Infective endocarditis presenting as ST-elevation myocardial infarction: an angiographic diagnosis

Multidisciplinary Perspectives of Challenges in Infective Endocarditis Complicated by Septic Embolic-Induced Acute Myocardial Infarction

BACKGROUND

Infective endocarditis (IE) management is challenging, usually requiring multidisciplinary collaboration from cardiologists, infectious disease specialists, interventional cardiologists, and cardiovascular surgeons, as more than half of the cases will require surgical procedures. Therefore, it is essential for all healthcare providers involved in managing IE to understand the disease's characteristics, potential complications, and treatment options. While systemic embolization is one of the most frequent complications of IE, the coronary localization of emboli causing acute myocardial infarction (AMI) is less common, with an incidence ranging from 1% to 10% of cases, but it has a much higher rate of morbidity and mortality. There are no guidelines for this type of AMI management in IE.

METHODS

This narrative review summarizes the current knowledge regarding septic coronary embolization in patients with IE. Additionally, this paper highlights the diagnosis and management challenges in such cases, particularly due to the lack of protocols or consensus in the field.

RESULTS

Data extracted from case reports indicate that septic coronary embolization often occurs within the first two weeks of the disease. The aortic valve is most commonly involved with vegetation, and the occluded vessel is frequently the left anterior descending artery. Broad-spectrum antibiotic therapy followed by targeted antibiotic therapy for infection control is essential, and surgical treatment offers promising results through surgical embolectomy, concomitant with valve replacement or aspiration thrombectomy, with or without subsequent stent insertion. Thrombolytics are to be avoided due to the increased risk of bleeding.

CONCLUSIONS

All these aspects should constitute future lines of research, allowing the integration of all current knowledge from multidisciplinary team studies on larger patient cohorts and, subsequently, creating a consensus for assessing the risk and guiding the management of this potentially fatal complication.

ST segment elevation caused by ostial right coronary artery obstruction in infective endocarditis: a case report

Background

Acute coronary syndrome (ACS) is a rare, but serious complication of infective endocarditis, and diagnosis can be challenging given clinical overlap with other syndromes. A rare cause of ACS in infective endocarditis is mechanical obstruction of the coronary artery. We present the case of a patient with infective endocarditis who developed ST segment myocardial infarction due to occlusion of the right coronary artery ostium by a vegetation.

Case presentation

A 53-year-old female with no prior history of coronary artery disease was transferred to our tertiary care facility for evaluation and treatment of suspected myopericarditis. After transfer she developed inferior ST segment elevations on ECG along with fever and positive blood cultures for methicillin susceptible Staphylococcus aureus (MSSA). A transesophageal echocardiogram revealed a vegetation on the aortic valve that intermittently prolapsed into the right coronary ostium. She decompensated from a hemorrhagic brain infarct and subsequently transferred to the intensive care unit. She underwent surgical aortic valve debridement without prior cardiac catheterization given the danger of septic coronary embolization. After a prolonged hospital course with multiple complications, she was able to discharge home, with no neurologic deficits on follow-up.

Conclusions

ACS presents a diagnostic and therapeutic challenge in the setting of infective endocarditis. Careful attention to the history, physical exam and testing can help differentiate infective endocarditis from other conditions sharing similar symptoms. Traditional atherosclerotic ACS management may cause great harm when treating patients with infective endocarditis. The presence of a multidisciplinary endocarditis team is ideal to provide the best clinical outcomes for this population.

Infective Aortic Valve Endocarditis Causing Embolic Consecutive ST-Elevation Myocardial Infarctions

ST-elevation myocardial infarction (STEMI) is a rare and potentially fatal complication of infective endocarditis. We report the ninth case of embolic native aortic valve infective endocarditis causing STEMI and the first case to describe consecutive embolisms leading to infarctions of separate coronary territories. Through examination of this case in the context of the previous eight similar documented cases in the past, we find that infective endocarditis of the aortic valve can and frequently affect more than a single myocardial territory and can occur consecutively. Further, current treatment modalities for embolic infective endocarditis causing acute myocardial infarction are limited and unproven. This index case illustrates the potential severity of complications and the challenges in developing standardized management for such patients.

Role of complement C5a and histones in septic cardiomyopathy

Polymicrobial sepsis (after cecal ligation and puncture, CLP) causes robust complement activation with release of C5a. Many adverse events develop thereafter and will be discussed in this review article. Activation of complement system results in generation of C5a which interacts with its receptors (C5aR1, C5aR2). This leads to a series of harmful events, some of which are connected to the cardiomyopathy of sepsis, resulting in defective action potentials in cardiomyocytes (CMs), activation of the NLRP3 inflammasome in CMs and the appearance of extracellular histones, likely arising from activated neutrophils which form neutrophil extracellular traps (NETs). These events are associated with activation of mitogen-activated protein kinases (MAPKs) in CMs. The ensuing release of histones results in defective action potentials in CMs and reduced levels of [Ca²⁺]i-regulatory enzymes including sarco/endoplasmic reticulum Ca²⁺-ATPase (SERCA2) and Na⁺/Ca²⁺ exchanger (NCX) as well as Na⁺/K⁺-ATPase in CMs. There is also evidence that CLP causes release of IL-1β via activation of the NLRP3 inflammasome in CMs of septic hearts or in CMs incubated in vitro with C5a. Many of these events occur after in vivo or in vitro contact of CMs with histones. Together, these data emphasize the role of complement (C5a) and C5a receptors (C5aR1, C5aR2), as well as extracellular histones in events that lead to cardiac dysfunction of sepsis (septic cardiomyopathy).

Anesthesia for Patients with Concomitant Sepsis and Cardiac Dysfunction

Anesthesiologists faced with a patient with sepsis and concurrent cardiac dysfunction must be cognizant of the patient's cardiac status and cause of the cardiac problem to appropriately adapt physiologic and metabolic monitoring and anesthetic management. Anesthesia in such patients is challenging because the interaction of sepsis and cardiac dysfunction greatly complicates management. Intraoperative anesthesia management requires careful induction and maintenance of anesthesia; optimizing intravascular volume status; avoiding lung injury during mechanical ventilation; and close monitoring of arterial blood gases, serum lactate concentrations, and hematology renal and electrolyte parameters. Such patients have increased mortality because of their inability to adequately compensate for the cardiovascular changes caused by sepsis.

Late Silent Stent Abscess

BACKGROUND

Coronary stent infections in general and stent abscesses (SAs) in particular are rare but often deadly complications. Most SAs manifest with fever and chest pain within 30 days after intervention and require antibiotics and stent removal.

CASE REPORT

A 45-year-old man with second ST elevated myocardial infarction and cardiogenic shock was admitted to a hospital that had no cardiac catheterization laboratory. The patient underwent fibrinolytic therapy with alteplase but died 1 h later. His medical history revealed posterior myocardial infarction 7 years before, which had been successfully treated with a bare metal stent of the right coronary artery. The post-discharge observation had been unremarkable with no evidence of ischaemia or infection but gross non-compliance. Autopsy revealed complete closure of the left main coronary artery and a surprise additional finding, namely SA; the stented portion of the artery was enveloped by an abscess, and purulent material completely occluded the stent, which was floating in pus. Impressions: Since coronary angioplasty is so common, the incidence of late silent SA is probably higher than expected, especially considering that there is often a lack of clinical manifestations. Clinicians should be cognizant of this complication. More attention may be required to assess the condition of existing stents during repeated interventions. Gross non-compliance and/or early withdrawal from dual anti-platelet therapy may be directly responsible for the development of silent delayed SA.

Acute coronary syndrome in two patients with mechanical valve prostheses

We report 2 similar cases of embolic myocardial infarction due to thrombus on a mechanical prosthesis despite anticoagulation therapy. In our first case, aspiration of the thrombus was performed successfully. Our second patient was given medical treatment with target international normalized ratio values between 3.5 and 4.0.