Association of influenza vaccination and reduced risk of recurrent myocardial infarction

A Focus on the Pathophysiology of Adrenomedullin Expression: Endothelitis and Organ Damage in Severe Viral and Bacterial Infections

Adrenomedullin (ADM) is a peptide hormone produced primarily in the adrenal glands, playing a crucial role in various physiological processes. As well as improving vascular integrity and decreasing vascular permeability, ADM acts as a vasodilator, positive inotrope, diuretic, natriuretic and bronchodilator, antagonizing angiotensin II by inhibiting aldosterone secretion. ADM also has antihypertrophic, anti-apoptotic, antifibrotic, antioxidant, angiogenic and immunoregulatory effects and antimicrobial properties. ADM expression is upregulated by hypoxia, inflammation-inducing cytokines, viral or bacterial substances, strength of shear stress, and leakage of blood vessels. These pathological conditions are established during systemic inflammation that can result from infections, surgery, trauma/accidents or burns. The ability to rapidly identify infections and the prognostic, predictive power makes it a valuable tool in severe viral and bacterial infections burdened by high incidence and mortality. This review sheds light on the pathophysiological processes that in severe viral or bacterial infections cause endothelitis up to the development of organ damage, the resulting increase in ADM levels dosed through its more stable peptide mid-regional proadrenomedullin (MR-proADM), the most significant studies that attest to its diagnostic and prognostic accuracy in highlighting the severity of viral or bacterial infections and appropriate therapeutic insights.

Association of respiratory infections and the impact of vaccinations on cardiovascular diseases

Influenza, pneumococcal, severe acute respiratory syndrome coronavirus 2, and respiratory syncytial virus infections are important causes of high morbidity and mortality in the elderly. Beyond the burden of infectious diseases, they are also associated with several non-infectious complications like cardiovascular events. A growing body of evidence in prospective studies and meta-analyses has shown the impact of influenza and pneumococcal vaccines on types of cardiovascular outcomes in the general population. Influenza vaccination showed a potential benefit for primary and secondary prevention of cardiovascular diseases across all ages. A reduced risk of cardiovascular events for individuals aged 65 years and older was associated with pneumococcal vaccination. Despite scientific evidence on the effectiveness, safety, and benefits of the vaccines and recommendations to vaccinate elderly patients and those with risk factors, vaccination rates remain sub-optimal in this population. Doubts about vaccine necessity or efficacy and concerns about possible adverse events in patients and physicians refer to delayed acceptance. Vaccination campaigns targeting increasing professional recommendations and public perceptions should be implemented in the coming years. The aim of this review paper is to summarize the effect of vaccination in the field of cardiovascular disease to achieve a higher vaccination rate in this patient population.

Step up to the platelet: Role of platelets in inflammation and infection

Platelets are anucleated cells derived from megakaryocytes that are primarily responsible for hemostasis. However, in recent years, these cytoplasts have become increasingly recognized as immune cells, able to detect, interact with, and kill pathogens. As platelets are involved in both immunity and coagulation, they have a central role in immunothrombosis, a physiological process in which immune cells induce the formation of microthrombi to both prevent the spread of pathogens, and to help facilitate clearance. In this review, we will highlight the role of platelets as key players in the inflammatory and innate immune response against bacterial and viral infection, including direct and indirect interactions with pathogens and other immune cells.

Systematic influenza screening in cardiac intensive care units during the influenza season: A prospective study in Spain

BACKGROUND

Little is known about the incidence of influenza among admissions to the cardiac intensive care unit (C-ICU), accuracy of clinical suspicion, and influenza vaccination uptake. We evaluated the incidence of influenza at C-ICU admission during the influenza season, potential underdiagnosis, and vaccination uptake.

METHODS

Prospective study at five C-ICUs during the 2017-2020 influenza seasons. A nasopharyngeal swab was collected at admission from patients who consented (n = 788). Testing was with Xpert®XpressFlu/RSV.

RESULTS

Influenza was detected in 43 patients (5.5%) (40 FluA; 3 FluB) and clinically suspected in 27 (62.8%). Compared to patients without influenza, patients with influenza more frequently had heart failure (37.2% vs 22.8%, P = 0.031), previous contact with relatives with influenza-like illnesses (23.3% vs 12.5%, P = 0.042), antimicrobial use (67.4% vs 23.2%, P <0.01), and need for mechanical ventilation (25.6% vs 14.5%, P = 0.048). Patients received oseltamivir promptly. We found no differences in mortality (11.6% vs 5.2%, P = 0.076). Patients with influenza more frequently had myocarditis (9.3% vs 0.9%, P <0.01) and pericarditis (7.0% vs 0.8%, P = 0.01). Overall, 43.0% of patients (339/788) were vaccinated (51.9% of those with a clear indication [303/584]).

CONCLUSION

Influenza seems to be a frequently underdiagnosed underlying condition in admissions to the C-ICU. Influenza should be screened for at C-ICU admission during influenza epidemics.

Pleiotropic Effects of Influenza Vaccination

Influenza vaccines are designed to mimic natural influenza virus exposure and stimulate a long-lasting immune response to future infections. The evolving nature of the influenza virus makes vaccination an important and efficacious strategy to reduce healthcare-related complications of influenza. Several lines of evidence indicate that influenza vaccination may induce nonspecific effects, also referred to as heterologous or pleiotropic effects, that go beyond protection against infection. Different explanations are proposed, including the upregulation and downregulation of cytokines and epigenetic reprogramming in monocytes and natural killer cells, imprinting an immunological memory in the innate immune system, a phenomenon termed "trained immunity". Also, cross-reactivity between related stimuli and bystander activation, which entails activation of B and T lymphocytes without specific recognition of antigens, may play a role. In this review, we will discuss the possible nonspecific effects of influenza vaccination in cardiovascular disease, type 1 diabetes, cancer, and Alzheimer's disease, future research questions, and potential implications. A discussion of the potential effects on infections by other pathogens is beyond the scope of this review.

The Presence of Pneumonia Is Strongly Associated With Higher Prevalence of Non-ST-Elevation Myocardial Infarction Using a Large NIS Database

OBJECTIVE

Inflammation is a risk factor for myocardial infarction. Pneumonia leads to severe inflammatory response. Some studies suggest higher risk of myocardial infarction in patients with pneumonia. We used a large inpatient database (National Inpatient Sample) to evaluate this association.

METHODS

This study includes patients from a Nationwide Inpatient Sample hospital in 2005 to 2014 with International Classification of Diseases, Ninth Revision, and Clinical Modification codes consistent with pneumonia and non-ST elevation myocardial infarction (NSTEMI). Subjects were stratified into all hospitalized patients aged 30 and above. Univariate and multivariate analysis was performed adjusting for age, race, gender, tobacco use, diabetes mellitus, hypertension, and hyperlipidemia.

RESULTS

NSTEMI was present in 3.2% of pneumonia patients versus 1.8% in the non-pneumonia population over 10-year period. For example, the 2005 database: [odds ratio (OR), 1.77; 95% confidence interval (CI), 1.73-1.80; P < 0.001]. For 2014, NSTEMI was present in 4.1% of pneumonia patients (PNA) versus 2.4% in the non-pneumonia population (OR, 1.72; 95% CI, 1.70-1.75; P < 0.001). NSTEMI remained independently associated with pneumonia following a multivariate analysis in 2005 (OR, 1.477; 95% CI, 1.447-1.508; P < 0.001) with a similar value in 2014 (OR, 1.445; 95% CI, 1.421-1.469; P < 0.001).

CONCLUSIONS

Using a large inpatient database, we found that NSTEMI was strongly associated with PNA versus non-pneumonia population over a 10-year period. Suggesting acute inflammatory cytokines or hypoxia which occurs during lung infection may play a role in NSTEMI development, reinforcing the importance of acute cardiac monitoring in patients with PNA.

Vaccines and cardiovascular outcomes: lessons learned from influenza epidemics

Cardiovascular disease (CVD) is the leading cause of death in the world and is largely preventable. An increasing amount of evidence suggests that annual influenza vaccination reduces CVD-related morbidity and mortality. Despite various clinical guidelines recommending annual influenza vaccination for the general population for influenza-like illness risk reduction, with a particular emphasis on people with CVD, vaccination rates fall consistently below the goal established by the World Health Organization. This review outlines the importance of influenza vaccination, mechanisms of cardiovascular events in influenza, summarizing the available literature on the effects of influenza vaccine in CVD and the benefits of influenza vaccine during the COVID-19 pandemic.

Postinfluenza Cardiac Tamponade: A Review of Published Case Reports

Increased vaccination rates and better understanding of influenza virus infection and clinical presentation have improved the disease's overall prognosis. However, influenza can cause life-threatening complications such as cardiac tamponade, which has only been documented in case reports. We searched PubMed/Medline and SCOPUS and EMBASE through December 2021 and identified 25 case reports on echocardiographically confirmed cardiac tamponade in our review of influenza-associated cardiac tamponade. Demographics, clinical presentation, investigations, management, and outcomes were analyzed using descriptive statistics. Among 25 cases reports [19 adults (47.6 ±15.12) and 6 pediatric (10.1 ± 4.5)], 15 (60%) were females and 10 (40%) were male patients. From flu infection to the occurrence of cardiac tamponade, the average duration was 7±8.5 days. Fever (64%), weakness (40%), dyspnea (24%), cough (32%), and chest pain (32%) were the most prevalent symptoms. Hypertension, diabetes, and renal failure were most commonly encountered comorbidities. Sinus tachycardia (11 cases, 44%) and ST-segment elevation (7 cases, 28%) were the most common ECG findings. Fourteen cases (56%) reported complications, the most common being hypotension (24%), cardiac arrest (16%), and acute kidney injury (8%). Mechanical circulatory/respiratory support was required for 14 cases (56%), the most common being intubation (9 cases, 64%). Outcomes included recovery in 88% and death in 3 cases. With improving vaccination rates, pericardial tamponade remains an infrequently encountered complication following influenza virus infection. The complicated cases appear within the first week of diagnosis, of which nearly half suffer from concurrent complications including cardiac arrest or acute kidney injury. Majority of patients recovered with timely diagnoses and therapeutic interventions.

Influenza vaccine to reduce adverse vascular events in patients with heart failure: a multinational randomised, double-blind, placebo-controlled trial

BACKGROUND

Influenza increases the risk of cardiovascular events and deaths. We aimed to see whether influenza vaccination reduces death and vascular events in patients with heart failure.

METHODS

We did a pragmatic, randomised, double-blind, placebo-controlled trial in 30 centres (mostly hospitals affliated with universities or a research institute) in ten countries in Asia, the Middle East, and Africa (7 in India, 4 in Philippines, 4 in Nigeria, 6 in China, 1 in Zambia, 2 in Mozambique, 3 in Saudi Arabia, 1 in Kenya, 1 in Uganda, and 1 in Zambia). Participants (aged ≥18 years; 52·1% female; not disaggregated by race or ethnicity) with heart failure (New York Heart Association class II, III, or IV) were randomly assigned (1:1) by a centralised web-based system with block randomisation stratified by site, to receive 0·5 ml intramuscularly once a year for up to 3 years of either inactivated standard dose influenza vaccine or placebo (saline). We excluded people who had received influenza vaccine in 2 of the previous 3 years, and those likely to require valve repair or replacement. Those who administered assigned treatments were not masked and had no further role in the study. Investigators, study coordinators, outcome adjudicators, and participants were masked to group assignment. The first of two co-primary outcomes was a first-event composite for cardiovascular death, non-fatal myocardial infarction, and non-fatal stroke, and the second was a recurrent-events composite for cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and hospitalisation for heart failure. Outcomes were assessed every 6 months in the intention-to-treat population. Secondary outcomes were all-cause death, cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, all-cause hospitalisation, hospitalisation for heart failure, and pneumonia, both overall and during periods of peak influenza exposure. This study is registered with ClinicalTrials.gov, NCT02762851.

FINDINGS

Between June 2, 2015, and Nov 21, 2021, we enrolled 5129 participants and randomly assigned (1:1) 2560 (50·0%) to influenza vaccine and 2569 (50·0%) to placebo. The first co-primary outcome occurred in 380 (14·8%) of 2560 participants in the vaccine group and 410 (16·0%) of 2569 participants in the placebo group (hazard ratio [HR] 0·93 [95% CI 0·81-1·07]; p=0·30). The second co-primary outcome occurred in 754 (29·5%) of 2560 participants in the vaccine group and 819 (31·9%) of 2569 participants in the placebo group; HR 0·92 [95% CI 0·84-1·02]; p=0·12). The secondary outcomes of all-cause hospitalisations (HR 0·84 [95% CI 0·74-0·97]; p=0·013) and pneumonia (HR 0·58 [0·42-0·80]; p=0·0006) were significantly reduced in the vaccine group compared with in the placebo group but there was no significant difference between groups for all-cause death, cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and hospitalisation for heart failure. In a prespecified analysis, in which events were limited to periods of peak influenza circulation, the first co-primary outcome, and the secondary outcomes of all-cause death, cardiovasular death, and pneumonia were significantly lower in the vaccinated group than in the placebo group, whereas the second co-primary outcome and the secondary outcomes of non-fatal myocardial infarction, non-fatal stroke, all-cause hospitalisation, and hospitalisation for heart failure were not significantly lower.

INTERPRETATION

Although the prespecified co-primary outcomes during the entire period of observation were not statistically significant, the reduction during the peak influenza circulating period suggests that there is likely to be a clinical benefit of giving influenza vaccine, given the clear reduction in pneumonia, a moderate reduction in hospitalisations, and a reduction in cardiovascular events and deaths during periods of peak circulation of influenza. Taken in conjunction with previous trials and the observational studies, the collective data suggest benefit.

FUNDING

UK Joint Global Health Trials Scheme and Canadian Institutes for Health Research Foundation.

The need for vaccination in adults with chronic (noncommunicable) diseases in India - lessons from around the world

Worldwide, chronic diseases (noncommunicable diseases [NCDs]) cause 41 million (71%) deaths annually. They are the leading cause of mortality in India, contributing to 60% of total deaths each year. Individuals with these diseases are more susceptible to vaccine-preventable diseases (VPDs) and have an increased risk of associated disease severity and complications. This poses a substantial burden on healthcare systems and economies, exemplified by the COVID-19 pandemic. Vaccines are an effective strategy to combat these challenges; however, utilization rates are inadequate. With India running one of the world’s largest COVID-19 vaccination programs, this presents an opportunity to improve vaccination coverage for all VPDs. Here we discuss the burden of VPDs in those with NCDs, the benefit of vaccinations, current challenges and possible strategies that may facilitate implementation and accessibility of vaccination programs. Effective vaccination will have a significant impact on the disease burden of both VPDs and NCDs and beyond.

What is already known on this topic?

Annually, chronic or noncommunicable diseases (NCDs) cause >40 million deaths worldwide and 60% of all deaths in India

Adults with these diseases are more susceptible to vaccine-preventable diseases (VPDs); however, vaccine utilization is inadequate in this population

What is added by this report?

We highlight the benefits of vaccination in adults with NCDs that extend beyond disease prevention

We discuss key challenges in implementing adult vaccination programs and provide practical solutions

What are the implications for public health practice?

Raising awareness about the benefits of vaccinations, particularly for those with NCDs, and providing national guidelines with recommendations from medical societies, will increase vaccine acceptance

Adequate vaccine acceptance will reduce the VPD burden in this vulnerable population

Synergistic effect of myocardial injury and mid-regional proAdrenomedullin elevation in determining clinical outcomes of SARS-CoV-2 patients

OBJECTIVE

Coronavirus disease 2019 (COVID-19) is a systemic disease induced by SARS-CoV-2 causing myocardial injury. To date, there are few data on the correlation between mid-regional proAdrenomedullin (MR-proADM) and myocardial injury. The aim of this study was to evaluate whether the association of myocardial injury and elevated mid-regional proAdrenomedullin values could predict mortality of SARS-CoV-2 patients, to offer the best management to COVID-19 patients.

MATERIALS AND METHODS

All patients hospitalized for SARS-CoV-2 infection at the COVID-19 Center of the Campus Bio-Medico of Rome University were included between October 2020 and March 2021 and were retrospectively analyzed. Myocardial injury was defined as rising and/or fall of cardiac hs Troponin I values with at least one value above the 99th percentile of the upper reference limit (≥15.6 ng/L in women and ≥34.2 ng/L in men). The primary outcome was 30-day mortality. Secondary outcomes were the comparison of MR-proADM, CRP, ferritin, and PCT as diagnostic and prognostic biomarkers of myocardial injury. Additionally, we analyzed the development of ARDS, the need for ICU transfer, and length of stay (LOS).

RESULTS

A total of 161 patients were included in this study. Of these, 58 (36.0%) presented myocardial injury at admission. An MR-proADM value ≥ 1.19 nmol/L was defined as the optimal cut-off to identify patients with myocardial injury (sensitivity 81.0% and specificity 73.5%). A total of 121 patients (75.2%) developed ARDS, which was significantly more frequent among patients with myocardial injury (86.2 vs. 68.9%, p = 0.015). The overall 30-day mortality was 21%. Patients with myocardial injury presented significantly higher mortality compared to those without the same (46.6 vs. 6.8%, p < 0.001). When dividing the entire study population into four groups, based on the presence of myocardial injury and MR-proADM values, those patients with both myocardial injury and MR-proADM ≥ 1.19 nmol/L presented the highest mortality (53.2%, p < 0.001). The combination of myocardial injury and MR-proADM values ≥ 1.19 nmol/L was an independent predictor of death (OR = 7.82, 95% CI = 2.87-21.30; p < 0.001).

CONCLUSION

The study is focused on the correlation between myocardial injury and MR-proADM. Myocardial injury induced by SARS-CoV-2 is strongly associated with high MR-proADM values and mortality.

Atherosclerosis by Virus Infection—A Short Review

Atherosclerosis manifests by the thickening of artery walls and their narrowed channels through the accumulation of plaque. It is one of the most important indicators of cardiovascular disease. It can be caused by various factors, such as smoking, a high cholesterol diet, hypertension, hyperglycemia, and genetic factors. However, atherosclerosis can also develop due to infection. It has been reported that some bacteria and viruses can cause the development of atherosclerosis. Examples of these viruses are influenza viruses, herpes viruses, hepatitis viruses, or papillomaviruses, which are all prevalent and eminent globally for infecting the population worldwide. Moreover, many patients with coronavirus disease 2019 (COVID-19) showed symptoms of cardiovascular disease. In this review paper, the viruses linked to the development of atherosclerosis are introduced, and their viral characteristics, the mechanisms of the development of atherosclerosis, and the current vaccines and antiviral treatment methods are summarized.

[Expert opinion on strategies to improve vaccination coverage against seasonal influenza]

Seasonal flu continues to be a major public health concern, and the influenza vaccine remains the most effective preventive measure. In Spain, vaccination coverage data from previous seasons show vaccination rates well below official targets; however, these figures improved significantly after the COVID-19 pandemic. Given the importance of achieving and maintaining high vaccination rates in order to avoid the clinical and economic impact of influenza, our multidisciplinary group of experts on vaccines analyzed the impact of low vaccination rates in Spain and drafted a series of measures to boost influenza vaccination coverage, particularly among priority groups.

Influenza Vaccination for Cardiovascular Prevention: Further Insights from the IAMI Trial and an Updated Meta-analysis

Purpose of Review

Influenza infection is a significant, well-established cause of cardiovascular disease (CVD) and CV mortality. Influenza vaccination has been shown to reduce major adverse cardiovascular events (MACE) and CV mortality. Therefore, major society guidelines have given a strong recommendation for its use in patients with established CVD or high risk for CVD. Nevertheless, influenza vaccination remains underutilized. Historically, influenza vaccination is administered to stable outpatients. Until recently, the safety and efficacy of influenza vaccination among patients with acute myocardial infarction (MI) had not been established.

Recent Findings

The recently published Influenza Vaccination after Myocardial Infarction (IAMI) trial showed that influenza vaccination within 72 h of hospitalization for MI led to a significant 28% reduction in MACE and a 41% reduction in CV mortality, without any excess in serious adverse events. Additionally, we newly performed an updated meta-analysis of randomized clinical trials (RCTs) including IAMI and the recent Influenza Vaccine to Prevent Adverse Vascular Events (IVVE) trial. In pooled analysis of 8 RCTs with a total of 14,420 patients, influenza vaccine, as compared with control/placebo, was associated with significantly lower risk of MACE at follow-up [RR 0.75 (95%CI 0.57–0.97), I² 56%].

Summary

The recent IAMI trial showed that influenza vaccination in patients with recent MI is safe and efficacious at reducing CV morbidity and mortality. Our updated meta-analysis confirms a 25% reduction in MACE. The influenza vaccine should be strongly encouraged in all patients with CVD and incorporated as an essential facet of post-MI care and secondary CVD prevention.

Factors Associated With Myocardial Infarction Reoccurrence

BACKGROUND

As recurrent myocardial infarctions (MIRs) constitute almost a third of the annual incidence of myocardial infarction, identifying the traditional and novel variables related to MIR is important.

OBJECTIVE

The aim of this study was to examine modifiable cardiac risks, adiposity, symptoms associated with inflammation (fatigue, depression, sleep) and inflammatory cytokines, and MIR by sex and race.

METHODS

Using a cross-sectional descriptive design, we recruited a convenience sample of adults (N = 156) discharged with first myocardial infarction or had MIR in the last 3 to 7 years. Surveys measured demographics, cardiac risk factors, depression, sleep, and fatigue. Anthropometric measures and cytokines tumor necrosis factor-α, interleukin-6, and high-sensitivity C-reactive protein (hsCRP) were obtained. A maximum likelihood regression was calculated to predict MIR.

RESULTS

The sample included 57% male and 30% Black participants, and the mean (SD) age was 65 (12) years. The hsCRP was the only cytokine related to symptoms: fatigue ( r = 0.309, P < .001) and depression ( r = 0.255, P = .002). An MIR was not associated with race despite White participants reporting better sleep ( t146 = -3.25, P = .002), lower body mass index ( t154 = -3.49, P = .001), and fewer modifiable risk factors ( t152 = -2.05, P = .04). An MIR was associated with being male, higher hsCRP and tumor necrosis factor-α levels ( P < .001), and higher inflammatory symptoms of fatigue ( P = .04), depression ( P = .01), and poor sleep ( P < .001).

CONCLUSION

Further examination of biomarkers to understand the mechanisms associated with inflammatory symptoms of fatigue, depression, and poor sleep and MIR is needed.

Influenza vaccination and prognosis for patients with high cardiovascular risk

Cardiovascular and respiratory diseases have been one of the leading causes of mortality in the world for over 15 years. According to the results of various studies, a clear connection was revealed between the incidence of influenza and the decompensation of cardiovascular diseases, which leads to the development of acute coronary syndrome, acute heart failure and myocardial infarction. Also, the incidence of influenza is associated with an increase in the length of hospitalization, treatment costs and patient mortality. Influenza vaccination, especially in patients with high cardiovascular risk, is one of the most important secondary prevention measures. The article is dedicated to an overview of the problems of vaccination against influenza, the study of the prognosis of patients with high cardiovascular risk, as well as general points in the pathogenesis of influenza and cardiovascular diseases.

In-hospital outcomes of COVID-19 infection in patients with underlying cardiovascular disease

BACKGROUND

The effects of cardiovascular comorbidities on outcomes in COVID-19 hospitalized patients has not been well studied.

METHODS

This is a hospital-based study evaluating the effects of CVD on the outcomes in patients admitted with COVID-19. Clinical outcomes were studied in patients with and without CVD.

RESULTS

Eighty-seven patients had CVD, and 193 patients had no history of CVD. Ischemic heart disease was the most common CVD (63%). When compared with patients with no CVD, those with CVD had higher mortality (29% vs 9%, p < 0.001), discharge to a skilled nursing facility (SNF) (36% vs 15%, p < 0.001), and change of code status to 'do not resuscitate' (41% vs 14%, p < 0.001). The odds for mortality were high with ischemic heart disease (OR 3.6, 95% CI 1.8-7.3, p < 0.001), and systolic heart failure (OR 3.8,95% CI 1.2-12.3, p = 0.02). Patients in the CVD group were more likely to have incident atrial fibrillation (22% vs 3%, p < 0.001), type 2 Mi (17% vs 6%, p = 0.002), high BNP (57% vs 14%, p < 0.001), acute kidney injury (64% vs 29%, p < 0.001), and any type of circulatory shock (27% vs 12%, p = 0.001).

CONCLUSION

CVD is associated with increased mortality, myocardial injury, arrhythmias, and discharges to an SNF.

No effect modification of influenza virus vaccine effectiveness by age or chronic condition was observed in the 2010/11 to 2017/18 seasons

PURPOSE

Most European influenza vaccine strategies target individuals at higher risk of complications, which include, among others, individuals aged ≥65 years and with chronic conditions. These individuals not only have a high-risk of post-infection complications but also could have lower capacity of acquiring adequate vaccine-induced protection. As such, chronic conditions and age could modify the effect of vaccines. This study aimed at assessing the potential effect modification of influenza vaccine effectiveness (IVE) by age and chronic conditions.

METHODS

We used eight-season data from the Portuguese vaccine effectiveness study. Every season, physicians at primary care units recruited patients with influenza-like illness. Clinical data and swabs were collected for Reverse Transverse Polymerase Chain Reaction (RT-PCR) detection of influenza. Trivalent inactivated IVE was estimated as 1 - odds ratio (OR) of being vaccinated in cases (RT-PCR positive for influenza) versus negative controls. ORs were obtained using a multivariable conditional logistic regression model, paired by week of onset within each season. Confounders were assessed by designing a specific causal diagram. Age (< 65 or ≥65 years) and chronic conditions (diabetes, cardiovascular disease, chronic renal disease, chronic hepatic disease, obesity, chronic respiratory disease, and congenital or acquired immunodeficiency) were studied as effect modifiers by including an interaction term in the regression models. Significance was established at 5%.

RESULTS

Point estimates indicate a higher IVE in the chronic condition strata compared to that in the no chronic condition strata. Regarding age, different results were obtained considering the virus type and (sub)type. When comparing the ≥65 years with the <65 years of age strata, we observed a higher IVE against A(H1N1)pdm09, an equal IVE against A(H3N2) and a lower IVE against B virus. However, all interaction terms were statistically insignificant, and this may be due to a small sample size.

CONCLUSION

The potential effect modification of age or chronic condition was not observed within our study.

Proatherogenic Sialidases and Desialylated Lipoproteins: 35 Years of Research and Current State from Bench to Bedside

This review summarizes the main achievements in basic and clinical research of atherosclerosis. Focusing on desialylation as the first and the most important reaction of proatherogenic pathological cascade, we speak of how desialylation increases the atherogenic properties of low density lipoproteins and decreases the anti-atherogenic properties of high density lipoproteins. The separate sections of this paper are devoted to immunogenicity of lipoproteins, the enzymes contributing to their desialylation and animal models of atherosclerosis. In addition, we evaluate the available experimental and diagnostic protocols that can be used to develop new therapeutic approaches for atherosclerosis.

In Vivo Models to Study the Pathogenesis of Extra-Respiratory Complications of Influenza A Virus Infection

Animal models are an inimitable method to study the systemic pathogenesis of virus-induced disease. Extra-respiratory complications of influenza A virus infections are not extensively studied even though they are often associated with severe disease and mortality. Here we review and recommend mammalian animal models that can be used to study extra-respiratory complications of the central nervous system and cardiovascular system as well as involvement of the eye, placenta, fetus, lacteal gland, liver, pancreas, intestinal tract, and lymphoid tissues during influenza A virus infections.

Protective effect of influenza vaccination on cardiovascular diseases: a systematic review and meta-analysis

Cardiovascular diseases (CVDs) are among the leading causes of mortality and morbidity worldwide. There are many contrasting ideas on the effectiveness of influenza vaccination on CVDs. This study aimed to investigate the association between influenza vaccination and the risk of CVDs. We systematically searched all PubMed/Medline, EMBASE, and the Cochrane library entries up to November 2019 for studies of influenza vs. the CVDs outcomes. We conducted a random-effects meta‐analysis using the inverse variance method for pooled risk ratios (RR) or odds ratios (OR) and evaluated statistical heterogeneity using the I² statistic. We identified 17 studies (6 randomized controlled trial [RCT], 5 cohorts, and 6 case–control) with a total of 180,043 cases and 276,898 control participants. The pooled RR of developing CVDs after influenza vaccination in RCT studies was 0.55 (95% CI 0.41–0.73), which was significant (P-value = 0.00). The pooled OR of decreasing CVDs after influenza vaccination in cohort studies was 0.89 (95% CI 0.77–1.04). The pooled OR of developing CVDs after influenza vaccination by pooling case–control studies was 0.70 (95% CI 0.57–0.86, (P-value = 0.00). All of these studies suggest decreased risks of CVDs with influenza vaccination. The current study does support the protective role of influenza vaccination on CVDs events. Health authorities may develop evidence-based preventive strategies to offer influenza vaccination in patients with CVDs.

Immune Mechanisms in Cardiovascular Diseases Associated With Viral Infection

Influenza virus infection causes 3-5 million cases of severe illness and 250,000-500,000 deaths worldwide annually. Although pneumonia is the most common complication associated with influenza, there are several reports demonstrating increased risk for cardiovascular diseases. Several clinical case reports, as well as both prospective and retrospective studies, have shown that influenza can trigger cardiovascular events including myocardial infarction (MI), myocarditis, ventricular arrhythmia, and heart failure. A recent study has demonstrated that influenza-infected patients are at highest risk of having MI during the first seven days of diagnosis. Influenza virus infection induces a variety of pro-inflammatory cytokines and chemokines and recruitment of immune cells as part of the host immune response. Understanding the cellular and molecular mechanisms involved in influenza-associated cardiovascular diseases will help to improve treatment plans. This review discusses the direct and indirect effects of influenza virus infection on triggering cardiovascular events. Further, we discussed the similarities and differences in epidemiological and pathogenic mechanisms involved in cardiovascular events associated with coronavirus disease 2019 (COVID-19) compared to influenza infection.

Sociodemographic Disparities in Influenza Vaccination Among Adults With Atherosclerotic Cardiovascular Disease in the United States

Importance

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of death and disability in the US and worldwide. Influenza vaccination has shown to decrease overall morbidity, mortality, severity of infection, and hospital readmissions among these individuals. However, national estimates of influenza vaccination among individuals with ASCVD in the US are not well studied.

Objective

To evaluate the prevalence of and sociodemographic disparities in influenza vaccination among a nationally representative sample of individuals with ASCVD.

Design, Setting, and Participants

Pooled Medical Expenditure Panel Survey data from 2008 to 2016 were used and included adults 40 years or older with ASCVD. Participants' ASCVD status was ascertained via self-report and/or International Classification of Diseases, Ninth Revision diagnosis of coronary heart disease, peripheral artery disease, and/or cerebrovascular disease. Analysis began April 2020.

Main Outcomes and Measures

Prevalence and characteristics of adults with ASCVD who lacked influenza vaccination during the past year. Covariates including age, sex, race/ethnicity, family income, insurance status, education level, and usual source of care were assessed.

Results

Of 131 881 adults, 19 793 (15.7%) had ASCVD, corresponding to 22.8 million US adults annually. A total of 7028 adults with ASCVD (32.7%), representing 7.4 million adults, lacked influenza vaccination. The highest odds of lacking vaccination were observed among individuals aged 40 to 64 years (odds ratio [OR], 2.32; 95% CI, 2.06-2.62), without a usual source of care (OR, 2.00; 95% CI, 1.71-2.33), without insurance (OR, 2.05; 95% CI, 1.63-2.58), with a lower education level (OR, 1. 25; 95% CI, 1.12-1.40), with a lower income level (OR, 1.14; 95% CI, 1.01-1.27), and of non-Hispanic Black race/ethnicity (OR, 1.24, 95% CI, 1.10-1.41). A stepwise increase was found in the prevalence and odds of lacking influenza vaccination among individuals with increase in high-risk characteristics. Overall, 1171 individuals (59.7%; 95% CI, 55.8%-63.5%) with 4 or more high-risk characteristics and ASCVD (representing 732 524 US adults annually) reported lack of influenza vaccination (OR, 6.06; 95% CI, 4.88-7.53).

Conclusion and Relevance

Despite current recommendations, a large proportion of US adults with established ASCVD lack influenza vaccination, with several sociodemographic subgroups having greater risk. Focused public health initiatives are needed to increase access to influenza vaccinations for high-risk and underserved populations.

Effects of influenza vaccination on the risk of cardiovascular and respiratory diseases and all-cause mortality

BACKGROUND

Influenza vaccination is a simple strategy recommended for the prevention of influenza infection and its complications. This meta-analysis aimed to provide current supportive evidence for the breadth and validity of the observed protective effects of influenza vaccination on cardiovascular and respiratory adverse outcomes and all-cause mortality in older adults and in general adult population.

METHODS

We searched PubMed, Embase, Web of Science, and the Cochrane Library to identify all published studies comparing influenza vaccination with placebo from the database inception to November 11, 2018. These included studies reporting the associations of influenza vaccination with the risk of aforementioned adverse outcomes.

RESULTS

The pooled adjusted relative risks among influenza-vaccinated people relative to unvaccinated people for the outcomes of interest were 0.74 (95 % confidence interval [CI] = 0.70-0.78) for cardiovascular diseases (63 studies), 0.82 (95 % CI = 0.75-0.91) for respiratory diseases (29 studies), and 0.57 (95 % CI = 0.51-0.63) for all-cause mortality (43 studies). We performed subgroup analysis of age, sex, and region/country and found that these protective effects were evident in the general adult population and particularly robust in older adults and in those with pre-existing specific diseases.

CONCLUSION

Influenza vaccine is associated with a significant risk reduction of cardiovascular and respiratory adverse outcomes as well as all-cause mortality. Such a preventative measure can benefit the general population as well as those in old age and with pre-existing specific diseases.

Possible mechanisms responsible for acute coronary events in COVID-19

The novel coronavirus (SARS-CoV-2) is primarily a respiratory pathogen and its clinical manifestations are dominated by respiratory symptoms, the most severe of which is acute respiratory distress syndrome (ARDS). However, COVID-19 is increasingly recognized to cause an overwhelming inflammatory response and cytokine storm leading to end organ damage. End organ damage to heart is one of the most severe complications of COVID-19 that increases the risk of death. We proposed a two-fold mechanism responsible for causing acute coronary events in patients with COVID-19 infection: Cytokine storm leading to rapid onset formation of new coronary plaques along with destabilization of pre-existing plaques and direct myocardial injury secondary to acute systemic viral infection. A well-coordinated immune response is the first line innate immunity against a viral infection. However, an uncoordinated response and hypersecretion of cytokines and chemokines lead to immune related damage to the human body. Human Coronavirus (HCoV) infection causes infiltration of inflammatory cells that cause excessive production of cytokines, proteases, coagulation factors, oxygen radicals and vasoactive molecules causing endothelial damage, disruption of fibrous cap and initiation of formation of thrombus. Systemic viral infections also cause vasoconstriction leading to narrowing of vascular lumen and stimulation of platelet activation via shear stress. The resultant cytokine storm causes secretion of hypercoagulable tissue factor without consequential increase in counter-regulatory pathways such as AT-III, activated protein C and plasminogen activator type 1. Lastly, influx of CD4+ T-cells in cardiac vasculature results in an increased production of cytokines that stimulate smooth muscle cells to migrate into the intima and generate collagen and other fibrous products leading to advancement of fatty streaks to advanced atherosclerotic lesions. Direct myocardial damage and cytokine storm leading to destabilization of pre-existing plaques and accelerated formation of new plaques are the two instigating mechanisms for acute coronary syndromes in COVID-19.

Influenza vaccination as a novel means of preventing coronary heart disease: Effectiveness in older adults

Atherosclerosis can have various etiologies, including several newly recognized immunoinflammatory mechanisms. A growing body of evidence suggests that influenza infection is chronologically linked to acute myocardial infarction (AMI), and thus that the virus is a novel cardiovascular disease (CVD) risk factor. Morbidity and mortality rates for both influenza infection and AMI rise markedly with age. Epidemiological studies have demonstrated that influenza vaccination (IV) has a cardioprotective effect, especially in people aged 65 and over; hence, IV may be of value in the management of CVD. These observations justify efforts to better understand the underlying mechanisms and to identify therapeutic targets in older adults. In view of the above, the objective of the present study was to review the literature data on the cellular mechanisms that link IV to the prevention of atherosclerotic complications. Given the greater burden of CVD in older subjects, we also questioned the impact of aging on this association. The most widely recognized benefit of IV is the prevention of influenza infection and the latter's cardiovascular complications. In a new hypothesis, however, an influenza-independent effect is driven by vaccine immunity and modulation of the ongoing immunoinflammatory response in individuals with CVD. Although influenza infection and IV both induce a proinflammatory response, they have opposite effects on the progression of atherosclerosis - suggesting a hormetic phenomenon. Aging is characterized by chronic inflammation (sometimes referred to as "inflammaging") that progresses insidiously during the course of aging-related diseases, including CVD. It remains to be determined whether vaccination has an effect on aging-related diseases other than CVD. Although the studies of this topic had various limitations, the results highlight the potential benefits of vaccination in protecting the health of older adults, and should drive research on the molecular immunology of the response to IV and its correlation with atheroprotective processes.

Postimplantation Syndrome Is Not Associated with Myocardial Injury after Noncardiac Surgery after Endovascular Aneurysm Repair

BACKGROUND

Postimplantation syndrome (PIS) is the clinical and biochemical expression of an inflammatory response following endovascular aneurysm repair (EVAR), with a reported incidence ranging from 2% to 100%. Although generally benign, some studies report an association between PIS and postoperative major adverse cardiovascular events (MACEs). Nonetheless, the role of PIS in postoperative myocardial injury after noncardiac surgery (MINS) is unknown. This work aims to evaluate the relationship between PIS and MINS in a subset of EVAR patients, as well as assess the impact of PIS in all-cause mortality.

METHODS

All patients undergoing elective standard EVAR between January 2008 and June 2017, and with at least one measurement of contemporary (cTnI) or high sensitivity troponin I (hSTnI) in the first 48h after surgery, were retrospectively analyzed. PIS was defined as the presence of fever and leukocytosis in the postoperative period in the absence of infectious complications. MINS was defined as the value exceeding the 99th percentile of a normal reference population with a coefficient of variation <10%, which was >0.032 ng/mL for cTnI and 0.0114 (female) and 0.027 ng/mL (male) for hSTnI. Patients' demographics, comorbidities, medication, access, and anesthesia were also evaluated.

RESULTS

One hundred thirty-three consecutive patients were included (95.5% male; mean age 75.66 ± 7.13 years). Mean follow-up was 46.35 months. Survival rate was 86.5%, 80.5%, and 57.6% at 1, 3, and 5 years of follow-up, with 2 fatalities at 30 days of follow-up. The prevalence of PIS was 11.4%. MACE occurred in 2.3% of the patients, while MINS was reported in 16.5% of the patients. No association was found between PIS and patients' gender, comorbidities, type of anesthesia, or transfusional support. The type of graft used significantly affected the prevalence of PIS, with all cases reported when polyester grafts were used (P = 0.031). MACE occurred in 2.3% of the patients, while MINS was reported in 16.5% of the patients. PIS was found to be significantly associated with postoperative MACE (P = 0.001), but not MINS. Survival analysis revealed no differences between patients with or without PIS regarding 30-day mortality as well as long-term all-cause mortality. American Society of Anesthesiologists score (hazard ratio [HR] 2.157, 95% confidence interval [CI] 1.07-4.33, P = 0.031) and heart failure (HR 2.284, 95% CI 1.25-4.18, P = 0.008) were found to be independently associated with increased long-term all-cause mortality in this cohort of patients.

CONCLUSIONS

PIS is a common complication after EVAR, occurring in 11.4% of the patients from this cohort. Graft type seems to significantly affect the risk of PIS, since all reported cases occurred when polyester grafts were used. PIS did not influence 30-day or long-term survival and was found to be significantly associated with postoperative MACE but not MINS, suggesting the involvement of different pathophysiological mechanisms.

Outcomes of Acute Myocardial Infarction in Patients with Influenza and Other Viral Respiratory Infections

BACKGROUND

Acute influenza infection can trigger acute myocardial infarction, however, outcome of patients with acute myocardial infarction during influenza infection is largely unknown.

METHODS

Patients ≥18 years old with ST-elevation and non-ST-elevation myocardial infarction during January 2013-December 2014 were identified using the National Inpatient Sample. The clinical outcomes were compared among patients who had no respiratory infection to the ones with influenza and other viral respiratory infections using propensity score-matched analysis.

RESULTS

Of 1,884,985 admissions for acute myocardial infarction, acute influenza and other viral infections were diagnosed in 9,885 and 11,485 patients, respectively, accounting for 1.1% of patients. Acute myocardial infarction patients with concomitant influenza infection had a worse outcome than those with acute myocardial infarction alone, in terms of in-hospital case fatality rate, development of shock, acute respiratory failure, acute kidney injury, and higher rate of blood transfusion after propensity scores. The length of stay is also significantly longer in influenza patients with acute myocardial infarction, compared with patients with acute myocardial infarction alone. However, patients who developed acute myocardial infarction during other viral respiratory infection have a higher rate of acute respiratory failure but overall lower mortality rate, and are less likely to develop shock or require blood transfusion after propensity match. Despite presenting with acute myocardial infarction, less than one-fourth of patients with concomitant influenza infection underwent coronary angiography, but more than half (51.4%) required revascularization.

CONCLUSION

Influenza infection is associated with worse outcomes in acute myocardial infarction patients, and patients were less likely to receive further evaluation with invasive coronary angiography.

Influenza virus and atherosclerosis

Influenza viruses infect the upper respiratory system, causing usually a self-limited disease with mild respiratory symptoms. Acute lung injury, pulmonary microvascular leakage and cardiovascular collapse may occur in severe cases, usually in the elderly or in immunocompromised patients. Acute lung injury is a syndrome associated with pulmonary oedema, hypoxaemia and respiratory failure. Influenza virus primarily binds to the epithelium, interfering with the epithelial sodium channel function. However, the main clinical devastating effects are caused by endothelial dysfunction, thought to be the main mechanism leading to pulmonary oedema, respiratory failure and cardiovascular collapse. A significant association was found between influenza infection and acute myocardial infarction (AMI). The incidence of admission due to AMI during an acute viral infection was six times as high during the 7 days after laboratory confirmation of influenza infection as during the control interval (10-fold in influenza B, 5-fold in influenza A, 3.5-fold in respiratory syncytial virus and 2.7-fold for all other viruses). Our review will focus on the mechanisms responsible for endothelial dysfunction during influenza infection leading to cardiovascular collapse and death.

Prognostic Implications of Influenza Virus Infection in a Cardiac Intensive Care Unit: Potential Impact of a Screening Program

Objectives: Our goal was to determine the presentation and prognosis of influenza in an intensive cardiac care unit and to analyze the impact of an active surveillance program in the diagnosis. Methods: We performed a prospective registry during the flu season in a coronary unit. In the first phase, no systematic screening was performed. Systematic influenza A and B detection was performed in a second phase for all patients admitted. Results: From 227 patients, we identified 17 (7.5%) with influenza. Influenza patients were more likely to have a non-ischemic cause of admission (14 patients [82.4%] vs. 48 patients [40.3%], p = 0.002), fever (8 patients [47.1%] vs. 3 patients [2.6%], p < 0.001), and respiratory failure (7 patients [41.2%] vs. 8 patients [7%], p = 0.001). Influenza infection was an independent predictor of mortality (odds ratio 12.0, 95% confidence interval 1.9–13.6, p < 0.001). The incidence of influenza was 6.6% (6 patients) when no active screening was performed and 7.9% (11 patients) when systematic detection was performed (p = 0.005). The time to diagnosis was shorter in the systematic screening phase (0.92 ± 1.6 vs. 5.2 ± 3.8 days, p = 0.01). Conclusions: Influenza affects approximately 8% of patients admitted to an intensive cardiac care unit during the flu season, with a high mortality rate. An active surveillance program improves early detection.

Effect of High Influenza Activity on Risk of Ventricular Arrhythmias Requiring Therapy in Patients With Implantable Cardiac Defibrillators and Cardiac Resynchronization Therapy Defibrillators

Influenza is associated with an increased risk of cardiovascular events. Influenza's association with ventricular arrhythmias (VAs) has not been adequately studied. We investigated the relation of seasonal influenza activity with the incidence of VAs requiring therapy in patients with an implantable cardiac defibrillator or cardiac resynchronization therapy defibrillator. We retrospectively studied 163,831 patients with an implantable cardiac defibrillator or cardiac resynchronization therapy defibrillator who were enrolled in the Abbott Medical Merlin.net remote-monitoring network between January 2009 and December 2015. We used cross-correlation to assess the temporal relationship between influenza activity and the incidence of VAs requiring shock or antitachycardia pacing (ATP). We used a generalized linear model to test the possible effect of seasonal influenza activity on the occurrence of VAs requiring shock or ATP treatment, after adjustment for within-patient effects, age, gender, device type, and calendar year. We found a significant correlation between influenza activity and the incidence of VAs requiring shock or ATP treatment. The multivariate generalized linear model showed that during high influenza activity, patients were more likely to have a VA treated with shock (odds ratio = 1.06, p < 0.001) or ATP (odds ratio = 1.06, p < 0.0001). The impact of high influenza activity was most prominent during the years 2014 and 2015. We conclude that high influenza activity is associated with increased risk of VAs requiring therapy.

Pathogenesis and prevention of risk of cardiovascular events in patients with pneumococcal community-acquired pneumonia

It is now well recognized that cardiovascular events (CVE) occur quite commonly, both in the acute phase and in the long-term, in patients with community-acquired pneumonia (CAP). CVE have been noted in up to 30% of patients hospitalized with all-cause CAP. One systematic review and meta-analysis of hospitalized patients with all-cause CAP noted that the incidence rates for overall cardiac events were 17.7%, for incident heart failure were 14.1%, for acute coronary syndromes were 5.3% and for incident cardiac arrhythmias were 4.7%. In the case of pneumococcal CAP, almost 20% of patients studied had one or more of these cardiac events. Recent research has provided insights into the pathogenesis of the acute cardiac events occurring in pneumococcal infections. With respect to the former, key involvements of the major pneumococcal protein virulence factor, pneumolysin, are now well documented, whilst systemic platelet-driven neutrophil activation may also contribute. However, events involved in the pathogenesis of the long-term cardiovascular sequelae remain largely unexplored. Emerging evidence suggests that persistent antigenaemia may predispose to the development of a systemic pro-inflammatory/prothrombotic phenotype underpinning the risk of future cardiovascular events. The current manuscript briefly reviews the occurrence of cardiovascular events in patients with all-cause CAP, as well as in pneumococcal and influenza infections. It highlights the close interaction between influenza and pneumococcal pneumonia. It also includes a brief discussion of mechanisms of the acute cardiac events in CAP. However, the primary focus is on the prevalence, pathogenesis and prevention of the longer-term cardiac sequelae of severe pneumococcal disease, particularly in the context of persistent antigenaemia and associated inflammation.

Randomized controlled trial of influenza vaccine in patients with heart failure to reduce adverse vascular events (IVVE): Rationale and design

Background

Influenza is associated with an increase in the risk of cardiac and other vascular events. Observational data and small randomized trials suggest that influenza vaccination may reduce such adverse vascular events.

Research Design and Methods

In a randomized controlled trial patients with heart failure are randomized to receive either inactivated influenza vaccine or placebo annually for 3 years. Patients aged ≥18 years with a clinical diagnosis of heart failure and NYHA functional class II, III and IV are eligible. Five thousand patients from 10 countries where influenza vaccination is not common (Asia, the Middle East, and Africa) have been enrolled. The primary outcome is a composite of the following: cardiovascular death, non-fatal myocardial infarction, non-fatal stroke and hospitalizations for heart failure using standardized criteria. Analyses will be based on comparing event rates between influenza vaccine and control groups and will include time to event, rate comparisons using Poisson methods, and logistic regression. The analysis will be conducted by intention to treat i.e. patients will be analyzed in the group in which they were assigned. Multivariable secondary analyses to assess whether variables such as age, sex, seasonality modify the benefits of vaccination are also planned for the primary outcome.

Conclusion

This is the largest randomized trial to test if influenza vaccine compared to control reduces adverse vascular events in high risk individuals.

Trial registration number

Clinicaltrials.govNCT02762851

Cost-effectiveness of increased influenza vaccination uptake against readmissions of major adverse cardiac events in the US

Background

Although influenza vaccination has been shown to reduce the incidence of major adverse cardiac events (MACE) among those with existing cardiovascular disease (CVD), in the 2015–16 season, coverage for persons with heart disease was only 48% in the US.

Methods

We built a Monte Carlo (probabilistic) spreadsheet-based decision tree in 2018 to estimate the cost-effectiveness of increased influenza vaccination to prevent MACE readmissions. We based our model on current US influenza vaccination coverage of the estimated 493,750 US acute coronary syndrome (ACS) patients from the healthcare payer perspective. We excluded outpatient costs and time lost from work and included only hospitalization and vaccination costs. We also estimated the incremental cost/MACE case averted and incremental cost/QALY gained (ICER) if 75% hospitalized ACS patients were vaccinated by discharge and estimated the impact of increasing vaccination coverage incrementally by 5% up to 95% in a sensitivity analysis, among hospitalized adults aged ≥ 65 years and 18–64 years, and varying vaccine effectiveness from 30–40%.

Result

At 75% vaccination coverage by discharge, vaccination was cost-saving from the healthcare payer perspective in adults ≥ 65 years and the ICER was $12,680/QALY (95% CI: 6,273–20,264) in adults 18–64 years and $2,400 (95% CI: -1,992–7,398) in all adults 18 + years. These resulted in ~ 500 (95% CI: 439–625) additional averted MACEs/year for all adult patients aged ≥18 years and added ~700 (95% CI: 578–825) QALYs. In the sensitivity analysis, vaccination becomes cost-saving in adults 18+years after about 80% vaccination rate. To achieve 75% vaccination rate in all adults aged ≥ 18 years will require an additional cost of $3 million. The effectiveness of the vaccine, cost of vaccination, and vaccination coverage rate had the most impact on the results.

Conclusion

Increasing vaccination rate among hospitalized ACS patients has a favorable cost-effectiveness profile and becomes cost-saving when at least 80% are vaccinated.

[Mortality due to cerebrovascular disease among the elderly and vaccination against influenza: São Paulo State, Brazil, 1980-2012]

This study describes the trend of the coefficients of mortality due to cerebrovascular diseases (CbVD) among the elderly in São Paulo State, Brazil, from 1980 to 2012, before and after influenza vaccination campaigns, and identifies change points. It is an ecological, time-series study carried out with death data from the Health Ministry's Mortality Information System and population data from the Brazilian Institute of Geography and Statistics. We used linear, polynomial and joinpoint regression models in the data analysis. Between 1980 and 2012, there were 480,955 deaths due to CbVD. The mean mortality coefficients decreased for both sexes in all age groups we analyzed, with the greatest reduction in the older ages and male sex. We observed a significant reduction in the mortality trend in 1998 for male sex in the age group 60-69 years (annual percent change - APC = -3%, 95%CI: -4.3; -1.6) and for all elderly (APC = -3.8%, 95%CI: -4.4; -3.1). Considering the period as a whole, we did not observe change points for the age group 70-79 (average annual percent change - AAPC = -3.3%, 95%CI: -3.5; -3.1) and, for male sex, for the group ≥ 80 years (AAPC = -2.9%, 95%CI: -3.1; -2.6). For all elderly, the mean percentage reduction was of 3.1% per year (AAPC = -3.1%, 95%CI: -3.5; -2.7). Results show a reduction in the mortality due to CbVD in the period, with different percentage variations in coefficient reduction. The study's findings add information to the debate regarding possible effects of vaccination campaigns in reducing mortality due to CbVD among the elderly.

Influenza B virus infection complicated by life-threatening pericarditis: a unique case-report and literature review

Background

Acute pericarditis may occur frequently after viral infections. To our knowledge, influenza B virus infection complicated by pericarditis without myocardial involvement has never been reported. We report the first case of life-threatening pericarditis caused by influenza B virus infection.

Case presentation

A 48-years-old woman with trisomy 21 and ostium primum atrial septal defect was transferred from Cardiology to our Internal Medicine Department for severe pericardial effusion unresponsive to ibuprofen and colchicine. Based on the recent patient history of flu-like syndrome, and presence of pleuro-pericardial effusion, a viral etiology was suspected. Laboratory evaluation and molecular assay of tracheal aspirate identified influenza B virus. Therefore, the ongoing metilprednisolone and colchicine therapy was implemented with oseltamivir with progressive patient improvement and no evidence of pericardial effusion recurrence during follow-up.

Conclusions

Especially in autumn and winter periods, clinicians should include Influenza B virus infection on differential diagnosis of pericarditis with large pericardial effusion.

Acute and Subacute Triggers of Cardiovascular Events

Inability to predict short-term cardiovascular (CV) events and take immediate preemptive actions has long been the Achilles heel of cardiology. However, certain triggers of these events have come to light. Although these triggers are nonspecific and are part of normal life, studying their temporal relationship with the onset of CV events provides an opportunity to alert high-risk atherosclerotic patients who may be most vulnerable to such triggers, the "vulnerable patient". Herein, we review the literature and shed light on the epidemiology and underlying pathophysiology of different triggers. We describe that certain adrenergic triggers can precipitate a CV event within minutes or hours; whereas triggers that elicit an immune or inflammatory response such as infections may tip an asymptomatic "vulnerable patient" to become symptomatic days and weeks later. In conclusion, healthcare providers should counsel high-risk CV patients (e.g., in secondary prevention clinics or those with coronary artery Calcium >75th percentile) on the topic, advise them to avoid such triggers, take protective measures once exposed, and seek emergency care immediately after becoming symptomatic after such triggers. Furthermore, clinical trials targeting triggers (prevention or intervention) are needed.

Extreme influenza epidemics and out-of-hospital cardiac arrest

INTRODUCTION

There is compelling evidence for an association between influenza epidemics and major adverse cardiovascular events. However, the role of extreme influenza epidemics as a trigger of out-of-hospital cardiac arrest (OHCA) is unclear. Thus, we evaluated the potential association between extreme influenza epidemics and incidence of OHCA.

METHODS

We used a quasi-experimental design with time-series analysis of national registry data for cases of OHCA from all 47 prefectures of Japan during influenza seasons between 2005 and 2014. A Poisson regression time-series model with a distributed lag non-linear model was used to estimate prefecture-specific effects of influenza epidemics on OHCA. A multivariate meta-analysis was conducted for nationally pooled estimates.

RESULTS

In total, 481,516 OHCAs of presumed cardiac origin were reported during the study period. The minimum morbidity percentile (MMP) was estimated as the 0th percentile for influenza incidence. The overall cumulative relative risk versus the MMP was 1.25 (95% confidence interval, 1.16-1.34) for extreme influenza epidemics (at the 99th percentile of influenza incidence). The effect of extreme influenza epidemics was significant for lag periods of 1.5-7.1 and 17.9-21 days. Multivariate random-effects meta-analysis indicated significant spatial heterogeneity among prefectures (Cochran Q test, p = 0.011; I² = 23.2%).

CONCLUSION

Extreme influenza epidemics are associated with higher risk of OHCA. Our findings suggest that several weeks' prevention for extreme influenza infections should be implemented to reduce the risk of OHCA.

Viral infection and atherosclerosis

Several risk factors have been described for the pathogenesis of atherosclerosis. Infectious diseases are suggested to be a causative factor, and some viruses have been studied for their relation with atherosclerotic diseases. Studies report two hypotheses, direct and indirect effects, for the role of viral infections in atherogenesis. Viruses are able to initiate atherosclerosis by two different pathways. They can exert their direct effects on atherogenesis by infecting vascular cells and then inducing inflammation in the endothelium and smooth muscle cells. Alternatively, they can also apply indirect effects by infecting non-vascular cells and inducing systemic inflammation. In this review, we consider the available data about the effects and correlations of DNA and RNA viruses on atherosclerosis.

Seasonal Influenza Infections and Cardiovascular Disease Mortality

IMPORTANCE

Cardiovascular deaths and influenza epidemics peak during winter in temperate regions.

OBJECTIVES

To quantify the temporal association between population increases in seasonal influenza infections and mortality due to cardiovascular causes and to test if influenza incidence indicators are predictive of cardiovascular mortality during the influenza season.

DESIGN, SETTING, AND PARTICIPANTS

Time-series analysis of vital statistics records and emergency department visits in New York City, among cardiovascular deaths that occurred during influenza seasons between January 1, 2006, and December 31, 2012. The 2009 novel influenza A(H1N1) pandemic period was excluded from temporal analyses.

EXPOSURES

Emergency department visits for influenza-like illness, grouped by age (≥0 years and ≥65 years) and scaled by laboratory surveillance data for viral types and subtypes, in the previous 28 days.

MAIN OUTCOMES AND MEASURES

Mortality due to cardiovascular disease, ischemic heart disease, and myocardial infarction.

RESULTS

Among adults 65 years and older, who accounted for 83.0% (73 363 deaths) of nonpandemic cardiovascular mortality during influenza seasons, seasonal average influenza incidence was correlated year to year with excess cardiovascular mortality (Pearson correlation coefficients ≥0.75, P ≤ .05 for 4 different influenza indicators). In daily time-series analyses using 4 different influenza metrics, interquartile range increases in influenza incidence during the previous 21 days were associated with an increase between 2.3% (95% CI, 0.7%-3.9%) and 6.3% (95% CI, 3.7%-8.9%) for cardiovascular disease mortality and between 2.4% (95% CI, 1.1%-3.6%) and 6.9% (95% CI, 4.0%-9.9%) for ischemic heart disease mortality among adults 65 years and older. The associations were most acute and strongest for myocardial infarction mortality, with each interquartile range increase in influenza incidence during the previous 14 days associated with mortality increases between 5.8% (95% CI, 2.5%-9.1%) and 13.1% (95% CI, 5.3%-20.9%). Out-of-sample prediction of cardiovascular mortality among adults 65 years and older during the 2009-2010 influenza season yielded average estimates with 94.0% accuracy using 4 different influenza metrics.

CONCLUSIONS AND RELEVANCE

Emergency department visits for influenza-like illness were associated with and predictive of cardiovascular disease mortality. Retrospective estimation of influenza-attributable cardiovascular mortality burden combined with accurate and reliable influenza forecasts could predict the timing and burden of seasonal increases in cardiovascular mortality.

The hidden burden of influenza: A review of the extra-pulmonary complications of influenza infection

Severe influenza infection represents a leading cause of global morbidity and mortality. Although influenza is primarily considered a viral infection that results in pathology limited to the respiratory system, clinical reports suggest that influenza infection is frequently associated with a number of clinical syndromes that involve organ systems outside the respiratory tract. A comprehensive MEDLINE literature review of articles pertaining to extra‐pulmonary complications of influenza infection, using organ‐specific search terms, yielded 218 articles including case reports, epidemiologic investigations, and autopsy studies that were reviewed to determine the clinical involvement of other organs. The most frequently described clinical entities were viral myocarditis and viral encephalitis. Recognition of these extra‐pulmonary complications is critical to determining the true burden of influenza infection and initiating organ‐specific supportive care.

The public health value of vaccination for seniors in Europe

Longer life expectancy and decreasing fertility rates mean that the proportion of older people is continually increasing worldwide, and particularly in Europe. Ageing is associated with an increase in the risk and severity of infectious diseases. These diseases are also more difficult to diagnose and manage in seniors who often have at least one comorbid condition (60% of seniors have two or more conditions). Infectious diseases increase the risk of hospitalization, loss of autonomy and death in seniors. Effective vaccines are available in Europe for infectious diseases such as influenza, pneumococcal diseases, herpes zoster, diphtheria, tetanus and pertussis. Their effectiveness has been demonstrated in terms of reducing the rates of hospitalization, disability, dependency and death. The prevention of diseases in seniors also results in savings in healthcare and societal costs each year in Europe. Despite the availability of vaccines, vaccine-preventable diseases affect millions of European citizens annually, with the greatest burden of disease occurring in seniors, and the medical and economic benefits associated with are not being achieved. Vaccination coverage rates must be improved to achieve the full benefits of vaccination of seniors in Europe.

Effect of influenza vaccine on tumor necrosis factor-like weak inducer of apoptosis (TWEAK) in older adults

Influenza immunization is recommended for older adults annually, and has been reported to have cardiovascular protective effects. TNF-related weak inducer of apoptosis (TWEAK), an inflammatory mediator implicated in the development of cardiovascular diseases, could be a mechanism for such effect. The objective of this study was to evaluate the effect of influenza vaccine on TWEAK levels. Older persons over 70 years of age were recruited during 2007-2008 influenza season and immunized with the standard dose trivalent inactivated influenza vaccine. Frailty was evaluated using a validated set of criteria. Sera were collected immediately before and during the 4th week after vaccination. Pre- and post-vaccination levels of TWEAK, soluble CD163 (sCD163) and strain-specific influenza antibody titers were measured in 69 participants. Multiple regression analyses were employed to examine the effect of influenza vaccine on TWEAK and sCD163, adjusting for age, sex, and hypertension. Post-vaccination TWEAK [mean ± standard deviation (SD) = 591.7 ± 290.1 pg/ml] was significantly lower than pre-vaccination level (690.6 ± 330.0 pg/ml) (p = .003). No significant difference was observed between pre and post-vaccination sCD163 levels (p = .71). Post-vaccination TWEAK levels were significantly higher in men (p = .01) and in participants with college or higher level of education (p = .044). There was no significant difference in post-vaccination TWEAK according to other demographics or pre-existing medical conditions. A 2-fold or greater antibody titer against H1N1 vaccine strain was associated with a more pronounced reduction in TWEAK at the p < .10 level (p = .091). A time by frailty interaction term (p = .091) indicated that the vaccination-induced reduction of TWEAK was greatest among frail individuals. These results of this observational study indicate that the impact of Influenza vaccine on TWEAK, including the role of specific antibody responses of specific vaccine strains and frailty status, warrants further investigation. Such investigation may elucidate whether this effect plays a role in mediating cardiovascular protection of influenza vaccination.

Triggering of acute myocardial infarction by respiratory infection

BACKGROUND

Respiratory infection has been associated with an increased short-term risk of myocardial infarction (MI). However, previous studies have predominantly been conducted without angiographic confirmation of MI. The possibility can therefore not be excluded that raised troponin levels or electrocardiogram abnormalities that may be seen with respiratory infections are due to non-ischaemic causes.

AIMS

To investigate the association between respiratory infection and angiographically confirmed MI.

METHODS

Interviews were conducted within 4 days of hospitalisation in 578 patients with angiographically confirmed MI, to assess for recent exposure to respiratory infection symptoms and the usual annual frequency of these symptoms. Using case-crossover methodology, exposure to respiratory infection prior to the onset of MI was compared against the usual frequency of exposure in the past year.

RESULTS

Symptoms of respiratory infection were reported by 100 (17%) and 123 (21%) within 7 and 35 days, respectively, prior to MI. The relative risk (RR) for MI occurring within 1-7 days after respiratory infection symptoms was 17.0 (95% confidence interval (CI) 13.2-21.8), and declined with subsequent time periods. In a subgroup analysis, the RR tended to be lower in groups taking regular cardiac medications. For those who reported milder, upper respiratory tract infection symptoms, the RR for the 1-7-day time period was 13.5 (95% CI 10.2-17.7).

CONCLUSION

These findings confirm that respiratory infection can trigger MI. Further study is indicated to identify treatment strategies to decrease this risk, particularly in individuals who may have increased susceptibility.

Seasonal Periodicity of Ischemic Heart Disease and Heart Failure

Seasonal variation for ischemic heart disease and heart failure is known. The interplay of environmental, biological, and physiologic changes is fascinating. This article highlights the seasonal periodicity of ischemic heart disease and heart failure and examines some of the potential reasons for these unique observations.

An Unsettled Debate About the Potential Role of Infection in Pathogenesis of Atherosclerosis

Association of infection with atherosclerosis is by no means new. Several sero-epidemiological and pathologic studies as well as animal models have shown a link between infection and atherosclerosis. Exciting discoveries in recent times related to role of inter-individual genetic variation in modulating inflammatory response to infection have reignited the enthusiasm in proving a causal link between infection and atherosclerosis. The purpose of this article was to review and analyze the available evidence linking infection with atherosclerosis.

Acute Respiratory Infection and Use of Nonsteroidal Anti-Inflammatory Drugs on Risk of Acute Myocardial Infarction: A Nationwide Case-Crossover Study

Background

Previous studies have suggested that acute respiratory infection (ARI) and nonsteroidal anti-inflammatory drugs (NSAIDs) use could trigger acute myocardial infarction (AMI). In some countries, physicians prescribe NSAIDs for patients with ARI for symptom relief. However, there is no research evaluating whether NSAIDs use during ARI episodes may increase the risk of AMI.

Methods

We identified 9793 patients with an incident hospitalization of AMI (index date) between 2007 and 2011. Using case-crossover design, we compared the following exposure status between the case (1-7-day before index date) and matched control period (366-372-day before index date): NSAIDs use during ARI episodes, ARI episodes without NSAIDs use, NSAIDs use only, or no exposure. Multivariable conditional logistic regression models were used to estimate odds ratios adjusted for potential confounders.

Results

Nonsteroidal anti-inflammatory drugs use during ARI was associated with a 3.4-fold increased risk of AMI (adjusted odds ratio [aOR] = 3.41; 95% confidence interval [CI] = 2.80-4.16), ARI without NSAIDs use was associated with a 2.7-fold increased risk (aOR = 2.65; 95% CI = 2.29-3.06), and NSAIDs use only was associated with a 1.5-fold increased risk (aOR = 1.47; 95% CI = 1.33-1.62). Moreover, parenteral NSAIDs were associated with much higher risk in ARI patients (aOR = 7.22; 95% CI = 4.07-12.81).

Conclusions

Nonsteroidal anti-inflammatory drugs use during ARI episodes, especially parenteral NSAIDs, was associated with a further increased risk of AMI.

Influenza Vaccination for Secondary Prevention of Cardiovascular Events: A Systematic Review

BACKGROUND

Influenza is a common respiratory infection that may cause complications, including cardiovascular events. Influenza illness has been shown to double the risk of myocardial infarction, with the highest risk among patients with established cardiovascular disease. Vaccination against influenza has been associated with reductions in myocardial infarction, cerebrovascular disease, and death.

OBJECTIVE

To evaluate the evidence for influenza vaccination as a strategy to reduce cardiovascular events specifically in patients with established cardiovascular disease.

DATA SOURCES AND STUDY SELECTION

MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched with the terms "influenza vaccine" and "cardiovascular disease". Included in this review were randomized controlled trials (RCTs), nonrandomized studies, and meta-analyses that compared influenza vaccination against control in patients with established cardiovascular disease and that reported clinically meaningful cardiovascular outcomes (defined as cardiovascular death, myocardial infarction, and stroke).

DATA EXTRACTION AND SYNTHESIS

The search yielded 10 studies (3 nonrandomized studies, 5 RCTs, and 2 meta-analyses). The nonrandomized studies and the RCTs had inconsistent results with respect to cardiovascular death and adverse cardiovascular events. The 2 meta-analyses, which included the same 4 RCTs involving patients with established cardiovascular disease, showed that the influenza vaccine reduced cardiovascular death by about 50% relative to control. Vaccination also reduced major cardiovascular events by about 43%; the reduction was greater (54%) in the subgroup of patients with recent (≤ 1 year) acute coronary syndrome. However, these data are potentially confounded by small sample sizes, low event rates, and variable outcome reporting. There was also high clinical heterogeneity among the studies, which may not reflect contemporary practice.

CONCLUSIONS

Given the limitations of these data, it is unclear whether the cardiovascular benefit with influenza vaccination in patients with cardiovascular disease is a true effect. Nevertheless, because of the potential benefit and the low risk of adverse events, the annual influenza vaccine should be recommended for all patients with established cardiovascular disease.