The Effects of Aspirin dose in Children with Congenital and Acquired Heart Disease. Results from the Paediatric Study of Aspirin Efficacy using Diagnostic and Monitoring Tools (PAED-M)

The optimal dose of aspirin required in children with congenital and acquired heart disease is not known. The primary aim of this prospective observational study was to evaluate the effects of aspirin dose on platelet inhibition. The secondary aim was to determine the prevalence and clinical predictors of aspirin non-responsiveness. Measurements were by Thromboelastography with Platelet Mapping (TEGPM) only in children less than 2 years (y) of age with particular emphasis on the parameter known as maximum amplitude with arachidonic acid (MAAA) and using both TEGPM, and light transmission aggregometry (LTA) in children greater than 2 y. We prospectively studied 101 patients with congenital and acquired cardiac disease who were receiving empirical doses of aspirin for a minimum of 4 weeks but no other antiplatelet agents. Patients were stratified according to dose concentration and age. There was a trend toward lower age in patients with no response or semi-response to aspirin. All patients were considered responsive to aspirin in the higher-dose quartile (Q4) with a median dose of 4.72 (4.18-6.05) mg/kg/day suggesting that patients in this age group may require 5 mg/kg/day as an empirical dose. In children > 2 y, there was no significant difference in inhibition found in patients dosed at higher doses in Q3 versus Q4 suggesting that patients in this cohort are responsive with 3 mg/kg/day dose. The current practices may lead to reduced platelet inhibition in some children due to under-dosing or overdosing in others. In conclusion, younger children require higher doses of aspirin. Laboratory assessment is warranted in this population to mitigate against under and overdosing.

Diflunisal Attenuates Virulence Factor Gene Regulation and Phenotypes in Staphylococcus aureus

Virulence factor expression is integral to pathogenicity of Staphylococcus aureus. We previously demonstrated that aspirin, through its major metabolite, salicylic acid (SAL), modulates S. aureus virulence phenotypes in vitro and in vivo. We compared salicylate metabolites and a structural analogue for their ability to modulate S. aureus virulence factor expression and phenotypes: (i) acetylsalicylic acid (ASA, aspirin); (ii) ASA metabolites, salicylic acid (SAL), gentisic acid (GTA) and salicyluric acid (SUA); or (iii) diflunisal (DIF), a SAL structural analogue. None of these compounds altered the growth rate of any strain tested. ASA and its metabolites SAL, GTA and SUA moderately impaired hemolysis and proteolysis phenotypes in multiple S. aureus strain backgrounds and their respective deletion mutants. Only DIF significantly inhibited these virulence phenotypes in all strains. The kinetic profiles of ASA, SAL or DIF on expression of hla (alpha hemolysin), sspA (V8 protease) and their regulators (sigB, sarA, agr (RNAIII)) were assessed in two prototypic strain backgrounds: SH1000 (methicillin-sensitive S. aureus; MSSA) and LAC-USA300 (methicillin-resistant S. aureus; MRSA). DIF induced sigB expression which is coincident with the significant inhibition of RNAIII expression in both strains and precedes significant reductions in hla and sspA expression. The inhibited expression of these genes within 2 h resulted in the durable suppression of hemolysis and proteolysis phenotypes. These results indicate that DIF modulates the expression of key virulence factors in S. aureus via a coordinated impact on their relevant regulons and target effector genes. This strategy may hold opportunities to develop novel antivirulence strategies to address the ongoing challenge of antibiotic-resistant S. aureus.

Outcomes in cardiac implantable electronic device-related infective endocarditis: a systematic review of current literature

Aim: Cardiac implantable electronic device infective endocarditis is a serious infection with poor prognosis. Materials & methods: The systematic review of the literature was conducted using searches from the various databases. We included studies published between January 2010 and June 2021. Results: A total of 35 articles met the inclusion criteria. Patients were approximately 70 years old and an average of 71.2% of patients were male. The most common presenting feature was a fever. The modified Duke criteria was used to aid diagnosis. Management entailed extraction of the cardiac implantable electronic device in 80.5% of the studies. The overall mortality rates ranged from 4 to 36%. The most frequently isolated organism was Staphylococcus aureus. Conclusion: Cardiac implantable electronic device infective endocarditis needs timely diagnosis and effective management for promising outcomes.

Staphylococcus aureus increases platelet reactivity in patients with infective endocarditis

Thromboembolism is frequent in infective endocarditis (IE). However, the optimal antithrombotic regimen in IE is unknown. Staphylococcus aureus (SA) is the leading cause of IE. First studies emphasize increased platelet reactivity by SA. In this pilot study, we hypothesized that platelet reactivity is increased in patients with SA− IE, which could be abrogated by antiplatelet medication. We conducted a prospective, observatory, single-center cohort study in 114 patients with IE, with four cohorts: (1) SA coagulase positive IE without aspirin (ASA) medication, (2) coagulase negative IE without ASA, (3) SA coagulase positive IE with ASA, (4) coagulase negative IE with ASA. Platelet function was measured by Multiplate electrode aggregometry, blood clotting by ROTEM thromboelastometry. Bleeding events were assessed according to TIMI classification. In ASA-naïve patients, aggregation with ADP was increased with coag. pos. IE (coagulase negative: 39.47 ± 4.13 AUC vs. coagulase positive: 59.46 ± 8.19 AUC, p = 0.0219). This was abrogated with ASA medication (coagulase negative: 42.4 ± 4.67 AUC vs. coagulase positive: 45.11 ± 6.063 AUC p = 0.7824). Aspirin did not increase bleeding in SA positive patients. However, in SA negative patients with aspirin, red blood cell transfusions were enhanced. SA coagulase positive IE is associated with increased platelet reactivity. This could be abrogated by aspirin without increased bleeding risk. The results of this pilot study suggest that ASA might be beneficial in SA coagulase positive IE. This needs to be confirmed in clinical trials.

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.

Aspirin or Ticagrelor in Staphylococcus aureus Infective Endocarditis: Where Do We Stand?

Infective endocarditis is a challenging disease with a high mortality and morbidity rate. Antibiotic prophylaxis is currently recommended in high-risk infective endocarditis patients. However, the use of antibiotics faces the challenge of a low efficacy and contributes further to the emerging infection rate by antibiotic-resistant strains, emphasizing the need for new therapeutic strategies. Platelets are essential in the initial phase of infective endocarditis, acting as first-line immune responders. During the first phase of disease, bacteria can interact with platelets and counteract platelet antimicrobial activities. Mechanistic in vitro and animal studies on the effect of aspirin on bacteria-platelet interactions and the prevention of vegetation development showed promising results. However, data from clinical studies on the outcome of infective endocarditis patients who were receiving medically indicated aspirin therapy remain controversial. Therefore, the benefit of antiplatelet agents in infective endocarditis prevention has been questioned. Besides aspirin, it has been discovered that the platelet P2Y12 receptor antagonist ticagrelor has antibacterial properties in addition to its potent antiplatelet activity. Furthermore, a recent study in mice and a case report remarkably indicated the ability of this drug to eradicate Staphylococcus aureus bacteremia. This review will focus on current knowledge on antibacterial activity of ticagrelor, compared to aspirin, pointing out main unanswered questions. The goal is to provide food for thought as to whether a prior ticagrelor therapy might be beneficial for the prevention of infective endocarditis.

Association between high vancomycin minimum inhibitory concentration and clinical outcomes in patients with methicillin-resistant Staphylococcus aureus bacteremia: a meta-analysis

PURPOSE

To assess the relationship between high vancomycin minimum inhibitory concentrations (MIC), in patients with methicillin-resistant Staphylococcus aureus bacteremia (MRSAB), and both mortality and complicated bacteremia.

METHODS

Embase, Medline, EBM, Scopus and Web of Science were searched for studies published from January 1st 2014 to February 29th 2020. "High" vancomycin MIC cut off was defined as ≥ 1.5 mg/L. Three referees independently reviewed studies that compared outcomes in patients with MRSAB stratified by vancomycin MIC. Subgroup analyses were performed for rates of mortality and complicated bacteremia.

RESULTS

A total of 13 studies with 2089 patients were included. Overall, mortality was 27.7% and 23.3% in the high and low vancomycin MIC group, respectively. No significant difference was found between vancomycin MIC groups for overall mortality, in-hospital mortality, late mortality, persistent bacteremia, severe sepsis or septic shock, acute renal failure, septic emboli or endocarditis, and osteomyelitis or septic arthritis. Early mortality was significantly associated with low vancomycin MIC. Mortality in studies using broth microdilution method (BMD) and need for mechanical ventilation were significantly associated with high vancomycin MIC.

CONCLUSION

Overall mortality and complicated bacteremia were not significantly associated with high vancomycin MICs in a patient with MRSAB. Randomized controlled trials to assess the utility of vancomycin MIC values in predicting mortality and other adverse clinical outcomes are warranted.

Impact of Chronic Kidney Disease on Short-Term Cardiac Implantable Electronic Device Related Infection: A Nationwide Population-Based Cohort Study

Chronic kidney disease (CKD) increased the incident cardiac implantable electronic device (CIED) infection, but risk factors of CIED infection in CKD patients remain unclear.Patients who received new CIED implantation between January 1, 1997 and December 31, 2011 were selected from the Taiwan National Health Insurance Database and were divided into 3 groups: patients with normal renal function, CKD patients without dialysis, and CKD patient with dialysis. Two outcomes, CIED infection during index hospitalization and within 1 year after discharge, were evaluated.This study included 38,354 patients, 35,060 patients in normal renal function group, 1927 patients in CKD without dialysis group, and 1367 patients in CKD with dialysis group. CKD patients without dialysis (adjusted odds ratio [aOR], 2.14, 95% confidence interval [CI], 1.32-3.46) and CKD patients with dialysis (aOR, 3.78, 95% CI, 2.37-6.02) increased incident CIED infection during index hospitalization compared to patients with normal renal function. Use of steroid (aOR: 2.74, 95% CI, 1.08-6.98) increased the risk of CIED infection in CKD patients without dialysis while chronic obstructive pulmonary disease (COPD) (aOR: 2.76, 95% CI, 1.06-7.16) increased the risk of CIED infection in CKD patient with dialysis during index hospitalization.CKD is a risk of CIED infection during index hospitalization. Use of steroid and COPD are important risks factors for CIED infection in CKD patients.

Incidence and predictors of Melody® valve endocarditis: a prospective study

BACKGROUND

Percutaneous pulmonary valve replacement (PPVR) has achieved standard of care for the management of dysfunctional right ventricular outflow tract.

AIM

Because of increasing reports of Melody(®) valve (Medtronic, Inc., Minneapolis, MN, USA) infective endocarditis (IE), we aimed to evaluate its incidence and predictors of occurrence.

METHODS

We collected data on all patients who received a Melody valve in the pulmonary position from 2009 to 2012.

RESULTS

A total of 86 consecutive patients underwent PPVR from 2009 to 2012; of these, five developed IE (5.8%). Freedom from IE was 91% at 50 months. Baseline demographics, type of conduit, PPVR procedural success, residual gradients and in situ duration of Melody valve were similar in IE and non-IE patients. A significant number of IE patients had additional unprotected invasive procedures during follow-up and abruptly discontinued antiplatelet therapy (P=0.0139 and P=0.002, respectively). The cumulative probability of survival without cardiovascular events for IE patients was 20% at 20 months, compared with 98.1% for non-IE patients (P<0.0001). Death was statistically associated with IE.

CONCLUSION

Early- and late-onset IE of the Melody valve is emerging as a catastrophic complication of PPVR. Abrupt aspirin discontinuation and additional unprotected invasive procedures during follow-up are significant predictors of Melody valve IE. Owing to its rapidly progressive nature, aggressive invasive management should not be delayed.