Cardiac troponin elevations among critically ill patients

Association of Maximum Troponin Levels With Diagnosis of Acute Myocardial Infarction and Elevated Risk of Mortality

Background: Cardiac troponins I and T are highly sensitive and specific markers for acute myocardial infarction (AMI). However, a wide range of non-AMI conditions can also cause significant elevations in cardiac troponins. Given the deleterious impact of misdiagnosis of AMI, the ability to risk-stratify patients who present with an elevated troponin is paramount. We hypothesized that the maximum troponin level would be more predictive of mortality and the diagnosis of AMI than the initial troponin level or change in troponin level. Methods: Patient records from a 9-hospital system (n=30,173) in Texas were reviewed during a 24-month period in 2016-2017. Data collected for patients aged ≥40 years included International Classification of Diseases, Tenth Revision diagnoses, troponin I, demographic data (age, sex, smoking history, and chronic medical conditions), and death during hospitalization. We used logistic regression with the Firth penalized likelihood approach to determine the predictive ability of initial, maximum, and change in troponin level for mortality and the diagnosis of AMI. Results: Demographic characteristics of our cohort included a median age of 70 years, with 48.05% male and 51.95% female. The most common preexisting risk factor was hypertension in 78.81% of the cohort. Notable findings from the logistic regression include the predictive ability of maximum troponin on the odds of death by 0.7% for each unit of increase in troponin value. Also, the odds of AMI increased by 3.1% for each unit of increase in the maximum troponin value. Conclusion: Regardless of the level, a detectable amount of troponin in the serum results in a significantly elevated risk of mortality. Many patients with elevated troponin levels leave the hospital without a specific diagnosis, which can lead to poor outcomes because a detectable troponin does not represent a no-risk population. Our study demonstrates that maximum troponin level is a more sensitive and specific predictor of mortality than initial or change in troponin. Similarly, maximum troponin is the most predictive of AMI vs other causes of troponin elevation, likely because of the correlation between rising troponin levels and cardiomyocyte damage. Further studies are needed to correlate maximum troponin levels and clinical manifestations, which may be helpful in redefining AMI so that AMI can be distinguished more easily from non-AMI diagnoses.

Electrocardiographic Findings in Bitches Affected by Closed Cervix Pyometra

Pyometra is considered the most common disease in intact bitches, being associated with potentially life-threatening disorders. Myocardial damage is a potentially life-threatening consequence of pyometra. The aim of this study was to describe the electrocardiographic patterns in bitches affected by closed cervix pyometra, to assess the clinical relevance of electrocardiographic changes with the occurrence of pyometra, and to relate their severity with laboratory and clinical findings. A total of 39 bitches with closed cervix pyometra and 10 healthy female dogs were included in this study. During the hospitalization, bitches underwent a complete physical examination. An electrocardiographic examination before the ovariohysterectomy was performed. Blood samples for biochemical and hematological analysis were also evaluated. Bitches suffering pyometra at least one arrhythmia 31/39 (79.4%), sinus tachycardia (22/39, 56.4%), ventricular premature complexes (9/39, 23%), increased amplitude of T wave (7/39, 17.9%), ST depression (4/39, 10.2%), second-degree atrioventricular block (2/39, 5.1%), increase of QT interval (2/39, 5.1%), sinus bradycardia (2/39, 5.1%), and first-degree atrioventricular block (1/39, 2.5%). Some bitches were also detected with low wave amplitude (17/39, 43.5%). Cardiac arrhythmias associated with canine pyometra are frequent events. These data suggest that arrhythmias may be the consequence of one or more factors that can occur during pyometra, such as myocardial damage, electrolyte/metabolic disorders, and/or sepsis.

Monitoring Acute Myocardial Infarction Complicated with Cardiogenic Shock — from the Emergency Room to Coronary Care Units

Cardiogenic shock remains the leading cause of death in patients hospitalized for acute myocardial infarction, despite many advances encountered in the last years in reperfusion, mechanical, and pharmacological therapies addressed to stabilization of the hemodynamic condition of these critical patients. Such patients require immediate initiation of the most effective therapy, as well as a continuous monitoring in the Coronary Care Unit. Novel biomarkers have been shown to improve diagnosis and risk stratification in patients with cardiogenic shock, and their proper use may be especially important for the identification of the critical condition, leading to prompt therapeutic interventions. The aim of this review was to evaluate the current literature data on complex biomarker assessment and monitoring of patients with acute myocardial infarction complicated with cardiogenic shock in the Coronary Care Unit.

Recent developments in the detection and management of acute kidney injury

Acute kidney injury (AKI) is a common condition in children admitted to hospital and existing serum and urine biomarkers are insensitive. There have been significant developments in stratifying the risk of AKI in children and also in the identification of new AKI biomarkers. Risk stratification coupled with a panel of AKI biomarkers will improve future detection of AKI, however, paediatric validation studies in mixed patient cohorts are required. The principles of effective management rely on treating the underlying cause and preventing secondary AKI by the appropriate use of fluids and medication. Further therapeutic innovation will depend on improving our understanding of the basic mechanisms underlying AKI in children.

Catastrophic Antiphospholipid Syndrome

Catastrophic antiphospholipid syndrome is a rapidly progressive life-threatening disease that causes multiple organ thromboses and dysfunction in the presence of antiphospholipid antibodies. A high index of clinical suspicion and careful investigation are required to make an early diagnosis so that treatment with anticoagulation and corticosteroids can be initiated; plasma exchange and/or intravenous immunoglobulins can be added if the life-threatening condition persists. Despite aggressive treatment and intensive care unit management, patients with catastrophic antiphospholipid syndrome have a 48% mortality rate, primarily attributable to cardiopulmonary failure. This article reviews the current information on the etiopathogenesis, clinical manifestations, diagnosis, management, and prognosis of catastrophic antiphospholipid syndrome.

Avaliação dos valores de troponina I, eletrocardiograma e ecocardiograma em felinos sedados com cetamina e midazolam, suplementados ou não com oxigênio

Lesões no miocárdio, causadas por baixa perfusão e oxigenação cardíaca, podem ser ocasionadas por fármacos anestésicos, como a cetamina. Essas lesões podem ser identificadas por meio de biomarcadores específicos e, dentre estes, destaca-se a troponina I. O objetivo deste estudo foi avaliar as alterações cardiovasculares com base nos valores de troponina I (TnI), eletrocardiograma (ECG) e ecocardiograma em gatos sedados com cetamina e midazolam, suplementados ou não com oxigênio. Utilizaram-se 12 gatos machos, hígidos, nos quais se avaliaram os valores de troponina I, eletro e ecocardiografia, frequência cardíaca (FC) e pressão arterial sistólica (PAS) no momento basal (M0). Na sequência, os animais foram sedados com a associação de 10mg.kg-1 de cetamina e 0,5mg.kg-1 de midazolam pela via intramuscular. Decorridos aproximadamente 10 minutos, os animais foram alocados aleatoriamente em dois grupos: com e sem suplementação de oxigênio via máscara facial (GCO e GSO, respectivamente), sendo submetidos novamente aos exames citados. Foram coletadas amostras sanguíneas, para dosagem de TnI em seis, 12 e 24 horas após a administração dos agentes anestésicos. Não foram observadas alterações significativas na FC, na PAS e no ECG após a administração dos tratamentos em ambos os grupos. Os valores médios de TnI elevaram-se significativamente em T6 quando comparados ao basal em ambos os grupos, com médias de 0,507±0,335ng/mL no GSO e 0,777±0,505ng/mL no GCO. Na ecocardiografia, o débito cardíaco (DC) reduziu em M1 em ambos os grupos, quando comparados aos valores basais, sendo M0 0,472±0,115 e M1 0,234±0,08 no GSO e M0 0,356±0,095 e M1 0,222±0,09 no GCO, expressos em L/min. Conclui-se que a administração de cetamina e midazolam em gatos hígidos não promove alterações eletrocardiográficas, aumenta os valores de troponina I, com pico de seis horas após a administração, reduz o débito cardíaco, e que a suplementação de oxigênio 100% via máscara facial não atenua tais alterações.

Decision limits and the reporting of cardiac troponin: Meeting the needs of both the cardiologist and the ED physician

Cardiac troponin is the preferred biomarker for defining the acute coronary syndrome and acute myocardial infarction. Currently, the only decision limit formally endorsed with regard to the cardiac troponins is the 99th percentile. This is a "rule-in" criterion, intended to ensure that only persons with the acute coronary syndrome are reviewed. The 99th percentile is an arbitrary cut point and there are many problems associated with its application, including defining a truly healthy population, the difficulty of standardisation of cardiac troponin assays, especially but not only cardiac troponin I, and the effects of age and sex on this parameter. The Emergency Department (ED) screens many more persons for possible acute coronary syndromes than actually have the condition and their needs are best met by a "rule-out" test that enables them to clear their busy departments of the many persons who do not actually have the condition. The needs of the ED are not optimally met using the 99th percentile. The index of individuality for the cardiac troponins is small and significant changes consistent with an acute coronary syndrome can occur without the 99th percentile being exceeded. It appears that the ED may be better served by use of delta troponin changes rather than the 99th percentile, but there are problems with this approach, particularly in persons who present late when troponin release has plateaued. In addition, there are many non-acute coronary syndrome causes for cardiac troponin release. The needs of the cardiologist and the ED physician are so different that it may be inappropriate for both groups to use the same diagnostic criteria for cardiac troponin, and it is of great importance that cardiac troponin measurement be used as only one part of the assessment of the person presenting with possible acute coronary syndrome.

Mineralocorticoid receptor antagonism confers cardioprotection in heart failure

The symptoms and signs constituting the congestive heart failure (CHF) syndrome have their pathophysiologic origins rooted in a salt-avid renal state mediated by effector hormones of the renin-angiotensin-aldosterone and adrenergic nervous systems. Controlled clinical trials, conducted over the past decade in patients having minimally to markedly severe symptomatic heart failure, have demonstrated the efficacy of a pharmacologic regimen that interferes with these hormones, including aldosterone receptor binding with either spironolactone or eplerenone. Potential pathophysiologic mechanisms, which have not hitherto been considered involved for the salutary responses and cardioprotection provided by these mineralocorticoid receptor antagonists, are reviewed herein. In particular, we focus on the less well-recognized impact of catecholamines and aldosterone on monovalent and divalent cation dyshomeostasis, which leads to hypokalemia, hypomagnesemia, ionized hypocalcemia with secondary hyperparathyroidism and hypozincemia. Attendant adverse cardiac consequences include a delay in myocardial repolarization with increased propensity for supraventricular and ventricular arrhythmias, and compromised antioxidant defenses with increased susceptibility to nonischemic cardiomyocyte necrosis.

Cation interdependency in acute stressor states

Acute stressor states are inextricably linked to neurohormonal activation which includes the adrenergic nervous system. Consequent elevations in circulating epinephrine and norepinephrine unmask an interdependency that exists between K+, Mg2+ and Ca2+. Catecholamines, for example, regulate the large number of Mg2+-dependent Na/K ATPase pumps present in skeletal muscle. A hyperadrenergic state accounts for a sudden translocation of K+ into muscle and rapid appearance of hypokalemia. In the myocardium, catecholamines promote Mg2+ efflux from cardiomyocytes, whereas intracellular Ca2+ influx and overloading account for the induction of oxidative stress and necrosis of these cells with leakage of their contents, including troponins. Accordingly, acute stressor states can be accompanied by nonischemic elevations in serum troponins, together with the concordant appearance of hypokalemia, hypomagnesemia and ionized hypocalcemia, causing a delay in myocardial repolarization and electrocardiographic QTc prolongation raising the propensity for arrhythmias, including atrial fibrillation and polymorphic ventricular tachycardia. In this review, we focus on the interdependency between K+, Mg2+ and Ca2+ which are clinically relevant to acute stressor states.

Plasma Brain Natriuretic Peptide and Troponin Levels in Severe Sepsis and Septic Shock

The aim of this study was to evaluate and compare brain natriuretic peptide (BNP) and cardiac troponin I (cTnI) levels as mortality prognosticator and predictor for myocardial dysfunction in severe sepsis and septic shock. Baseline clinical and biological variables were collected from 47 patients with severe sepsis or septic shock. Ventricular systolic function assessed by echocardiography was measured over a 5-day period. Both cTnI and BNP plasmatic levels were determined at intensive care unit (ICU) admission and during the following 15 days. At admission, cTnI and BNP levels were compared to those of 12 control critically ill nonseptic patients. The plasma levels of BNP and cTnI in patients with sepsis were elevated at admission and significantly higher than in the controls. Among patients with sepsis, BNP levels were significantly more elevated in nonsurvivors compared to survivors at admission and 1 day later. The cTnI levels were also significantly more elevated in nonsurvivors compared to survivors, but only at admission. From admission to day 5, patients with sepsis with left ventricular systolic dysfunction had higher BNP plasmatic concentrations than those without; differences were significant at days 3 and 4. In contrast, plasma cTnI levels were similar between the 2 groups. In critically ill patients, sepsis induces significant increase in BNP and cTnI levels. High BNP and cTnI plasma levels during ICU admission appear to be associated with poor outcome of sepsis. Time course of BNP levels seems helpful to discriminate between surviving and nonsurviving patients with sepsis and to detect myocardial dysfunction where troponin levels fail to do so.

Troponin I: how high is too high?

Elevated cardiac troponin I can occur in patients with cardiac injury or sepsis. However, extreme elevations of serum cardiac troponin I in pediatric patients without myocardial injury are rare. We present a case of a 14-year-old girl involved in a motor vehicle accident with muscle injury, who was readmitted with sepsis and severely elevated serum cardiac troponin I level in the absence of myocardial injury.

Mitochondria play a central role in nonischemic cardiomyocyte necrosis: common to acute and chronic stressor states

The survival of cardiomyocytes must be ensured as the myocardium adjusts to a myriad of competing physiological and pathophysiological demands. A significant loss of these contractile cells, together with their replacement by stiff fibrillar collagen in the form of fibrous tissue accounts for a transition from a usually efficient muscular pump into one that is failing. Cellular and subcellular mechanisms involved in the pathogenic origins of cardiomyocyte cell death have long been of interest. This includes programmed molecular pathways to either necrosis or apoptosis, which are initiated from ischemic or nonischemic origins. Herein, we focus on the central role played by a mitochondriocentric signal-transducer-effector pathway to nonischemic cardiomyocyte necrosis, which is common to acute and chronic stressor states. We begin by building upon the hypothesis advanced by Albrecht Fleckenstein and coworkers some 40 years ago based on the importance of calcitropic hormone-mediated intracellular Ca(2+) overloading, which predominantly involves subsarcolemmal mitochondria and is the signal to pathway activation. Other pathway components, which came to be recognized in subsequent years, include the induction of oxidative stress and opening of the mitochondrial inner membrane permeability transition pore. The ensuing loss of cardiomyocytes and consequent replacement fibrosis, or scarring, represents a disease of adaptation and a classic example of when homeostasis begets dyshomeostasis.

Stressor states and the cation crossroads

Neurohormonal activation involving the hypothalamic-pituitary-adrenal axis and adrenergic nervous and renin-angiotensin-aldosterone systems is integral to stressor state-mediated homeostatic responses. The levels of effector hormones, depending upon the degree of stress, orchestrate the concordant appearance of hypokalemia, ionized hypocalcemia and hypomagnesemia, hypozincemia, and hyposelenemia. Seemingly contradictory to homeostatic responses wherein the constancy of extracellular fluid would be preserved, upregulation of cognate-binding proteins promotes coordinated translocation of cations to injured tissues, where they participate in wound healing. Associated catecholamine-mediated intracellular cation shifts regulate the equilibrium between pro-oxidants and antioxidant defenses, a critical determinant of cell survival. These acute and chronic stressor-induced iterations in extracellular and intracellular cations are collectively referred to as the cation crossroads. Intracellular cation shifts, particularly excessive accumulation of Ca2+, converge on mitochondria to induce oxidative stress and raise the opening potential of their inner membrane permeability transition pores (mPTPs). The ensuing loss of cationic homeostasis and adenosine triphosphate (ATP) production, together with osmotic swelling, leads to organellar degeneration and cellular necrosis. The overall impact of iterations in extracellular and intracellular cations and their influence on cardiac redox state, cardiomyocyte survival, and myocardial structure and function are addressed herein.

Troponin elevation in conditions other than acute coronary syndromes

Acute coronary syndromes comprise a large spectrum of clinical conditions ranging from unstable angina pectoris to acute ST-elevation myocardial infarction. Chest pain is usually the major symptom of atherosclerotic heart disease; however, it may be challenging to diagnose correctly, especially in the emergency department, because of the ambiguous way that pain is characterized by some patients. Cardiac troponins are sensitive and specific biomarkers used in the diagnosis of myocardial infarction that are released into the bloodstream when cardiac myocytes are damaged by acute ischemia or any other mechanism. They are the cornerstone for the diagnosis, risk assessment, prognosis, and determination of antithrombotic and revascularization strategies. However, troponin elevation indicates the presence, not the mechanism, of myocardial injury. There are many clinical conditions other than myocardial infarction that cause troponin elevation; thus, the physician should be aware of the wide spectrum of disease states that may result in troponin elevation and have a clear understanding of the related pathophysiology to effectively make a differential diagnosis. This review focuses on causes of troponin elevation other than acute coronary syndromes.

Myocardial dysfunction in malnourished children

Background:

Malnourished children suffer several alterations in body composition that could produce cardiac abnormalities.

Aim:

The aim of the present study was to detect the frequency of myocardial damage in malnourished children as shown by echocardiography and cardiac troponin T (cTnT) level.

Methods:

Forty-five malnourished infants and young children (mean±SD of age was 11.24 ±7.88 months) were matched with 25 apparently healthy controls (mean±SD of age was 10.78±6.29 months). Blood sample was taken for complete blood picture, liver and kidney function tests, serum sodium, potassium, calcium levels and cTnT. All the malnourished children were subjected to echocardiographic evaluation.

Results:

Malnourished children showed a significantly lower left ventricular (LV) mass than the control group. The LV systolic functions were significantly impaired in patients with severe malnutrition. The cTnT level was higher than the upper reference limits in 11 (24.44%) of the studied malnourished children and all of them had a severe degree of malnutrition. The cTnT level was significantly higher in patients with anemia, sepsis and electrolyte abnormalities and it correlated negatively with LV ejection fraction (EF). Six of the studied children with high cTnT levels (54.5%) died within 21 days of treatment while only one case (2.9%) with normal level of cTnT died within the same period.

Conclusions:

LV mass is reduced in malnourished children. Children with severe malnutrition have a significant decrease in LV systolic functions. Elevated cTnT levels in malnourished children has both diagnostic and prognostic significance for cardiomyocyte damage.

Cation dyshomeostasis and cardiomyocyte necrosis: the Fleckenstein hypothesis revisited

An ongoing loss of cardiomyocytes to apoptotic and necrotic cell death pathways contributes to the progressive nature of heart failure. The pathophysiological origins of necrotic cell loss relate to the neurohormonal activation that accompanies acute and chronic stressor states and which includes effector hormones of the adrenergic nervous system. Fifty years ago, Albrecht Fleckenstein and coworkers hypothesized the hyperadrenergic state, which accompanies such stressors, causes cardiomyocyte necrosis based on catecholamine-initiated excessive intracellular Ca(2+) accumulation (EICA), and mitochondrial Ca(2+) overloading in particular, in which the ensuing dysfunction and structural degeneration of these organelles leads to necrosis. In recent years, two downstream factors have been identified which, together with EICA, constitute a signal-transducer-effector pathway: (i) mitochondria-based induction of oxidative stress, in which the rate of reactive oxygen metabolite generation exceeds their rate of detoxification by endogenous antioxidant defences; and (ii) the opening of the mitochondrial inner membrane permeability transition pore (mPTP) followed by organellar swelling and degeneration. The pathogenesis of stress-related cardiomyopathy syndromes is likely related to this pathway. Other factors which can account for cytotoxicity in stressor states include: hypokalaemia; ionized hypocalcaemia and hypomagnesaemia with resultant elevations in parathyroid hormone serving as a potent mediator of EICA; and hypozincaemia with hyposelenaemia, which compromise antioxidant defences. Herein, we revisit the Fleckenstein hypothesis of EICA in leading to cardiomyocyte necrosis and the central role played by mitochondria.

Incidence of elevation of cardiac troponin I prior to and following routine general anaesthesia in dogs

OBJECTIVE

To estimate the incidence of raised cTnI after general anaesthesia in dogs and to explore major risk factors influencing this.

STUDY DESIGN

Prospective clinical study. Animals A total of 107 (ASA physical status 1-2) dogs, 63% male and 37% female, median age 5 years (range 0.3-13.4), median weight 24.4 kg (range 4.2-66.5 kg) undergoing anaesthesia for clinical purposes.

METHODS

Venous blood samples were taken within 24 hours prior to induction and 24 hours after the termination of anaesthesia. Serum concentrations of cardiac troponin I were measured using a chemiluminescent enzyme immunometric assay with a lower level of detection of 0.20 ng mL(-1) (below this level <0.20 ng mL(-1)). Continuous data were assessed graphically for normality and paired and unpaired data compared with the Wilcoxon signed ranks and Mann-Whitney U-tests respectively. Categorical data were compared with the Chi squared or Fisher's exact test as appropriate (p < 0.05).

RESULTS

Of the 107 dogs recruited, 100 had pre- and post-anaesthetic cTnI measured. The median pre-anaesthesia cTnI was '<0.20' ng mL(-1) (range '<0.20'-0.43 ng mL(-1)) and the median increase from pre-anaesthesia level was 0.00 ng mL(-1) (range -0.12 to 0.61 ng mL(-1)). Fourteen dogs had increased cTnI after anaesthesia relative to pre-anaesthesia (14%, 95% CI 7.2-20.8%, range of increase 0.03-0.61 ng mL(-1)). Six animals had cTnI levels that decreased (range 0.02-0.12 ng mL(-1)). Older dogs were more likely to have increased cTnI prior to anaesthesia (OR = 5.32, 95% CI 1.35-21.0, p = 0.007) and dogs 8 years and over were 3.6 times as likely to have an increased cTnI after anaesthesia (95% CI 1.1-12.4, p = 0.028).

CONCLUSION AND CLINICAL RELEVANCE

Increased cTnI after anaesthesia relative to pre-anaesthesia levels was observed in a number of apparently healthy dogs undergoing routine anaesthesia.

A dyshomeostasis of electrolytes and trace elements in acute stressor states: impact on the heart

Acute stressor states are associated with a homeostatic activation of the hypothalamic-pituitary-adrenal axis. A hyperadrenergic state follows and leads to a dyshomeostasis of several intra- and extracellular cations, including K, Mg, and Ca. Prolongation of myocardial repolarization and corrected QT interval (QTc) of the ECG are useful biomarkers of hypokalemia and/or hypomagnesemia and should be monitored to address the adequacy of cation replacement. A dyshomeostasis of several trace elements, including Zn and Se, are also found in critically-ill patients to compromise metalloenzyme-based antioxidant defenses. Collectively, dyshomeostasis of these electrolytes and trace elements have deleterious consequences on the myocardium: atrial and ventricular arrhythmias; induction of oxidative stress with reduced antioxidant defenses; and adverse myocardial remodeling, including cardiomyocytes lost to necrosis and replaced by fibrous tissue. To minimize such consequences during hyperadrenergic states, systematic surveillance of electrolytes and trace elements, together with QTc, are warranted. Plasma K and Mg should be maintained at > or =4.0 mEq/L and > or =2.0 mg/dL, respectively (the 4 and 2 rule).

Role of tissue disorder markers in the evaluation of disease progress and outcome prediction: a prospective cohort study in non-cardiac critically ill patients

BACKGROUND

Acute Physiology and Chronic Health Evaluation (APACHE) has a remarkable association with clinical syndrome, life expectancy, and length of ward stay. But the defects are obvious. It is crucial to detect an effective and convenient evaluation method to monitor disease progress and predict outcome.

OBJECTIVE

To determine whether myoglobin (Mb) and other five tissue disorder biomarkers, troponin-I, creatine-kinase, creatine kinase-muscle brain, aspartate aminotransferase, and lactate dehydrogenase are independent predictors of disease progress and mortality in non-cardiac critical illness.

METHODS

A prospective study with 179 patients admitted to the Intensive Care Unit was conducted. All serum tissue disorder markers and APACHE-II score were measured within 24  hr of admission.

RESULTS

All the six biomarkers were significantly correlated with disease severity stratified by APACHE-II and outcome. Serial blood samples were taken from 17 patients on detection of two new organs failure. The occurrence of organs failure was significantly associated with the elevation of Mb, troponin-I, and APACHE-II. Multivariate analysis demonstrated that elevated Mb was the principal risk factor related to mortality either during hospitalization or 180-day followup. Kaplan-Meier method and log-rank test also showed that patients with elevated Mb levels had significantly shorter survival. The mortality was higher in patients with both Mb>500  ng/ml and APACHE-II>20 than in those with only Mb>500  ng/ml or APACHE-II>20.

CONCLUSION

All the six tissue disorder markers are predictors of disease severity, organ failure, and outcome in non-cardiac critically illness. Among them, Mb plays a pivotable role. The combined use of Mb and APACHE-II suggest an effective method to determine the outcome of critical ill syndrome.

Increases of cardiac troponin in conditions other than acute coronary syndrome and heart failure

BACKGROUND

Although cardiac troponin (cTn) is a cornerstone marker in the assessment and management of patients with acute coronary syndrome (ACS) and heart failure (HF), cTn is not diagnostically specific for any single myocardial disease process. This narrative review discusses increases in cTn that result from acute and chronic diseases, iatrogenic causes, and myocardial injury other than ACS and HF.

CONTENT

Increased cTn concentrations have been reported in cardiac, vascular, and respiratory disease and in association with infectious processes. In cases involving acute aortic dissection, cerebrovascular accident, treatment in an intensive care unit, and upper gastrointestinal bleeding, increased cTn predicts a longer time to diagnosis and treatment, increased length of hospital stay, and increased mortality. cTn increases are diagnostically and prognostically useful in patients with cardiac inflammatory diseases and in patients with respiratory disease; in respiratory disease cTn can help identify patients who would benefit from aggressive management. In chronic renal failure patients the diagnostic sensitivity of cTn for ACS is decreased, but cTn is prognostic for the development of cardiovascular disease. cTn also provides useful information when increases are attributable to various iatrogenic causes and blunt chest trauma.

SUMMARY

Information on the diagnostic and prognostic uses of cTn in conditions other than ACS and heart failure is accumulating. Although increased cTn in settings other than ACS or heart failure is frequently considered a clinical confounder, the astute physician must be able to interpret cTn as a dynamic marker of myocardial damage, using clinical acumen to determine the source and significance of any reported cTn increase.

Troponin I rise after pacemaker implantation at the time of "universal definition of myocardial infarction"

We assessed incidence, magnitude, and time course of cardiac troponin I (cTnI) increase after pacemaker implantation in patients without acute coronary syndromes (ACSs). Seventy patients (mean age 71 years, interquartile range 44 to 92, 38 men) undergoing elective implantation of a single-/dual-chamber pacemaker with active/passive fixation leads were enrolled, excluding subjects with clinical suspicion of ACS, abnormal basal cTnI level, or presenting conditions predisposing to abnormal cTnI. Cardiac TnI concentrations were determined in basal conditions, at the end of the procedure, and after 8, 12, and 24 hours. Single-/dual-chamber devices were implanted in 31 of 39 patients. Cardiac TnI peak concentration occurred within the 12-hour assay in 69 of 70 patients; 26 of 70 had a cTnI above the normal cut-off range. All patients presented normal cTnI at 24-hour assay. In conclusion, pacemaker implantation is associated with increases of cTnI levels in up to 37% of patients. This can affect the specificity of cTnI assessment for ruling out ACS, especially within 12 hours after the procedure. These data deserve consideration in a contemporary setting, in which troponin has gathered a pivotal role in the diagnosis and therapy of ACS, and in particular clinical presentations in which electrocardiogram loses its diagnostic capabilities (due to paced rhythms) and symptoms may be lacking or confusing.

Decreases in myocardial glucose and increases in pyruvate but not ischaemia are observed during porcine endotoxaemia

BACKGROUND

Myocardial dysfunction occurs commonly in septic shock. It is not known whether this is due to local ischaemia and metabolic disturbances. Our hypothesis was that endotoxaemic myocardial dysfunction may be associated with interstitial ischaemic and metabolic changes, measured using interstitial microdialysis (MD).

METHODS

Eighteen pigs were randomized to control (n=6) or endotoxin infusion (n=12). MD catheters were inserted into the myocardium for measurement of interstitial glucose, pyruvate and lactate concentrations. Plasma glucose and lactate concentrations and systemic haemodynamic parameters were measured simultaneously.

RESULTS

Compared with the control group, the endotoxaemic animals had significantly decreased left ventricular stroke work and venous oxygen saturation (SvO2), and increased mean pulmonary artery pressure and plasma lactate. In the endotoxaemic group, decreases in interstitial glucose were observed, occurring simultaneously with increases in interstitial pruvate. Interstitial lactate: pyruvate ratios decreased with time in all animals.

CONCLUSIONS

Despite severe systemic and pulmonary haemodynamic changes, interstitial MD measurements revealed no evidence of anaerobic metabolism in the myocardium of endotoxaemic pigs. There were, however, changes in glucose and pyruvate concentrations, suggesting local energy metabolic disturbances.

Activated protein C improves survival in severe sepsis patients with elevated troponin

OBJECTIVE

Multiple studies in sepsis have demonstrated that elevated troponin is associated with poor outcome. The elevated troponin in this situation is thought to be secondary to microthrombi. We hypothesized that recombinant human activated protein C (APC) treatment would improve outcomes in severe sepsis patients who have elevated troponin.

METHODS

Patients with severe sepsis by consensus criteria in a university ICU were divided into a troponin elevated group (cTnI+) and a normal troponin (cTnI(-)) group. Outcome was compared using Fisher's exact test. APACHE[Symbol: see text]II and MODS were calculated by standard methods.

PATIENTS

We identified 105 patients with severe sepsis and troponin measured, of which 48 (46%) were in the cTnI+ group. The two groups were similar in terms of age and other comorbid conditions.

RESULTS

APACHE II (28+/-8 vs. 25+/-8) was slightly higher and MODS (11+/-4 vs. 9+/-3) was significantly higher in the cTnI+ group. Mortality was 52% (25/48) in cTnI+ group and 30% (17/57) in cTnI(-) group. Mortality was 30% in cTnI+ patients treated with APC and 72% in untreated cTnI+ patients.

CONCLUSIONS

Patients with severe sepsis who have elevated troponin have increased mortality. In patients with severe sepsis who have elevated troponin, treatment with APC improves outcome. Further study is needed to determine whether troponin can serve as a simple, readily available marker to identify which patients with severe sepsis will benefit from APC.

Cardiac troponin I levels in canine pyometra

BACKGROUND

Myocardial injury may contribute to unexpected deaths due to pyometra. To detect myocardial damage, measurement of cardiac troponin I (cTnI) is currently the most sensitive and specific method. The aims of the present study were to evaluate presence of myocardial damage in canine pyometra by analysis of cTnI, to explore whether myocardial injury was associated with systemic inflammatory response syndrome (SIRS) and to evaluate whether other clinical or laboratory parameters were associated with cTnI increase.

METHODS

Preoperative plasma levels of cTnI were investigated in 58 female dogs with pyometra and 9 controls. The value of physical examination findings, haematological, serum biochemical and pro-inflammatory (CRP and TNF-alpha) parameters as possible predictors of increased cTnI levels was also evaluated.

RESULTS

Seven dogs with pyometra (12%) and one control dog (11%) had increased levels of cTnI. In the pyometra group, the levels ranged between 0.3-0.9 microg l-1 and in the control dog the level was 0.3 microg l-1. The cTnI levels did not differ significantly between the two groups. No cardiac abnormalities were evident on preoperative physical examinations. Four of the pyometra patients died within two weeks of surgery, of which two were examined post mortem. In one of these cases (later diagnosed with myocarditis and disseminated bacterial infection) the cTnI levels increased from 0.9 microg l-1 preoperatively to 180 microg l-1 the following day when also heart arrhythmia was also detected. The other patient had cTnI levels of 0.7 microg l-1 with no detectable heart pathology post mortem. CTnI increase was not associated with presence of SIRS. There was a trend for the association of cTnI increase with increased mortality. No preoperative physical examination findings and few but unspecific laboratory parameters were associated with increased cTnI levels.

CONCLUSION

Increased cTnI levels were observed in 12% of the dogs with pyometra. The proportions of dogs with cTnI increase did not differ significantly in the pyometra group compared with the control group. CTnI increase was not associated with presence of SIRS. A trend for association of cTnI increase and mortality was observed. Preoperative physical examination findings and included laboratory parameters were poor predictors of increased cTnI levels.

Therapeutic and prognostic considerations in catastrophic antiphospholipid syndrome

Catastrophic antiphospholipid syndrome (CAPS) is a rapidly progressive life-threatening disease that causes multiple organ thromboses in the presence of antiphospholipid antibodies. High index of clinical suspicion and careful investigation are required to make an early diagnosis so that treatment with anticoagulation, corticosteroids, and plasma exchange or intravenous immunoglobulins can be initiated. Despite this multi-modal treatment, CAPS is associated with high mortality; evidence-based management recommendations do not exist due to the rarity of the condition and the lack of controlled studies. This article reviews the therapeutic and prognostic controversies that were addressed during the 1st International Symposium on CAPS.

Sepsis-associated myocardial dysfunction: diagnostic and prognostic impact of cardiac troponins and natriuretic peptides

Myocardial dysfunction, which is characterized by transient biventricular impairment of intrinsic myocardial contractility, is a common complication in patients with sepsis. Left ventricular systolic dysfunction is reflected by a reduced left ventricular stroke work index or, less accurately, by an impaired left ventricular ejection fraction (LVEF). Early recognition of myocardial dysfunction is crucial for the administration of the most appropriate therapy. Cardiac troponins and natriuretic peptides are biomarkers that were previously introduced for diagnosis and risk stratification in patients with acute coronary syndrome and congestive heart failure, respectively. However, their prognostic and diagnostic impact in critically ill patients warrants definition. The elevation of cardiac troponin levels in patients with sepsis, severe sepsis, or septic shock has been shown to indicate left ventricular dysfunction and a poor prognosis. Troponin release in this population occurs in the absence of flow-limiting coronary artery disease, suggesting the presence of mechanisms other than thrombotic coronary artery occlusion, probably a transient loss in membrane integrity with subsequent troponin leakage or microvascular thrombotic injury. In contrast to the rather uniform results of studies dealing with cardiac troponins, the impact of raised B-type natriuretic peptide (BNP) levels in patients with sepsis is less clear. The relationship between BNP and both LVEF and left-sided filling pressures is weak, and data on the prognostic impact of high BNP levels in patients with sepsis are conflicting. Mechanisms other than left ventricular wall stress may contribute to BNP release, including right ventricular overload, catecholamine therapy, renal failure, diseases of the CNS, and cytokine up-regulation. Whereas cardiac troponins may be integrated into the monitoring of myocardial dysfunction in patients with severe sepsis or septic shock to identify those patients requiring early and aggressive supportive therapy, the routine use of BNP and other natriuretic peptides in this setting is discouraged at the moment.