Role of acute infection in triggering acute coronary syndromes

Early cardiac arrest in patients hospitalized with pneumonia: a report from the American Heart Association's Get With The Guidelines-Resuscitation Program

BACKGROUND

Pneumonia is the leading infectious cause of death. Early deterioration and death commonly result from progressive sepsis, shock, respiratory failure, and cardiac complications. Recent data suggest that cardiac arrest may also be common, yet few previous studies have addressed this. Accordingly, we sought to characterize early cardiac arrest in patients who are hospitalized with coexisting pneumonia.

METHODS

We performed a retrospective analysis of a multicenter cardiac arrest database, with data from > 500 North American hospitals. We included in-hospital cardiac arrest events that occurred in community-dwelling adults with pneumonia within the first 72 h after hospital admission. We compared patient and event characteristics for patients with and without pneumonia. For patients with pneumonia, we also compared events according to event location.

RESULTS

We identified 4,453 episodes of early cardiac arrest in patients who were hospitalized with pneumonia. Among patients with preexisting pneumonia, only 36.5% were receiving mechanical ventilation and only 33.3% were receiving infusions of vasoactive drugs prior to cardiac arrest. Only 52.3% of patients on the ward were receiving ECG monitoring prior to cardiac arrest. Shockable rhythms were uncommon in all patients with pneumonia (ventricular tachycardia or fibrillation, 14.8%). Patients on the ward were significantly older than patients in the ICU.

CONCLUSIONS

In patients with preexisting pneumonia, cardiac arrest may occur in the absence of preceding shock or respiratory failure. Physicians should be alert to the possibility of abrupt cardiopulmonary collapse, and future studies should address this possibility. The mechanism may involve myocardial ischemia, a maladaptive response to hypoxia, sepsis-related cardiomyopathy, or other phenomena.

Increased levels of inflammatory cytokines and endothelin-1 in alveolar macrophages from patients with chronic heart failure

Background

Pathophysiological interactions between heart and lungs in heart failure (HF) are well recognized. We investigated whether expression of different factors known to be increased in the myocardium and/or the circulation in HF is also increased in alveolar macrophages in HF.

Methodology/Principal Findings

Lung function, hemodynamic parameters, gene expression in alveolar macrophages, and plasma levels in the pulmonary and femoral arteries of HF patients (n = 20) were compared to control subjects (n = 16). Our principal findings were: (1) Lung function was significantly lower in HF patients compared to controls (P<0.05). (2) mRNA levels of ET-1, tumor necrosis factor (TNF)-α and interleukin-6 (IL-6) were increased in alveolar macrophages from HF patients. (3) Plasma levels of ET-1, TNFα, IL-6 and MCP-1 were significantly increased in HF patients, whereas our data indicate a net pulmonary release of MCP-1 into the circulation in HF.

Conclusions/Significance

Several important cytokines and ET-1 are induced in alveolar macrophages in human HF. Further studies should clarify whether increased synthesis of these factors affects pulmonary remodeling and, directly or indirectly, adversely affects the failing myocardium.

Clinical effectiveness of pneumococcal vaccination against acute myocardial infarction and stroke in people over 60 years: the CAPAMIS study, one-year follow-up

BACKGROUND

Conflicting results have been recently reported evaluating the relationship between pneumococcal vaccination and the risk of thrombotic vascular events. This study assessed the clinical effectiveness of the 23-valent polysaccharide pneumococcal vaccine (PPV23) against acute myocardial infarction and ischaemic stroke in older adults.

METHODS

Population-based prospective cohort study conducted from December 1, 2008 until November 30, 2009, including all individuals ≥ 60 years-old assigned to nine Primary Care Centres in Tarragona, Spain (N = 27,204 individuals). Primary outcomes were hospitalisation for acute myocardial infarction and/or ischaemic stroke. All cases were validated by checking clinical records. The association between pneumococcal vaccination and the risk of each outcome was evaluated by Multivariable Cox proportional-hazard models (adjusted by age, sex, influenza vaccine status, presence of comorbidities and cardiovascular risk factors).

RESULTS

Cohort members were followed for a total of 26,444 person-years, of which 34% were for vaccinated subjects. Overall incidence rates (per 1000 person-years) were 4.9 for myocardial infarction and 4.6 for ischaemic stroke. In the multivariable analysis, vaccination was associated with a marginally significant 35% lower risk of stroke (hazard ratio [HR]: 0.65; 95% confidence interval [CI]: 0.42-0.99; p = 0.046). We found no evidence for an association between pneumococcal vaccination and reduced risk of myocardial infarction (HR: 0.83; 95% CI: 0.56-1.22; p = 0.347).

CONCLUSIONS

Our data supports a benefit of PPV23 against ischaemic stroke among the general population over 60 years, suggesting a possible protective role of pneumococcal vaccination against some acute thrombotic events.

Platelet activation by Streptococcus sanguinis is accompanied by MAP kinase phosphorylation

There is increasing interest in the role of infections in atherothrombotic conditions. In particular, bacteria, notably those of oral origin, have been shown to activate platelets using a variety of mechanisms. Previous studies have shown that S. sanguinis strain 2017-78 induces platelet aggregation which requires the presence of both vWF and IgG. This aggregation is accompanied by the consecutive phosphorylation/desphosphorylation/rephosphorylation of several signalling proteins. The first two phases are thromboxane-dependent whereas the rephosphorylation phase is mediated by engagement of the αIIbβ3 integrin. Here signalling events, specifically the potential role of MAP kinases, associated with S. sanguinis strain 2017-78-induced platelet activation have been further examined using an immunoblotting approach. The addition of S. sanguinis strain 2017-78 caused a similar triphasic phosphorylation profile of the platelet MAP kinase Erk2 to that seen with other phosphoproteins. Pretreatment with aspirin or RGDS did not affect 2017-78-induced Erk2 phosphorylation or desphosphorylation but both inhibited the rephosphorylation phase. In contrast the level of 2017-78-induced platelet MAP kinase p38 phosphorylation remained at an elevated level, and this was unaffected by aspirin. Similarly, 2017-78-induced cPLA(2) phosphorylation remained above basal levels during the aggregation process. The p38 inhibitor SB203580 inhibited S. sanguinis-induced aggregation with no effect on the phosphorylation of either p38 or cPLA(2). Thus the current study demonstrates the activation of both the Erk2 and p38 forms of MAP kinases, and of cPLA(2), in platelets stimulated with S. sanguinis strain 2017-78, and is consistent with a role for Erk2, but not for p38, in the cPLA(2) phosphorylation in response to S. sanguinis.

Cardiac complications in patients with community-acquired pneumonia: incidence, timing, risk factors, and association with short-term mortality

BACKGROUND

Community-acquired pneumonia (CAP) affects >5 million adults each year in the United States. Although incident cardiac complications occur in patients with community-acquired pneumonia, their incidence, timing, risk factors, and associations with short-term mortality are not well understood.

METHODS AND RESULTS

A total of 1343 inpatients and 944 outpatients with community-acquired pneumonia were followed up prospectively for 30 days after presentation. Incident cardiac complications (new or worsening heart failure, new or worsening arrhythmias, or myocardial infarction) were diagnosed in 358 inpatients (26.7%) and 20 outpatients (2.1%). Although most events (89.1% in inpatients, 75% in outpatients) were diagnosed within the first week, more than half of them were recognized in the first 24 hours. Factors associated with their diagnosis included older age (odds ratio [OR]=1.03; 95% confidence interval [CI], 1.02-1.04), nursing home residence (OR, 1.8; 95% CI, 1.2-2.9), history of heart failure (OR, 4.3; 95% CI, 3.0-6.3), prior cardiac arrhythmias (OR, 1.8; 95% CI, 1.2-2.7), previously diagnosed coronary artery disease (OR, 1.5; 95% CI, 1.04-2.0), arterial hypertension (OR, 1.5; 95% CI, 1.1-2.1), respiratory rate ≥30 breaths per minute (OR, 1.6; 95% CI, 1.1-2.3), blood pH <7.35 (OR, 3.2; 95% CI, 1.8-5.7), blood urea nitrogen ≥30 mg/dL (OR, 1.5; 95% CI, 1.1-2.2), serum sodium <130 mmol/L (OR, 1.8; 95% CI, 1.02-3.1), hematocrit <30% (OR, 2.0; 95% CI, 1.3-3.2), pleural effusion on presenting chest x-ray (OR, 1.6; 95% CI, 1.1-2.4), and inpatient care (OR, 4.8; 95% CI, 2.8-8.3). Incident cardiac complications were associated with increased risk of death at 30 days after adjustment for baseline Pneumonia Severity Index score (OR, 1.6; 95% CI, 1.04-2.5).

CONCLUSIONS

Incident cardiac complications are common in patients with community-acquired pneumonia and are associated with increased short-term mortality. Older age, nursing home residence, preexisting cardiovascular disease, and pneumonia severity are associated with their occurrence. Further studies are required to test risk stratification and prevention and treatment strategies for cardiac complications in this population.

Streptococcus sanguinis-induced cytokine release from platelets

BACKGROUND

There is increasing evidence that both chronic and acute infections play a role in the development and progression of atherothrombotic disorders. One potential mechanism is the direct activation of platelets by bacteria. A wide range of bacterial species activate platelets through heterogeneous mechanisms. The oral micro-organism S. sanguinis stimulates platelet aggregation in vitro in a strain-dependent manner, although there are no reports of associated cytokine production.

OBJECTIVE

The aim of the present study was to determine whether platelet activation by S. sanguinis involved the release of pro-inflammatory and immune modulating factors, and whether activation was enhanced by epinephrine.

METHODS AND RESULTS

Four strains of S. sanguinis and one of S. gordonii stimulated the release of RANTES, PF4, sCD40L and PDGF-AB, whereas only one S. sanguinis strain caused the release of sCD62p. Epinephrine enhanced S. sanguinis-induced platelet aggregation and phosphorylation of phospholipase Cγ2 and Erk, but inhibited RANTES, PF4, sCD40L and PDGF-AB release. Wortmannin inhibited S. sanguinis-induced aggregation and release; however, only aggregation was partially reversed by epinephrine.

CONCLUSIONS

The present study demonstrates that platelets respond to S. sanguinis with both prothrombotic and pro-inflammatory/immune-modulating responses. Epinephrine, potentially released in response to infection and/or stress, can significantly enhance the prothrombotic response, thereby providing a putative link between bacteraemia and acute coronary events during stress. In contrast, epinephrine inhibited the pro-inflammatory/immune-modulating response by an undetermined mechanism.

Time trends in mortality in patients with type 1 diabetes: nationwide population based cohort study

OBJECTIVE

To examine short and long term time trends in mortality among patients with early onset (age 0-14 years) and late onset (15-29 years) type 1 diabetes and causes of deaths over time.

DESIGN

Population based nationwide cohort study.

SETTING

Finland.

PARTICIPANTS

All Finnish patients diagnosed as having type 1 diabetes below age 30 years between 1970 and 1999 (n = 17,306).

MAIN OUTCOME MEASURES

Crude mortality, standardised mortality ratios, time trends, and cumulative mortality.

RESULTS

A total of 1338 deaths occurred during 370,733 person years of follow-up, giving an all cause mortality rate of 361/100,000 person years. The standardised mortality ratio was 3.6 in the early onset cohort and 2.8 in the late onset cohort. Women had higher standardised mortality ratios than did men in both cohorts (5.5 v 3.0 in the early onset cohort; 3.6 v 2.6 in the late onset cohort). The standardised mortality ratio at 20 years' duration of diabetes in the early onset cohort decreased from 3.5 in the patients diagnosed in 1970-4 to 1.9 in those diagnosed in 1985-9. In contrast, the standardised mortality ratio in the late onset cohort increased from 1.4 in those diagnosed in 1970-4 to 2.9 in those diagnosed in 1985-9. Mortality due to chronic complications of diabetes decreased with time in the early onset cohort but not in the late onset cohort. Mortality due to alcohol related and drug related causes increased in the late onset cohort and accounted for 39% of the deaths during the first 20 years of diabetes. Accordingly, mortality due to acute diabetic complications increased significantly in the late onset cohort.

CONCLUSION

Survival of people with early onset type 1 diabetes has improved over time, whereas survival of people with late onset type 1 diabetes has deteriorated since the 1980s. Alcohol has become an important cause of death in patients with type 1 diabetes, and the proportion of deaths caused by acute complications of diabetes has increased in patients with late onset type 1 diabetes.

Elevated hemostasis markers after pneumonia increases one-year risk of all-cause and cardiovascular deaths

Background

Acceleration of chronic diseases, particularly cardiovascular disease, may increase long-term mortality after community-acquired pneumonia (CAP), but underlying mechanisms are unknown. Persistence of the prothrombotic state that occurs during an acute infection may increase risk of subsequent atherothrombosis in patients with pre-existing cardiovascular disease and increase subsequent risk of death. We hypothesized that circulating hemostasis markers activated during CAP persist at hospital discharge, when patients appear to have recovered clinically, and are associated with higher mortality, particularly due to cardiovascular causes.

Methods

In a cohort of survivors of CAP hospitalization from 28 US sites, we measured D-Dimer, thrombin-antithrombin complexes [TAT], Factor IX, antithrombin, and plasminogen activator inhibitor-1 at hospital discharge, and determined 1-year all-cause and cardiovascular mortality.

Results

Of 893 subjects, most did not have severe pneumonia (70.6% never developed severe sepsis) and only 13.4% required intensive care unit admission. At discharge, 88.4% of subjects had normal vital signs and appeared to have clinically recovered. D-dimer and TAT levels were elevated at discharge in 78.8% and 30.1% of all subjects, and in 51.3% and 25.3% of those without severe sepsis. Higher D-dimer and TAT levels were associated with higher risk of all-cause mortality (range of hazard ratios were 1.66-1.17, p = 0.0001 and 1.46-1.04, p = 0.001 after adjusting for demographics and comorbid illnesses) and cardiovascular mortality (p = 0.009 and 0.003 in competing risk analyses).

Conclusions

Elevations of TAT and D-dimer levels are common at hospital discharge in patients who appeared to have recovered clinically from pneumonia and are associated with higher risk of subsequent deaths, particularly due to cardiovascular disease.

Cardiac complications in patients with community-acquired pneumonia: a systematic review and meta-analysis of observational studies

BACKGROUND

Community-acquired pneumonia (CAP) is a leading cause of morbidity and mortality. CAP can trigger acute cardiac events. We sought to determine the incidence of major cardiac complications in CAP patients to characterize the magnitude of this problem.

METHODS AND FINDINGS

Two investigators searched MEDLINE, Scopus, and EMBASE for observational studies of immunocompetent adults with clinical and radiological evidence of CAP that reported any of the following: overall cardiac complications, incident heart failure, acute coronary syndromes (ACS), or incident cardiac arrhythmias occurring within 30 days of CAP diagnosis. At a minimum, studies had to establish enrolment procedures and inclusion and exclusion criteria, enroll their patients sequentially, and report the incidence of cardiac complications as a function of their entire cohorts. Studies with focus on nosocomial or health care-associated pneumonia were not included. Review of 2,176 citations yielded 25 articles that met eligibility and minimum quality criteria. Seventeen articles (68%) reported cohorts of CAP inpatients. In this group, the pooled incidence rates for overall cardiac complications (six cohorts, 2,119 patients), incident heart failure (eight cohorts, 4,215 patients), acute coronary syndromes (six cohorts, 2,657 patients), and incident cardiac arrhythmias (six cohorts, 2,596 patients), were 17.7% (confidence interval [CI] 13.9-22.2), 14.1% (9.3-20.6), 5.3% (3.2-8.6), and 4.7% (2.4-8.9), respectively. One article reported cardiac complications in CAP outpatients, four in low-risk (not severely ill) inpatients, and three in high-risk inpatients. The incidences for all outcomes except overall cardiac complications were lower in the two former groups and higher in the latter. One additional study reported on CAP outpatients and low-risk inpatients without discriminating between these groups. Twelve studies (48%) asserted the evaluation of cardiac complications in their methods but only six (24%) provided a definition for them. Only three studies, all examining ACS, carried out risk factor analysis for these events. No study analyzed the association between cardiac complications and other medical complications or their impact on other CAP outcomes.

CONCLUSIONS

Major cardiac complications occur in a substantial proportion of patients with CAP. Physicians and patients need to appreciate the significance of this association for timely recognition and management of these events. Strategies aimed at preventing pneumonia (i.e., influenza and pneumococcal vaccination) in high-risk populations need to be optimized. Further research is needed to understand the mechanisms underlying this association, measure the impact of cardiac complications on other CAP outcomes, identify those patients with CAP at high risk of developing cardiac complications, and design strategies to prevent their occurrence in this population.

New modalities in treating pneumococcal pneumonia

Despite the availability of effective antibiotics and intensive medical care, pneumococcal pneumonia is still associated with substantial mortality. Early diagnosis is becoming increasingly possible. This article reviews several adjunctive measures that might be instituted at or soon after admission in patients who are hospitalized for community-acquired pneumonia that is found to be due to Streptococcus pneumoniae. Available data favor the use of a macrolide together with a β-lactam antibiotic for treatment, based largely on immunomodulatory activity of macrolides. Two large subgroup analyses from a single major study suggest that activated protein C (eg, drotrecogin) should be considered for patients with severe sepsis, organ failure, and an Acute Physiology and Chronic Health Evaluation II score > 25 due to pneumococcal pneumonia. Statins exert an anti-inflammatory effect and several retrospective studies suggest that their use might ameliorate the adverse effects of pneumonia. Because inflammation elsewhere in the body is associated with inflammation in coronary arteries and because pneumococcal pneumonia has been shown to precipitate myocardial infarction, statins might be of further benefit by decreasing the likelihood of associated myocardial infarction. Aspirin, which inhibits platelet aggregation in inflamed coronary arteries, might also be considered for initial therapy. One reason that the association between myocardial infarction and pneumonia was not previously recognized is that aspirin was widely used in the past when people had acute febrile conditions. The literature on the benefits of corticosteroids in pneumonia is not convincing, and a particularly well-done, very recent study shows no benefit with corticosteroid use in patients with pneumococcal pneumonia, and perhaps even a worse outcome. No clinical data favor the use of platelet-activating factor antagonists.

Epidemiology, clinical features and outcomes of pneumonia in patients with chronic kidney disease

BACKGROUND

Although infection remains among the most common causes of morbidity and mortality in patients with chronic kidney disease (CKD), data on epidemiology, clinical features and outcomes of pneumonia in this population are scarce.

METHODS

Observational analysis of a prospective cohort of hospitalized adults with pneumonia, between 13 February 1995 and 30 April 2010, in a tertiary teaching hospital. CKD patients, defined as patients with a baseline glomerular filtration rate <60 mL/min/1.73 m(2), were compared with non-CKD patients.

RESULTS

During the study period, 3800 patients with pneumonia required hospitalization. Two-hundred and three (5.3%) patients had CKD, of whom 46 were on dialysis therapy. Patients with CKD were older (77 versus 70 years; P < 0.001), were more likely to have comorbidities (82.3 versus 63.3%; P < 0.001) and more commonly classified into high-risk pneumonia severity index classes (89.6 versus 57%; P < 0.001) than were the remaining patients. Streptococcus pneumoniae was the most frequent pathogen (28.1 versus 34.7%; P = 0.05). Mortality was higher in patients with CKD (15.8 versus 8.3%; P < 0.001). Among CKD patients, age [+1 year increase; adjusted odds ratio, 1.25; 95% confidence interval (CI) 1.07-1.46] and cardiac complications during hospitalization (adjusted odds ratio, 9.23; 95% CI 1.39-61.1) were found to be independent risk factors for mortality, whereas prior pneumococcal vaccination (adjusted odds ratio, 0.05; 95% CI 0.005-0.69) and leukocytosis at hospital admission (adjusted odds ratio, 0.10; 95% CI 0.01-0.64) were protective factors.

CONCLUSIONS

Pneumonia is a serious complication in CKD patients. Independent factors for mortality are older age and cardiac complications, whereas prior pneumococcal vaccination and leucokytosis at hospital admission are protective factors. These findings should encourage physicians to increase pneumococcal vaccine coverage among CKD patients.

Infectious atherosclerosis: is the hypothesis still alive? A clinically based approach to the dilemma

Among the multiple factors involved in the pathophysiology of heart disease, infections have been proposed to play a role in atherosclerosis with most of the available evidence implicating Chlamydia pneumonia, influenza virus and Mycoplasma pneumoniae. Based on a model case presentation, we speculate that in the absence of traditional risk factors and in the context of an ongoing respiratory infection caused by a pro-inflammatory pathogen (M. pneumoniae) along with a past positive serologic history for potentially proven atherogenic microorganism (C. pneumoniae) and infection may elicit potentially pathogenic events on vascular wall cells and leukocytes of atheromatous lesions, supporting the hypothesis that such infections may potentiate atherosclerotic cardiovascular disease (CVD).

Testosterone and coronary artery disease in men

Coronary artery disease (CAD) is the leading cardiovascular cause of death, and in men, endogenous testosterone concentrations are inversely related to the extent and severity of CAD. Testosterone is known to affect a number of risk factors for CAD and has effects on vascular tone, vasoreactivity and blood flow of blood vessels beyond the reproductive system, indicating that testosterone may be involved in the pathogenesis of CAD. In this review we will present and discuss the actions of endogenous testosterone and testosterone treatment on risk factors for CAD, on the blood vessel wall and blood flow, and on atheroma development and progression, and discuss the potential for testosterone use in men with CAD.