrial fibrillation had a CHADS2 score of 0 or 1. When those patients were reevaluated using CHA2DS2-VASc, 61% were reassigned to a higher risk category. During a median follow-up of 49 months, CE and thromboembolism recurred in 5 atrial fibrillation patients. The 5-year rate of major adverse cardiac and cerebrovascular events was 27.1%. In the propensity score-matched cohorts (n=45 each), Kaplan-Meier analysis showed a significantly higher incidence of cardiac death in the CE group than in the non-CE group (hazard ratio, 9.29; 95% confidence interval, 1.13-76.5; P<0.001).

CONCLUSIONS

Atrial fibrillation is the most frequent cause of CE. Patients with CE represent a high-risk subgroup of patients with acute myocardial infarction and require close follow-up.

Dual prosthetic heart valve presented with chest pain: a case report of coronary thromboembolism

Coronary embolism from a prosthetic heart valve is a rare but remarkable cause of acute coronary syndrome. There is no definite management of an entity like this. Here we report a case of 54-year-old male with a history of rheumatic heart disease with dual prosthetic heart valve and atrial fibrillation who developed chest pain from acute myocardial infarction. The laboratory values showed inadequate anticoagulation. Cardiac catheterization and thrombectomy with the aspiration catheter were chosen to be the treatment for this patient, and it showed satisfactory outcome.

Atherosclerotic geometries exacerbate pathological thrombus formation poststenosis in a von Willebrand factor-dependent manner

Rupture of a vulnerable atherosclerotic plaque causes thrombus formation and precipitates cardiovascular diseases. In addition to the thrombogenic content of a plaque, also the hemodynamic microenvironment plays a major role in thrombus formation. How the altered hemodynamics around a plaque promote pathological thrombus formation is not well understood. In this study, we provide evidence that plaque geometries result in fluid mechanical conditions that promote platelet aggregation and thrombus formation by increased accumulation and activity of von Willebrand factor (vWF) at poststenotic sites. Resonant-scanning multiphoton microscopy revealed that in vivo arterial stenosis of a damaged carotid artery markedly increased platelet aggregate formation in the stenotic outlet region. Complementary in vitro studies using microfluidic stenotic chambers, designed to mimic the flow conditions in a stenotic artery, showed enhanced platelet aggregation in the stenotic outlet region at 60-80% channel occlusion over a range of input wall shear rates. The poststenotic thrombus formation was critically dependent on bloodborne vWF and autocrine platelet stimulation. In stenotic chambers containing endothelial cells, flow provoked increased endothelial vWF secretion in the stenotic outlet region, contributing to exacerbated platelet aggregation. Taken together, this study identifies a role for the shear-sensitive protein vWF in transducing hemodynamic forces that are present around a stenosis to a prothrombogenic microenvironment resulting in spatially confined and exacerbated platelet aggregation in the stenosis outlet region. The developed stenotic microfluidic chamber offers a realistic platform for in vitro evaluation of shear-dependent thrombus formation in the setting of atherosclerosis.

Mitral stenosis as a risk factor for embolic myocardial infarction--anticoagulation for some patients, individual treatment for all

A 28 year-old lady with severe rheumatic mitral stenosis presented with non-ST-elevation myocardial infarction secondary to angiographically confirmed right coronary artery embolus with a likely source of mitral valve stenosis origin. This patient was successfully treated medically with dual anti-platelet and 72 hours of intravenous heparin, glycoprotein IIb/IIIa inhibitor and eptifibitide (Integrilin) with a repeated coronary angiogram showing complete resolution of embolus. The management of embolic myocardial infarction is discussed along with the risks of embolism in patients with mitral stenosis who remain in sinus rhythm.

Combined therapeutic strategy for multiple coronary thromboemboli

A female with mitral valvular disease presented an acute myocardial infarction. She suddenly complained of recurrent chest pain with symptoms of pulmonary edema. The angiogram evidenced multiple coronary thromboemboli. A combined strategy using intracoronary thrombolysis, a platelet glycoprotein IIb/IIIa antagonist (abciximab) and percutaneous transluminal coronary angioplasty to help disrupt the thrombus was performed. Clinical and angiographic signs of coronary reperfusion were rapidly achieved. No bleeding complications appeared.

Coronary embolism following aortic and mitral valve replacement: successful management with abciximab and urokinase

We report a case of coronary embolism in a 63-year-old woman with St. Jude aortic and mitral valve replacements who presented with acute myocardial infarction. Urgent catheterization revealed a saddle embolus in the proximal part of the circumflex and ramus arteries and another embolus in a diagonal branch. After employing angioplasty for the totally occluding diagonal embolus, a combined regimen of intracoronary urokinase and intravenous abciximab was successful in achieving complete resolution of the emboli.