The role of hemostasis in infective endocarditis

Hemostatic disorders in patients with infective endocarditis undergoing urgent surgical valve replacement - Rethinking current beliefs

BACKGROUND

Although infective endocarditis (IE) represents a unique model of thrombo-inflammatory disease, the most frequent early complications of surgical valve replacement (SVR) in IE population are coagulopathy and bleeding. The hemostatic capacity and procedure-related coagulation disorders of IE patients undergoing SVR are unknown. The aims of this study were to test periprocedural hemostasis in IE patients undergoing urgent SVR, and to assess the association between disorders of hemostasis and early bleeding as well as with thromboembolic events.

METHODS

A prospective, two-center, hypothesis generating, observational study was performed between Dec 2017 and Jan 2020. Periprocedural hemostasis of IE patients was assessed using Total Thrombus-formation Analysis System (T-TAS Plus) within 24 h before and 72 h post SVR.

RESULTS

Overall, 25 patients with active IE undergoing urgent SVR were tested. Hemostatic capacity of IE patients was significantly impaired pre-SVR as well as post-SVR compared to normal values, in most aspects of T-TAS assays under high and low shear forces, including prolonged activation of coagulation (T10), final clot formation (OT) and clot strength (AUC30). Post-SVR T-TAS results were significantly associated with early bleeding and with red blood cell, platelet, and fresh frozen plasma administration. No association with thrombo-embolic events was found.

CONCLUSIONS

Patients with active IE undergoing urgent SVR have significantly reduced hemostatic capacity before and after SVR. Hemostatic insufficiency post-SVR is related to bleeding and blood products transfusion. T-TAS may be helpful in assessment of periprocedural hemostasis in patients with IE undergoing SVR.

Perioperative Complications in Infective Endocarditis

Infective endocarditis is a challenging condition to manage, requiring collaboration among various medical professionals. Interdisciplinary teamwork within endocarditis teams is essential. About half of the patients diagnosed with the disease will ultimately have to undergo cardiac surgery. As a result, it is vital for all healthcare providers involved in the perioperative period to have a comprehensive understanding of the unique features of infective endocarditis, including clinical presentation, echocardiographic signs, coagulopathy, bleeding control, and treatment of possible organ dysfunction. This narrative review provides a summary of the current knowledge on the incidence of complications and their management in the perioperative period in patients with infective endocarditis.

Coagulation Disorders in Infective Endocarditis: Role of Pathogens, Biomarkers, Antithrombotic Therapy (Systematic Review)

The issue of antithrombotic therapy in patients with infective endocarditis has been studied for over 75 years. During that time studying of pathogenesis of the disease and its embolic complications, lead to the introduction of the concept of “immunothrombosis”. That mechanism allows infective agents (mostly bacteria) to be cloaked from the immune system and to multiply freely, leading to growth of vegetation, thus resulting in higher chance of fragmentation. Small-scale experimental and clinical studies on the correction of hemostatic disorders in infective endocarditis, that were performed in 20th century, didn’t show any significant results, that could affect clinical practice. However, reinterpretation of available data on coagulative system will allow to have elements of hemostasis as an application point in treating infective endocarditis. The article will discuss latest insights on the role of hemostasis system in pathophysisology of infective endocarditis, its effects on the development of the embolic complications, perspectives for diagnostics and treatment.

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.

Hypercoagulation detected by routine and global laboratory hemostasis assays in patients with infective endocarditis

Background

Coagulation system is heavily involved into the process of infective endocarditis (IE) vegetation formation and can facilitate further embolization. In this study we aimed to assess the coagulation and platelet state in IE implementing a wide range of standard and global laboratory assays. We also aim to determine whether prothrombotic genetic polymorphisms play any role in embolization and mortality in IE patients.

Methods

37 patients with IE were enrolled into the study. Coagulation was assessed using standard coagulation assays (activated partial thromboplastin time (APTT), prothrombin, fibrinogen, D-dimer concentrations) and integral assays (thromboelastography (TEG) and thrombodynamics (TD)). Platelet functional activity was estimated by flow cytometry. Single nuclear polymorphisms of coagulation system genes were studied.

Results

Fibrinogen concentration and fibrinogen-dependent parameters of TEG and TD were increased in patients indicating systemic inflammation. In majority of patients clot growth rate in thrombodynamics was significantly shifted towards hypercoagulation in consistency with D-dimers elevation. However, in some patients prothrombin, thromboelastography and thrombodynamics were shifted towards hypocoagulation. Resting platelets were characterized by glycoprotein IIb-IIIa activation and degranulation. In patients with fatal IE, we observed a significant decrease in fibrinogen and thrombodynamics. In patients with embolism, we observed a significant decrease in the TEG R parameter. No association of embolism or mortality with genetic polymorphisms was found in our cohort.

Conclusions

Our findings suggest that coagulation in patients with infective endocarditis is characterized by general hypercoagulability and platelet pre-activation. Some patients, however, have hypocoagulant coagulation profile, which presumably can indicate progressing of hypercoagulation into consumption coagulopathy.

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.

Infective Endocarditis: A Focus on Oral Microbiota

Infective endocarditis (IE) is an inflammatory disease usually caused by bacteria entering the bloodstream and settling in the heart lining valves or blood vessels. Despite modern antimicrobial and surgical treatments, IE continues to cause substantial morbidity and mortality. Thus, primary prevention and enhanced diagnosis remain the most important strategies to fight this disease. In this regard, it is worth noting that for over 50 years, oral microbiota has been considered one of the significant risk factors for IE. Indeed, among the disparate recommendations from the American heart association and the European Society of Cardiology, there are good oral hygiene and prophylaxis for high-risk patients undergoing dental procedures. Thus, significant interest has grown in the role of oral microbiota and it continues to be a subject of research interest, especially if we consider that antimicrobial treatments can generate drug-resistant mutant bacteria, becoming a severe social problem. This review will describe the current knowledge about the relationship between oral microbiota, dental procedures, and IE. Further, it will discuss current methods used to prevent IE cases that originate from oral pathogens and how these should be focused on improving oral hygiene, which remains the significant persuasible way to prevent bacteremia and systemic disorders.

Increased Risk of Ischemic Stroke After Treatment of Infective Endocarditis: A Danish, Nationwide, Propensity Score-Matched Cohort Study

BACKGROUND

Several studies have reported a high risk of ischemic stroke (IS) during the acute phase of infective endocarditis (IE). The long-term risk of IS after IE, however, is not fully illuminated.

METHODS

This Danish, nationwide, register-based, propensity score-matched cohort study used Cox regression to estimate hazard ratios (HRs) of IS for persons with vs without a history of left-sided IE, from 1977 to 2015.

RESULTS

We followed 9312 patients exposed to a first-time IE and 91 996 nonexposed, matched control persons. Compared to persons without IE, patients with a history of IE had a significantly increased risk of IS; the risk was highest during the first 4 weeks after IE diagnosis (HR 57.20, 95% confidence interval [CI] 45.58-71.78; P < .0001) and a moderately elevated risk persisted until 2 years after IE (4 weeks to 3 months after IE, HR 5.40, 95% CI 4.11-7.19; 3 months to 2 years after IE, HR 1.73, 95% CI 1.48-2.01). Mediation analyses showed that the higher risk of IS the first 2 years after IE could not be explained by atrial fibrillation (AF) or inserted mechanical valves in IE patients. In the period from 4 weeks to 3 months after IE diagnosis, patients treated with anticoagulative therapy had a lower risk of IS (HR 0.30, 95% CI .10-0.96; P = .04).

CONCLUSIONS

Patients with a history of IE had an increased risk of IS for up to 2 years after IE diagnosis. The increased risk was unrelated to AF and inserted mechanical valves. During the initial phase after IE, patients taking an anticoagulative medication had a lower risk of IS.

Aspirin Effect on Staphylococcus aureus-Platelet Interactions During Infectious Endocarditis

Infectious endocarditis (IE) is a rare disease associated with high mortality and morbidity rate. The platelet-bacterial interaction presents the cornerstone of the development of endocardial vegetation. The epidemiology of IE has undergone profound changes between the last and the new decade, with Staphylococcus aureus becoming the main incriminated species. Despite improvements in antibiotic and surgical therapies, embolic disorders remain highly associated with IE that can be fatal. Antiplatelet drugs have been widely proposed to overcome embolic events associated with IE. This proposal has been supported by numerous in vitro, experimental, and clinical studies. However, other studies have yielded conflicting results. In this review, we focus on the effect of aspirin on the genesis of S. aureus endocarditic vegetation, as well as on the management of embolic and hemorrhagic events related to it, starting by its influence on the platelet-bacteria interaction.

Streptococcus gallolyticus subsp. gallolyticus endocarditis isolate interferes with coagulation and activates the contact system

Streptococcus gallolyticus subsp. gallolyticus, formerly classified as S. bovis biotype I, is an increasing cause of bacteremia and infective endocarditis in the elderly. The physiopathology of infective endocarditis is poorly understood and involves immune and coagulation systems. In this study, we found that S. gallolyticus subsp. gallolyticus activates the human contact system, which in turn has two consequences: cleavage of high-molecular-weight kininogen (HK) resulting in release of the potent pro-inflammatory peptide bradykinin, and initiation of the intrinsic pathway of coagulation. S. gallolyticus subsp. gallolyticus was found to bind and activate factors of the human contact system at its surface, leading to a significant prolongation of the intrinsic coagulation time and to the release of bradykinin. High-affinity binding of factor XII to the bacterial Pil1 collagen binding protein was demonstrated with a K_D of 13 nM. Of note, Pil1 expression was exclusively found in S. gallolyticus subsp. gallolyticus, further supporting an essential contribution of this pilus in virulence.

Inherited Variation in Cytokine, Acute Phase Response, and Calcium Metabolism Genes Affects Susceptibility to Infective Endocarditis

Infective endocarditis (IE) is a septic inflammation of the endocardium. Recognition of microbial patterns, cytokine and acute phase responses, hemostasis features, and alterations in plasma lipid and calcium profile all have been reported to affect pathogenesis and clinical course of IE. Having recruited 123 patients with IE and 300 age-, sex-, and ethnicity-matched healthy blood donors, we profiled their genomic DNA for 35 functionally significant polymorphisms within the 22 selected genes involved in the abovementioned pathways, with the further genetic association analysis. We found that the G/A genotype of the rs1143634 polymorphism within the IL1B gene, the G/T genotype of the rs3212227 polymorphism within the IL12B gene, the A/G genotype of the rs1130864 polymorphism within the CRP gene, and the G allele of the rs1801197 polymorphism within the CALCR gene were associated with a decreased risk of IE whereas the T/T genotype of the rs1205 polymorphism within the CRP gene was associated with a higher risk of IE. Furthermore, heterozygous genotypes of the rs1143634 and rs3212227 polymorphisms were associated with the higher plasma levels of IL-1β and IL-12, respectively. Our results indicate that inherited variation in the cytokine, acute phase response, and calcium metabolism pathways may be linked to IE.

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

Blood coagulation plays a key role in the pathogenesis of infective endocarditis (IE). Conditions associated with thrombophilia could enhance IE vegetation formation and promote embolic complications.In this study, we assessed prevalence, correlates, and clinical consequences of hyper-homocysteinemia (h-Hcy) in IE.Homocysteine (Hcy) plasma levels were studied in 246 IE patients and 258 valvular heart disease (VHD) patients, as well as in 106 healthy controls.IE patients showed Hcy levels comparable to VHD patients (14.9 [3-81] vs 16 [5-50] μmol/L, respectively; P = 0.08). H-Hcy was observed in 48.8% of IE patients and 55.8% of VHD (P = 0.13). Vegetation size and major embolic complications were not related to Hcy levels. IE patients with h-Hcy had a higher prevalence of chronic kidney disease and a higher 1-year mortality (19.6% vs 9.9% in those without h-Hcy; OR 2.21 [1.00-4.89], P = 0.05). However, at logistic regression analysis, h-Hcy was not an independent predictor of 1-year mortality (OR 1.87 [95% CI 0.8-4.2]; P = 0.13).Our data suggest h-Hcy in IE is common, is related to a worse renal function, and may be a marker of cardiac dysfunction rather than infection. H-Hcy does not appear to favor IE vegetation formation or its symptomatic embolic complications.

Prevalence and significance of two major inherited thrombophilias in infective endocarditis

The pathogenesis of infective endocarditis (IE) involves activation of the haemostasis system at the site of endocardial defects. Whether prothrombotic conditions are associated with IE by enhancing early vegetation formation is unknown. In this study, we assess the prevalence and clinical significance of two major conditions associated with thrombophilia in patients with IE. Mutations G20210A of the prothrombin (PTH) gene and G1691A of factor V (FV Leiden) gene were studied by means of allele-specific polymerase chain reaction in 203 IE patients, 175 valvular heart disease (VHD) patients and 200 blood donors (BD). IE patients show higher cumulative frequencies of mutated alleles of PTH and FV Leiden [6.4 vs 3.25 %; OR 2.03 (95 % CI 0.97-3.66); p = 0.047] compared to BD, but not VHD. Device-related IE is enriched with FV Leiden, and prosthetic valve IE with PTH mutations (allele frequency 8.3 vs 2.2 % in native valve IE; p = 0.021). Vegetation size and embolic complications are not influenced by the examined thrombophilias. A trend for a higher mortality was observed in IE patients with any of the two thrombophilias studied. Our data do not support a role for factor V Leiden and G20210A prothrombin gene mutations in the susceptibility to IE. Whether any of these genetic polymorphisms play a role in a specific subtype of IE needs to be re-examined in larger studies.