Septic cardiomyopathy: hemodynamic quantification, occurrence, and prognostic implications

Clinical implications of septic cardiomyopathy: A narrative review

Sepsis is caused by the body's dysregulated response to infection, which can lead to multiorgan injury and death. Patients with sepsis may develop acute cardiac dysfunction, termed septic cardiomyopathy, which is a global but reversible dysfunction of both sides of the heart. This narrative review discusses the mechanistic changes in the heart during septic cardiomyopathy, its diagnosis, existing treatment options regarding severity and course, and emerging treatment approaches. Although no standardized definition for septic cardiomyopathy exists, it is described as a reversible myocardial dysfunction that typically resolves within 7 to 10 days. Septic cardiomyopathy is often diagnosed based on electrocardiography, cardiac magnetic resonance imaging, biomarkers, and direct invasive and noninvasive measures of cardiac output. Presently, the treatment of septic cardiomyopathy is similar to that of sepsis, primarily focusing on acute interventions. Treatments for cardiomyopathy often include angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and diuretics. However, because of profound hypotension in sepsis, many cardiomyopathy treatments are contraindicated in patients with septic cardiomyopathy. Substantial efforts have been made to study the pathophysiological mechanisms and diagnostic options; however, the lack of a uniform definition for septic cardiomyopathy is challenging for physicians when considering treatments. Another challenge for physicians is that the treatment for septic cardiomyopathy has only focused on acute intervention, whereas the treatment for other cardiomyopathies has been provided on a long-term basis. A better understanding of the underlying mechanisms of septic cardiomyopathy may contribute to the development of a unified definition of the condition and novel treatment options.

Treatment of patients with multiple organ dysfunction syndrome (MODS) with an electromagnetic field coupled to biorhythmically defined impulse configuration: the MicrocircMODS study

BACKGROUND

To potentially improve impaired vasomotion of patients with multiple organ dysfunction syndrome (MODS), we tested whether an electromagnetic field of low flux density coupled with a biorhythmically defined impulse configuration (Physical Vascular Therapy BEMER®, PVT), in addition to standard care, is safe and feasible and might improve disturbed microcirculatory blood flow and thereby improve global haemodynamics.

METHODS

In a prospective, monocentric, one-arm pilot study, 10 MODS patients (APACHE II score 20-35) were included. Patients were treated, in addition to standard care, for 4 days with PVT (3 treatment periods of 8 min each day; day 1: field intensity 10.5 μT; day 2:14 μT, day 3:17.5 μT; day 4:21.0 μT). Primary endpoint was the effect of PVT on sublingual microcirculatory perfusion, documented by microvascular flow index (MFI). Patient safety, adverse events, and outcomes were documented.

RESULTS

An increase in MFI by approximately 25% paralleled 4-day PVT, with the increase starting immediately after the first PVT and lasting over the total 4-day treatment period. Concerning global haemodynamics (secondary endpoints), halving vasopressor use within 24 h, and haemodynamic stabilisation paralleled 4-day PVT with an increase in cardiac index, stroke volume index, and cardiac power index by 30%-50%. No adverse events (AEs) or serious adverse events (SAEs) were classified as causally related to the medical product (PVT) or study. Three patients died within 28 days and one patient between 28 and 180 days.

CONCLUSION

PVT treatment was feasible and safe and could be performed without obstruction of standard patient care. An increase in microcirculatory blood flow, a rapid reduction in vasopressor use, and an improvement in global haemodynamics paralleled PVT treatment. Findings of this pilot study allowed forming a concept for a randomized trial for further proof.

Therapeutic Strategies Targeting Mitochondrial Dysfunction in Sepsis-induced Cardiomyopathy

Sepsis is an increasingly worldwide problem; it is currently regarded as a complex life-threatening dysfunction of one or more organs as a result of dysregulated host immune response to infections. The heart is one of the most affected organs, as roughly 10% to 70% of sepsis cases are estimated to turn into sepsis-induced cardiomyopathy (SIC). SIC can be defined as a reversible myocardial dysfunction characterized by dilated ventricles, impaired contractility, and decreased ejection fraction. Mitochondria play a critical role in the normal functioning of cardiac tissues as the heart is highly dependent on its production of adenosine triphosphate (ATP), its damage during SIC includes morphology impairment, mitophagy, biogenesis disequilibrium, electron transport chain disturbance, molecular damage from the actions of pro-inflammatory cytokines and many other different impairments that are major contributing factors to the severity of SIC. Although mitochondria-targeted therapies usage is still inadequate in clinical settings, the preclinical study outcomes promise that the implementation of these therapies may effectively treat SIC. This review summarizes the different therapeutic strategies targeting mitochondria structure, quality, and quantity abnormalities for the treatment of SIC.

Research Progress on the Mechanism and Management of Septic Cardiomyopathy: A Comprehensive Review

Sepsis is defined as a kind of life-threatening organ dysfunction due to a dysregulated host immune response to infection and is a leading cause of mortality in the intensive care unit. Sepsis-induced myocardial dysfunction, also called septic cardiomyopathy, is a common and serious complication in patients with sepsis, which may indicate a bad prognosis. Although efforts have been made to uncover the pathophysiology of septic cardiomyopathy, a number of uncertainties remain. This article sought to review available literature to summarize the existing knowledge on current diagnostic tools and biomarkers, pathogenesis, and treatments for septic cardiomyopathy.

Afterload-related cardiac performance is a powerful hemodynamic predictor of mortality in patients with chronic heart failure

Background

Afterload-related cardiac performance (ACP), a diagnostic parameter for septic cardiomyopathy, integrates both cardiac performance and vascular effects and could predict prognosis in septic shock.

Objectives

We hypothesized that ACP would also correlate with clinical outcomes in patients with chronic heart failure (HF).

Design

A retrospective study.

Methods

We retrospectively studied consecutive patients with chronic HF who underwent right heart catheterization and established an expected cardiac output-systemic vascular resistance (CO-SVR) curve model in chronic HF for the first time. ACP was calculated as COmeasured/COpredicted × 100%. ACP > 80%, 60% < ACP ⩽ 80%, and ACP ⩽ 60% represented less impaired, mildly impaired, and severely impaired cardiovascular function, respectively. The primary outcome was all-cause mortality, and the secondary outcome was event-free survival.

Results

A total of 965 individual measurements from 290 eligible patients were used to establish the expected CO-SVR curve model (COpredicted = 53.468 × SVR -0.799). Patients with ACP ⩽ 60% had higher serum NT-proBNP levels (P < 0.001), lower left ventricular ejection fraction (P = 0.001), and required dopamine more frequently (P < 0.001). Complete follow-up data were available in 263 of 290 patients (90.7%). After multivariate adjustment, ACP remained associated with both primary outcome (hazard ratio (HR) 0.956, 95% confidence interval (CI) 0.927-0.987) and secondary outcome (HR 0.977, 95% CI 0.963-0.992). Patients with ACP ⩽ 60% had the worst prognosis (all P < 0.001). ACP was significantly more discriminating (area under the curve of 0.770) than other conventional hemodynamic parameters in predicting mortality (Delong test, all P < 0.05).

Conclusion

ACP is a powerful independent hemodynamic predictor of mortality in patients with chronic HF. ACP and the novel CO-SVR two-dimensional graph could be useful in assessing cardiovascular function and making clinical decisions.

Clinical trial registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02664818.

Utility of Cardiac Power Hemodynamic Measurements in the Evaluation and Risk Stratification of Cardiovascular Conditions

Despite numerous advancements in prevention, diagnosis and treatment, cardiovascular disease has remained the leading cause of mortality globally for the past 20 years. Part of the explanation for this trend is persistent difficulty in determining the severity of cardiac conditions in order to allow for the deployment of prompt therapies. This review seeks to determine the prognostic importance of cardiac power (CP) measurements, including cardiac power output (CPO) and cardiac power index (CPI), in various cardiac pathologies. CP was evaluated across respective disease-state categories which include cardiogenic shock (CS), septic shock, transcatheter aortic valve replacement (TAVR), heart failure (HF), post-myocardial infarction (MI), critical cardiac illness (CCI) and an "other" category. Literature review was undertaken of articles discussing CP in various conditions and this review found utility and prognostic significance in the evaluation of TAVR patients with a significant correlation between one-year mortality and CPI; in HF patients showing CPI and CPO as valuable tools to assess cardiac function in the acute setting; and, additionally, CPO was found to be an essential tool in patients with CCI, as the literature showed that CPO was statistically correlated with mortality. Cardiac power and the derived measures obtained from this relatively easily obtained variable can allow for essential estimations of prognostic outcomes in cardiac patients.

Septic Cardiomyopathy: From Pathophysiology to the Clinical Setting

The onset of cardiomyopathy is a common feature in sepsis, with relevant effects on its pathophysiology and clinical care. Septic cardiomyopathy is characterized by reduced left ventricular (LV) contractility eventually associated with LV dilatation with or without right ventricle failure. Unfortunately, such a wide range of ultrasonographic findings does not reflect a deep comprehension of sepsis-induced cardiomyopathy, but rather a lack of consensus about its definition. Several echocardiographic parameters intrinsically depend on loading conditions (both preload and afterload) so that it may be challenging to discriminate which is primitive and which is induced by hemodynamic perturbances. Here, we explore the state of the art in sepsis-related cardiomyopathy. We focus on the shortcomings in its definition and point out how cardiac performance dynamically changes in response to different hemodynamic clusters. A special attention is also given to update the knowledge about molecular mechanisms leading to myocardial dysfunction and that recall those of myocardial hibernation. Ultimately, the aim of this review is to highlight the unsolved issue in the field of sepsis-induced cardiomyopathy as their implementation would lead to improve risk stratification and clinical care.

Septic cardiomyopathy: Diagnosis and management

There is an extensive body of literature focused on sepsis-induced myocardial dysfunction, but results are conflicting and no objective definition of septic cardiomyopathy (SCM) has been established. SCM may be defined as a sepsis-associated acute syndrome of non-ischemic cardiac dysfunction with systolic and/or diastolic left ventricular (LV) dysfunction and/or right ventricular dysfunction. Physicians should consider this diagnosis in patients with sepsis-associated organ dysfunction, and particularly in cases of septic shock that require vasopressors. Echocardiography is currently the gold standard for diagnosis of SCM. Left ventricular ejection fraction is the most common parameter used to describe LV function in the literature, but its dependence on loading conditions, particularly afterload, limits its use as a measure of intrinsic myocardial contractility. Therefore, repeated echocardiography evaluation is mandatory. Evaluation of global longitudinal strain (GLS) may be more sensitive and specific for SCM than LV ejection fraction (LVEF). Standard management includes etiological treatment, adapted fluid resuscitation, use of vasopressors, and monitoring. Use of inotropes remains uncertain, and heart rate control could be an option in some patients.

Initial Derivation of a Predictive Model for Left Ventricular Longitudinal Strain (LS) in Early Sepsis

Septic shock is a common deadly disease often associated with cardiovascular dysfunction. Left ventricular longitudinal strain (LV LS) has been proposed as a sensitive marker to measure cardiovascular function; however, it is not available universally in standard clinical echocardiograms. We sought to derive a predictive model for LV LS, using machine learning techniques with the hope that we may uncover surrogates for LV LS. We found that left ventricular ejection fraction, tricuspid annular plane systolic excursion, sepsis source, height, mitral valve Tei index, LV systolic dimension, aortic valve ejection time, and peak acceleration rate were all predictive of LV LS in this initial exploratory model. Future modeling work may uncover combinations of these variables which may be powerful surrogates for LV LS and cardiovascular function.

Afterload-related cardiac performance predicts prognosis in critical ill patients with sepsis: A prospective observational pilot study

ABSTRACT

To investigate the usefulness of afterload-related cardiac performance (ACP) for assessing cardiac impairment and predicting prognosis in septic patients.Adult patients with sepsis in the intensive care unit were included. Cardiac output, cardiac index, cardiac power index, and ACP were calculated at the time of admission (D0) and 48-72 h after admission (D3). They were correlated with Acute Physiology and Chronic Health Evaluation II and sequential organ failure assessment scores, then the prognostic values were analyzed.A total of 41 patients with sepsis were selected. ACP showed a stronger negative correlation with Acute Physiology and Chronic Health Evaluation II and sequential organ failure assessment scores than cardiac output, cardiac index, and cardiac power index. ACP predicted 28-day mortality with an area under the curve of 0.775 and 0.976 on D0 and D3, respectively. In addition, most non-survivors had emergent cardiac impairment (ACP ≤ 80%) on D0, and cardiac function was deteriorated on D3. Survival analysis showed that the patients with a decreased ACP from D0 to D3 had the highest mortality. The decrease of ACP on D3 was an independent risk factor for mortality (hazard ratio, 11.89; P = .0028).ACP can be used to assess the severity of cardiac impairment in sepsis. Continued decline of ACP during the first 3 days strongly suggests a poor prognosis.

Clinical and Laboratory Parameters Associated with Septic Myocardial Dysfunction in Children with Septic Shock

The authors' objective was to determine the association of clinical and laboratory parameters at admission with septic myocardial dysfunction (SMD) in children with septic shock. A chart review of children aged 3 mo-17 y with fluid refractory septic shock who underwent echocardiography within 3 h of admission was undertaken (2015-2017). Univariate followed by multivariate analysis was performed to identify factors associated with SMD. Of the 95 children fulfilling the inclusion criteria, SMD was diagnosed in 44 (46%) children. Children 'with SMD' had longer capillary refill time (CRT), increased lactate, lower platelet count, increased blood urea, and increased alanine aminotransferase (ALT) (p < 0.05 for all) compared to those 'without SMD'. On multivariate analysis, none of these were significant. The mortality rate was higher in those 'with SMD' than 'without SMD' [36% vs. 20% (p = 0.07)]. Prolonged CRT, increased lactate, lower platelet count, increased blood urea and elevated liver enzymes at admission may be associated with SMD in children with septic shock and may warrant early assessment of cardiac function.

Role of Concomitant Coronary Artery Bypass Grafting in Valve Surgery for Infective Endocarditis

BACKGROUND

It is current practice to perform concomitant coronary artery bypass grafting (CABG) in patients with infective endocarditis (IE) who have relevant coronary artery disease (CAD). However, CABG may add complexity to the operation. We aimed to investigate the impact of concomitant CABG on perioperative outcomes in patients undergoing surgery for IE.

METHODS

We retrospectively used data of surgically treated IE patients between 1994 and 2018 in six German cardiac surgery centers. We performed inverse probability weighting (IPW), multivariable adjustment, chi-square analysis, and Kaplan-Meier survival estimates.

RESULTS

CAD was reported in 1242/4917 (25%) patients. Among them, 527 received concomitant CABG. After adjustment for basal characteristics between CABG and no-CABG patients using IPW, concomitant CABG was associated with higher postoperative stroke (26% vs. 21%, p = 0.003) and a trend towards higher postoperative hemodialysis (29% vs. 25%, p = 0.052). Thirty-day mortality was similar in both groups (24% vs. 23%, p = 0.370). Multivariate Cox regression analysis after IPW showed that CABG was not associated with better long-term survival (HR: 1.00, 95% CI: 0.82-1.23, p = 0.998).

CONCLUSION

In endocarditis patients with CAD, adding CABG to valve surgery may be associated with a higher likelihood of postoperative stroke without adding long-term survival benefits. Therefore, in the absence of critical CAD, concomitant CABG may be omitted without impacting outcome. The results are limited due to a lack of data on the severity of CAD, and therefore there is a need for a randomized trial.

Diagnostic value of combined detection of IL-1β, IL-6, and TNF-α for sepsis-induced cardiomyopathy

INTRODUCTION

This study aimed to explore the diagnostic value and the correlation of the combined detection of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) with sepsis-induced cardiomyopathy (SIC).

PATIENTS AND METHODS

Admitted to our hospital from January 2017 to January 2019, 96 patients with SIC (a study group) and 90 patients with sepsis (a control group) were enrolled. The three cytokines were determined and the diagnostic value of their combined detection for SIC was analyzed.

RESULTS

The cytokines were remarkably higher in the study group (p<.001). The combined detection of the three had a better diagnostic value for SIC (p<.001). The three cytokines were independent risk factors for the death of patients with SIC.

CONCLUSION

IL-1β, IL-6, and TNF-α in SIC patients rise markedly. The combined detection of the three has a better predictive value for patients with SIC and is closely related to the patients' prognoses, so it may be crucial in diagnosing and treating the disease.

Pathophysiology of sepsis-induced cardiomyopathy

Sepsis is the life-threatening organ dysfunction caused by a dysregulated host response to infection and is the leading cause of death in intensive care units. Cardiac dysfunction caused by sepsis, usually termed sepsis-induced cardiomyopathy, is common and has long been a subject of interest. In this Review, we explore the definition, epidemiology, diagnosis and pathophysiology of septic cardiomyopathy, with an emphasis on how best to interpret this condition in the clinical context. Advances in diagnostic techniques have increased the sensitivity of detection of myocardial abnormalities but have posed challenges in linking those abnormalities to therapeutic strategies and relevant clinical outcomes. Sophisticated methodologies have elucidated various pathophysiological mechanisms but the extent to which these are adaptive responses is yet to be definitively answered. Although the indications for monitoring and treating septic cardiomyopathy are clinical and directed towards restoring tissue perfusion, a better understanding of the course and implications of septic cardiomyopathy can help to optimize interventions and improve clinical outcomes.

SIRT1 Mediates Septic Cardiomyopathy in a Murine Model of Polymicrobial Sepsis

BACKGROUND

Cardiac dysfunction, a common complication from severe sepsis, is associated with increased morbidity and mortality. However, the molecular mechanisms of septic cardiac dysfunction are poorly understood. SIRT1, a member of the sirtuin family of NAD+-dependent protein deacetylases, is an important immunometabolic regulator of sepsis, and sustained SIRT1 elevation is associated with worse outcomes and organ dysfunction in severe sepsis. Herein, we explore the role of SIRT1 in septic cardiac dysfunction using a murine model of sepsis.

METHODS

An in vitro model of inflammation in isolated H9c2 cardiomyocytes was used to confirm SIRT1 response to stimulation with lipopolysaccharide (LPS), followed by a murine model of cecal ligation and puncture (CLP) to investigate the molecular and echocardiographic response to sepsis. A selective SIRT1 inhibitor, EX-527, was employed to test for SIRT1 participation in septic cardiac dysfunction.

RESULTS

SIRT1 mRNA and protein levels in cultured H9c2 cardiomyocytes were significantly elevated at later time points after stimulation with LPS. Similarly, cardiac tissue harvested from C57BL/6 mice 36 h after CLP demonstrated increased expression of SIRT1 mRNA and protein compared with sham controls. Administration of EX-527 18 h after CLP reduced SIRT1 protein expression in cardiac tissue at 36 h. Moreover, treatment with EX-527 improved cardiac performance with increased global longitudinal strain and longitudinal strain rate.

CONCLUSIONS

Our findings reveal that SIRT1 expression increases in isolated cardiomyocytes and cardiac tissue after sepsis inflammation. Moreover, rebalancing SIRT1 excess in late sepsis improves cardiac performance, suggesting that SIRT1 may serve as a therapeutic target for septic cardiomyopathy.

Afterload-related cardiac performance identifies cardiac impairment and associates with outcome in patients with septic shock: a retrospective cohort study

Background

Septic patients with cardiac impairment are with high mortality. Afterload-related cardiac performance (ACP), as a new tool for diagnosing septic cardiomyopathy (SCM), still needs to be evaluated for its impact on the prognosis for patients with septic shock.

Methods

In this retrospective study, 100 patients with septic shock undertaken PiCCO monitoring were included. The ability of ACP, cardiac index (CI), and cardiac power index (CPI) to discriminate between survivors and non-survivors was tested by comparing the area under the receiver operating characteristic curve (AUROC) analysis. Cox proportional hazards regression analyses were performed to assess the associations of ACP with day-28 mortality. Curve estimation was used to describe the relationship between the hazard ratio (HR) of death and ACP.

Results

ACP had a strong linear correlation with CI and CPI (P < 0.001). ACP demonstrated significantly greater discrimination for day-28 mortality than CI before adjusted [AUROC 0.723 (95% CI 0.625 to 0.822) vs. 0.580 (95% CI 0.468 to 0.692), P = 0.007] and CPI after adjusted [AUROC 0.693 (95% CI 0.590 to 0.797) vs. 0.448 (0.332 to 0.565), P < 0.001]. Compared with ACP > 68.78%, HR for ACP ≤ 68.78% was 3.55 (1.93 to 6.54) (P < 0.001). When adjusted with age, APACHE-II score, Vasoactive Inotropic Score, Lactate, CRRT, day-1 volume, fibrinogen and total bilirubin as possible confounders, and decrease ACP are still associated with increasing day-28 mortality (P < 0.05). An exponential relationship was observed between ACP12h and HR of day-28 death.

Conclusions

Our results suggested thatACP could improve mortality predictions when compared to CI and CPI. Decreased ACP was still an independent risk factor for increased day-28 mortality.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40560-021-00549-5.

Current Challenges in the Management of Infective Endocarditis

Infective endocarditis is a relatively rare, but deadly cause of sepsis, with an overall mortality ranging from 20 to 25% in most series. Although the classic clinical classification into syndromes of acute or subacute endocarditis have not completely lost their usefulness, current clinical forms have changed according to the profound epidemiological changes observed in developed countries. In this review, we aim to address the changing epidemiology of endocarditis, several recent advances in the understanding of the pathophysiology of endocarditis and endocarditis-triggered sepsis, new useful diagnostic tools as well as current concepts in the medical and surgical management of this disease. Given its complexity, the management of infective endocarditis requires the close collaboration of multidisciplinary endocarditis teams that must decide on the diagnostic approach; the appropriate initial treatment in the critical phase; the detection of patients needing surgery and the timing of this intervention; and finally the accurate selection of patients for out-of-hospital treatment, either at home hospitalization or with oral antibiotic treatment.

Heart Dysfunction in Sepsis

Cardiac involvement during sepsis frequently occurs. A series of molecules induces a set of changes at the cellular level that result in the malfunction of the myocardium. The understanding of these molecular alterations has simultaneously promoted the implementation of diagnostic strategies that are much more precise and allowed the advance of the therapeutics. The heart is a vital organ for survival. Its well-being ensures the adequate supply of essential elements for organs and tissues.

The Effect of Xinmailong Infusion on Sepsis-Induced Myocardial Dysfunction: a Pragmatic Randomized Controlled Trial

ABSTRACT

Sepsis-induced myocardial dysfunction (SIMD) contributes significantly to cardiovascular dysfunction during septic shock. We aimed to evaluate the potential role of Xinmailong injection (XMLI), a polypeptide medicine extracted from Periplaneta americana, in reversing the progression of myocardial damage to SIMD in sepsis patients. This was a multicenter, randomized, double-blind, parallel-group trial. We recruited all patients consecutively admitted to intensive care units (ICUs) who were aged 18 to 85 years old and met the sepsis 3.0 criteria. The primary outcome measure was the incidence of sepsis-induced myocardial dysfunction while in the ICU. Of the 192 patients, 96 were assigned to the treatment group, and 96 to the control group. Subsequently, 41 patients [41/96 (42.7%)] in the XMLI group and 61 patients in the placebo group [61/96 (63.5%)] were confirmed to have diastolic dysfunction on the fifth day (D5). The incidence of diastolic SIMD was significantly different between the two groups (P = 0.004). There were 36 deaths in the two groups during the 28-day follow-up, with a general mortality rate of 18.8% (36/192). The 28-day mortality rates were not significantly different between the groups (P = 0.45). However, the brain natriuretic peptide (BNP) plasma concentration trends on D0, D2, and D5 significantly differed between the two groups (P = 0.049). In septic patients, XMLI decreased the occurrence rate of diastolic SIMD more effectively than the placebo. The improvement in serum BNP concentration was also greater in the XMLI group. XMLI may, therefore, effectively and safely improve cardiac function in patients with sepsis.

Sepsis-Induced Cardiomyopathy: a Comprehensive Review

Purpose of Review

To briefly review epidemiology and pathophysiology of SICM and provide a more extensive review of the data on diagnostic and management strategies.

Recent Findings

SICM is likely underdiagnosed and that has mortality implications. Current evidence supports speckle tracking echocardiography to identify decreased contractility irrespective of left ventricular ejection fraction for the diagnosis of SICM. There continues to be a dearth of large clinical trials evaluating the treatment of SICM and current consensus focuses on supportive measures such as vasopressors and inotropes.

Summary

Sepsis is a significant cause of mortality, and sepsis-induced cardiomyopathy has both prognostic and management implications for these patients. Individualized work-up and management of these patients is crucial to improving outcomes.

Factors associated with abnormal left ventricular ejection fraction (decreased or increased) in patients with sepsis in the intensive care unit

BACKGROUND

Sepsis-induced cardiomyopathy (SIC) is known to show cardiac dysfunction in patients with sepsis. Both a decrease or an increase in ejection fraction (EF), an indicator of cardiac function, can occur. The purpose of this study was to identify factors associated with abnormal left ventricular (LV) function measured by EF in patients with sepsis in the intensive care unit (ICU).

METHODS

This was a retrospective study performed from November 2016 to December 2018. Three-hundred and sixty-six patients (mean age, 73 ± 13 years; 191 [52%] men) admitted to the ICU with sepsis were included. Patients were classified into three categories according to LV EF (group 1 -[EF<50%, n = 36], group 2 -[50≤EF<70%, n = 252], and group 3 -[EF≥70%, n = 78]). Echocardiographic assessment was performed within 48 hours of diagnosis of sepsis. We analyzed clinical factors including mortality, echocardiographic findings, and laboratory parameters.

RESULTS

Decreased LV EF occurred in 36 (10%) patients and hyper-dynamic EF developed in 78 (21%) patients. Of 366 patients, 103 (28%) patients died. Baseline characteristics were similar in the three groups, except female sex an indicator of abnormal EF. Mortality rates were also similar in the three groups; however, mortality rates were significantly higher in patients with abnormal EF (decreased or increased vs. normal). Echocardiographic parameters were significantly different in the three groups, in terms of LV systolic parameters and chamber size. Small left atrium (LA) and small LV were significantly associated with abnormal EF (especially in patients with increased EF). High brain natriuretic peptide was associated with decreased EF. Among these factors, female sex and small LA were significantly associated with abnormal EF in the multiple regression analysis.

CONCLUSION

Our findings highlight that female sex and small cardiac size are associated with abnormal EF, and therefore, death. Therefore, female patients and patients with small LA should be monitored closely when they present with sepsis.

Circumferential strain rate to detect lipopolysaccharide-induced cardiac dysfunction: a speckle tracking echocardiography study

Background

Lipopolysaccharide (LPS)-induced myocardial dysfunction is a widely used indicator to study septic cardiomyopathy (SC). This study investigated the efficiency of strain rate imaging (SRI) in detecting LPS-induced myocardial dysfunction.

Methods

A total of 30 mice were randomly assigned to saline group (n=10), 10 mg/kg LPS group (n=10) and 20 mg/kg LPS group (n=10). Then at baseline, 6 and 20 h after LPS injection, 2-D and M-mode echocardiography were conducted with GE Vivid 7 ultrasound (il3L linear probe, 10.0-14.0 MHz) and Echopac PC software. Ejection fraction (EF) and fractional shortening (FS) were measured with M-mode tracings. Serum biochemical examination was then performed to evaluate sepsis-induced myocardial injury.

Results

In LPS 20 mg/kg group, at 6 h after LPS injection, SRI found significantly decreased early diastolic strain rate (SRe, 1.76±1.05 vs. 3.18±0.83 unit/s, P<0.05), but M-mode echo found no change in EF and FS. In 10 mg/kg LPS group, compared with those at 6 h after LPS injection, SRI found a decline in SRe (1.57±0.75 vs. 3.18±0.83 unit/s, P<0.05), and M-mode tracings found an elevation in EF (71.31%±11.68% vs. 55.36%±7.42%, P<0.05) and FS (35.67%±8.79% vs. 25.43%±4.32%, P<0.05) at 20 h. Furthermore, LPS elevated the levels of serum creatine kinase-MB (CK-MB) and cardiac troponin-T (cTnT) at 20 h.

Conclusions

SRI is useful to early assess LPS-induced cardiac deformation in mice. circumferential strain rate (SRcirc) is a sensitive indicator for LPS-induced myocardial injury in severe sepsis.

Prevalence, Determinants, and Clinical Associations of High-Sensitivity Cardiac Troponin in Patients Attending Emergency Departments

BACKGROUND

High-sensitivity cardiac troponin assays may improve the diagnosis of myocardial infarction but increase the detection of elevated cardiac troponin in patients without acute coronary syndrome.

METHODS

In a prospective cohort study, we evaluated the prevalence, determinants, and outcome of patients with elevated cardiac troponin attending the emergency department without suspected acute coronary syndrome. We measured high-sensitivity cardiac troponin in 918 consecutive patients attending the emergency department without suspected acute coronary syndrome who had blood sampling performed by the attending clinician. Elevated high-sensitivity cardiac troponin I was defined as concentrations above the sex-specific 99th percentile threshold. Clinical demographics, physiological measures, and all-cause mortality at 1 year associated with elevated high-sensitivity cardiac troponin concentrations were recorded.

RESULTS

Elevated cardiac troponin concentration occurred in 114 (12.4%) patients, of whom 2 (0.2%), 3 (0.3%), and 109 (11.9%) were adjudicated as type 1 myocardial infarction, type 2 myocardial infarction, and myocardial injury, respectively. Elevated troponin concentrations were associated with increasing age, worsening renal function, multimorbidity, and adverse physiology. Across a total of 912 patient-years follow-up, cardiac troponin concentration was a strong predictor of death (hazard ratio [HR] 1.26 per 2-fold increase, 95% confidence interval [CI] 1.06 to 1.49) independent of age, sex, multimorbidity, and adverse physiology.

CONCLUSIONS

High-sensitivity cardiac troponin concentrations were elevated in 1 in 8 consecutive patients without suspected acute coronary syndrome attending the emergency department and were associated with increasing age, multimorbidity, adverse physiology, and death. Elevated cardiac troponin in unselected patients predominantly reflects myocardial injury rather than myocardial infarction.

Evaluation of sepsis induced cardiac dysfunction as a predictor of mortality

Background

Sepsis is characterized by life threatening organ dysfunction with dysregulated immune response. Cardiac dysfunction seen in sepsis is unique as it is reversible within 7–10 days. Initial study by Parker et al. in 1984, showed, paradoxically lower ejection fraction in survivors of septic shock. Subsequent meta-analysis did not support that survivors had lower ejection fraction. Aim of our study was to assess the sepsis induced cardiac dysfunction by 2D echocardiography and Troponin I.

Methods

After obtaining institutional ethical committee approval (ref 125/2016), a prospective observational study was done in an university medical college from February 2016 to April 2016. Inclusion criteria were patients diagnosed with sepsis by new sepsis definition. Pregnant patients and patients with poor echo window were excluded. Echocardiographic assessment was done within 48 h of diagnosis of sepsis by standard methods. Primary outcome was ICU mortality and secondary outcome was ICU length of stay. Statistical analysis was done using STATA™ (Version14, College station TX).

Results

Fifty eight patients were screened, ten were excluded due to poor echo window. Baseline characteristics were similar in survivors and non survivors, except APACHE II, SOFA age and cumulative fluid balance. Echocardiographic parameters, mitral annular plane systolic excursion (MAPSE), E/e’ and LV systolic function assessed by visual gestalt method were found to be statistically significant. Parameters found significant in bivariate analysis were used as a covariate in logistic regression. APACHE II and MAPSE were significant co-variates in logistic regression with ROC (0.95) and calibration was satisfactory (chi2(df8),1.98, p = 0.98).

Conclusions

Sepsis induced cardiac dysfunction assessed by echocardiography showed measurement of MAPSE when combined with APACHE II was a good predictor of mortality. Among the echocardiographic parameters MAPSE alone was a good predictor of mortality. Results of this study need further validation from larger study.

Heller A, Sabashnikov A, Teske W. The Nomenclature, Definition and Distinction of Types of Shock

BACKGROUND

A severe mismatch between the supply and demand of oxygen is the common feature of all types of shock. We present a newly developed, clinically oriented classification of the various types of shock and their therapeutic implications.

METHODS

This review is based on pertinent publications (1990-2018) retrieved by a selective search in PubMed, and on the relevant guidelines and meta-analyses.

RESULTS

There are only four major categories of shock, each of which is mainly related to one of four organ systems. Hypovolemic shock relates to the blood and fluids compartment while distributive shock relates to the vascular system; cardiogenic shock arises from primary cardiac dysfunction; and obstructive shock arises from a blockage of the circulation. Hypovolemic shock is due to intravascular volume loss and is treated by fluid replacement with balanced crystalloids. Distributive shock, on the other hand, is a state of relative hypovolemia resulting from pathological redistribution of the absolute intravascular volume and is treated with a combination of vasoconstrictors and fluid replacement. Cardiogenic shock is due to inadequate function of the heart, which shall be treated, depending on the situation, with drugs, surgery, or other interventional procedures. In obstructive shock, hypoperfusion due to elevated resistance shall be treated with an immediate life-saving intervention.

CONCLUSION

The new classification is intended to facilitate the goal-driven treatment of shock in both the pre-hospital and the inpatient setting. A uniform treatment strategy should be established for each of the four types of shock.

The Septic Heart: Current Understanding of Molecular Mechanisms and Clinical Implications

Septic cardiomyopathy is a key feature of sepsis-associated cardiovascular failure. Despite the lack of consistent diagnostic criteria, patients typically exhibit ventricular dilatation, reduced ventricular contractility, and/or both right and left ventricular dysfunction with a reduced response to volume infusion. Although there is solid evidence that the presence of septic cardiomyopathy is a relevant contributor to organ dysfunction and an important factor in the already complicated therapeutic management of patients with sepsis, there are still several questions to be asked: Which factors/mechanisms cause a cardiac dysfunction associated with sepsis? How do we diagnose septic cardiomyopathy? How do we treat septic cardiomyopathy? How does septic cardiomyopathy influence the long-term outcome of the patient? Each of these questions is interrelated, and the answers require a profound understanding of the underlying pathophysiology that involves a complex mix of systemic factors and molecular, metabolic, and structural changes of the cardiomyocyte. The afterload-related cardiac performance, together with speckle-tracking echocardiography, could provide methods to improve the diagnostic accuracy and guide therapeutic strategies in patients with septic cardiomyopathy. Because there are no specific/causal therapeutics for the treatment of septic cardiomyopathy, the current guidelines for the treatment of septic shock represent the cornerstone of septic cardiomyopathy therapy. This review provides an up-to-date overview of the current understanding of the pathophysiology, summarizes the evidence of currently available diagnostic tools and treatment options, and highlights the importance of further urgently needed studies aimed at improving diagnosis and investigating novel therapeutic targets for septic cardiomyopathy.

Protective effect of Xuebijing injection on myocardial injury in patients with sepsis: a randomized clinical trial

OBJECTIVE

To investigate the protective effect and possible mechanism of Xuebijing Injection on myocardial injury in patients with sepsis, and to evaluate its prognostic implications.

METHODS

Patients with septic myocardial injury were recruited, and were randomly divided into two groups: treatment group and control group. All patients in two groups received conventional cluster treatment, the patients in treatment group additional received Xuebijing injection dissolved in 0.9% sodium chloride injection, and the patients in control group received the same amount of 0.9% sodium chloride injection. At the beginning of treatment and 3, 7 and 10-day after treatment, laboratory indicators of cardiac troponin I (cTnI), N-terminal proB-type natriuretic peptide (NT-proBNP) and procalcitonin (PCT) were respectively tested in venous blood. The patient's length of stay in Intensive Care Unit (ICU) and the mortality in 28 days were recorded.

RESULTS

At 3, 7 and 10-day after treatment, the improvements of cTnI, NT-proBNP and PCT in treatment group were better than those in control group, and the differences were statistically significant (P < 0.05). The mortality of treatment group in 28 days was not significantly different from that of control group (P > 0.05). The ICU length of stay of treatment group was shorter than that of control group (P > 0.05).

CONCLUSION

Xuebijing injection could improve the levels of cTnI, NT-proBNP and PCT in patients with septic myocardial injury. and it had a protective effect on myocardial injury.

[Heart in sepsis : Molecular mechanisms, diagnosis and therapy of septic cardiomyopathy]

An impairment of cardiac function is a key feature of cardiovascular failure associated with sepsis; however, its clinical relevance is still underestimated. Recent advancements in echocardiography in patients with septic shock enable a better characterization of septic cardiomyopathy by unmasking a severe, cardiac dysfunction even in the presence of preserved left ventricular ejection fraction. The pathophysiology of septic cardiomyopathy involves a complex mixture of systemic factors and molecular, metabolic, and structural changes of the cardiomyocytes. A better understanding of these factors will enable the discovery of new therapeutic targets for urgently needed disease-modifying therapeutic interventions. To date, the cornerstone of therapeutic management lies in control of the underlying infectious process and hemodynamic stabilization. This review summarizes the pathogenesis, diagnosis, and treatment of septic cardiomyopathy, and highlights the importance of further urgently needed studies aimed at improving diagnosis and treatment for septic cardiomyopathy.

Ablation of the Right Cardiac Vagus Nerve Reduces Acetylcholine Content without Changing the Inflammatory Response during Endotoxemia

Acetylcholine is the main transmitter of the parasympathetic vagus nerve. According to the cholinergic anti-inflammatory pathway (CAP) concept, acetylcholine has been shown to be important for signal transmission within the immune system and also for a variety of other functions throughout the organism. The spleen is thought to play an important role in regulating the CAP. In contrast, the existence of a “non-neuronal cardiac cholinergic system” that influences cardiac innervation during inflammation has been hypothesized, with recent publications introducing the heart instead of the spleen as a possible interface between the immune and nervous systems. To prove this hypothesis, we investigated whether selectively disrupting vagal stimulation of the right ventricle plays an important role in rat CAP regulation during endotoxemia. We performed a selective resection of the right cardiac branch of the Nervus vagus (VGX) with a corresponding sham resection in vehicle-injected and endotoxemic rats. Rats were injected with lipopolysaccharide (LPS, 1 mg/kg body weight, intravenously) and observed for 4 h. Intraoperative blood gas analysis was performed, and hemodynamic parameters were assessed using a left ventricular pressure-volume catheter. Rat hearts and blood were collected, and the expression and concentration of proinflammatory cytokines using quantitative reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay were measured, respectively. Four hours after injection, LPS induced a marked deterioration in rat blood gas parameters such as pH value, potassium, base excess, glucose, and lactate. The mean arterial blood pressure and the end-diastolic volume had decreased significantly. Further, significant increases in blood cholinesterases and in proinflammatory (IL-1β, IL-6, TNF-α) cytokine concentration and gene expression were obtained. Right cardiac vagus nerve resection (VGX) led to a marked decrease in heart acetylcholine concentration and an increase in cardiac acetylcholinesterase activity. Without LPS, VGX changed rat hemodynamic parameters, including heart frequency, cardiac output, and end-diastolic volume. In contrast, VGX during endotoxemia did not significantly change the concentration and expression of proinflammatory cytokines in the heart. In conclusion we demonstrate that right cardiac vagal innervation regulates cardiac acetylcholine content but neither improves nor worsens systemic inflammation.

Zymosan-Induced Peritonitis: Effects on Cardiac Function, Temperature Regulation, Translocation of Bacteria, and Role of Dectin-1

Zymosan-induced peritonitis is a model commonly used to study systemic inflammatory response syndrome and multiple organ dysfunction syndrome. However, effects of zymosan on cardiac function have not been reported. We evaluated cardiac responses to zymosan in mice and the role of β-glucan and dectin-1 in mediating these responses. Temperature and cardiac function were evaluated before and after intraperitoneal (i.p.) injection of zymosan (100 or 500 mg/kg) or saline. Chronotropic and dromotropic functions were measured using electrocardiograms (ECGs) collected from conscious mice. Cardiac inotropic function was determined by echocardiography. High-dose zymosan caused a rapid and maintained hypothermia along with visual signs of illness. Baseline heart rate (HR) was unaffected but HR variability (HRV) increased, and there was a modest slowing of ventricular conduction. High-dose zymosan also caused prominent decreases in cardiac contractility at 4 and 24 h. Because zymosan is known to cause gastrointestinal tract pathology, peritoneal wash and blood samples were evaluated for bacteria at 24 h after zymosan or saline injection. Translocation of bacterial occurred in all zymosan-treated mice (n = 3), and two had bacteremia. Purified β-glucan (50 and 125 mg/kg, i.p.) had no effect on temperature or ECG parameters. However, deletion of dectin-1 modified the ECG responses to high-dose zymosan; slowing of ventricular conduction and the increase in HRV were eliminated but a marked bradycardia appeared at 24 h after zymosan treatment. Zymosan-treated dectin-1 knockout mice also showed hypothermia and visual signs of illness. Fecal samples from dectin-1 knockout mice contained more bacteria than wild types, but zymosan caused less translocation of bacteria. Collectively, these findings demonstrate that zymosan-induced systemic inflammation causes cardiac dysfunction in mice. The data suggest that dectin-1-dependent and -independent mechanisms are involved. Although zymosan treatment causes translocation of bacteria, this effect does not have a major role in the overall systemic response to zymosan.

The Effect of Esmolol on Tissue Perfusion and Clinical Prognosis of Patients with Severe Sepsis: A Prospective Cohort Study

Purpose. This study was aimed at investigating the effect of esmolol on tissue perfusion and the clinical prognosis of patients with severe sepsis. Materials and Methods. One hundred fifty-one patients with severe sepsis were selected and divided into the esmolol group (n = 75) or the control group (n = 76), who received conventional antiseptic shock treatment. The esmolol group received a continuous infusion of esmolol via a central venous catheter, and their heart rate (HR) was maintained at 70–100 bpm over 72 hours. Results. The HR of all patients reached the target level within 72 hours of treatment for both groups. The effect of esmolol on PvaCO₂ was only significant at 48 hours (P < 0.05). ScvO₂ increased in the esmolol group and decreased in the control group (P < 0.01). Lac showed a linear downward trend over the treatment time, but the reduction was more significant in the control group at 48 hours (P < 0.05) between the two groups. Kaplan-Meier analysis showed a significantly shorter duration of mechanical ventilation in the esmolol group than in the control group (P < 0.05). Conclusions. Esmolol reduced the duration of mechanical ventilation in patients with severe sepsis, with no significant effect on circulatory function or tissue perfusion.

Direct inhibition, but indirect sensitization of pacemaker activity to sympathetic tone by the interaction of endotoxin with HCN-channels

In critically ill patients regulation of heart-rate is often severely disturbed. Interaction of bacterial endotoxin (lipopolysaccharide, LPS) with hyperpolarization-activated cyclic nucleotide-gated cation-(HCN)-channels may interfere with heart-rate regulation. This study analyzes the effect of LPS, the HCN-channel blocker ivabradine or Ca(2+) -channel blockers (nifedipine, verapamil) on pacemaking in spontaneously beating neonatal rat cardiomyocytes (CM) in vitro. In vivo, the effect of LPS on the heart-rate of adult CD1-mice with and without autonomic blockade is analyzed telemetrically. LPS (100 ng/mL) and ivabradine (5 μg/mL) reduced the beating-rate of CM by 20.1% and 24.6%, respectively. Coincubation of CM with both, LPS and ivabradine, did not further reduce the beating-rate, indicating interaction of both compounds with HCN-channels, while coincubation with Ca(2+) -channel blockers and LPS caused additive beating-rate reduction. In CD1-mice (containing an active autonomic-nervous-system), injection of LPS (0.4 mg/kg) expectedly resulted in increased heart-rate. However, if the autonomic nervous system was blocked by propranolol and atropine, in line with the in vitro data, LPS induced a significant reduction of heart-rate, which was not additive to ivabradine. The in vivo and in vitro results indicate that LPS interacts with HCN-channels of cardiomyocytes. Thus, LPS indirectly sensitizes HCN-channels for sympathetic activation (tachycardic-effect), and in parallel directly inhibits channel activity (bradycardic-effect). Both effects may contribute to the detrimental effects of septic cardiomyopathy and septic autonomic dysfunction.

The role of speckle tracking echocardiography in assessment of lipopolysaccharide-induced myocardial dysfunction in mice

BACKGROUND

Sepsis-induced myocardial dysfunction is a common and severe complication of septic shock. Conventional echocardiography often fails to reveal myocardial depression in severe sepsis due to hemodynamic changes; in contrast, decline of strain measurements by speckle tracking echocardiography (STE) may indicate impaired cardiac function. This study investigates the role of STE in detecting lipopolysaccharide (LPS)-induced cardiac dysfunction with mouse models.

METHODS

We evaluated cardiac function in 20 mice at baseline, 6 h (n=10) and 20 h (n=10) after LPS injection to monitor the development of heart failure induced by severe sepsis using 2-D and M-mode echocardiography. Ejection fraction (EF) and fractional shortening (FS) were measured with standard M-mode tracings, whereas circumferential and radial strain was derived from STE. Serum biochemical and cardiac histopathological examinations were performed to determine sepsis-induced myocardial injury.

RESULTS

Left ventricular (LV) myocardial function was significantly reduced at 6 h after LPS treatment assessed by circumferential strain (-14.65%±3.00% to -8.48%±1.72%, P=0.006), whereas there were no significant differences between 6 and 20 h group. Conversely, EF and FS were significantly increased at 20 h when comparing to 6 h (P<0.05) accompanied with marked decreases in EF and FS 6 h following LPS administration. Consistent with strain echocardiographic results, we showed that LPS injection leaded to elevated serum level of cardiac Troponin-T (cTnT), CK-MB and rising leucocytes infiltration into myocardium within 20 h.

CONCLUSIONS

Altogether, these results demonstrate that, circumferential strain by STE is a specific and reliable value for evaluating LPS-induced cardiac dysfunction in mice.

Cardiac Effects of Echinocandins in Endotoxemic Rats

Echinocandins are known as effective and safe agents for the prophylaxis and treatment of different cohorts of patients with fungal infections. Recent studies revealed that certain pharmacokinetics of echinocandin antifungals might impact clinical efficacy and safety in special patient populations. The aim of our study was to evaluate echinocandin-induced aggravation of cardiac impairment in septic shock. Using an in vivo endotoxemic shock model in rats, we assessed hemodynamic parameters and time to hemodynamic failure (THF) after additional central-venous application of anidulafungin (2.5 mg/kg of body weight [BW]), caspofungin (0.875 mg/kg BW), micafungin (3 mg/kg BW), and control (0.9% sodium chloride). In addition, echinocandin-induced cytotoxicity was evaluated in isolated rat cardiac myocytes. THF of the animals in the caspofungin group (n = 7) was significantly reduced compared to that in the control (n = 6) (136 min versus 180 min; P = 0.0209). The anidulafungin group (n = 7) also showed a trend of reduced THF (136 min versus 180 min; log-rank test P = 0.0578). Animals in the micafungin group (n = 7) did not show significant differences in THF compared to those in the control. Control group animals and also micafungin group animals did not show altered cardiac output (CO) during our experiments. In contrast, administration of anidulafungin or caspofungin induced a decrease in CO. We also revealed a dose-dependent increase of cytotoxicity in anidulafungin- and caspofungin-treated cardiac myocytes. Treatment with micafungin did not cause significantly increased cytotoxicity. Further studies are needed to explore the underlying mechanism.

Impaired heart rate regulation and depression of cardiac chronotropic and dromotropic function in polymicrobial sepsis

The scope of cardiac pathophysiology in sepsis has not been fully defined. Accordingly, we evaluated the effects of sepsis on heart rate (HR), HR variability, and conduction parameters in a murine model of sepsis. Electrocardiograms were recorded noninvasively from conscious mice before and after cecal ligation and puncture (CLP) or sham surgery. Responses of isolated atria to tyramine and isoproterenol were quantified to assess the functional state of sympathetic nerves and postjunctional sensitivity to adrenergic stimulation. Cecal ligation and puncture mice had lower HR compared with sham at 16 to 18 h postsurgery (sham, 741 ± 7 beats/min; CLP, 557 ± 31 beats/min; n = 6/group; P < 0.001), and there was significant prolongation of the PR, QRS, and QTc intervals. Slowing of HR and conduction developed within 4 to 6 h after CLP and were preceded by a decrease in HR variability. Treatment of CLP mice with isoproterenol (5 mg/kg, intraperitoneally) at 25 h after surgery failed to increase HR or decrease conduction intervals. The lack of in vivo response to isoproterenol cannot be attributed to hypothermia because robust chronotropic and inotropic responses to isoproterenol were evoked from isolated atria at 25 °C and 30 °C. These findings demonstrate that impaired regulation of HR (i.e., reduced HR variability) develops before the onset of overt cardiac rate and conduction changes in septic mice. Subsequent time-dependent decreases in HR and cardiac conduction can be attributed to hypothermia and would contribute to decreased cardiac output and organ perfusion. Because isolated atria from septic mice showed normal responsiveness to adrenergic stimulation, we conclude that impaired effectiveness of isoproterenol in vivo can be attributed to reversible effects of systemic factors on adrenergic receptors and/or postreceptor signaling.

Phosphoinositide 3-kinase gamma controls inflammation-induced myocardial depression via sequential cAMP and iNOS signalling

AIMS

Sepsis-induced myocardial depression (SIMD), an early and frequent event of infection-induced systemic inflammatory response syndrome (SIRS), is characterized by reduced contractility irrespective of enhanced adrenergic stimulation. Phosphoinositide-3 kinase γ (PI3Kγ) is known to prevent β-adrenergic overstimulation via its scaffold function by activating major cardiac phosphodiesterases and restricting cAMP levels. However, the role of PI3Kγ in SIRS-induced myocardial depression is unknown. This study is aimed at determining the specific role of lipid kinase-dependent and -independent functions of PI3Kγ in the pathogenesis of SIRS-induced myocardial depression.

METHODS AND RESULTS

PI3Kγ knockout mice (PI3Kγ(-/-)), mice expressing catalytically inactive PI3Kγ (PI3Kγ(KD/KD)), and wild-type mice (P3Kγ(+/+)) were exposed to lipopolysaccharide (LPS)-induced systemic inflammation and assessed for survival, cardiac autonomic nervous system function, and left ventricular performance. Additionally, primary adult cardiomyocytes were used to analyse PI3Kγ effects on myocardial contractility and inflammatory response. SIRS-induced adrenergic overstimulation induced a transient hypercontractility state in PI3Kγ(-/-) mice, followed by reduced contractility. In contrast, P3Kγ(+/+) mice and PI3Kγ(KD/KD) mice developed an early and ongoing myocardial depression despite exposure to similarly increased catecholamine levels. Compared with cells from P3Kγ(+/+) and PI3Kγ(KD/KD) mice, cardiomyocytes from PI3Kγ(-/-) mice showed an enhanced and prolonged cAMP-mediated signalling upon norepinephrine and an intensified LPS-induced proinflammatory response characterized by nuclear factor of activated T-cells-mediated inducible nitric oxide synthase up-regulation.

CONCLUSIONS

This study reveals the lipid kinase-independent scaffold function of PI3Kγ as a mediator of SIMD during inflammation-induced SIRS. Activation of cardiac phosphodiesterases via PI3Kγ is shown to restrict myocardial hypercontractility early after SIRS induction as well as the subsequent inflammatory responses.

Advantages of strain echocardiography in assessment of myocardial function in severe sepsis: an experimental study

OBJECTIVES

Cardiovascular failure is an important feature of severe sepsis and mortality in sepsis. The aim of our study was to explore myocardial dysfunction in severe sepsis.

DESIGN

Prospective experimental study.

SETTING

Operating room at Intervention Centre, Oslo University Hospital.

SUBJECTS

Eight Norwegian Landrace pigs.

INTERVENTIONS

The pigs were anesthetized, a medial sternotomy performed and miniature sensors for wall-thickness measurements attached to the epicardium and invasive pressure monitoring established, and an infusion of Escherichia coli started. Hemodynamic response was monitored and myocardial strain assessed by echocardiography.

MEASUREMENTS AND MAIN RESULTS

Left ventricular myocardial function was significantly reduced assessed by longitudinal myocardial strain (-17.2% ± 2.8% to -12.3% ± 3.2%, p = 0.04), despite a reduced afterload as expressed by the left ventricular end-systolic meridional wall stress (35 ± 13 to 18 ± 8 kdyn/cm, p = 0.04). Left ventricular ejection fraction remained unaltered (48% ± 7% to 49% ± 5%, p = 0.4) as did cardiac output (6.3 ± 1.3 to 5.9 ± 3 L/min, p = 0.7). The decline in left ventricular function was further supported by significant reductions in the index of regional work by pressure-wall thickness loop area (121 ± 45 to 73 ± 37 mm × mm Hg, p = 0.005). Left ventricular myocardial wall thickness increased in both end diastole (11.5 ± 2.7 to 13.7 ± 2.4 mm, p = 0.03) and end systole (16.1 ± 2.9 to 18.5 ± 1.8 mm, p = 0.03), implying edema of the left ventricular myocardial wall. Right ventricular myocardial function by strain was reduced (-24.2% ± 4.1% to -16.9% ± 5.7%, p = 0.02). High right ventricular pressures caused septal shift as demonstrated by the end-diastolic transseptal pressure gradient (4.1 ± 3.3 to -2.2 ± 5.8 mm Hg, p = 0.01).

CONCLUSIONS

The present study demonstrates myocardial dysfunction in severe sepsis. Strain echocardiography reveals myocardial dysfunction before significant changes in ejection fraction and cardiac output and could prove to be a useful tool in clinical evaluation of septic patients.

Correlation of left ventricular systolic dysfunction determined by low ejection fraction and 30-day mortality in patients with severe sepsis and septic shock: a systematic review and meta-analysis

INTRODUCTION

The prognostic implications of myocardial dysfunction in patients with sepsis and its association with mortality are controversial. Several tools have been proposed to evaluate cardiac function in these patients, but their usefulness beyond guiding therapy is unclear. We review the value of echocardiographic estimate of left ventricular ejection fraction (LVEF) in the setting of severe sepsis and/or septic shock and its correlation with 30-day mortality.

METHODS

We conducted a systematic review and meta-analysis to evaluate the prognostic functionality of newly diagnosed LV systolic dysfunction by transthoracic echocardiography on critical ill patients admitted to the intensive care unit with severe sepsis or septic shock.

RESULTS

A search of EMBASE and PubMed, Ovide MEDLINE, and Cochrane CENTRAL medical databases yielded 7 studies meeting inclusion criteria reporting on a total of 585 patients. The pooled sensitivity of depressed LVEF for mortality was 52% (95% confidence interval [CI], 29%-73%), and pooled specificity was 63% (95% CI, 53%-71%). Summary receiver operating characteristic curve showed an area under the curve of 0.62 (95% CI, 0.58-0.67). The overall mortality diagnostic odd ratio for septic patients with LV systolic dysfunction was 1.92 (95% CI, 1.27-2.899). Statistical heterogeneity of studies was moderate.

CONCLUSION

The presence of new LV systolic dysfunction associated with sepsis and defined as low LVEF is neither a sensitive nor a specific predictor of mortality. These findings are limited because of the heterogeneity and underpower of the studies. Further research into this method is warranted.

Loss of vagal tone aggravates systemic inflammation and cardiac impairment in endotoxemic rats

BACKGROUND

During the course of sepsis, often myocardial depression with hemodynamic impairment occurs. Acetylcholine, the main transmitter of the parasympathetic Nervus vagus, has been shown to be of importance for the transmission of signals within the immune system and also for a variety of other functions throughout the organism. Hypothesizing a potential correlation between this dysfunction and hemodynamic impairment, we wanted to assess the impact of vagal stimulation on myocardial inflammation and function in a rat model of lipopolysaccharide (LPS)-induced septic shock. As the myocardial tissue is (sparsely) innervated by the N. vagus, there might be an important anti-inflammatory effect in the heart, inhibiting proinflammatory gene expression in cardiomyocytes and improving cardiac function.

MATERIALS AND METHODS

We performed stimulation of the right cervical branch of the N. vagus in vagotomized, endotoxemic (1 mg/kg body weight LPS, intravenously) rats. Hemodynamic parameters were assessed over time using a left ventricular pressure-volume catheter. After the experiments, hearts and blood plasma were collected, and the expression of proinflammatory cytokines was measured using quantitative reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay.

RESULTS

After vagotomy, the inflammatory response was aggravated, measurable by elevated cytokine levels in plasma and ventricular tissue. In concordance, cardiac impairment during septic shock was pronounced in these animals. To reverse both hemodynamic and immunologic effects of diminished vagal tone, even a brief stimulation of the N. vagus was enough during initial LPS infusion.

CONCLUSIONS

Overall, the N. vagus might play a major role in maintaining hemodynamic stability and cardiac immune homeostasis during septic shock.

Cardiac contractile reserve parameters are related to prognosis in septic shock

INTRODUCTION

Cardiac reserve could be defined as the spontaneous magnitude from basal to maximal cardiac power under stress conditions. The aim of this study was to evaluate the prognostic value of cardiac reserve parameters in resuscitated septic shock patients.

METHODS

Seventy patients with septic shock were included in a prospective and observational study. Prior to inclusion, patients were resuscitated to reach a mean arterial pressure of 65-75 mmHg with an euvolemic status. General, hemodynamic, and cardiac reserve-related parameters (cardiac index, double product, and cardiac power index) were collected at inclusion and at day 1.

RESULTS

Seventy patients were included with 28-day mortality at 38.5%. Ten of the 70 patients died during the first day. In multivariate analysis, independent predictors of death were SAPS II ≥ 58 (OR: 3.36 [1.11-10.17]; P = 0.032), a high double product at inclusion (OR [95% IC]: 1.20 [1.00-1.45] per 10(3) mmHg · min; P = 0.047), and at day 1, a decrease in cardiac index (1.30 [1.08-1.56] per 0.5 L/min/m(2); P = 0.007) or cardiac power index (1.84 [1.18-2.87] per 0.1 W/m(2), P = 0.008).

CONCLUSION

In the first 24 hours, parameters related to cardiac reserve, such as double product and cardiac index evolution, provide crucial and easy to achieve hemodynamic physiological information, which may impact the outcome.