Clinical significance of hyperhomocysteinemia in infective endocarditis: A case-control study

Anesthesia Considerations in Infective Endocarditis

The management of infective endocarditis is complex and inherently requires multidisciplinary cooperation. About half of all patients diagnosed with infective endocarditis will meet the criteria to undergo cardiac surgery, which regularly takes place in urgent or emergency settings. The pathophysiology and clinical presentation of infective endocarditis make it a unique disorder within cardiac surgery that warrants a thorough understanding of specific characteristics in the perioperative period. This includes, among others, echocardiography, coagulation, bleeding management, or treatment of organ dysfunction. In this narrative review article, the authors summarize the current knowledge on infective endocarditis relevant for the clinical anesthesiologist in perioperative management of respective patients. Furthermore, the authors advocate for the anesthesiologist to become a structural member of the endocarditis team.

Clinical Significance and Prognostic Value of Hemostasis Parameters in 337 Patients with Acute Infective Endocarditis

(1) Background: The aim of this study was to assess the clinical significance and prognostic role of the main hemostasis parameters in infective endocarditis (IE): prothrombin time as international normalized ratio (PT-INR), activated partial thromboplastin time (aPTT), fibrinogen, D-dimers, platelet count, homocysteine. (2) Methods: We studied 337 patients with IE. Clinical, hemato-chemical and echocardiography parameters were analyzed. Coagulation parameters were measured on admission. (3) Results: D-dimers levels (p = 0.012) and a prolonged PT-INR (p = 0.013) were associated with higher in-hospital mortality, while prolonged aPTT (p = 0.021) was associated with increased 1-year mortality. Staphylococcus aureus (S. aureus) infection (p = 0.003), prosthetic valve endocarditis (PVE) (p = 0.001), surgical indication (p = 0.002) and higher D-dimer levels (p = 0.005) were independent predictors of in-hospital mortality. PVE (p = 0.001), a higher Charlson Comorbidity Index (p = 0.049), surgical indication (p = 0.001) and prolonged aPTT (p = 0.012) were independent predictors of 1-year mortality. Higher levels of D-dimers (p < 0.001) and a shorter aPTT (p < 0.001) were associated with embolic complications of IE. S. aureus etiology was bound to higher D-dimers levels (p < 0.001) and a shorter aPTT (p = 0.006). (4) Conclusions: Elevated D-dimers are associated with a higher risk for in-hospital mortality in IE patients. High D-dimers and a short aPTT are associated with a higher risk for embolic events in IE. A longer aPTT is associated with 1-year mortality.

Coagulation: At the heart of infective endocarditis

Infective endocarditis is a life-threatening and enigmatic disease with a mortality of 30% and a pathophysiology that is poorly understood. However, at its core, an endocarditis lesion is mainly a fibrin and platelet blood clot infested with bacteria, clinging at the cardiac valves. Infective endocarditis therefore serves as a paradigm of immunothrombosis gone wrong. Immunothrombosis refers to the entanglement of the coagulation system with innate immunity and the role of coagulation in the isolation and clearance of invading pathogens. However, in the case of infective endocarditis, instead of containing the infection, immunothrombosis inadvertently creates the optimal shelter from the immune system and allows some bacteria to grow almost unimpeded. In every step of the disease, the coagulation system is heavily involved. It mediates the initial adhesion of bacteria to the leaflets, fuels the growth and maturation of a vegetation, and facilitates complications such as embolization and valve destruction. In addition, the number one cause of infective endocarditis, Staphylococcus aureus, has proven to be a true manipulator of immunothrombosis and thrives in the fibrin rich environment of an endocarditis vegetation. Considering its central role in infective endocarditis, the coagulation system is an attractive therapeutic target for this deadly disease. There is, however, a very delicate balance at play and the use of antithrombotic drugs in patients with endocarditis is often accompanied with a high bleeding risk.

The comparative biochemistry of viruses and humans: an evolutionary path towards autoimmunity

Analyses of the peptide sharing between five common human viruses (Borna disease virus, influenza A virus, measles virus, mumps virus and rubella virus) and the human proteome highlight a massive viral vs. human peptide overlap that is mathematically unexpected. Evolutionarily, the data underscore a strict relationship between viruses and the origin of eukaryotic cells. Indeed, according to the viral eukaryogenesis hypothesis and in light of the endosymbiotic theory, the first eukaryotic cell (our lineage) originated as a consortium consisting of an archaeal ancestor of the eukaryotic cytoplasm, a bacterial ancestor of the mitochondria and a viral ancestor of the nucleus. From a pathologic point of view, the peptide sequence similarity between viruses and humans may provide a molecular platform for autoimmune crossreactions during immune responses following viral infections/immunizations.

Ablation of toll-like receptor 4 mitigates cardiac mitochondrial dysfunction in hyperhomocysteinemia

Hyperhomocysteinemia (HHcy) is a risk factor for adverse cardiovascular events; however, the mechanism for development of this disease is still unknown. Toll-like receptor 4 (TRL4) is a molecule involved in the immune response pathway and is quickly becoming a receptor of interest in the field of hypertension. In this study, we hypothesized that ablation of TLR4 mitigates cardiac mitochondrial dysfunction in a model of HHcy. Five strains of mice (C57BL/6J, CBS+/−, C3H, CBS+/−/C3H, and C3H/HeOuJ) 10–12 weeks old were utilized. We found that HHcy causes heart hypertrophy and promotes oxidative stress while mice with HHcy and inactivated TLR4 showed significant improvement in examined parameters. A dominance of endothelial cell mitochondrial fission over mitochondrial fusion in HHcy and oxidative stress was observed, which may explain the endothelial cell loss and dysfunction that contributes to inward cardiac remodeling.