Cardiovascular complications following pneumonia: focus on pneumococcus and heart failure

Developing a Preliminary Clinical Prediction Model for Prognosis of Pneumonia Complicated with Heart Failure Based on Metagenomic Sequencing

Background

The predictive factors of prognosis in patients with pneumonia complicated with heart failure (HF) have not been fully investigated yet, especially with the use of next-generation sequencing (NGS) of metagenome.

Methods

Patients diagnosed with pneumonia complicated with HF were collected and divided into control group and NGS group. Univariate and multivariate logistic regression and LASSO regression analysis were conducted to screen the predictive factors for the prognosis, followed by nomogram construction, ROC curve plot, and internal validation. Data analysis was conducted in SPSS and R software.

Results

The NGS of metagenome detected more microbial species. Univariate and multivariate logistic regression and LASSO regression analysis revealed that Enterococcus (χ² = 7.449, P = 0.006), Hb (Wals = 6.289, P = 0.012), and ProBNP (Wals = 4.037, P = 0.045) were screened out as potential predictive factors for the prognosis. Nomogram was constructed with these 3 parameters, and the performance of nomogram was checked in ROC curves (AUC = 0.772). The specificity and sensitivity of this model were calculated as 0.579 and 0.851, respectively, with the threshold of 0.630 in ROC curve. Further internal verification indicated that the predictive value of our constructed model was efficient.

Conclusion

This study developed a preliminary clinical prediction model for the prognosis of pneumonia complicated with HF based on NGS of metagenome. More objects will be collected and tested to improve the predictive model in the near future.

Impact of infection-related admission in patients with heart failure: a 10 years national cohort study

Infection is a common cause of hospitalization in patients with heart failure (HF). The impact of infection on long term cardiovascular outcome in HF is not well studied. The aim of this study was to compare the long term risk of major adverse cardiovascular events (MACE) in HF patients with or without prior hospitalization for infection. From 2009 to 2015, 310,485 patients with their first HF admissions were enrolled from the Taiwan National Health Insurance Research Database. Among the patients, those with readmission due to infection within one year after HF discharge were defined as infection group and those without any infection admission were controls. The propensity score matching method was used to balance covariates between the two groups. Patients were followed until the occurrence of any component of the MACE or the end date of the study, December 31, 2019. In a mean follow-up time of 4.29 ± 2.92 years, 86.19% of patients in the infection group and 63.63% of patients in the control group had MACE. Multivariate Cox proportional hazards analysis showed the infection group had a higher risk of MACE (HR 1.760, 95% CI 1.714-1.807), including all-cause mortality (HR 1.587, 95% CI 1.540-1.636), myocardial infarction (HR 1.332, 95% CI 1.224-1.450), stroke (HR 1.769, 95% CI 1.664-1.882) and hospitalization for HF (HR 1.993, 95% CI 1.922-2.066). In conclusion, many HF patients discharged from the hospital experienced acute infection that required readmission. The patients had worse cardiovascular outcome after readmission for infectious disease compared to those without any infection.

A multiple comorbidities mouse lung infection model in ApoE‑deficient mice

Acute pneumonia is characterised by a period of intense inflammation. Inflammation is now considered to be a key step in atherosclerosis progression. In addition, pre-existing atherosclerotic inflammation is considered to play a role in pneumonia progression and risk. In the present study, a multiple comorbidities murine model was used to study respiratory and systemic inflammation that results from pneumonia in the setting of atherosclerosis. Firstly, a minimal infectious dose of Streptococcus pneumoniae (TIGR4 strain) to produce clinical pneumonia with a low mortality rate (20%) was established. C57Bl/6 ApoE ^-/- mice were fed a high-fat diet prior to administering intranasally 10⁵ colony forming units of TIGR4 or phosphate-buffered saline (PBS). At days 2, 7 and 28 post inoculation (PI), the lungs of mice were imaged by magnetic resonance imaging (MRI) and positron emission tomography (PET). Mice were euthanised and investigated for changes in lung morphology and changes in systemic inflammation using ELISA, Luminex assay and real-time PCR. TIGR4-inoculated mice presented with varying degrees of lung infiltrate, pleural effusion and consolidation on MRI at all time points up to 28 days PI. Moreover, PET scans identified significantly higher FDG uptake in the lungs of TIGR4-inoculated mice up to 28 days PI. The majority (90%) TIGR4-inoculated mice developed pneumococcal-specific IgG antibody response at 28 days PI. Consistent with these observations, TIGR4-inoculated mice displayed significantly increased inflammatory gene expression [interleukin (IL)-1β and IL-6] in the lungs and significantly increased levels of circulating inflammatory protein (CCL3) at 7 and 28 days PI respectively. The mouse model developed by the authors presents a discovery tool to understand the link between inflammation related to acute infection such as pneumonia and increased risk of cardiovascular disease observed in humans.

Cardiovascular changes after pneumonia in a dual disease mouse model

Residual inflammation in cardiovascular organs is thought to be one of the catalysts for the increased risk of cardiovascular complications seen following pneumonia. To test this hypothesis, we investigated changes in plaque characteristics and inflammatory features in ApoE−/− mouse aorta and heart following pneumonia. Male ApoE−/− mice were fed a high fat diet for 8 weeks before intranasal inoculation with either Streptococcus pneumoniae serotype 4 (test group) or phosphate buffered saline (control group). Mice were sacrificed at 2-, 7- and 28-days post-challenge. Changes in plaque burden and characteristics in aortic root and thoracic aorta were characterized by Oil red O and Trichrome stains. Inflammatory changes were investigated by FDG-PET imaging and immunofluorescence staining. We found TIGR4-infected mice present with increased plaque presence in the aortic root and thoracic aorta at 2- and 28-days post-inoculation, respectively. Aortic wall remodelling was also more pronounced in mice challenged with pneumococci at 28 days post-inoculation. Aortic root plaques of infected mice had reduced collagen and smooth muscle cells, consistent with an unstable plaque phenotype. Pneumonia alters plaque burden, plaque characteristics, and aortic wall remodelling in ApoE−/− mice. These effects caused by Streptococcus pneumoniae TIGR4, may contribute to the increased risk of cardiovascular complications seen in survivors of this infection.

Heart failure among US nursing home residents with diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus is associated with an increased risk of developing heart failure. However, few recent studies have examined the characteristics of older adults living in US nursing homes with heart failure and diabetes mellitus. This study is important for clinical practice and public health action plans for heart failure.

OBJECTIVE

To estimate the prevalence of, and factors associated with, heart failure in long-stay nursing home residents with diabetes mellitus.

METHODS

We conducted a cross-sectional study using the US 2016 Minimum Data Set data consisting of all residents with diabetes aged ≥65 years in Medicare/Medicaid certified nursing homes (n = 297,570). Diabetes mellitus and heart failure were operationalized using the resident's transfer notes at admission and the progress notes during admission through physical examination findings and current treatment orders.

RESULTS

Among all residents with diabetes, 26.4% had heart failure. Increasing age of residents, and comorbidities including coronary artery disease (aOR: 1.34; 95% CI: 1.31-1.37), end stage renal disease (aOR: 1.30; 95% CI: 1.26-1.35), and chronic obstructive pulmonary disease (aOR: 1.60; 95% CI: 1.57-1.63) were associated with a higher odds of heart failure.

CONCLUSIONS

This is one of the first U.S studies to examine the prevalence and factors associated with heart failure in nursing home residents with diabetes mellitus. It highlights a clinically complex population with multiple comorbid conditions. Future research is needed to understand the pharmacological management of these residents and the extent to which appropriate management can improve quality of life for a medically vulnerable population.

Hospitalization costs of adult community-acquired pneumonia in England

OBJECTIVE

Accurate and up-to-date figures of the cost of community-acquired pneumonia (CAP) hospitalization are needed to understand the associated economic burden for public health decision-makers. Recent estimates are lacking, and previously published estimates differ markedly. Our objective was to estimate the current mean cost to the UK National Health Service (NHS) for adult hospitalized CAP.

METHODS

All CAP hospitalizations in 2019 for those aged ≥18 years were identified from English Hospital Episode Statistics (HES). Each hospitalization was mapped to the tariff cost paid to the care provider within the NHS, including critical care costs and accounting for length of stay and complexity of the case. Mean hospitalization costs were estimated in total and in individuals with defined underlying comorbidities.

RESULTS

A mean cost of £3,904 was estimated for 187,251 CAP admissions providing a total cost of approximately £731 million per annum. The mean cost was £3,402, excluding critical care costs, and £11,654 for critical care episodes in the 4.4% of admissions receiving this care. Groups at high risk of CAP had higher mean costs, ranging from £4,458 for people with diabetes to £5,215 for those with heart disease aged <65 years and £4,356 for those with heart disease to £4,751 for those with liver disease aged >65 years who comprised 74.3% of admissions overall.

CONCLUSION

This estimate of the cost of hospitalization for CAP from the total population and in those with certain underlying comorbidities will allow a valid understanding of the cost-benefit of vaccination and evidence-based prioritization of pneumococcal vaccination to those at highest risk.

Major Adverse Cardiovascular Events During Invasive Pneumococcal Disease Are Serotype Dependent

BACKGROUND

Up to 30% of patients admitted to hospitals with invasive pneumococcal disease (IPD) experience major adverse cardiovascular event (MACE) including new/worsening heart failure, new/worsening arrhythmia, and/or myocardial infarction. Streptococcus pneumoniae (Spn) is the most frequently isolated bacterial pathogen among community-acquired pneumonia (CAP) patients and the only etiological agent linked independently to MACE. Nevertheless, no clinical data exist identifying which serotypes of Spn are principally responsible for MACE.

METHODS

This was an observational multicenter retrospective study conducted through the Public Health Secretary of Bogotá, Colombia. We included patients with a confirmed clinical diagnosis of IPD with record of pneumococcal serotyping and clinical information between 2012 and 2019. Spn were serotyped using the quellung method by the National Center of Microbiology. MACE were determined by a retrospective chart review.

RESULTS

The prevalence of MACE was 23% (71/310) in IPD patients and 28% (53/181) in patients admitted for CAP. The most prevalent S. pneumoniae serotype identified in our study was the 19A, responsible for the 13% (42/310) of IPD in our cohort, of which 21% (9/42) presented MACE. Serotypes independently associated with MACE in IPD patients were serotype 3 (odds ratio [OR] 1, 48; 95% confidence interval [CI] [1.21-2.27]; P = .013) and serotype 9n (OR 1.29; 95% CI [1.08-2.24]; P = .020). Bacteremia occurred in 87% of patients with MACE. Moreover, serum concentrations of C-reactive protein were elevated in patients with MACE versus in non-MACE patients (mean [standard deviation], 138 [145] vs 73 [106], P = .01).

CONCLUSIONS

MACE are common during IPD with serotype 3 and 9n independently of frequency.

Bacterial Membrane Vesicles in Pneumonia: From Mediators of Virulence to Innovative Vaccine Candidates

Pneumonia due to respiratory infection with most prominently bacteria, but also viruses, fungi, or parasites is the leading cause of death worldwide among all infectious disease in both adults and infants. The introduction of modern antibiotic treatment regimens and vaccine strategies has helped to lower the burden of bacterial pneumonia, yet due to the unavailability or refusal of vaccines and antimicrobials in parts of the global population, the rise of multidrug resistant pathogens, and high fatality rates even in patients treated with appropriate antibiotics pneumonia remains a global threat. As such, a better understanding of pathogen virulence on the one, and the development of innovative vaccine strategies on the other hand are once again in dire need in the perennial fight of men against microbes. Recent data show that the secretome of bacteria consists not only of soluble mediators of virulence but also to a significant proportion of extracellular vesicles—lipid bilayer-delimited particles that form integral mediators of intercellular communication. Extracellular vesicles are released from cells of all kinds of organisms, including both Gram-negative and Gram-positive bacteria in which case they are commonly termed outer membrane vesicles (OMVs) and membrane vesicles (MVs), respectively. (O)MVs can trigger inflammatory responses to specific pathogens including S. pneumonia, P. aeruginosa, and L. pneumophila and as such, mediate bacterial virulence in pneumonia by challenging the host respiratory epithelium and cellular and humoral immunity. In parallel, however, (O)MVs have recently emerged as auspicious vaccine candidates due to their natural antigenicity and favorable biochemical properties. First studies highlight the efficacy of such vaccines in animal models exposed to (O)MVs from B. pertussis, S. pneumoniae, A. baumannii, and K. pneumoniae. An advanced and balanced recognition of both the detrimental effects of (O)MVs and their immunogenic potential could pave the way to novel treatment strategies in pneumonia and effective preventive approaches.

Incidence and Outcomes of Pneumonia in Patients With Heart Failure

BACKGROUND

The incidence of pneumonia and subsequent outcomes has not been compared in patients with heart failure and reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF).

OBJECTIVES

This study aimed to examine the rate and impact of pneumonia in the PARADIGM-HF (Prospective Comparison of Angiotensin Receptor-Neprilysin Inhibitor With Angiotensin Converting Enzyme Inhibitor to Determine Impact on Global Mortality and Morbidity in Heart Failure) and PARAGON-HF (Prospective Comparison of ARNI with ARB Global Outcomes in Heart Failure with Preserved Ejection Fraction) trials.

METHODS

The authors analyzed the incidence of investigator-reported pneumonia and the rates of HF hospitalization, cardiovascular death, and all-cause death before and after the occurrence of pneumonia, and estimated risk after the first occurrence of pneumonia in unadjusted and adjusted analyses (the latter including N-terminal pro-B-type natriuretic peptide).

RESULTS

In PARADIGM-HF, 528 patients (6.3%) developed pneumonia after randomization, giving an incidence rate of 29 (95% CI: 27 to 32) per 1,000 patient-years. In PARAGON-HF, 510 patients (10.6%) developed pneumonia, giving an incidence rate of 39 (95% CI: 36 to 42) per 1,000 patient-years. The subsequent risk of all trial outcomes was elevated after the occurrence of pneumonia. In PARADIGM-HF, the adjusted hazard ratio (HR) for the risk of death from any cause was 4.34 (95% CI: 3.73 to 5.05). The corresponding adjusted HR in PARAGON-HF was 3.76 (95% CI: 3.09 to 4.58).

CONCLUSIONS

The incidence of pneumonia was high in patients with HF, especially HFpEF, at around 3 times the expected rate. A first episode of pneumonia was associated with 4-fold higher mortality. (Prospective Comparison of Angiotensin Receptor-Neprilysin Inhibitor With Angiotensin-Converting Enzyme Inhibitor to Determine Impact on Global Mortality and Morbidity in Heart Failure [PARADIGM-HF], NCT01035255; Prospective Comparison of ARNI [Angiotensin Receptor-Neprilysin Inhibitor] With ARB [Angiotensin Receptor Blocker] Global Outcomes in Heart Failure With Preserved Ejection Fraction [PARAGON-HF], NCT01920711).

Advances in community-acquired pneumonia

Community-acquired pneumonia is one of the commonest and deadliest of the infectious diseases, yet our understanding of it remains relatively poor. The recently published American Thoracic Society and Infectious Diseases Society of America Community-acquired pneumonia guidelines acknowledged that most of what we accept as standard of care is supported only by low quality evidence, highlighting persistent uncertainty and deficiencies in our knowledge. However, progress in diagnostics, translational research, and epidemiology has changed our concept of pneumonia, contributing to a gradual improvement in prevention, diagnosis, treatment, and outcomes for our patients. The emergence of considerable evidence about adverse long-term health outcomes in pneumonia survivors has also challenged our concept of pneumonia as an acute disease and what treatment end points are important. This review focuses on advances in the research and care of community-acquired pneumonia in the past two decades. We summarize the evidence around our understanding of pathogenesis and diagnosis, discuss key contentious management issues including the role of procalcitonin and the use or non-use of corticosteroids, and explore the relationships between pneumonia and long-term outcomes including cardiovascular and cognitive health.

Platelets and Their Role in the Pathogenesis of Cardiovascular Events in Patients With Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) remains an important cause of morbidity and mortality throughout the world with much recent and ongoing research focused on the occurrence of cardiovascular events (CVEs) during the infection, which are associated with adverse short-term and long-term survival. Much of the research directed at unraveling the pathogenesis of these events has been undertaken in the settings of experimental and clinical CAP caused by the dangerous, bacterial respiratory pathogen, Streptococcus pneumoniae (pneumococcus), which remains the most common bacterial cause of CAP. Studies of this type have revealed that although platelets play an important role in host defense against infection, there is also increasing recognition that hyperactivation of these cells contributes to a pro-inflammatory, prothrombotic systemic milieu that contributes to the etiology of CVEs. In the case of the pneumococcus, platelet-driven myocardial damage and dysfunction is exacerbated by the direct cardiotoxic actions of pneumolysin, a major pore-forming toxin of this pathogen, which also acts as potent activator of platelets. This review is focused on the role of platelets in host defense against infection, including pneumococcal infection in particular, and reviews the current literature describing the potential mechanisms by which platelet activation contributes to cardiovascular complications in CAP. This is preceded by an evaluation of the burden of pneumococcal infection in CAP, the clinical features and putative pathogenic mechanisms of the CVE, and concludes with an evaluation of the potential utility of the anti-platelet activity of macrolides and various adjunctive therapies.

Cardiac complications in community-acquired pneumonia and COVID-19

Community-acquired pneumonia (CAP) remains a global health problem with significant morbidity and mortality. Much recent published literature about the infection has indicated that a substantial number of patients with CAP, particularly those ill enough to be admitted to hospital, will suffer a cardiovascular event. While these may include events such as deep venous thrombosis and stroke, most of the events involve the heart and include the occurrence of an arrhythmia (most commonly atrial fibrillation), new onset or worsening of heart failure and acute myocardial infarction. While such cardiac events may occur, for example, in all-cause CAP and CAP due to influenza virus infection, and more recently described with the SARS-CoV-2 pandemic, a significant amount of research work has been investigating the pathogenic mechanisms of these cardiac events in patients with CAP due to Streptococcus pneumoniae (pneumococcus) and, more recently, COVID-19 infections. Such research has identified a number of mechanisms by which these microorganisms may cause cardiovascular events. Importantly, these cardiac events appear not only to be associated with in-hospital mortality, but they also appear to contribute to longer-term mortality of patients with CAP, even after their discharge from hospital. This review will focus initially on studies of cardiovascular events in all-cause CAP and pneumococcal CAP, excluding COVID-19 infection, and then address similar issues in the latter infection.